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Nodda Duma
18-Nov-2014, 09:41
Hello!

I have recently joined this forum at the urging of members of the APUG forum and figured I'd introduce myself.

I am a lens designer by trade, having worked many years designing optics for visible and also infrared imaging systems. I was hired by the Navy out of college and basically taught myself optical design. After I got good at it, I went back to school to do the coursework (from the University of Arizona). Now I work in the private sector.


I use ZEMAX and of course know and understand the design forms for the camera lenses that you guys use.

Film photography provides me a break from the digital imaging world, while satisfying my interest and appreciation of optics. It actually spun out of my astronomy and astrophotography hobby...which I pursued (using film) a decade or so ago.

I own several cameras which cover the span of the twentieth century...primarily 35 mm and medium format (Kodak Brownie to a Nikon F3). I develop B&W but send out for color. I use Blue Moon Camera out of Portland OR. I have a nice scanner and printer at home.

I used to own a Jobo CPP-2 but unfortunately lost that with almost everything else when I moved my family from California to New Hampshire almost 4 years ago. We don't make as much as we used to, and with money being tight I haven't been able to replace the equipment I used to own. (My wife went back to school to earn a Physician's Assistant degree...she used to be an engineer). A handful of cameras and my scanner and printer survived. Still have enough to take pictures with tho.



In any case, I joined because I love doing lens design. It seems to me that the mainstream shift away from film has left you guys under served in the optical department. I'd like to see where I can help.... Not for profit but because I love turning designs into real glass. Kickstarter makes this idea viable.


I've designed many objectives, worked in an optical shop, assembled optics, tested optics, and of course used optics as well.


So let me know how I can help. You folks now have a lens designer at your service. :)


You'll see me post in the lens subgroup soon.


Cheers,
Jason

Ari
18-Nov-2014, 09:47
Hi Jason,

I was following your APUG thread with great interest; I realize everybody wants something specific, and you're bound to get many requests and points of view, so I hope you can eventually narrow down a good idea for a Kickstarter project.
There are many here who would get behind it.

Welcome, and if you want to solicit more lens opinions, the "Lenses & Lens Accessories" section is the best place for that.

Randy Moe
18-Nov-2014, 09:55
Welcome!

Perhaps you will ready when the herd rediscovers LF.

Good luck!

Old-N-Feeble
18-Nov-2014, 10:02
A multicoated Cooke XVa clone for less than $500. :D

Jody_S
18-Nov-2014, 10:19
Following the recent Lomo Petzval that seems to have been successful, I wonder if any 'new' classic lens has to be adaptable to dSLRs?

I don't personally have any requests, but the people doing ULF (like 20x24) are always complaining they can't find the lenses they want, even when they're prepared to pay for them. At $5k for an old process lens that covers the format, and much more for a Petzval, there is a niche market there somewhere. Doing the brasswork in these days of CNC machining doesn't seem to be as much of a hassle as it used to be. And can't the same lens-grinding gear be used to scale a particular element up or down according to needs (if you're grinding a certain curve, it doesn't matter what size element you're grinding)?

DrTang
18-Nov-2014, 10:24
A multicoated Cooke XVa clone for less than $500. :D

in about a 360mm size

Ari
18-Nov-2014, 10:37
A multicoated Cooke XVa clone for less than $500. :D


in about a 360mm size

And the convertible FLs would cover 11x14 and 16x20, respectively.
Make it fit any Copal 3 shutter, and I'd pay $1000 for one of those.

Having tried the new Cooke XVa, though, I can say that it's worth every penny, and cannot (should not?) be duplicated for less.
The coatings alone are extraordinary; they are what a very advanced alien civilization would give us as a token of friendship.
"Yeah, sure, why don't we give them the real secret to properly multi-coating optical lenses? Leave the teleportation for something important."

But I'm no lens expert, maybe it's a $10 job with Mr Cooke's name on it. :)

Old-N-Feeble
18-Nov-2014, 10:50
And the convertible FLs would cover 11x14 and 16x20, respectively.
Make it fit any Copal 3 shutter, and I'd pay $1000 for one of those.

Having tried the new Cooke XVa, though, I can say that it's worth every penny, and cannot (should not?) be duplicated for less.
The coatings alone are extraordinary; they are what a very advanced alien civilization would give us as a token of friendship.
"Yeah, sure, why don't we give them the real secret to properly multi-coating optical lenses? Leave the teleportation for something important."

But I'm no lens expert, maybe it's a $10 job with Mr Cooke's name on it. :)

Copal #3 mountable... or already in a shutter? :)

Old-N-Feeble
18-Nov-2014, 10:51
How about a Cooke for 4x5... maybe 200mm?

Ari
18-Nov-2014, 10:59
Copal #3 mountable... or already in a shutter? :)

Copal 3 mountable; it'd be great if the cells could just fit into a regular Copal 3, no shims or extras needed.
I don't think there are any more new Copal 3 shutters available; in fact, it may have been Cooke that bought the last stock.

Ari
18-Nov-2014, 11:00
How about a Cooke for 4x5... maybe 200mm?

And aren't you getting out of 4x5? to shoot 8x10? :)

Bernice Loui
18-Nov-2014, 11:04
How about some short tutorials on how to set up lens cell spacing for a range of image conjugates, where the aperture should be located for specific lens types, what gives specific lens types their out of focus personalities, modern coatings -vs- older coatings and more.

There are already SO many optics available today, it would be great to get a better understating of what really makes them different and how they work.



Bernice

Randy Moe
18-Nov-2014, 11:06
+1.

Nodda Duma
18-Nov-2014, 11:13
Over on APUG I'm finalizing a 165mm f/6.3 lens for 8x10" format that fits on a Copal 1 shutter. It has zero distortion and performance looks really good.

Here is a link so you can read the narrative

http://www.apug.org/forums/forum44/135253-there-interest-new-rapid-rectilinear-lens.html

If you shoot 8x10 feel free to take a look. I kind of used that thread to talk through the design path so you get to see that.

Sometime soon I'll post about this in the lens forum...to sort of pick up the narrative here as I gauge the level of interest and work with my mechanical engineer friend to wrap the glass in metal. Obviously the greater the interest the more feasible (and the lower the cost) of actually making them.


I can design anything there's interest for (Cooke's are easy), but since I do these designs at night after the kids are in bed and I also have a full time job, I'm somewhat bandwidth-limited. But that just gives me time to see where the next interest lies.

What I will try to do for designs of interest is take you along on the journey..so you get to see what's involved in lens design. Optical design is -- no joke -- 50% experience and 50% art. In the end the layout for a good lens just looks good...like a beautiful car or how pottery is shaped on the potter's wheel. Hard to describe but I do enjoy it.


Btw..Multi-layer coatings aren't really anything special...especially for visible. The coating run doesn't cost significantly more than single-layer coatings, and in a large enough coating run the cost of a coated is not significantly more when compared to the cost of an uncoated lens.


Oh and you should read "The History of the Photographic Lens" by Rudolph Kingslake if you haven't yet.

Regards,
Jason

8x10 user
18-Nov-2014, 11:33
Complete with Lanthanum oxide glass?


A multicoated Cooke XVa clone for less than $500. :D

Old-N-Feeble
18-Nov-2014, 11:40
And aren't you getting out of 4x5? to shoot 8x10? :)

Undecided... mostly depends on what kind of ambulatory help I can afford plus what I can afford in equipment. It's a darned difficult choice for me. I've already sold three excellent lenses dedicated for the 8x10 kit I was piecing together because I needed the funds. Hopefully, my financial situation will improve soon.

Anyway, yeah... a 200mm Cooke for 4x5 would be interesting. Whatever designs come out of this I would like the option of using perfectly round aperture discs rather than the rough hexagonal or octagonal apertures in modern shutters.

Nodda Duma
18-Nov-2014, 11:44
There are many inexpensive lanthanum-based glass types available to choose from.

Optical design software such as Code V & Zemax allow the designer to constrain glass selection by cost if desired. Many of the lanthanums will be included for use in that sort of list.


I'll start playing w/ a 200mm Cooke

Mark Sawyer
18-Nov-2014, 12:07
Welcome, Jason! I'm looking forward to your contributions!

Regarding the choice of a Rapid Rectilinear, I think you'll be competing with a lot of old RR's available cheaply, such as this 12" f/6 Versar I bought a few days ago:

http://www.ebay.com/itm/Wollensak-No-1-Studio-F-6-8-x-10-Versar-Portait-amp-View-Lens-/281485817409?ssPageName=STRK%3AMEBIDX%3AIT&_trksid=p2047675.l2557&nma=true&si=kx4RtaEWTH0TN4hmvcVRy9lMBaY%253D&orig_cvip=true&rt=nc

But that's no reason not to pursue your own version! My own feeling is that RR's are wonderful lenses, but occupy a grey area between lenses with strong individual signatures from their aberrations (either earlier designs where they didn't know how to eliminate the aberrations or later soft designs with aberrations deliberately designed in), and modern sharp lenses that are well-enough corrected for all aberrations that they all look the same. RR's give a conventional sharp look, but don't quite perform with the modern designs. (BTW, have you found a way to correct the RR's astigmatism?)

Nodda Duma
18-Nov-2014, 12:08
Mark: that thread evolved into a request for a wide angle design giving 80+ degrees field of view. I still have the RR, but there was more interest in the wide field. Keep reading :)


Shutters: When I need them I order electrical shutters from places like Melles Griot. Honestly though, for my day job all the optics I design are for digital imagers and thermal cameras, which of course have their exposure times controlled by the software/firmware.


I'm not in the business of making shutters (although I can ask my mechanical engineer), but if you look up Edmund Optics iris diaphragms you might find something to suit your need. They are manual. Put that at the aperture stop position and with some ingenuity you have a well-defined circular iris (you'd still need a shutter to stack with it).

Corran
18-Nov-2014, 12:52
Fascinating.
Will follow with interest.

adelorenzo
18-Nov-2014, 13:04
I've also been following the thread on APUG but hadn't chimed in. All I have to say is that I'm really interested in the design you have going and would back a kickstarter as long as the price was right.

Toyon
18-Nov-2014, 13:09
I've noticed that soft-focus designs (excepting perhaps the Imagon style lenses) are very popular and hold their value. There is a need for an affordable soft-focus lens in the a 6"-8" range for 4x5 that would offer reasonably wide coverage.

Toyon
18-Nov-2014, 13:11
I've noticed that soft-focus designs (excepting perhaps the Imagon style lenses) are very popular and hold their value. There is a need for an affordable soft-focus lens in the a 6"-8" range for 4x5 that would offer reasonably wide coverage. Please note: the Petzval is not a soft focus lens.

Will Frostmill
18-Nov-2014, 13:12
I saw the thread over on APUG, and I'm delighted you came here.

I have a special interest in a certain kind of lens that is at odds with the traditional 'make everything sharp at the hyper focal distance' theme. I like to do full and half length portraits, fairly wide open in order to render areas behind the plane of focus with low contrast, while simultaneously giving the plane of focus as much acutance as I can. My goal is to provide a clear outline of the high-local-contrast subject, unbroken by blur caused by too-shallow depth of field, against a backdrop of low-local contrast, at normal to mildly wide focal lengths.
For my purposes, dramatic field curvature can be an asset, rather than a liability, provided that I can figure out its three dimensional shape.

There are a bunch of ways to do this, with a bunch of trade offs - high acutance designs seem to get double-line bokeh, late 'soft' lenses seem to make everything glow which makes the contrast between foreground subject and background bokeh blur, high acutance developers sharpen everything which can make light-dark transitions in the bokeh weird, and sometimes I just run out of depth of field before I get the background knocked down to where I want it.

I guess what I'm saying is that I want something 'better' than a late model Tessar?

A pair of lenses for moderate wide (127mm on 4x5) and normal (150mm on 4x5) would be really neat. I also like small formats, and I do think a design that could be scaled down might be really popular with the "let's mount this on a mirrorless and see what we get" crowd.

If you are interested in a challenge, I think a redesign of the Aero-Ektar would be fantastic. They are big, heavy, radioactive, a little long for a normal lens, and seem to transmit light at f/3.5 or slower despite being designed for f2.8. Oh, and they are optimized for near-infinity and IR, so not as sharp as they could be at the plane of focus, while simultaneously blocking a bunch of useful UV for the wet plate folks hoping for a fast normal. Oh, and we love them. :) Pretty much any lens that dramatically improved on at least two of these characteristics would be really popular. Or, at least exciting to talk about. If you check out the November Portraits thread, I think there is a fine example from within the last few days.

Mark Sawyer
18-Nov-2014, 13:25
I've noticed that soft-focus designs (excepting perhaps the Imagon style lenses) are very popular and hold their value. There is a need for an affordable soft-focus lens in the a 6"-8" range for 4x5 that would offer reasonably wide coverage. Please note: the Petzval is not a soft focus lens.

Petzvals can be a soft focus lens if the element spacing is varied, as with the Dallmeyer Patent Portrait and the Wollensak Vitax. Similarly, the Tessar can be soft focus, as can the Cooke Triplet or Heliar.

Imagons are a classic soft achromatic doublet that don't go for quite as much as other soft lenses simply because they are so common, and perhaps because people are confused by the h-discs, which aren't necessary anyways...

richardman
18-Nov-2014, 13:43
Hi Jason, assuming you want the widest reach of audience, then a 4x5 lens is your best bet - there are just many more 4x5 users than other LF format.

So what's missing in the 4x5 segment? Not sharp lens, we have plenty of that. Not soft focus, we have plenty of that too. Petzval? Lots of choices too. Super-fast? Got that in the 150/2.8 Xenotar and Aero-Ektar, among others.

A modern triple convertible, OTOH, is solely missing. Cooke on their Convertible page says they may consider it but I have emailed them and they do not plan to make one.

Make it in something like 120-180-240, or 150-210-280, or 90-150-240 and I bet you will have a lot of buyers.


So there

Corran
18-Nov-2014, 13:50
Super-fast? Got that in the 150/2.8 Xenotar and Aero-Ektar, among others.

The Xenotar is really rare and expensive, and the Aero Ektar is big, heavy, kind of expensive now, usually isn't in shutter, and has the staining/transmission problem. So I think that area has room for another lens, maybe at f/3.5 or f/4 instead if costs are exorbitant. I wouldn't mind a lens that covers 4x5, that's ~100mm, but that fast.

The other thing about the Xenotar is the large size and Compur #2 shutter. At best, it gets up to 1/125 (that's what mine hits set to 1/200 after a fresh CLA), so if possible, a smaller design that gets in a #1 shutter and can get up to those faster speeds would be quite nice.

Nodda Duma
18-Nov-2014, 13:53
What's great for me is when I get the opportunity to learn something new. I also find differences in jargon between the user world and the designer world amusing but educational. I try to avoid optical engineering jargon for everyone's sake and I will try to warn the reader when I cannot resist and lapse into engineering-speak. :)

So it's great to learn what's important to photographers. For my photography I love a very sharp very fast lens...it appeals to the design perfectionist in me. My favorite goal is very sharp, very easy to make/assemble, and very cheap. But that's not necessarily important to everyone else.

Bokeh, for instance, is a characteristic that I've never had to consider before but is obviously important in photography. So, as I've looked at these designs I've taught myself how to "tune" when I can the bokeh.

Soft focus = spherical aberration, which is easy enough to adjust in a design (basically I shift each lens and evaluate the resulting spherical...and then when I make a real lens I'll say "move the second group back 2 3/4 turns for great soft focus").

Btw the 165 f/6.3 would be beautiful in and of itself for 4x5.



Please keep the ideas coming...I am making a list.

Jmarmck
18-Nov-2014, 13:56
As and Arkansas native and a lifetime Razorback fan, what is with the Running Razorback?

Nodda Duma
18-Nov-2014, 13:59
As and Arkansas native and a lifetime Razorback fan, what is with the Running Razorback?

Better looking logo than a Razorback standing there with its snout rooting in rotting veggies :)

drew.saunders
18-Nov-2014, 15:08
So what's missing in the 4x5 segment?...
A modern triple convertible, OTOH, is solely missing. Cooke on their Convertible page says they may consider it but I have emailed them and they do not plan to make one.

Make it in something like 120-180-240, or 150-210-280, or 90-150-240 and I bet you will have a lot of buyers.


What about resurrecting, at least in part, the idea of the Wisner Convertible Plasmat set for 4x5? See http://static.bhphotovideo.com/FrameWork/Product_Resources/SourceBookProPhoto/Section04LgFormatLenses.pdf for details and scroll to the last page for the Wisner set.

You could start with a triple convertible, and then add more cells later if there was interest. Looking at the old Wisner catalog, you could get the 250 and 350 single cells and put them together for a 182, and a 182/250/350 sounds like a very practical setup for 4x5. Personally, I like the idea of a 120/180/240 setup, but have no idea if a 180 cell plus a 240 cell combine to form a 120 lens. I still think a wide-ish/normal/long-ish triple would be best for me, even if the normal and long were both f/11 or so.

A "Half Cooke," with a 238 and 323 that combine to make a 156 (I just went here http://www.cookeoptics.com/l/xva.html and divided everything by 2) would be fine, especially if one could get additional single cells to make a front/front or rear/rear combo and get 5 focal lengths from 4 cells.

Oh, and make it cheap! :D

Nodda Duma
18-Nov-2014, 15:27
The lens I'm working on will have that kind of spread.

hoffner
18-Nov-2014, 15:54
Hello!


In any case, I joined because I love doing lens design.
I'd like to see where I can help.... Not for profit but because I love turning designs into real glass. Kickstarter makes this idea viable.

So let me know how I can help. You folks now have a lens designer at your service. :)

Cheers,
Jason

From Forum Guidelines:
New products and services - Announcements of new products and services of specific interest to large format photographers may be posted to the New products and services sub-forum. Promotional posts (as defined below) require moderator approval.
Other Commercial Posts - Except as noted in the two entries above, other "promotional" posts promoting your own business enterprise, or one to which you are financially connected (e.g. owner, employee, contractor), are not allowed.

Corran
18-Nov-2014, 15:59
There is not a new product or service on sale. This is not a commercial posting. Quit trolling, you aren't a moderator. If you have a problem, report the post, and they'll do as they deem necessary.

Old-N-Feeble
18-Nov-2014, 15:59
^^^ Corran beat me to it but I'll post anyway though I'll word it slightly more mildly.:)

Yeah... umkay... shoot it down flat. I'm sure the new guy will figure it out and follow forum rules as required. If he does err I'm sure a mod will set him straight. Sheesh...

Peter De Smidt
18-Nov-2014, 16:02
Fun stuff!

Tim Meisburger
18-Nov-2014, 16:24
I am missing a lightweight wide angle for 4x5. I have both an Angulon and an Optar 90mm, and while both cover the format, neither has the coverage needed for any significant movements.

I also thing a simple soft focus lens for 4x5 would be popular. Designed to screw into an existing shutter (Copal 3); sharp when fully seated and progressively softer unscrewed.

DrTang
18-Nov-2014, 16:33
Why isn't there a bigger Plannar? they stopped about what? 120? 150 maybe

a 240 might be sweet..3.5 maybe

Nodda Duma
18-Nov-2014, 17:08
Actually a moderator was already kind enough to move the thread from where I had originally posted in the Introductions area.


Just to clarify.. No one is paying me to ask what kind of lenses photographers need. Nor is anyone paying me to shed light on the design process. This is entirely a side hobby. In fact, I'd probably get a lot more sleep if I hadn't offered to do this. I'm just a guy sharing a common interest in lenses except I happen to be on the other side of the technical specs and can realize real hardware.

As they say talk is cheap (free in this case) and I'm certain there are those interested in seeing an optical design process. It's no different than a photographer with a commission discussing the process they go thru to make a print. Sales =/= discussing a process.

When and if it comes to the point where I say "ok I'll try to raise money to get the design made into something people will want" then I've noticed there's a sub-forum clearly labeled "Kickstarter Announcements". Despite my low forum post count and origins in Arkansas I can actually read with comprehension. :)

In any case, I'll continue on and leave it up to the moderators to set me straight as needed.

Regards,
Jason

Tim Meisburger
18-Nov-2014, 17:28
You are doing nothing wrong. This is exactly the process that led to the development of the Travelwide camera. And we love large format lenses, so press on!

Nodda Duma
18-Nov-2014, 17:54
The Aero-Ektar...

I actually have two of these lenses. I obtained them with the intention of turning (at least one of) them into an astrophotography rig. Haven't quite done that yet.

One is a Bausch & Lomb 24" f/6 with an imaging area that I estimated at about 1 meter diameter.

The other is a Kodak 12" f/2.5 with the Thorium-doped element which makes my Geiger counter click. That one sits down in a corner of the basement with the thorium element pointed towards the ground. I had one come across my desk once when I worked for the Navy. I asked the master optician --- a cranky old coot who considered polishing a 1/100-wave surface on an 8" mirror "a fun challenge" -- who said that you get more radiation from one flight to Europe at 35,000 feet than you do off that lens in a year....but to not store it underneath my desk chair if I wasn't done having kids.

I happen to have the prescription for the Aero-Ektar so I could certainly look at updating it. The layout is a double Gauss variant with a cemented doublet as the last element. In fact, here is kind of what it looks like:

125277

-Jason

NickyLai
18-Nov-2014, 17:55
Over on APUG I'm finalizing a 165mm f/6.3 lens for 8x10" format that fits on a Copal 1 shutter. It has zero distortion and performance looks really good.



I like this one. Keep it up and inform me when you are ready.

Good luck!
Nicky

Corran
18-Nov-2014, 18:02
I have no idea what that ray diagram or whatever means, but I do wonder, does the radioactive glass give a significant improvement to the lens?

If it's just a double Gauss variation...any improvements you would do? I wonder if it could be pushed to f/2, and with coatings that helped keep the transmission good?

I've had about 10 AE lenses in my hands, most 7" f/2.5 models but also one 12" and also a Harvard College Observatory lens that looked and behaved exactly like the standard 7" f/2.5 Aero Ektar...but wasn't stained and seemed to not have the radioactive elements. I don't have a Geiger counter though so I can't confirm that. That lens went off to a collector interested in the history of the HCO.

Dan Fromm
18-Nov-2014, 18:18
Um, Bryan, f/2 6/4 double Gauss lenses with interesting coverage have been made. Two of them are cult lenses, bring prices that I can't believe. Most buyers seem to be in the far east.

The longest, I think, TTH lenses in the Opic/Series 0 family are the 4"/1.8 (covers at least 6x6) and 4"/2.0 (covers 6x9) TTH Anastigmats made for a couple of British aerial cameras that shot 6x6 on 70 mm film. I have a 4 incher, it isn't compact or light. These days 4"/2 ones bring a couple of thousand dollars. I have no idea how much of that is due to being engraved TTH. I know, medium format, but the prices are interesting.

Dallmeyer made a roughly comparable lens called Super Six in a variety of focal lengths. Super Sixes cover at least their focal length. Ones of interest for LF are the 6"/1.9 and 8"/2.0. I've had a 6 incher, not compact or light. And usable only on a 4x5 Speed Graphic or at low shutter speeds in dim light, in which case a large Packard might be usable with it. I can't imagine how any of us could use an 8 incher. These days longer Super Sixes bring low five figures. I don't know whether similar lenses not engraved Super Six would bring nearly as much.

I've also, now that I think of it, had a 200/2.0 S.F.O.M. that just might have been made by Kinoptic. I've seen one so engraved. Around fifteen pounds and, yes, immense. For 4.5" x 4.5" on 5" roll film. The few I've seen sold, including mine, brought much less than a Super Six would have.

Be careful what you wish for.

jnanian
18-Nov-2014, 18:19
how about a modern "casket set"
for either 4x5 or 8x10 ( or bigger ! ) so someone can
buy ether the whole 7 focal lengths :) or
a few and whatever they might need down the road.

there are already so many "vintage" ( older than 1970 )
lenses of all sorts of designs on the market that your new ones will have to compete with
some of these lenses are great and cost next to nothing
not sure how you can compete with a 20$ folder ( for its lens )
but a casket sets ! wisner made one years ago and from what i
understand they are prized ...


john

Nodda Duma
18-Nov-2014, 18:21
I have no idea what that ray diagram or whatever means, but I do wonder, does the radioactive glass give a significant improvement to the lens?

If it's just a double Gauss variation...any improvements you would do? I wonder if it could be pushed to f/2, and with coatings that helped keep the transmission good?

I've had about 10 AE lenses in my hands, most 7" f/2.5 models but also one 12" and also a Harvard College Observatory lens that looked and behaved exactly like the standard 7" f/2.5 Aero Ektar...but wasn't stained and seemed to not have the radioactive elements. I don't have a Geiger counter though so I can't confirm that. That lens went off to a collector interested in the history of the HCO.

Ah well first let me describe the ray trace.

1st rule of lens design: Object is always on the left, image is always on the right.

This is a cutaway view of the glass (the lens shapes) with light rays from different field angles tracing through the glass onto the image plane.

If you were to zoom out you would see this:

125278

So you have to imagine that the lenses are wrapped in a barrel (the barrel design always comes after the optics are done).

The blue represents the zero degree field angle.... Note the blue-colored light ray paths are parallel before they enter the lens. That means the lens is focused at infinity (really far away). Refraction bends the ray paths through the lens and they are focused onto the image plane at right.

Other colors represent light rays coming from off-axis field angles. For this particular ray trace, they represent 8.8 degrees and 12.5 degrees off-axis (so a 25 degree total field of view). Those field angles map to 47.3 mm off-axis and 57.9 mm off-axis (or an image circle with diameter 115.8 mm.... optical designers usually talk in half-angles since circular lenses are radially symmetric).

Usually the other information I watch when designing a lens is either the spot diagram (Imagine imaging a point source like a star and seeing how large the resultant blur spot is on the image plane) or the MTF. Besides that the design of the lens is controlled via a merit function...where I enter in parameters which govern the design and then run an optimization algorithm against those parameters. For complex systems the number of parameters can run into the thousands. For this particular example I had to tweak the patented prescription (fyi patents rarely list the real prescription) to provide a meaningful ray trace...in that case I have 231 parameters. Most are automatically generated to control image quality. The rest I manually entered into the list to control focal length, mass, constraints on airgaps and glass thickness. Then of course there is the prescription itself.

This is what the software looks like (still have it opened for the illustrations above):

125279

Software is called ZEMAX and is pretty much the industry standard for lens design software. Code V and OSLO are the two other design packages. They all support both the design optimization, as well as tolerancing, thermal characteristics, stray light analysis, everything needed to design optics.


As for the radioactive glass.. yes it was very good for optical design at the time it was introduced. But there have been new glasses introduced since then as well as advancements in computer-aided design so nobody really misses the thorium-doped glass.

Nodda Duma
18-Nov-2014, 18:43
how about a modern "casket set"
for either 4x5 or 8x10 ( or bigger ! ) so someone can
buy ether the whole 7 focal lengths :) or
a few and whatever they might need down the road.

there are already so many "vintage" ( older than 1970 )
lenses of all sorts of designs on the market that your new ones will have to compete with
some of these lenses are great and cost next to nothing
not sure how you can compete with a 20$ folder ( for its lens )
but a casket sets ! wisner made one years ago and from what i
understand they are prized ...


john


Well I'm not really competing... as you say you can't compete with a $20 lens. But I'm certain there are things out there which people wish they had but cannot find or afford to buy. There I can probably help. Your suggestion for a casket lens, for example. Or perhaps an update of an old design with new glass and coatings. Whatever you'd like. If I were rich I would just puke out a bunch of optics and say come and get them.. but I'm not so I have to ask what people would like. Like the 165 f/6.3 for 8x10 that people seem interested in.

For me I get the design practice which is fun.

jp
18-Nov-2014, 18:49
Welcome!

I've gotta say if you want to go in headfirst, the 178 aero ektar has quite a cult and people would line up to get a lighter weight version or something that could be more easily shuttered.

I'm wondering what options we might have for grinding and polishing our own lens glass on a small scale; like a small town eye glasses shop or mfg would do 100+ years ago. Or do we have to go big or go home.

Nodda Duma
18-Nov-2014, 18:51
How about some short tutorials on how to set up lens cell spacing for a range of image conjugates, where the aperture should be located for specific lens types, what gives specific lens types their out of focus personalities, modern coatings -vs- older coatings and more.

There are already SO many optics available today, it would be great to get a better understating of what really makes them different and how they work.



Bernice


I think what I could do is post some documents that I wrote long ago as part of the design coursework I took. The class was real interesting because it stepped through the design evolution of camera lenses. So for example I know why the landscape lens works and what it corrects. Same with the Cooke and the Double Gauss. One interesting thing about the Cooke triplet is that you (well, a lens designer) can get to the Cooke triplet design form starting from a Petzval lens by simply increasing the fields that it corrects for and letting the glass types move into each other during optimization. I figured that out recently...before that I kind of viewed the Cooke triplet as a unique offshoot which didn't tie into anything else. But apparently it does, even if Taylor didn't know it at the time.

Oh and I can unequivocally say that the Tessar does not derive from the Cooke. It can be described as such, but it is not considered like that in the design community.

Also.. .a good book to pick up would be "The History of the Photographic Lens" by Rudolph Kingslake. Kingslake is like the lens design world's version of Ansel Adams.

jnanian
18-Nov-2014, 18:52
sounds good !

so while i can't afford it, how about a 8 element casket set
from 6" to 25" that will cover 8x10 and barely corner 11x14 ;)
i know it won't be for me cause i am broke ...
but i am sure that there are handfuls of people who would be
chomping at the bit for a modern glass, coated ( maybe not ? )
8 element casket set that has nice coverage...

sorry if my previous post was vague about my wish list ...

richardman
18-Nov-2014, 18:55
Actually a moderator was already kind enough to move the thread from where I had originally posted in the Introductions area.


Just to clarify.. No one is paying me to ask what kind of lenses photographers need. Nor is anyone paying me to shed light on the design process. This is entirely a side hobby. In fact, I'd probably get a lot more sleep if I hadn't offered to do this. I'm just a guy sharing a common interest in lenses except I happen to be on the other side of the technical specs and can realize real hardware.
...
Jason

Someone was on my arse a few months ago when I was inquiring about whether there are interested in, basically an electronic timer for LF shutters. Fortunately, even the mod agrees that I wasn't offering anything for sale, just asking for opinions and ideas.
Generally, I found people in LFF fairly tolerant, as long as it's LF related, and even if not, the lounge and the Image Sharing subforums do accept "smaller format" talks.

Nodda Duma
18-Nov-2014, 18:56
Welcome!

I've gotta say if you want to go in headfirst, the 178 aero ektar has quite a cult and people would line up to get a lighter weight version or something that could be more easily shuttered.

I'm wondering what options we might have for grinding and polishing our own lens glass on a small scale; like a small town eye glasses shop or mfg would do 100+ years ago. Or do we have to go big or go home.


Look up amateur telescope making. It is not that difficult but it does require access to polishing equipment or the motivation/handiwork to make the equipment yourself. I personally have polished / figured telescope primaries for my own use and have ended up with killer performers. Actually completed my first mirror (8" f/6) while I was at home after we had our first child. The hard part is knowing what you need to make, and to what tolerances. Telescope designs can be derived mathematically using well-defined equations. Camera lenses must be designed and optimized, or trial and error (like everything that came before the Petzval and Cooke). The only one I know of that can be mathematically designed successfully is the Petzval.

Nodda Duma
18-Nov-2014, 18:58
sounds good !

so while i can't afford it, how about a 8 element casket set
from 6" to 25" that will cover 8x10 and barely corner 11x14 ;)
i know it won't be for me cause i am broke ...
but i am sure that there are handfuls of people who would be
chomping at the bit for a modern glass, coated ( maybe not ? )
8 element casket set that has nice coverage...

sorry if my previous post was vague about my wish list ...

np.. you are not the first to ask about that. I'll give it some thought on how best to approach that. I think it would be a good project but it will take time.

Corran
18-Nov-2014, 19:06
Um, Bryan, f/2 6/4 double Gauss lenses with interesting coverage have been made. Two of them are cult lenses, bring prices that I can't believe. Most buyers seem to be in the far east.

Yes I'm aware, but as you said, they are rare, expensive, and pretty much irrelevant due to the unavailability. Indeed, perhaps f/2 is impossible from the viewpoint of size/weight. But neither did I mean to constrict ideas to a double Gauss design - nor would I, unless I had a reason to do so!

I do know there are some interesting lenses that cover larger formats and are very fast, but I'll not be mentioning one until I get mine shuttered - project for next year at SKG, probably - so as to not inflate the prices...


Ah well first let me describe the ray trace.

Fascinating, thanks! I don't really understand still, but give me some time and I'll figure it out. Maybe.

goamules
18-Nov-2014, 19:10
Welcome, Nodda. I'm something of a lens scholar, so I'm glad to have someone with the scientific background talking to us. (a recent Facebook project started with a similar "dream sheet" open comment period, but the only answers were speed and barrel material).

Would you be interested in making something never before done, or just recreating a known design?

I ask because the Sonnar in small format is about my favorite lens in normal focal lengths (for 35mm). You said yourself you like fast lenses, that are very sharp. I also love the color rendering the the bokeh of most Sonnar types I've shot, including the Jupiter 3, Canon 50/1.5, Nikkor 50/1.4. But I've heard it said "you cannot make a large format Sonnar type." I am very impressed with the early postwar Nikkor work perfecting the Zeiss sonar, and getting the speed from F1.5 to F1.4. So my first question is, is there a reason you couldn't make a 200mm or 300mm Sonnar type?

Dan Fromm
18-Nov-2014, 19:27
Garrett, wasn't there a 250/5.6 Sonnar for 4x5?

Corran
18-Nov-2014, 19:29
Yep there was, I own one...fabulous lens.

I'd like to see a ~150mm Sonnar though.

Nodda Duma
18-Nov-2014, 19:33
Welcome, Nodda. I'm something of a lens scholar, so I'm glad to have someone with the scientific background talking to us. (a recent Facebook project started with a similar "dream sheet" open comment period, but the only answers were speed and barrel material).

Would you be interested in making something never before done, or just recreating a known design?

I ask because the Sonnar in small format is about my favorite lens in normal focal lengths (for 35mm). You said yourself you like fast lenses, that are very sharp. I also love the color rendering the the bokeh of most Sonnar types I've shot, including the Jupiter 3, Canon 50/1.5, Nikkor 50/1.4. But I've heard it said "you cannot make a large format Sonnar type." I am very impressed with the early postwar Nikkor work perfecting the Zeiss sonar, and getting the speed from F1.5 to F1.4. So my first question is, is there a reason you couldn't make a 200mm or 300mm Sonnar type?

What, you mean like this?

125282

Depends on how much weight you want to carry. The 35mm version is like a pound of glass. Scaling up to 150 puts it at 1.7 kg. Of course I'd try to reduce that.

Corran
18-Nov-2014, 19:44
My 250mm Sonnar is indeed a hefty chunk of glass. That said, the little Nikkor 50mm f/1.4 Sonnar Garrett is referring to is 4.4oz according to my book about the Nikon rangefinder, including the barrel.

David Lobato
18-Nov-2014, 19:44
I was thinking of an Aero Ektar when I saw you mentioned it. A new design to fit into a shutter would be really nice, and an 8x10 variant too.

While we're dreaming, a simple shutter using 3D printing technology in an easy to fabricate metal shell. It would allow the large throat diameter Aero Ektars and Soft focus designs would need. I'm a mechanical engineer with design experience.

Tim Meisburger
18-Nov-2014, 20:18
Yes David. I do think we need a modern shutter, even if it is as simple as those from the turn of the 20th century.

Go for it!

I was thinking of an Aero Ektar when I saw you mentioned it. A new design to fit into a shutter would be really nice, and an 8x10 variant too.

While we're dreaming, a simple shutter using 3D printing technology in an easy to fabricate metal shell. It would allow the large throat diameter Aero Ektars and Soft focus designs would need. I'm a mechanical engineer with design experience.

David Karp
18-Nov-2014, 21:18
I really like the 120-125mm focal length on 4x5. The older 125mm Fujinon is nice, but has limited movements. The 120mm Nikkor is big for backpacking and the 115-125mm lenses from the other manufacturers are even bigger.

It would great to have a smallish lens in that focal length with an image circle larger than a 120mm Angulon. Sort of in between the Fujinon and the Nikkor. Perhaps a size that would fit in a Copal No. 1.

I know you are not a mechanical engineer, but coming up with a reasonable shutter solution would be great. It would not have to go up to 1/500 or 1/400 like the Copal 0 or 1. Few if any of us use those high speeds, and they are not going to be accurate anyway. A range like 1/60 to 1 Sec plus B and T, or even just B, would be great.

Of course, this is really interesting, but we are all just talking. When it comes time to pay, then reality and our budgets get in the way of us buying what we want. The success of the Travelwide Kickstarter was in large measure due to the super low price point for a 4x5 camera.

axs810
18-Nov-2014, 21:43
I would love to see a 150mm, 180mm, or 210mm with a f/2.8 aperture that could fit into a modern copal shutter. Then I'd feel comfortable selling all my 8x10 gear to stick with 4x5 for portraiture...I know I could always get a speed graphic and aero ektar but it would be nice to have a new lens option that could be easy to send in for shutter CLA and not be so limiting with what camera body it's used with (ie speed graphic + aero ektar)

Mark Sawyer
18-Nov-2014, 22:03
I'd really like a lens that causes beautiful young women to come up to me on the street and say "Oh, I've always wanted someone with a lens like that to do some tasteful, artistic nudes of me..."

I'm not fussy about focal length or maximum aperture, so that gives you some design freedom to work with...

Nodda Duma
18-Nov-2014, 22:23
axs810, are you talking for 4x5?


edit: Sorry Mark, that only works for lens designers and rock stars ;)

Jody_S
18-Nov-2014, 23:32
Of course, this is really interesting, but we are all just talking. When it comes time to pay, then reality and our budgets get in the way of us buying what we want. The success of the Travelwide Kickstarter was in large measure due to the super low price point for a 4x5 camera.

The reality is that most of us are very happy with the currently-depressed prices of large format lenses, and I for one still can't afford to buy most of the cheap modern LF lenses I would like to use. There are a few LF lenses that command top dollar, in 2 distinct categories: the latest and best from the big name manufacturers still sell for 'normal' prices for used lenses, and the other category is cult classics, collectibles, antiques and the lot whose price is being driven up essentially by nouveau riche collectors who may or may not ever mount the lens on a camera, but they want the prestige of owning it. This is a great market if you can break into it. Historical reproductions do sell, especially if they're usable.

You will have to find a niche somewhere in all of that if you want to make a go of selling these. ULF shooters will pay for a lens, either landscape or soft focus, because they don't have the luxury of buying the cheap lenses us 4x5 and 8x10 shooters can buy in a saturated used market. ULF lenses were always rare, and prices will not come down, ever. Then there's novelty lenses, anything that will cover 4x5 at f2.5 or larger, and perhaps f3 for 8x10, should sell. A shutter isn't that big an obstacle, none of the currently-available lenses in that niche can be mounted in a shutter, so it's Packard or focal-plane or whatever people can cobble together.

An ultra-wide lens for 8x10 (actually 5x7 and everything larger) might also sell, a modern equivalent of the Harrison Globe lens? I see lenses like the f18 Protar V still command decent prices in any size. I sort of regret selling my 8x10 copy, even if I couldn't use it on my camera because the front rail was in the frame. And then there's the Goerz Hypergon that still goes for ridiculous prices if the propeller is intact, and of course the original Globe lens, and the Hill 'cloud' lens, etc. A reproduction of any of these should sell, and an updated modern equivalent should also sell.

A somewhat off-topic question: would it be possible to build a center filter into one of these ultra-wide angles? Is there some technology to do this, like cementing a graduated film into one lens group? Or modern lens-makers are just making Photoshop profiles for their lenses, or building the corrections into digital cameras?

axs810
18-Nov-2014, 23:35
axs810, are you talking for 4x5?


edit: Sorry Mark, that only works for lens designers and rock stars ;)


Yes for 4x5 format.

Corran
18-Nov-2014, 23:54
Goerz Hypergon

+1!


A somewhat off-topic question: would it be possible to build a center filter into one of these ultra-wide angles? Is there some technology to do this, like cementing a graduated film into one lens group? Or modern lens-makers are just making Photoshop profiles for their lenses, or building the corrections into digital cameras?

I've wondered that as well, though of course that will severely limit the max aperture I imagine. But hey, what about a removable front element - one w/ and one w/o the center filter?

Reminds me, last week I was reading about a "center filter" that "increased noise in the shadows," but then I realized they were talking about a software solution! Obviously all that does is bring up exposure in the corners digitally - a poor replacement for a true optical CF.

Lachlan 717
19-Nov-2014, 01:51
A 200-210mm f9 that would cover 7x17", please!!!

hoffner
19-Nov-2014, 01:58
Please keep the ideas coming...I am making a list.

hoffner
19-Nov-2014, 02:19
For 4x5:
Duper Angulon 55mm/5.6
Sonnar 135/2.8
Sonnar 120mm/2.8
Sonnar 150mm/2.8
Sonnar 180mm/2.8 (I like Sonnars, you got it)
Sonnar 250mm/2.8
Plannar 300mm/2.8 (I like Plannars too)
Tessar 1200mm/5.6 (I like Tessars too)
Could you design a 1800mm/11 Tessar? (Now that would be great!)

For 8x10, please:
Duper Angulon 120mm/5.6 (yes, 5.6 - focusing is better then)
Sonnar 200mm/5.6 (5.6 for the same reason as above)
Sonnar 300mm/2.8 (I know, a beast but it would be great, wouldn't it?)
Sonnar 450mm/5.6 (so as not to make it too heavy)
Sonnar 600mm/8 (would be interesting, you can wait with this one though)
Tessar 1200/8 (so as not to make it too heavy yet pleasant for focusing)

For 11x14 please:
Sonnar 600mm/5.6 (everything is bigger in that format anyway)

for 20x24 please and please again:
A simple Tessar will do - 1200mm/11 (not in my collection yet)

Thank you so much!

Nodda Duma
19-Nov-2014, 03:12
Hoffner you could probably use a zoom. I'm sure there's one available off-the-shelf.

Henrim
19-Nov-2014, 03:24
I have a plethora of lenses in various formats but know next to nothing about the thinking behind them. So I really appreciate your time and willingness to share this stuff. Valuable reading. Thank you.

[moderator edit: removed quote of a deleted post.]

Hoffner, don't you have anything better to do?

hoffner
19-Nov-2014, 03:25
I have a plethora of lenses in various formats but know next to nothing about the thinking behind them. So I really appreciate your time and willingness to share this stuff. Valuable reading. Thank you.



+1.

hoffner
19-Nov-2014, 03:26
Hoffner you could probably use a zoom. I'm sure there's one available off-the-shelf.

Yeah, a LF zoom would be great! Can you add it to the list, please?

Nodda Duma
19-Nov-2014, 04:24
Hoffner I have no beef with you, don't know you from Adam, and neither you me. I'm not sure why you have issues with my offer to support large format photography. Perhaps you had considered lens designing as a career and couldn't cut it or you are simply hostile to the ideas of capitalism and trade. It doesn't really matter...I'm sure your reasons are justifiable in your mind but I pray it's not because you've gone through life bitter and miserable.

This is an honest and open discussion about what optics large format and ultra large format photographers could use. I certainly welcome serious discussion about optics and look forward to answering honest questions you may have. Until then, I can only ask that you refrain from posting nonsense to the thread (not that you will). It's not witty, it's not intelligent, and --- most importantly --- it reflects poorly on the large format photography community which you are a part of.

hoffner
19-Nov-2014, 04:34
You see, Nodda Duma, and me who thought I was quite clear! As I said, I'm fascinated, amazed watching this Schneider in making live, so to speak. Our LF community is under served with LF lenses, as you correctly noticed. You want to help all of us with new designs and I'm truly honoured to watch it. Hope my list was helpful. Hopefully others will see it that way too and come with more demands. This forum needed a lens designer. Thank you for your help.

richardman
19-Nov-2014, 04:35
Just ignore the negativity and proceed with some of the good ideas offered. Good luck with your project!

Nodda Duma
19-Nov-2014, 04:48
I have actually ignored him now. I'm pretty thick-skinned so it doesn't bother me...I'm just surprised at the negativity shown to a new forum member. It really does reflect poorly on the community, as unfortunate as that is to say. He's as much an ambassador as anybody else.

In any case, there are some good suggestions and common threads. I'll sort through them to see what makes sense.


Btw someone asked about filters... Look up apodization filter.

goamules
19-Nov-2014, 05:27
What, you mean like this?

125282

Depends on how much weight you want to carry. The 35mm version is like a pound of glass. Scaling up to 150 puts it at 1.7 kg. Of course I'd try to reduce that.

Weight is the least of my concerns, as a large format and wetplate photographer! If you are carrying a 5x7 or 8x10 camera and all the assessories and film holders, what's a 3 lb lens? Good to know about the 250mm Sonnar Corran and Dan, I'll look for one. So, how about a 300mm Sonnar, for 8x10?

goamules
19-Nov-2014, 05:34
Hoffner I have no beef with you, don't know you from Adam, and neither you me. I'm not sure why you have issues with my offer to support large format photography. Perhaps you had considered lens designing as a career and couldn't cut it or you are simply hostile to the ideas of capitalism and trade. It doesn't really matter...I'm sure your reasons are justifiable in your mind but I pray it's not because you've gone through life bitter and miserable.

This is an honest and open discussion about what optics large format and ultra large format photographers could use. I certainly welcome serious discussion about optics and look forward to answering honest questions you may have. Until then, I can only ask that you refrain from posting nonsense to the thread (not that you will). It's not witty, it's not intelligent, and --- most importantly --- it reflects poorly on the large format photography community which you are a part of.

Just ignore comments you don't like. You don't want to come across judging peoples lives, bitterness factor, intelligence, and telling them how to act in a forum you just joined yourself.

Now, back to lens requirements for a new manufacturer.

richardman
19-Nov-2014, 05:36
Of course Jason knows all these, this is just for people who might not realize them: one important factor to remember is that some lens designs ARE tough, otherwise you would have seen them already. Like all things, lens design and manufacturing are series of acceptable compromises that meet the achievable goals. For example, a 38mm Biogon for the Hasselblad SWC is reasonable size compared to other MF lens, but the 75 Biogon LF lens are huge. Rather than aiming for the moon, useful realistic goals should be set instead. This is why I proposed the triple convertible for 4x5. There is no modern version, but it clearly can be done and had been done, and it is immensely useful for LF users.

Ari
19-Nov-2014, 06:46
I really like the 120-125mm focal length on 4x5. The older 125mm Fujinon is nice, but has limited movements. The 120mm Nikkor is big for backpacking and the 115-125mm lenses from the other manufacturers are even bigger.

It would great to have a smallish lens in that focal length with an image circle larger than a 120mm Angulon. Sort of in between the Fujinon and the Nikkor. Perhaps a size that would fit in a Copal No. 1.


David, such a lens already exists.
The Grandagon (non-N version) 115 is much smaller than the 120 Nikkor, covers 8x10 (barely) and comes in a Copal 1 shutter.
It is on the heavier side, like many Rodenstock lenses seem to be, but still at a manageable 550-ish grams.
Or did you mean something even smaller?

Jac@stafford.net
19-Nov-2014, 07:05
Richard Man's mention of lens sizes reminds me once again that I do not really know whether merely scaling a design upwards works. That is, in the example of the 38mm Biogon for 2.25x2.25" film and a 3" Biogon for ~5x5" film, each lens having the same angle of view, is doubling the dimensions of the lens all that's necessary? I suspect that compromises in the larger version are attractive in order to reduce costs, and the degree of enlargement is likely less for the 3"?

I hope that made sense. First coffee of the day and the house is just warming up. :)
From the Tropics of Minnesota (https://www.google.com/search?q=2.25%5E2&oq=2.25%5E2&aqs=chrome..69i57.3181j0j8&sourceid=chrome&es_sm=119&ie=UTF-8#safe=off&q=weather+winona+mn),

jac

Nodda Duma
19-Nov-2014, 07:12
richardman your idea is intriguing and I've started thinking about it. I am seriously considering it.


goamules you are absolutely correct and I don't want to give that impression. We are after all only human and respect is a two-way street. My apologies to hoffner...I'll scrub that post you quoted. All I ask for is honest participation and his contributions are as welcome as anyone's so long as they are well-intended. I actually went back and forth for some time about posting here because I was worried about the reception. However I finally decided to because this is as educational and interesting for me as it is for anyone else. I'm not a salesman or marketing guy so I'm not a good smooth-talker (you can ask my wife). I just an optical engineer w designing optics and likes to put them together. That's all.

Dan Fromm
19-Nov-2014, 09:12
Richard Man's mention of lens sizes reminds me once again that I do not really know whether merely scaling a design upwards works. That is, in the example of the 38mm Biogon for 2.25x2.25" film and a 3" Biogon for ~5x5" film, each lens having the same angle of view, is doubling the dimensions of the lens all that's necessary? I suspect that compromises in the larger version are attractive in order to reduce costs, and the degree of enlargement is likely less for the 3"?

I hope that made sense. First coffee of the day and the house is just warming up. :)Tropics of Minnesota[/URL],

jac

Jac, multiplying elements' radii, thicknesses, and diameters, and intercell spaces by a constant multiplies focal length by the constant.

Old-N-Feeble
19-Nov-2014, 09:14
I'd really like a lens that causes beautiful young women to come up to me on the street and say "Oh, I've always wanted someone with a lens like that to do some tasteful, artistic nudes of me..."

I'm not fussy about focal length or maximum aperture, so that gives you some design freedom to work with...

Watch it, Mark. Pixies can be bitterly jealous little things......

Jody_S
19-Nov-2014, 09:22
Btw someone asked about filters... Look up apodization filter.

Interesting, I've taken enough physics classes to know such things are possible, but I had no idea there was such a commercially-produced lens as this: Minolta STF 135mm f/2.8 T4.5 (http://en.wikipedia.org/wiki/Minolta_STF_135mm_f/2.8_T4.5_lens). I need to try one!

As for the nattering nabobs of negativity, don't worry about it. Some of us are aware of the progress in lens design since the advent of computers of sufficient power. Even if we can't afford any of the newly-designed lenses of the last 20 years, in any format larger than a P&S digital camera. The issue is that we are practitioners of a dying art with a collectively small buying power (which is what drove away the big 4 LF lens-makers), not that we wouldn't benefit from the newest technology.

Dan Fromm
19-Nov-2014, 09:26
I just took a look at lenses, large format offered on eBay that were listed in the last two weeks. This may not be the best possible sample. It misses lenses offered "buy it now" that sold. And by ignoring lenses put up more than two weeks ago I may have undersampled exotics, especially overpriced long focus process lenses.

Short version, lenses that cover 4x5 with focal lengths from 47 mm to around 400 mm are abundant. Lenses that cover 5x7, especially wide angles are less abundant. But then, there seem to be many more photographers shooting 4x5 than shooting 5x7. There's not much but normal lenses and long process lenses for longer focal lengths. But, again even though they're quite vocal here there just aren't that many people shooting larger formats.

I also searched for large format in vintage lenses. Much the same story, but there was one interesting rarity, a 120/48 Hypergon that should cover up to 16x20.

There's really no empty niche in 4x5 except perhaps wide and inexpensive. Similarly for larger formats, but the larger the format the emptier normal and wider and inexpensive seems to be.

Corran
19-Nov-2014, 09:32
Weight is the least of my concerns, as a large format and wetplate photographer! If you are carrying a 5x7 or 8x10 camera and all the assessories and film holders, what's a 3 lb lens? Good to know about the 250mm Sonnar Corran and Dan, I'll look for one. So, how about a 300mm Sonnar, for 8x10?

Just for reference:
http://www.ebay.com/itm/251724491808

He's had that lens up for months now. I saw one sell for around $1k a few months ago. I bought mine late last year on eBay from a nice gentleman who apparently never used it, fully set up and cammed for a Technika V or later, so I was able to setup my infinity stops and shoot handheld with it immediately (http://valdostafilm.blogspot.com/2014/02/louisiana-leftovers.html). I definitely notice the weight! I use a monopod if possible...

Old-N-Feeble
19-Nov-2014, 09:34
I've noticed there's a limited selection of shuttered 135mm lenses that cover 5x7, or 4x5 with lots of room (225mm+ image circle). The only one's I'm aware of are the Wide Field Ektar, older Fujinon (with writing on front) and Meopta Largor (Russian clone of the E.F. Ektar). Only the Fujinon can be considered very common and can be bought at a reasonable price... sometimes quite cheaply. However, I've read that the sharpness at the corners is often lacking. I wonder if a 135mm f/5.6 plasmat that easily covers 5x7+ and is razor sharp to the corners and fits a Copal or Compur #1 would sell (aperture scale included).

Sal Santamaura
19-Nov-2014, 09:39
As with most aspects of life, I'm far outside the mainstream. I've no interest in Bokeh of any kind. I want everything in focus, sharp everywhere. As a result, I noticed but hadn't previously bothered to read your APUG thread. Your posting here prompted me to do so now. Nothing that's been described there is in any way attractive to me.

Here are the specifications for what I'd like to see you design and have made. Focal length 225mm. Corrected for near infinity. Image circle at least 350mm, preferably 400mm. "Circle" defined as edge sharpness near what it exhibits at the center, i.e. not just "illumination" circle. Virtually no falloff when centered on wholeplate film (260mm diagonal), and not much more near the circle's edge. Almost no field curvature or focus shift. Fits in a Copal 1. Speed f/x, where x is as small numerically as you can make it and still fit in the Copal 1. Weight with shutter not more than 500g. All elements multicoated.

If such a package, to include front and rear cells as well as a pair of aperture scales ready to screw onto a Copal 1, can be sold for $1,500, I'm in.

Corran
19-Nov-2014, 09:44
Everything in focus seems to be about as mainstream as it gets here, Sal. I mean sure, you've got your normal complement of portrait photographs with selective focus, and the soft-focus crowd, but I would say the vast majority of Landscape images in the relevant thread are f/64-inspired, everything-in-focus images.

And by the way, I'm pretty sure your lens has already been made - a 240mm Computar or similar. Maybe exchange the rear element with a 210mm, or whatever that trick is to get a slight variation in FL, if you want a slighter shorter lens. Edit: okay I guess that lens may come in a larger shutter, but it's already f/9. So maybe not, but maybe one of the Kowa lenses or even G-Claron (older Dagor ones?). I just got a 305mm G-Claron that covers 8x20....

Sal Santamaura
19-Nov-2014, 09:50
...I'm pretty sure your lens has already been made - a 240mm Computar or similar. Maybe exchange the rear element with a 210mm, or whatever that trick is to get a slight variation in FL, if you want a slighter shorter lens...Bryan, if you've got a lens (or pair of lenses to be combined) that meet the specifications I laid out, please send a PM advising what you're asking for it/them. Otherwise, I'll stand by the request in post #94. :D

Corran
19-Nov-2014, 09:51
:)
No one is getting my 210mm Graphic Kowa, I'll tell you that..........

Jody_S
19-Nov-2014, 09:54
As with most aspects of life, I'm far outside the mainstream. I've no interest in Bokeh of any kind. I want everything in focus, sharp everywhere. As a result, I noticed but hadn't previously bothered to read your APUG thread. Your posting here prompted me to do so now. Nothing that's been described there is in any way attractive to me.

Here are the specifications for what I'd like to see you design and have made. Focal length 225mm. Corrected for near infinity. Image circle at least 350mm, preferably 400mm. "Circle" defined as edge sharpness near what it exhibits at the center, i.e. not just "illumination" circle. Virtually no falloff when centered on wholeplate film (260mm diagonal), and not much more near the circle's edge. Almost no field curvature or focus shift. Fits in a Copal 1. Speed f/x, where x is as small numerically as you can make it and still fit in the Copal 1. Weight with shutter not more than 500g. All elements multicoated.

If such a package, to include front and rear cells as well as a pair of aperture scales ready to screw onto a Copal 1, can be sold for $1,500, I'm in.

The problem, for a new lens designer, is that last year I was able to buy an older Fujinon-W 210/5.6 (inside lettering) that does most of that. For $65. (before that I had a G-Claron 240/9 that was even better, that I bought for $45). I can't justify spending the additional $1435 (+ a shutter) to get slightly better edge sharpness. For a new LF lens, there needs to be some attribute that cannot be obtained any other way, since even with rare lenses, it's impossible to compete on price when you're dealing with a customer base that trawls eBay for bargains. Granted, it's not the entire LF community that goes bargain-hunting on eBay, but a large % of us do, and that's why the new lens market collapsed. Selling 2-5 lenses per year isn't a business model.

angusparker
19-Nov-2014, 09:57
You are doing nothing wrong. This is exactly the process that led to the development of the Travelwide camera. And we love large format lenses, so press on!

+1

Nodda Duma
19-Nov-2014, 10:00
Sal take the focal length you want and divide by the widest aperture diameter of the Copal 1. That will be your fastest speed possible.

So 225 / 41.6 ~= f/5.4.

With the short focal length and wide field you will have light fall-off due to cos^4 law ( illumination decreases as cos^4(theta) where theta is the incident angle on the film. This is why it's cold in the arctic.). The only way around that is either a) apodization filter -- which reduces the speed of the system, or b) you curve the film plane so the incident angle decreases.

B) is a very interesting approach because it solves two problems. 1 is as described above but also eliminating the need to correct for field curvature by curving the focal plane leads to a significantly less complex lens design for a given level of performance. Trying to take advantage of this fact is currently an active area of research in the optical engineering community: either by producing curved focal plane arrays (Sony just did this) or imaging into a fiber optic taper bonded to an FPA. But of course that doesn't do you any good.

The best approach I have for what you want is to use the Copal 1 as a pinhole camera with the film held on a curved surface (ie with a vacuum chuck). You'll get sharp imagery and even illumination across the entire plane...the pinhole diameter sets the equivalent focal length if I remember correctly. Of course the trade-off is long exposures. That's of course thinking a little outside the box.

Sal Santamaura
19-Nov-2014, 10:03
The problem, for a new lens designer, is that last year I was able to buy an older Fujinon-W 210/5.6 (inside lettering) that does most of that. For $65. (before that I had a G-Claron 240/9 that was even better, that I bought for $45)...For a new LF lens, there needs to be some attribute that cannot be obtained any other way...In my opinion, the "perfect" focal length is one that's 7/8 of a format's diagonal. For wholeplate, this is 225mm. None of the lenses you or anyone else references are 225mm. They're always 210mm or 240mm. And none of them performs the way my post specified they should.

Jason asked, I answered. :D

Nodda Duma
19-Nov-2014, 10:09
Sal I misread your post re the illumination. If it's just over that diagonal that falloff is controlled then physically it's possible. I'll take a look

Sal Santamaura
19-Nov-2014, 10:15
Sal take the focal length you want and divide by the widest aperture diameter of the Copal 1. That will be your fastest speed possible.

So 225 / 41.6 ~= f/5.4.

With the short focal length and wide field you will have light fall-off due to cos^4 law...Jason, thank you for helping me refine my specifications. :D I should have said "as numerically small as possible while fitting in a Copal 1 and also meeting all the other specifications."

I have a 360mm f/10 Fujinon A with 504mm of image circle that performs admirably. If you could design something to meet the specifications in Post #94 that does as well as my 360A, with a maximum aperture closer to its f/10 than the f/5.4 in your calculation, I'd still be very happy. And, if I'm unknowingly asking you to violate the laws of physics, or you can only meet my specifications with a fat-waisted design, I'd even be willing to "grant" more weight and a Copal 3. :D:D

Bernice Loui
19-Nov-2014, 10:20
Hello Jason,

Read that book (excellent) and The Photographic Lens by Sidney Ray. Both not enough technical information to gain further understanding of the intimate details of how this stuff works which means going into the optical text books far deeper.


There have already been an awful lot of LF optics designed and built over the years. Today, it appears the majority of LF folks are using field cameras from 6x9cm to beyond 8"x 10". For these folks they are looking for light weight and small lenses that are installed in modern (Copal or similar shutters). Other basic features appears to be greater than 80 degrees of useable image circle (there will be light fall off an it appears most are OK with it), "sharp" how ever that is defined, multi coated, exotic glass and all that stuff that has been learned as marks of excellence from publications, advertising, hear-say, internet posting and all that. This is where the 165mm lens currently being worked on could fit. Yet, there were a good sized body of LF optics made over the years that already fit these requirements quite well. It is a matter of finding one, overall condition and cost. Marketable lenses that would fit into this group would be lens like the Cooke convertible in a casket set, Dagor, Protar, and a host of others that were of modest full aperture (about f6.3 to f10) to limit their physical size making them reasonable to travel with.

Another group of LF folks is involved with selective focus better known as soft focus or Pictorialism. There was a time not too long ago when soft focus lenses where worth scrap (IMO due to the group f64 movement). Lenses like the Kodak Portrait Ektar in shutter sold for no more than $50 USD and they were purchased re-using the Ilex# 5 shutter and the lens element tossed in the trash. Today, these Kodak Portrait Ektars have gone up in value by no less than a factor of 10X or more as this style of image making has returned in various degrees. Due to the limited number of surviving soft focus lenses some of which date back to before 1900, some have become extremely valuable monetary wise due to their rarity. Reproduction of oft focus lenses like the Pinkham Smith Visual Quality lens (current Cooke PS945), Veritar, Kodak Portrait, Busch Nicola Perched, Imagon, Universal Heliar, Cooke Portrait (with the knuckle) These and others have become desirable and marketable. I do have an opinion about how these lensed are to be used, they should be used with a film format no smaller than 5x7, ideally prints are contact printed, lenses should have a working aperture of f5 to f8 and of longer than normal format focal length. All this means BIG lenses, it also means BIG shutters and shutters larger than the coveted Copal# 3. Speciality lenses with a following and a real need.

There speed seekers who are looking for large aperture LF optics of f3 and larger for any given focal length. Most these are of a double Gauss formulation like Planar, Xenotar, Kodak Aero Ektar and others. Some of these LF optics have become coveted like the Zeiss Planar, Schneider Xenotar (IMO cult lens). There is a place for LF lenses like this, they are a specialty and will be physically large due to their large aperture limiting their specifications if they are to be used in the desirable Copal# 3 shutter.

Modern LF wide angle lenses have done well enough with introduction of the Schneider Symmar XL. It has been a very reasonable trade off of view angle, image circle, performance and size. Others like the Grandagon, Super Angulon, SW Nikkor does very well too except the most common complaint, they are TOO BIG.

In recent years Ultra Large Format has returned with alternative process print making via contact prints . This has increased the demand for long focal length lenses with 80 degrees or more of usable image circle. Historic lenses like 19" Dagor, 30" or longer process lenses and others are what this group seeks. Problem and limitation again is the desirable Copal# 3 shutter.


Then there are the collectors that collect rarities and all that.

In most all cases, out of focus rendition aka Bokhen matters. This means correction of aberrations and using an iris that is round, not an iris with 5-7 blades common to many modern shutters. Color rendition appears to matter much less these days due to the slow and dying off LF color film availability and processing. Contrast and flare, these are an aspect of lens personality that is often fitted to the end image maker.

This is much the summary of the current state of LF optics, what has been done, what the market might need and what is desirable. Me, I'm quite content with the set of Kodak Ektars, Goerz Dagors & Artars, modern wide angle lenses and soft focus lenses. Most are used with a Sinar shutter to remove the problem of between the lens shutters that IMO is too limiting in many ways.


Bernice




Oh and you should read "The History of the Photographic Lens" by Rudolph Kingslake if you haven't yet.

Regards,
Jason

angusparker
19-Nov-2014, 10:25
Perhaps it would be worth coming up with a list of different lenses with criteria like, FL, Max Aperture, Shutter Size, Weight, Filter Size, Image Circle at F22, Price range and using the forum poll function to let the community vote on the option they would likely buy. It might narrow down the universe of possibilities. If production runs are around 100 lenses I suspect there are a number of lenses that might have a market.

Old-N-Feeble
19-Nov-2014, 10:37
I'd be extremely interested in coated clones of the Portrait Ektar in 135mm, 200mm, 300mm and 450mm focal lengths. These are easy to design (for you anyway) and relatively cheap to manufacture compared to more complicated designs. I'd prefer they fit in old Ilex shutters because I like the nice round apertures. I'd rather not deal with slip-on apertures like the Imagons use but that would be okay too. I like the OOF renderings of the Portrait Ektar and Imagon lenses but I don't much care for single-element meniscus lenses.

StoneNYC
19-Nov-2014, 10:44
Sort of part of what Bernice said.

A question.

Is there a way to replace the aperture blades in a modern copal shutter and replace them with more blades to create a more circular Bokah pattern?

goamules
19-Nov-2014, 10:54
This talk is good. But it's still just dreaming, as is the recent Collodion B'stds Facebook planning to make a "new Petzval 8x10 lens." There, everyone discussed the focal length, speed, and barrel materials, and came up with a pretty good consensus. Which is a very difficult thing to do. And why design is fun, it's all just an exercise unless the item can be manufactured at a price the market will bear. Like Dan researched, and a lot of us know, it's easy to get a 50 or 150 year old lens, made by a company that specialized in their mass production, for just a couple hundred dollars. With the Petzval project (which no one here mentioned), the driving goal was to make a Dallmeyer 3B clone, but get this, cheaper than the originals sell for. That might be possible, it's the highest priced cult Petzval out there. But it's pretty easy to buy a vintage other petzval, probably a lot cheaper than a new one can be made.

Is there a market? Would there be buyers for 5, 25, 300 new lenses? I guess I think in traditional ways about business startups, where you create a great product, THEN if you're lucky, the buyers come. With Kickstarter, you finance the endeavor up front, with a lot of dreamers willing to throw $20 or $50 into the wind. Kind of like handing a twenty to the homeless person at the light, it makes you feel good, and you don't care what happens with the money.

So, will building a lens that isn't available now going to be useful to more than a handful of Kickstarter backers? What if it's more expensive than comparable vintage ones? Does it matter? Lomo was extremely successful with their small "petzval" that really isn't. Are they in fulltime production now? Did the people that paid $500 or whatever they ended up costing happy they didn't just buy an antique one? Rhetorical questions.....

Nodda Duma
19-Nov-2014, 11:04
Jac, multiplying elements' radii, thicknesses, and diameters, and intercell spaces by a constant multiplies focal length by the constant.

To add..the aberration values will scale up as does the weight (weight increases as volume).

So increasing the focal length by 10x enlarges a 10um blur size to 100um.

Dan Fromm
19-Nov-2014, 11:10
And volume scales with the cube ...

hoffner
19-Nov-2014, 11:18
Just a thought - where will you get new Copal shutters needed for the lenses? A Kickstarter project for them will precede the lens Kickstarter?

jb7
19-Nov-2014, 11:20
Hello and welcome-

I look forward to your input here, and will be following this discussion with interest-

This forum (and others like it) may be useful as a tool for market research, but ultimately you're just going to have to make a call, and go for it. The responses that are made on forums account for a tiny proportion of the potential market; there are many more who don't engage with social media at all.

I think your work on a wide angle 8x10 lens is admirable, though just a little more room for movements might make it a lot more attractive-
in particular, for the contact printers, a gradual falloff in resolution while avoiding mechanical vignetting would perhaps be useful.

Precision machining the barrels for use in a copal 1 sounds like it could be expensive for small runs, no?

Since you're here, there's something I've been thinking about recently-
What would be your opinion on the optically clear casting resins?

I know there would be problems; distortion of the thicker elements during cooling might be the most major one, and finding resins of different and consistent refractive indices might prove difficult. However, tooling and production would be a lot less expensive, leading to the potential for a broader range of designs.

I know nothing about these things, just wondering aloud. There will be many who will expect their lenses to be made of glass, and will not consider an alternative. Glass is more robust, of course, but is there any other reason why optically clear castable resins should not be considered?

Look forward to following your progress-

joseph

Sal Santamaura
19-Nov-2014, 11:35
Just a thought - where will you get new Copal shutters needed for the lenses? A Kickstarter project for them will precede the lens Kickstarter?Yet another positive post from you.

There's no need for new Copal shutters. Plenty of good ones around. That's why my request was only for cells and scales to fit existing Copal shutters.

Nodda Duma
19-Nov-2014, 11:42
Thanks guys all good points. Thanks to Bernice for summarizing the state of the market.

Of course, when the rubber hits the road it's all about cost. Not just cost of a single lens but the cost curve...what price point will the market bear and will the market support that volume? I'm not looking to make money and I'm certainly not in a position to make them for free.

Fortunately it doesn't cost anything (except time) to get a design to the point where it can be quoted. That's when the true go / no go decision is made... When I can say that might be affordable or ugh, it's a beautiful lens but it'll never sell. What can I do to reduce cost? It's a process familiar to anyone who's developed product.

The cost is really not due to the glass. Glass is cheap. It just scales by volume. It's the cost of the labor that adds up. So a design that may cost $2500 per unit for 2 sets (you never order one) may only be $1000 per unit for a qty 20 order and $400 in qty 100. That's because the shop can block up several lenses and polish the radii out all at once (look up "Fabrication Methods for Precision Optics" by Hank Karow. That is the bible for optical shops). Anything that reduces touch labor reduces cost.

But I have to start somewhere to get to that point.

hoffner
19-Nov-2014, 12:04
Yet another positive post from you.

There's no need for new Copal shutters. Plenty of good ones around. That's why my request was only for cells and scales to fit existing Copal shutters.

You mean - we will need to buy an old lens to get the shutter for the new one? And the new Biogon or whatever will be sent to us in lens cells only?
Fun stuff. Not exactly a positive post though.

adelorenzo
19-Nov-2014, 12:12
Could everyone please stop feeding the troll and, more importantly, don't quote him? I'm sure I'm not the only one who has him on the ignore list.

Bernice Loui
19-Nov-2014, 12:17
That would be a rather complex and very involved project which involves designing and making iris blades, the operating cam and all related, getting all these precision bits made and installed into the Copal shutter.


If a round iris is really wanted, consider an older yet much despised and dis-liked Compur shutter that has a round iris or better yet, IMO one of the best shutters made the Compound.

For images made with the lens stopped down to f22 and smaller iris shape has less effect as the goal of stopping that far down is to achieve everything in the image in "focus". Iris shape matters more when the lens is used near full aperture.

Carted around a Hasselblad for decades until recently, the most irritating feature of the Zeiss lenses is the 5 bladed iris which would make it's appearance in images when least wanted. This is where the choice was made to eradicate 5-7 bladed iris lenses from the set with exception of modern wide angle lenses which are used stopped down no less than f16 most all of the time.

IMO, the 5-7 bladed iris and most related is a result if the f64 movement and their influence the idea that every area of the image to be in sharp focus. In time, this became the accepted norm for photographic images. Yet, not all agreed on this. It appears in recent years, the value of out of focus rendition aka Bokhen has become a factor. Notable, the major camera-lens manufactures have begun to offer much rounder iris as a selling feature in their most recent offerings.

Much of this is fashion and marketing, the knowledge of how these factors are known, it is a matter of what the market is looking for and what manufactures can sell in quantity for profit.


Bernice



Sort of part of what Bernice said.

A question.

Is there a way to replace the aperture blades in a modern copal shutter and replace them with more blades to create a more circular Bokah pattern?

hoffner
19-Nov-2014, 12:22
Thanks guys all good points.

I'm not looking to make money and I'm certainly not in a position to make them for free.

Fortunately it doesn't cost anything (except time) to get a design to the point where it can be quoted.


Unfortunately, we cannot take pics with a design printed on paper, (would be nice though) we still need that lens made of glass.





The cost is really not due to the glass. Glass is cheap. It just scales by volume. It's the cost of the labor that adds up. So a design that may cost $2500 per unit for 2 sets (you never order one) may only be $1000 per unit for a qty 20 order and $400 in qty 100. That's because the shop can block up several lenses and polish the radii out all at once (look up "Fabrication Methods for Precision Optics" by Hank Karow. That is the bible for optical shops).

Thanks goodness! Make as many as possible at once, I won't even bother to look it up. I trust you.

Mark Sawyer
19-Nov-2014, 12:25
Sal take the focal length you want and divide by the widest aperture diameter of the Copal 1. That will be your fastest speed possible...

You can get a bit more out of it depending on magnification from the front cell. Nitpicking, I know, but someone has to do it...


One interesting thing about the Cooke triplet is that you (well, a lens designer) can get to the Cooke triplet design form starting from a Petzval lens by simply increasing the fields that it corrects for and letting the glass types move into each other during optimization. I figured that out recently...before that I kind of viewed the Cooke triplet as a unique offshoot which didn't tie into anything else. But apparently it does, even if Taylor didn't know it at the time...

Not sure I'd go along with that, but out of curiosity, could you make an achromatic Petzval using a single front element instead of the achromatic doublet up front? It could reduce manufacturing costs significantly.

Bernice Loui
19-Nov-2014, 12:25
For most cost is a extremely serious consideration. Being a designer of tech stuff by day, there is a very good understanding of the cost involved. I'm figuring no less several thousands of dollars just to get started on making one prototype. After that volume production of say 100 units might lower the cost to maybe $1500 per lens with shutter and likely more. If the optics you're designing can be produce for lower, there will be a market, except the cost and availably of shutters will be THE obstacle. Offering lenses in barrel goes a long way to solving this problem except most LF image makers want lenses in a modern shutter as a rule.

This is IMO, why the four majors Fuji, Nikon, Schneider, Rodenstock has given up on the LF optics market. Adding to this problem is the glut of modern plasmas on the used market driving their market price down.


Bernice


Thanks guys all good points. Thanks to Bernice for summarizing the state of the market.

Of course, when the rubber hits the road it's all about cost. Not just cost of a single lens but the cost curve...what price point will the market bear and will the market support that volume? I'm not looking to make money and I'm certainly not in a position to make them for free.

Fortunately it doesn't cost anything (except time) to get a design to the point where it can be quoted. That's when the true go / no go decision is made... When I can say that might be affordable or ugh, it's a beautiful lens but it'll never sell. What can I do to reduce cost? It's a process familiar to anyone who's developed product.

The cost is really not due to the glass. Glass is cheap. It just scales by volume. It's the cost of the labor that adds up. So a design that may cost $2500 per unit for 2 sets (you never order one) may only be $1000 per unit for a qty 20 order and $400 in qty 100. That's because the shop can block up several lenses and polish the radii out all at once (look up "Fabrication Methods for Precision Optics" by Hank Karow. That is the bible for optical shops). Anything that reduces touch labor reduces cost.

But I have to start somewhere to get to that point.

Nodda Duma
19-Nov-2014, 12:25
jb7: yup.

The metal can be expensive if it's complicated. If it's simple than not as much so. Just have to quote it out.

Optical resins: You're talking about plastic optics. There's a place for them and it's certainly a good one, but here's the nub: Prototype molds----just the molds for making up to 1000 lenses---start at $10,000 and full rate production molds (for millions of lenses) start at $100,000. Once that is paid for then the plastic optics are cheap.

There are similar production methods for molded glass...useful if you want to incorporate an aspheric surface.

The really cool thing about Kickstarter is that I can set a threshold and if it's not met then no harm no foul. It is pretty easy to set a quantity and per unit cost goal without wasting anyone's money if the goal is not met.


Since design is cheap we'll just keep at it until the market itself says nice try.

-Jason

Old-N-Feeble
19-Nov-2014, 12:28
<snip> Plenty of good ones (Copal shutters) around. That's why my request was only for cells and scales to fit existing Copal shutters.

Right... We could even have dual or triple scales made to share one shutter with several sets of cells. Still... I'd prefer old Ilex shutters with those beautiful round apertures because I like to add depth with some OOF areas and modern shutters with minimal aperture blades just can't always do that with smoothness and finesse.

Nodda Duma
19-Nov-2014, 12:33
What's the feeling on electronic shutters? No moving parts (not counting a manually set aperture), accurate timing but requires electricity? Could be made in standard sizes up to super duper size if you were willing to pay enough.

Old-N-Feeble
19-Nov-2014, 12:39
What's the feeling on electronic shutters? No moving parts (not counting a manually set aperture), accurate timing but requires electricity? Could be made in standard sizes up to super duper size if you were willing to pay enough.

Fine with me. In my area cold is not a concern for battery use but even if it was I could adapt by adding a remote battery holder to keep the batteries inside my jacket and/or use lithium batteries. I still want extremely round apertures though. If you're designing from the ground up then drop in aperture discs are fine with me.

Mark Sawyer
19-Nov-2014, 12:47
Actually, a decent shutter for larger lenses would be more in demand than most lenses...

Sal Santamaura
19-Nov-2014, 12:56
What's the feeling on electronic shutters?...In the words of Bartleby the Scrivener, "I would prefer not to."


...No moving parts (not counting a manually set aperture)...Unless you're talking about the holy grail of electronically controlled crossed polarizers (which, as far as I know, haven't yet been developed to a level of photographic shutter usability), there'd better be moving parts beyond the aperture control. :)


...Could be made in standard sizes up to super duper size if you were willing to pay enough.There are already electronic shutters on the market in at least some smaller standard sizes. I'm neither interested in paying nor willing to pay the substantial difference in price between them and their mechanical Copal equivalents.

Bottom line: We have all the shutters we need. Outside the studio, simple, reliable mechanical Copal shutters are vastly preferable.

Ken Lee
19-Nov-2014, 13:05
After this thread has run its course and become long-winded, it might be helpful to create a new thread whose type is a poll.

With a finite list of discrete options, people can cast their vote and you can more quickly gauge their interest.

Dan Fromm
19-Nov-2014, 13:11
What's the feeling on electronic shutters? No moving parts (not counting a manually set aperture), accurate timing but requires electricity? Could be made in standard sizes up to super duper size if you were willing to pay enough.

There has to be a reason why electronically-timed leaf shutters have relatively low fastest speeds. Are you aware of the shutter used in the AGI F.135 aerial camera? The shutter was opened/closed by a lever that was whacked by small opposed solenoids. Very light blades, light lever, no hold current. I don't know the range of shutter speeds, sorry.

richardman
19-Nov-2014, 13:14
I was shocked, SHOCKED, I tell you.... that the question regarding where to source shutters is actually a good one. Fortunately, I believe Copal 1 is much easier to find than #3. I have SK Grimes to mount a barrel lens but I can't afford yet another Copal 3 so now two mounted ex-barrel lens share one shutter, which is of course not a bad thing at all. Save on weight and all that ;)

Ignore list eh? I need to find that feature.

Jac@stafford.net
19-Nov-2014, 13:16
Redirection

Perhaps instead of a complex lens, make a real niche product: apodization filters that fit right behind a diaphragm aperture. Waterhouse type stops with the filter might suffice, and if a shutter is desired it could be added at the end of the unit with adapters.

Certainly, LF lenses do not have over-acute correction (as recent Leica lenses do making for terrible OOF) so they don't suffer from other than poor diaphragm shapes, but still an apodization filter is an idea to pursue.


Dan Fromm: " Are you aware of the shutter used in the AGI F.135 aerial camera? "

Yes, are you familiar with the shutter used in some 8x10" NASA cameras that uses a dual guillotine shutter (perhaps 'scissors' type is more appropriate) with a rotary solenoid? It is a BTL shutter used with some Metrogon lenses. I have some photos of it on one of the off-line backups if needed.

Sal Santamaura
19-Nov-2014, 14:04
Could everyone please stop feeding the troll and, more importantly, don't quote him? I'm sure I'm not the only one who has him on the ignore list.The troll you're referring to has become somewhat adept at posting artificially sweetened things as a means of masking his apparent desire to undermine and debase this forum. He's not joined my very small list of ignored users because I feel it important to make clear for those who might not understand the situation that his posts are, in general, unworthy of attention.

My apologies in advance for the following quotes.


You mean - we will need to buy an old lens to get the shutter for the new one?...Most everyone here has quite a number of large format lenses. Swapping them between shutters is relatively common. There are even brand new Copal shutters still available, albeit at increased prices:


http://www.skgrimes.com/products/new-copal-shutters/standardcopals

In the worst case, as time passes, those new to the field might indeed need to buy used shutters, whether attached to a lens or not.


...And the new Biogon or whatever will be sent to us in lens cells only?...That's what I requested. With matching engraved scales for Copal shutters, of course.


...Fun stuff...Glad you find the possibility as enjoyable as I do.



...Not exactly a positive post though.It would be difficult to imagine anything more positive for large format photography in 2014.

Will Frostmill
19-Nov-2014, 14:18
it would be difficult to imagine anything more positive for large format photography in 2014.

this.

Will Frostmill
19-Nov-2014, 14:22
What's the feeling on electronic shutters? No moving parts (not counting a manually set aperture), accurate timing but requires electricity? Could be made in standard sizes up to super duper size if you were willing to pay enough.
Sounds good to me, but of course the two things I always want to know are: what's the highest speed and what's the flash synch speed. And, ya know, can I afford it.

djdister
19-Nov-2014, 14:37
Any "new" shutter will need to comply with the market rules that have driven the computer industry- better, faster, cheaper, or else it won't fly.

hoffner
19-Nov-2014, 15:22
What's the feeling on electronic shutters? No moving parts (not counting a manually set aperture), accurate timing but requires electricity? Could be made in standard sizes up to super duper size if you were willing to pay enough.

Any more details on the shutter?

StoneNYC
19-Nov-2014, 15:23
What's the feeling on electronic shutters? No moving parts (not counting a manually set aperture), accurate timing but requires electricity? Could be made in standard sizes up to super duper size if you were willing to pay enough.

Can you design one that is light, will function in -20 degree (Fahrenheit) weather and will have solar cells to recharge the battery while you are using it in sunlight when you're in the woods for a week or more, electricity issues can kill your whole trip, carry lots of batteries is not convenient, same goes for in-heat locations where temps hit 120 degrees (Fahrenheit) will the batteries explode in your case/pack? etc.

Not saying it's impossible just pointing out real world function over the studio.

I agree let's not feed the troll. But I do believe addressing the issue of copal shutter availability long term is important. Hacking an old lens isn't always an option and not everyone has expendable lenses or extra cash to buy them, plus think of all the good disassembled lenses by anyone wanting this new lens.

Ironically the shutter issue may be much more difficult than the lens design/production issues.

At $400 I'll take one whatever it is ;)

hoffner
19-Nov-2014, 15:28
Can you design one that is light, will function in -20 degree (Fahrenheit) weather and will have solar cells to recharge the battery while you are using it in sunlight when you're in the woods for a week or more, electricity issues can kill your whole trip, carry lots of batteries is not convenient, same goes for in-heat locations where temps hit 120 degrees (Fahrenheit) will the batteries explode in your case/pack? etc.

Not saying it's impossible just pointing out real world function over the studio.

I agree let's not feed the troll. But I do believe addressing the issue of copal shutter availability long term is important. Hacking an old lens isn't always an option and not everyone has expendable lenses or extra cash to buy them, plus think of all the good disassembled lenses by anyone wanting this new lens.

Ironically the shutter issue may be much more difficult than the lens design/production issues.

At $400 I'll take one whatever it is ;)

Com'on, no need to be so negative. The best thing that happened to the LF photography in 2014 cannot be so impossible to see. If Sal can have enough shutters, so can we.
Yes, we can!

Sal Santamaura
19-Nov-2014, 15:31
...not everyone has expendable lenses or extra cash to buy them..."Everyone" doesn't need to have expendable lenses or extra cash to buy them. Only the number of potential customers (however many that is) Jason would need to bring a lens cell set to market. :D

Old-N-Feeble
19-Nov-2014, 15:33
hoffner... maybe nothing will come from the OP's post. So what? At least he has the desire and interest and drive to consider making a contribution. That's more than either you or I or most others have. All you're doing is trying to beat him down. What is your motivation... to kill the future of large format analog photography?

StoneNYC
19-Nov-2014, 15:41
"Everyone" doesn't need to have expendable lenses or extra cash to buy them. Only the number of potential customers (however many that is) Jason would need to bring a lens cell set to market. :D

You know what I mean :-p

It's ok, when I buy the cells from him you can send me an extra shutter please :)

I don't mean to be negative, I'm excited about this, just also wanted to point out the reality.

The one thing that has to be realized is that studio photographers are all digital, and I'm using "all" loosely, but let's face it the majority of studio photographers who are using the work to make money are going to be shooting visual, so the majority of those interested in a lightweight brand-new lens will not be shooting in studio and will be using these in the field, because of this I need for a non-electrical shutter or some kind of miracle electrical shutter that never breaks down and never runs out of juice would be needed.

hoffner
19-Nov-2014, 15:42
hoffner... maybe nothing will come from the OP's post. So what? At least he has the desire and interest and drive to consider making a contribution. That's more than either you or I or most others have. All you're doing is trying to beat him down. What is your motivation... to kill the future of large format analog photography?

I tell you, frankly, I have that horrible feeling, that knowing how to operate an optical design program is not enough to put LF lenses on the market for us. I would have some difficulties to explain the feeling in words but, frankly again, who would produce the glass, assemble it and sell it? An optical amateur ( in the true sense of the word)? Does he have the machinery, the special space to put it in, the labour, etc. etc.
Frankly, I start to doubt. Hope someone knows better than me. The electronic shutter is so intriguing too, would love to know more about it in details. Wouldn't you?

Old-N-Feeble
19-Nov-2014, 15:43
All... please quote me in full or add a <snip> before and after text quoted by me. I don't disagree with Sal... I just want the full meaning of my statements fully understood.

Nodda Duma
19-Nov-2014, 15:43
Well Stone that's less stringent than the requirements I design optics for in my day job....except even our customers understand batteries are required in the field. Those guys end up just packing in lots of batteries.... But of course their batteries are paid for by the taxpayer.

Loud and clear that shutters are a problem and there's no real good answer since market demand can't drive the cost down. I'll keep my eyes open for workable solutions but don't hold your breath. Has there ever been something like a curtain shutter for attachment on the back end of the lens? Like in the 35mm world.

Old-N-Feeble
19-Nov-2014, 15:45
I tell you, frankly, I have that horrible feeling, that knowing how to operate an optical design program is not enough to put LF lenses on the market for us. I would have some difficulties to explain the feeling in words but, frankly again, who would produce the glass, assemble it and sell it? An optical amateur ( in the true sense of the word)? Does he have the machinery, the special space to put it in, the labour, etc. etc.
Frankly, I start to doubt. Hope someone knows better than me. The electronic shutter is so intriguing too, would love to know more about it in details. Wouldn't you?

Of course, you may be right. I don't think anyone is arguing against that possibility (or probability). But, hoffner, you're being far too negative. You see your posts as being "realistic". How about being a bit more "hopeful" without beating someone down in the process? "WHAT IF" and by that I mean "WHAT IF"??

Sal Santamaura
19-Nov-2014, 15:47
...please quote me in full or add a <snip> before and after text quoted by me...I just want the full meaning of my statements fully understood.The "..." before and after partial quotes is functionally equivalent to "<snip>."

Old-N-Feeble
19-Nov-2014, 15:48
Well Stone that's less stringent than the requirements I design optics for in my day job....except even our customers understand batteries are required in the field. Those guys end up just packing in lots of batteries.... But of course their batteries are paid for by the taxpayer.

Loud and clear that shutters are a problem and there's no real good answer since market demand can't drive the cost down. I'll keep my eyes open for workable solutions but don't hold your breath. Has there ever been something like a curtain shutter for attachment on the back end of the lens? Like in the 35mm world.

If that's really a problem then please consider drop shutters.:)

Old-N-Feeble
19-Nov-2014, 15:49
The "..." before and after partial quotes is functionally equivalent to "<snip>."

Please forgive my ignorance... I'm an old fart.

Ken Lee
19-Nov-2014, 15:50
If I have deleted too many posts - or not enough - please overlook it. Moderators have limited time.

If you can contribute to a thread in a polite and respectful manner, please feel free. If not, please resist the temptation.

Members who persist in being rude first get warned, then get banned for periods of time, then get kicked off the forum permanently.

Old-N-Feeble
19-Nov-2014, 15:54
If I have deleted too many posts - or not enough - please overlook it. Moderators have limited time.

If you can contribute to a thread in a polite and respectful manner, please feel free. If not, please resist the temptation.

Members who persist in being rude first get warned, then get banned for periods of time, then get kicked off the forum permanently.

Me again?:(

hoffner
19-Nov-2014, 15:55
Of course, you may be right. I don't think anyone is arguing against that possibility (or probability). But, hoffner, you're being far too negative. You see your posts as being "realistic". How about being a bit more "hopeful" without beating someone down in the process? "WHAT IF" and by that I mean "WHAT IF"??

You see your posts are being more "realistic" because they are positive? Positive or negative does not create any realism, I would say. Frankly, I have my doubts based on logical reasons and optimism alone, not even enthusiasm of masses doesn't make my doubts less prevalent. Anyway, thanks for the friendly exchange. Still would like to know more technical bases and details for the electronic shutter, in all sizes and speeds - must be a technical achievement beyond today's capacities. But again, the horrible doubts come to me.

Sal Santamaura
19-Nov-2014, 15:59
Me again?:(I can't speak for Ken, but suspect the answer is "far from it."

Nodda Duma
19-Nov-2014, 16:01
Whether Jason can bring product to market remains to be seen.


The next hurdle on the 165mm f/6.3 lens for 8x10 is tolerance analysis. That is, making sure it can be built. Actually, I'm not worried about that. At the ray angles I see in the design I don't expect any issues. If I can't just drop the lenses in then I'm not worth my salt as a designer. My real concern is cost just like you guys.

Old-N-Feeble
19-Nov-2014, 16:01
You see your posts are being more "realistic" because they are positive? Positive or negative does not create any realism, I would say. Frankly, I have my doubts based on logical reasons and optimism alone, not even enthusiasm of masses doesn't make my doubts less prevalent. Anyway, thanks for the friendly exchange. Still would like to know more technical bases and details for the electronic shutter, in all sizes and speeds - must be a technical achievement beyond today's capacities. But again, the horrible doubts come to me.

Possibilities often don't match probabilities. That's 99.99 percent of life and nearly all of whatever has been invented... but FAR more importantly... follow-through makes things happen!! Have you ever told your young child he "can't"? Why would you do that?? And should we do that to each other? Are we to limit progress this way... really?

Ken Lee
19-Nov-2014, 16:04
Me again?:(

No :)

The vast majority of forum members are civil and courteous at all times, but now and then it's helpful to remind the others.

Old-N-Feeble
19-Nov-2014, 16:04
I can't speak for Ken, but suspect the answer is "far from it."

You don't know my past with folks who are no longer mods here. :D


No :)

The vast majority of forum members are civil and courteous at all times, but now and then it's helpful to remind the others.

Thanks, Ken. :)

hoffner
19-Nov-2014, 16:05
Possibilities often don't match probabilities. That's 99.99 percent of life and nearly all of whatever has been invented... but FAR more importantly... follow-through makes things happen!! Have you ever told your young child he "can't"? Why would you do that?? And should we do that to each other? Are we to limit progress this way... really?

Yes, we can!

Lachlan 717
19-Nov-2014, 16:05
Well Stone that's less stringent than the requirements I design optics for in my day job....except even our customers understand batteries are required in the field. Those guys end up just packing in lots of batteries.... But of course their batteries are paid for by the taxpayer.

Loud and clear that shutters are a problem and there's no real good answer since market demand can't drive the cost down. I'll keep my eyes open for workable solutions but don't hold your breath. Has there ever been something like a curtain shutter for attachment on the back end of the lens? Like in the 35mm world.

I actually think that the whole "lack of shutters" theory is a bit overstated. There are plenty of shutters out there with rubbish lenses and/or undesirable lenses attached to them. These lenses generally don't command high prices, so buying them is not going to cost more than any shutter that you might be able to develop/source.

The key point is that, if you're intending to use a shutter, it will cost $$ regardless of which one. Perhaps go to the trouble of getting a Sinar shutter and a universal iris and be done with Copals once and for all?

It also strikes me that there are still ample numbers of lens repairers across the globe. You just need to look at how many people discuss getting lenses CLA'ed. Repairing shutters is not going to be too hard to have done (obviously within the limits of the required repair).

Keep in mind that this project will probably not be generating new lenses in the thousands. As such, there will not be a huge spike in demand for shutters.

hoffner
19-Nov-2014, 16:07
No :)

The vast majority of forum members are civil and courteous at all times, but now and then it's helpful to remind the others.

Please, leave him alone. Old-N-Feeble is surely a good guy. Take my word for it.

Jac@stafford.net
19-Nov-2014, 16:15
[...]carry lots of batteries is not convenient)

When you are in the wilderness your lunch and water even for one day occupies far more space and weight than a few spare batteries. As your days continue, they occupy even less of the total 'burden'. Me thinks Metro New Yorkers imagine too much.

StoneNYC
19-Nov-2014, 16:48
Well Stone that's less stringent than the requirements I design optics for in my day job....except even our customers understand batteries are required in the field. Those guys end up just packing in lots of batteries.... But of course their batteries are paid for by the taxpayer.

Loud and clear that shutters are a problem and there's no real good answer since market demand can't drive the cost down. I'll keep my eyes open for workable solutions but don't hold your breath. Has there ever been something like a curtain shutter for attachment on the back end of the lens? Like in the 35mm world.

Thanks Nodda,

I don't mean to be a nay sayer, it's not the cost of the batteries it's the added bulk and weight of them, I don't bring a pack mule ;)

Your job must be very interesting for sure.

StoneNYC
19-Nov-2014, 16:50
When you are in the wilderness your lunch and water even for one day occupies far more space and weight than a few spare batteries. As your days continue, they occupy even less of the total 'burden'. Me thinks Metro New Yorkers imagine too much.

I'm in CT not NYC :-p

Yes but I don't want to sacrifice some GORP for the battery space.

Plus even more than the space/weight is the fact they don't work in sub-zero conditions, but mechanical shutters do.

Dan Fromm
19-Nov-2014, 16:54
Well Stone that's less stringent than the requirements I design optics for in my day job....except even our customers understand batteries are required in the field. Those guys end up just packing in lots of batteries.... But of course their batteries are paid for by the taxpayer.

Loud and clear that shutters are a problem and there's no real good answer since market demand can't drive the cost down. I'll keep my eyes open for workable solutions but don't hold your breath. Has there ever been something like a curtain shutter for attachment on the back end of the lens? Like in the 35mm world.

Thornton-Pickard roller blind shutter. And there were other similar shutters. Not made in the US, AFAIK.

koh303
19-Nov-2014, 17:24
My two drachmas:

Recently at photokina i discussed shutters with all rodenstock, schneider, cambo and a couple of others in field not directly related to consumer photography and there is a clear answer - there are plenty of shutters left, stocked by all of the above companies, including spare parts, service parts etc.

As they have all, almost completely moved their interest to medium format capture devices, there is almost no market for larger shutters, and crazy coverage angles. Bob solomon explained once why there is no more need for huge shutters like copal 3 any longer, and i feel if they could, lens makers would make lenses smaller, and simpler then what they are already doing.

In some cases they are also avilable for purchase directly with no lens.

The real problem i see is the price. Shutters are extraordinarily expensive, especially when compared to their extrmely
ong service life, prolifiration in the used market, and thus a relativley low market value when sold used.

So, if someone wanted to make a new lens in shutter, the shutters are there to be had (copal/mechanical or otherwise), but while as i understabd from this thread the actual cost to make the lens might be low, the shutters, new ones that is, never will be.

There is something to be said about re using existing shutters for such a project, but whoever does that will need to manually purchase, examine and adjust them one by one. On a scale of 100 producton lenses, that is not a big deal. On a scale of 1000 it would become a logistical nightmare.

Either way i am all for the general idea of a new lens, and would support a KS project for such a thing at a heart beat, just as much as i support the producton of new LF cameras.

Sal Santamaura
19-Nov-2014, 17:44
...there are plenty of shutters left...In some cases they are also avilable for purchase directly with no lens...For example, see the link I included in post #129.

Nodda Duma
19-Nov-2014, 18:10
My thinking is just supply the optics and mounting to standard shutter and let you guys supply your own. I could give the option of supplying a shutter but it's cheaper for you guys and easier for me not to have to buy them for you.

Perhaps I'd include a simple spacer or a manual aperture (like from Edmund Optics) so you could use it with your MF flip mirror camera if you hadn't won that eBay auction for a proper shutter yet.

And then I suppose add option to buy one for you but that's just kind of silly.

Sal Santamaura
19-Nov-2014, 18:15
My thinking is just supply the optics and mounting to standard shutter and let you guys supply your own. I could give the option of supplying a shutter but it's cheaper for you guys and easier for me not to have to buy them for you...Cooke does it both ways with the XVa:


http://www.badgergraphic.com/opencart/index.php?route=product/product&path=3_246&product_id=3034

http://www.badgergraphic.com/opencart/index.php?route=product/product&path=3_246&product_id=3948

Nodda Duma
19-Nov-2014, 18:18
Holy crap those are expensive !!


Bet they polish them out 1 at a time. 8 weeks is typical delivery time for a lens order.

Jac@stafford.net
19-Nov-2014, 18:22
I'm in CT not NYC
Plus even more than the space/weight is the fact they don't work in sub-zero conditions, but mechanical shutters do.

I doubt that you regularly work in sub-zero (F) conditions.

BTW, I lived in Connecticut for many years.

Jac@stafford.net
19-Nov-2014, 18:28
BUMP

Redirection

Perhaps instead of a complex lens, make a real niche product: apodization filters that fit right behind a diaphragm aperture. Waterhouse type stops with the filter might suffice, and if a shutter is desired it could be added at the end of the unit with adapters.

Certainly, LF lenses do not have over-acute correction (as recent Leica lenses do making for terrible OOF) so they don't suffer from other than poor diaphragm shapes, but still an apodization filter is an idea to pursue.



Yes, are you familiar with the shutter used in some 8x10" NASA cameras that uses a dual guillotine shutter (perhaps 'scissors' type is more appropriate) with a rotary solenoid? It is a BTL shutter used with some Metrogon lenses. I have some photos of it on one of the off-line backups if needed.

richardman
19-Nov-2014, 18:46
Holy crap those are expensive !!


Bet they polish them out 1 at a time. 8 weeks is typical delivery time for a lens order.

Jason, scale that puppy down to 4x5, and you have a winner. Check out the other thread with the lens name in the subject to see samples.

AFAIK, Cooke makes this and the PS945 a batch at a time. When they are sold out, then they would decide whether to make a new batch or not.

Nodda Duma
19-Nov-2014, 19:39
Apodizing filters:

http://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1163&gclid=CjwKEAiAnLGjBRCk_I-y_4iAmB0SJADGjWWzSsgR5ks8HWYZ0JlOUEhWxFZk5CKpKK8zr8bFN5adNhoCzWnw_wcB

http://www.edmundoptics.com/optics/optical-filters/neutral-density-filters/continuously-variable-apodizing-filters/3121

http://www.telescope-optics.net/apodizing_mask.htm

Custom filters from Reynard. I've done business with them in the past...I turn to them for difficult coatings (not that an apodizing filter is what I'd consider "tough"). I could RFQ a batch of apodizing filters from them and stick them in a mount.

http://www.reynardcorp.com/optical-production-capabilities/advanced-optics/121-bullseye-apodizing-coatings.html

DIY:

http://www.fredmiranda.com/forum/topic/1041243/0

http://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1163&gclid=CjwKEAiAnLGjBRCk_I-y_4iAmB0SJADGjWWzSsgR5ks8HWYZ0JlOUEhWxFZk5CKpKK8zr8bFN5adNhoCzWnw_wcB

StoneNYC
19-Nov-2014, 20:38
I doubt that you regularly work in sub-zero (F) conditions.

BTW, I lived in Connecticut for many years.

125314

Grand Canyon January 2013, -15 degrees Fahrenheit, 3 rolls of Velvia (50/100/100f) 1.5 hours, the battery in the camera plus 2 brand new lithium camera batteries dead from the cold...

Not the only time I've had batteries die, just the most extreme case I can think of.

It also died for this shot, the stars should have a much longer trail, but the shutter shut down after 10 minutes as the battery died. This one WAS in Connecticut (CT) USA.

125315

StoneNYC
19-Nov-2014, 20:41
Cooke does it both ways with the XVa:


http://www.badgergraphic.com/opencart/index.php?route=product/product&path=3_246&product_id=3034

http://www.badgergraphic.com/opencart/index.php?route=product/product&path=3_246&product_id=3948

I thought the problem with convertibles was that without both cells the sharpness of the image was poor?

Although it would take up less space, I think even if I add all 3 Fujinon C lenses together the weight is still less than 2lbs? So not sure about the appeal of this lens, but PLEASE educate me as it's interesting at least.

richardman
19-Nov-2014, 21:32
I thought the problem with convertibles was that without both cells the sharpness of the image was poor?

Although it would take up less space, I think even if I add all 3 Fujinon C lenses together the weight is still less than 2lbs? So not sure about the appeal of this lens, but PLEASE educate me as it's interesting at least.

Please check the thread on the Cooke XVa Convertible.

Jody_S
19-Nov-2014, 21:37
Apodizing filters:



DIY:

http://www.fredmiranda.com/forum/topic/1041243/0

http://www.thorlabs.com/newgrouppage9.cfm?objectgroup_id=1163&gclid=CjwKEAiAnLGjBRCk_I-y_4iAmB0SJADGjWWzSsgR5ks8HWYZ0JlOUEhWxFZk5CKpKK8zr8bFN5adNhoCzWnw_wcB

Love the DIY link. I'm pretty sure I can cobble together the required image on thin-film imagesetting film, and I have a Heliar-design 14" process lens that takes Waterhouse stops just waiting for experimentation. I was in the process of copying the Imagon discs to insert as soft-focus stops, but this opens up so many more possibilities.

Sal Santamaura
19-Nov-2014, 21:52
Holy crap those are expensive !!...Well, Cooke does need to make a profit. As does the retailer. Even if you're going to be a benevolent not-for-profit, I don't expect you'll be able to offer things for too much less than, say, 1/3 - 1/2 those prices. That's why a number of posters in this thread are skeptical.


...Although it would take up less space, I think even if I add all 3 Fujinon C lenses together the weight is still less than 2lbs? So not sure about the appeal of this lens, but PLEASE educate me as it's interesting at least.I can't help with that. My analysis has always agreed with yours. Also, I can't imagine unscrewing elements and handling them in rugged field conditions. For better answers to that plus...


I thought the problem with convertibles was that without both cells the sharpness of the image was poor?...


Please check the thread on the Cooke XVa Convertible....which you can read here:


http://www.largeformatphotography.info/forum/showthread.php?117713-Cooke-Series-XVa-Convertible-Opinions-and-Experiences

StoneNYC
19-Nov-2014, 22:57
Well, Cooke does need to make a profit. As does the retailer. Even if you're going to be a benevolent not-for-profit, I don't expect you'll be able to offer things for too much less than, say, 1/3 - 1/2 those prices. That's why a number of posters in this thread are skeptical.

I can't help with that. My analysis has always agreed with yours. Also, I can't imagine unscrewing elements and handling them in rugged field conditions. For better answers to that plus...



...which you can read here:


http://www.largeformatphotography.info/forum/showthread.php?117713-Cooke-Series-XVa-Convertible-Opinions-and-Experiences

Thanks Sal, interesting. The second link was interesting too.

Good info.

Nathan Potter
21-Nov-2014, 15:57
Possibilities often don't match probabilities. That's 99.99 percent of life and nearly all of whatever has been invented... but FAR more importantly... follow-through makes things happen!! Have you ever told your young child he "can't"? Why would you do that?? And should we do that to each other? Are we to limit progress this way... really?

Reminds me of ditti from the "Space Childs' Mother Goose" :

"Probable possible my black hen;
She lays eggs in the relative when.
She doesn't lay eggs in the positive now,
Because she's unable to postulate how."

Nate Potter, Austin TX.

hoffner
21-Nov-2014, 16:05
Fun stuff. I was thinking for the whole time of the old proverb - "the proof of the pudding is in the eating".

hoffner
21-Nov-2014, 16:24
On the other hand - with the new promised electronic shutter in all sizes we don't even need the missing Copal shutters for the promised lenses! The pudding, the pudding, brothers.

Sal Santamaura
21-Nov-2014, 16:46
...brothers.Let's make this completely clear. I am in no way related to the quoted forum member. The rest of you can speak for yourselves. :D

hoffner
21-Nov-2014, 17:04
Related or not, you still need the pudding. Which do you prefer - the promised electronic shutter or the missing Copal shutter for the promised lens? Oh well, I guess, without the pudding, it doesn't matter.

Lachlan 717
21-Nov-2014, 17:56
...we don't even need the missing Copal shutters for the promised lenses!

Seems that the previous posts about the availability of Copal shutters has eluded you. They are NOT missing.

hoffner
21-Nov-2014, 18:01
Seems that the previous posts about the availability of Copal shutters has eluded you. They are NOT missing.

Missing as on the new promised lenses. There they are missing. To get them from old lenses there where you miss them is a small problem, I suppose. On the other hand, the new promised (sadly, still missing,) electronic shutter in all sizes would be good. The pudding, the pudding, brothers and not related ones.

Dan Fromm
21-Nov-2014, 18:36
Missing as on the new promised lenses. There they are missing. To get them from old lenses there where you miss them is a small problem, I suppose. On the other hand, the new promised (sadly, still missing,) electronic shutter in all sizes would be good. The pudding, the pudding, brothers and not related ones.

The OP is doing something like market research to assess demand for a new LF lens so he can decide whether the project is worth taking to Kickstarter. He's trying to learn what combination of focal length, maximum aperture, coverage and price might sell well enough to be worth bringing to market. He's exploring, has made no promises.

One prerequisite for a usable lens is a shutter to use with it. The OP has mentioned that it might be possible to make one, too. I think -- don't know for sure, haven't asked him -- that he intends to nail down shutter options (sell naked cells, let the buyers find shutters; sell new cells in used shutters; design and make a shutter, deliver lenses ready to shoot) before he decides whether to take the project to Kickstarter. Again, he's exploring, has made no promises.

Why are you demanding pudding? Are you hungry?

And why are you demanding finality from preliminary exploration? Preliminary means preliminary. Exploration means exploration. And no commitments beyond the time the OP has put into designing a possible lens and doing the work needed to estimate costs of production means no commitments to potential buyers.

You haven't been offered anything at all. You're getting no pudding.

hoffner
21-Nov-2014, 19:37
You haven't been offered anything at all. You're getting no pudding.

Somehow, I had no doubt about it. But thank you, you sound assuring.

hoffner
21-Nov-2014, 19:53
It would be difficult to imagine anything more positive for large format photography in 2014.




You haven't been offered anything at all. You're getting no pudding.

One of you is very probably right. I think I will just forget the whole thing.

Corran
21-Nov-2014, 20:01
Good, shut up and take your negativity elsewhere.

Bernice Loui
21-Nov-2014, 20:05
Not all who are interested in lenses need them in shutter. Lens in barrel with a proper round iris is fine for some who use a Sinar shutter or similar.

Bernice

hoffner
21-Nov-2014, 20:11
Good, shut up and take your negativity elsewhere.

Hope you don't say this to Sal Santamaura or Dan Fromm, they wouldn't take it so easily from you. When it comes to me I will still look for the beef, bro. Positively so.

hoffner
21-Nov-2014, 20:14
Not all who are interested in lenses need them in shutter. Lens in barrel with a proper round iris is fine for some who use a Sinar shutter or similar.

Bernice

That's right. You know, on the positive note, I even thought the optional electronic shutter (I know, no pudding offered) in all sizes could even replace the focal shutter in some Graphic cameras and there you go - shutterless lenses are all yours.

Sal Santamaura
21-Nov-2014, 21:22
Hope you don't say this to Sal Santamaura...wouldn't take it so easily from you...On the other hand, no one has said anything like that to me. Perhaps because I'm not a font of negativity? And/or because I passionately defend this forum rather than degrade and undermine it?

richardman
21-Nov-2014, 21:25
There are curmudgeons, and highly opinionated people on this forum, but there is only one... what's his name :-)

Randy Moe
21-Nov-2014, 21:50
Speed Graphic focal plane curtain shutter runs up to 1/1000th and was made 2x3, 4x5 and 5x7" for a very long time. I have 2 1940's Speeds that still work fine.


http://graflex.org/speed-graphic/features.html#FocalPlane

Batteries are fine for any modern shutter, these guys are dreaming. Nothing works forever and batteries are much better these days.

A simple battery run shutter would be great.

I suggest using waterhouse stops for simplicity and roundness, as aperture roundness is a big deal in OOF.

Tim Meisburger
21-Nov-2014, 23:02
I think at some point it would be helpful to post your list of potential lenses as a poll. Then people could choose those they are most interested in. Quickly it would become apparent which lens designs would be most popular. Then, in a second stage poll, you could take the most popular designs and estimate a sale price for each and ask people which they would be willing to buy at that price point. At that point you would know what to start with, and whether it would make sense to even do it.

StoneNYC
22-Nov-2014, 00:35
There are curmudgeons, and highly opinionated people on this forum, but there is only one... what's his name :-)

As I said elsewhere, the one "know it all lens guy" wouldn't dare post here because it would prove how little he really knows compared to this lens designer who's AMAZINGLY knowledgeable and shouldn't be contradicted by any...Wiley...forum members ;)

So I'm confused OP, which lens design are you working on right now? Still the original proposal?

LF_rookie_to_be
22-Nov-2014, 02:18
On a somewhat OT note, does anyone know whether Wista still manufactures Shanel 5 shutters? Those seem pretty durable.

Nodda Duma
22-Nov-2014, 06:14
Hi StoneNYC,

Well yesterday I took a break. It was my day off from work (I work a 9/80 schedule) and from watching the kids. So I grabbed my Nikon F3HP which I got off eBay last month for $20 "does not work - film advance jammed", a borrowed Zeiss Planar 50mm f/1.4 IR, some very expired Tmax P3200 and 100, then shot some photos. Shot them at ISO 800 and 50 to compensate for the age. After the family went to bed I developed the rolls and made some prints in the darkroom. Heresy to talk about shooting 35mm I know :) but you work with what you got. I really wanted to see what effect the "IR" callout had....looks like it's in the coatings.

I'm multi-tasking. The 165 f/6.3 is being finalized. If you're following the APUG thread then you'll see that I saw an opportunity to replace the doublets with singlets. I'm letting that optimize over the weekend. It's wanting to try to use some more costly glass types for the replacement so I'm finessing the optimization to avoid that. I looked at it yesterday morning and it won't be too hard.

The 8/6 design (8 elements, 6 groups in your jargon... 2 doublet, 4 singlet semi-symmetric in my jargon) is finalized, and Thursday night I test plate-matched to the vendors I'll get quotes from. So it's just mop-up work for that one. But it won't make sense to get it quoted if the 6/6 (all-singlet semi-symmetric) version gives pretty much the same performance. Quotes are free but I don't want to waste the vendors' time on lenses they'd never make. The 6/6 will need test plate matching, physical diameter set, tolerance analysis, and then I can generate drawings and share the solid model with my colleague who will perform the mechanical design.

That lens is for the 8x10 crowd of course.


The other thing I'm doing is compiling the list of sensible requests that I've gleaned from here and APUG. I'll take that and generate a poll thread to see what's most desirable. I may ask for clarification on what format is desired for the requests.

If progress seems to travel at a snail's pace, that's because it does. Welcome to the wonderful world of engineering :) Well that and I keep a pretty busy schedule. Today is devoted to playing with the kids!

Steven Tribe
22-Nov-2014, 14:21
Just a few notes - late, because I didn't see this thread (on steroids?) before last night!


1. Please think about simple bayonet fittings for lens cells instead of screw in. I love my French casket sets with this feature and it makes sense for simpler convertibles too. Another wonderful innovation would be be bayonet fixture of the lens barrel to the flange. The present screw system is totally over dimensioned and the use of standard barrel sizes (30, 35, 40, 45mm etc.) would reduce the number of flanges in circulation.

2. I believe more in the reproduction /improvement of classic designs that is, pre-plasmat. I don't use modern lenses in my photography - they are too close to digital performance for me. This is an area where there are currently high prices, not because of the glass/brass work involved, but plain scarcity and growing photographer interest. Not too exciting for a lens designer, I'm afraid!

3. Because of my interest for barrel lens, I don't feel the need for shutters which fit. I use copal sinar shutters or front mounted T-P curtain shutters. If you started a production using standard barrel widths, just a few T-P shutters (or a modern version promoted through a QS venture) would suffice.
Many early WA lenses don't have room for a set of shutter leaves and iris between the cells (including the Goerz Hypergon).

4. Waterhouse stops are a wonderful system and, as others have said, shutter iris apertures are pretty rudimentary. And the same WH stop sets would fit several lenses ( as Dallmeyer showed in the 19thC.) IF you used the principle of few barrel sizes.

5. I would have thought that the following would be sought after (at reasonable price)

- Any large achromatic meniscus landscape lens with coverage from 8x10 to 20x24. There are plenty of starting points, including the Port-land and the TT&H RVP.
- The Goerz Hypergon. A classic periscope design which, I beieve, is non-existant in large sizes and would require quite a lot of development work. Suggested by someone else as well.
- Larger, faster periscopes like the Objectif d'Artiste and and Dallmeyer Bergheim.
- BUT NOT the Globe! It is fun in a collection, but as user lenses the WAR RRs are much better.

Nodda Duma
23-Nov-2014, 06:11
What film format would the Hypergon be wanted for? 8x10? 5x4? That's an important specification. :) Same goes for all suggestions.

StoneNYC
23-Nov-2014, 06:43
All 8x10 for me but I know a few that have need for 14x17 and 16x20.

One really talented photographer who shoots 20x24 told me that the only reason he resorts to 16x20 sometimes is about the additional lens choices he doesn't have with 16x20.

So, there's always a wide angle 20x24 ;)

Nodda Duma
23-Nov-2014, 07:02
Yeah I plan to support those guys too but I haven't gotten as many suggestions from that realm as of yet.

StoneNYC
23-Nov-2014, 07:11
Yeah I plan to support those guys too but I haven't gotten as many suggestions from that realm as of yet.

There aren't as many of them... I can ask...

Jody_S
23-Nov-2014, 10:52
What film format would the Hypergon be wanted for? 8x10? 5x4? That's an important specification. :) Same goes for all suggestions.

I think in 8x10 you're running into stiff competition from modern ultra-wide angles (115 Grandagon?), and there are already quite a few vintage lenses on the market. For example, I rather like the look of the Darlot lever-stop wide angles, and they're not that hard to find. But for 11x14 and up, they are quite rare to non-existent. Any wide angle, modern or historical reproduction, should find a (small) market in ULF sizes, with people who are not averse to paying real money for a lens.

Corran
23-Nov-2014, 11:35
The Hypergon is more than just an ultra-wide angle. The Hypergon designated for 8x10 is the 75mm Hypergon (000a)! There was then the 60mm Hypergon for 5x7. No 4x5 size. I don't know how expensive such an exotic piece of glass would cost but I would love a 75mm and 120mm modern Hypgergon.

I'll leave the solution for falloff to the lens designer. But a waterhouse stop combined with centerfilter would be cool, if possible.

BTW, a 4x5 Hypergon would then be around 38mm. The Schneider 38mm XL just almost covers 4x5, so that's close, if you are looking for such a wide angle.

StoneNYC
23-Nov-2014, 11:39
I think in 8x10 you're running into stiff competition from modern ultra-wide angles (115 Grandagon?), and there are already quite a few vintage lenses on the market. For example, I rather like the look of the Darlot lever-stop wide angles, and they're not that hard to find. But for 11x14 and up, they are quite rare to non-existent. Any wide angle, modern or historical reproduction, should find a (small) market in ULF sizes, with people who are not averse to paying real money for a lens.

Jody,

Part of the point of this was that this nice gentleman is able to make these kinds of lenses at much lower prices than the asking prices of some of those grand lenses you speak of for 8x10, although there are a few out there, they aren't that common, and they certainly aren't coming in at prices that are as reasonable as they could be.

Again my personal biggest search is for a fujinon 600 C which when they do show up, the prices are all over the place from $1,000 to $1,800 and for me, if I could get a brand-new lens made with similar characteristics I would be very happy to buy it from this gentleman, perhaps to make it more appealing he will create a 720 C version as to not directly compete with the Fuji lens but also to give a little more reach.

In 4x5 I love 300mm it's a great FL, but in 8x10, 600 really isn't the same, 720 is closer to the equivalent and I'm sure many 8x10'ers would agree that a semi-compact non telephoto 720mm lens for hiking would be a valuable option to buy NEW.

And on the wide-angle front as you mentioned, although those lenses are nice, they leave very little room for movement on 8x10, so perhaps this gentleman will create something with a larger image circle which would allow for a lot more movement and give good competition against the expensive wide angles.

However I also agree that lenses for 11x14 and up would be grand in some of the farther ends of the spectrum.

I personally feel that if you're going to make a set of lenses, why not just make it a full set, make it so that there's a full length lineup that covers everything up to 20x24 and that can translate downward to the smaller formats, trailing off at say 210mm for 14x17, 300mm for 16x20, 400mm in 20x24 and then 550mm, 700mm, 900mm, 1200mm, 1800mm all for 20x24+

Those 20x24 lenses would have to be "on demand" rather than building them as a set, but the option to buy them new instead of searching for them for years (which I've seen people do, look at the 1800mm threads where people are searching for one).

Nodda Duma
23-Nov-2014, 12:28
StoneNYC,

Thanks for replying to Jody but one thing...I don't know what the prices will be and cannot make (nor have I made) any promises. I do have an idea of what it could be, but it is all speculation at this point (and good engineers don't speculate out loud!). It will be a simple case of demand driving cost. Right now the only thing I have going is that I'm doing this on the side in my free time so cost of design is nil.

My goal is to fill gaps in focal lengths for larger formats or provide lenses which can no longer be found or which cost an extraordinary amount due to scarcity. So base your recommendation on what's not available or what's just crazy expensive rather than trying to get something which is readily available but at a lower price.

So we must wait until the lenses can be quoted before we talk about price (and that is a discussion for the Kickstarter announcement).

And of course, cost is not a discussion for this thread :)


But yes, ultra large format is one of the groups I'd like to help, because the lens landscape up there seems to be rather bleak.

I can add a Hypergon for 11x14 (or ? You tell me, I don't want to guess) to the list.

Jody_S
23-Nov-2014, 12:34
I actually have some hope for an affordable Hypergon, as construction would be much simpler than anything else discussed in these threads. We're talking 2 identical pieces of glass mounted in a brass or aluminum pancake with a slot for waterhouse stops (or a set of removable apodization filters!). I don't know where prices will be for more complex lenses, but I do believe the Hypergon could be constructed new for less than antiques sell for, certainly once we get above 8x10 in coverage. I don't think there's much point in making 5x7 or 4x5 ones, since resolution isn't great for anything except contact printing (?).

Another candidate for 'new built to sell cheaper than used' would be the Plasticca.

Nodda Duma
23-Nov-2014, 12:38
What film size for the Hypergon?

Old-N-Feeble
23-Nov-2014, 12:46
What film size for Hypergon? I'd guess nearly all from 6x9cm through 20x24 inch if they're affordable. The Hypergon is one of those lenses with "magic" built it. Honestly though... I wouldn't buy one because I prefer something like a SAXL and will never shoot larger than 8x10 film.

Jody_S
23-Nov-2014, 12:56
What film size for the Hypergon?

I would start with 11x14 with a little room for movements (most common ULF size, plus will cover panoramic formats up to ??x17") and one that just covers 16x20 (and will cover all the panoramic sizes with a long edge of 18" - 24"). If those are priced to sell, then add 20x24 and 8x10 with room for movements.

Dan Fromm
23-Nov-2014, 13:04
OnF, the 35/4.5 Grandagon covers 110 degrees on nominal 6x9. I'm not sure there's much demand for something wider. These days a careful buyer can probably get one and a center filter (separate transactions) for around $1k. Prices of used center filters seem to be falling.

Old-N-Feeble
23-Nov-2014, 13:09
Dan, I agree and I stated I wouldn't buy one because I prefer something like a SAXL because it's better corrected and a CF is available. In fact, I have a 38mm SAXL. But for those wanting the absolute ultimate extreme wide angle for 6x9cm a Hypergon would be something like 24mm.

Corran
23-Nov-2014, 13:11
I, personally, would want the 75mm and 120mm, as mentioned. But that's me - and I'm thinking for 8x10 and for 8x20 ULF.

But think about it - 8x10 users will be biggest market. Most don't shoot larger than that. I'm not seeing an explicit 11x14 size on the list of Hypergons, but it'd likely have to be about 110-115mm. And as Jody mentioned, there are some lenses at that FL already available that cover 8x10, and many others if you push it to 120mm. But who needs several inches of movements for an ultra-wide angle on 8x10?? Serious question there, because I doubt many do (and there's always the 150mm SSXL or Nikkor that covers 8x10 in excess). So an extreme wide-angle that can't be had any other way, like a 75mm or 90mm Hypergon, would be of more interest, I would think. At least for me. I wouldn't buy one if it was a 110mm, I would see little to no point.

120mm Hypergon is rated to 12x16 (500+ image circle) so would cover 8x20, but not 12x20, so I guess pushing it to 150mm and covering up to 16x20 would be better for the ULF crowd, but I'm just speculating.

Corran
23-Nov-2014, 13:15
24mm.

The SAXL 24mm should just cover 6x9 (100mm IC on the specs, but I bet that's conservative for digital capture).
http://www.bhphotovideo.com/c/product/400263-REG/Schneider_03_010353_24mm_f_5_6_Apo_Digitar_XL.html

I also have a 38XL (and CF) and it covers 6x12 easy. Pretty nice little lens. Can shoot 4x4 square too if you like that sort of crop.

My understanding of the Hypergon is that one made for 6x9 would be something like an 18mm (of course, never done before). I doubt the resolution would be worth even bothering though, plus the tiny aperture (diffraction). Assuming no design changes and a simple transposition of the design to a smaller piece of glass.

Edit: BTW, my info on Hypergons come from various online sources such as https://www.cameraquest.com/hyper.htm

I have no direct hands-on experience. Never seen one of the 75mm lenses for sale other than ridiculous eBay listings. If I could actually find the fan, I'd consider making an offer on this: http://www.ebay.com/itm/321583967185

Nodda Duma
23-Nov-2014, 13:23
Dumb question: is the 110 degrees measured diagonally? Horizontally?

Jac@stafford.net
23-Nov-2014, 13:25
My understanding of the Hypergon is that one made for 6x9 would be something like an 18mm (of course, never done before). I doubt the resolution would be worth even bothering though [...]

It also has something like a nine-stop fall-off to the edges.

Corran
23-Nov-2014, 13:28
That's what the fan is for though. A tiny little fan would be needed though!

I wish there were more Hypergon photos out there. I'd like to see someone make use of them and do some really cool work with a unique tool.

Old-N-Feeble
23-Nov-2014, 13:29
RE focal length of Hypergon for 6x9cm: The Hypergon for 8x10 inch is 75mm focal length.

The diagonal of the image are of 8x10 film is 315mm.

75/315 = .2381

The diagonal of the image area of 6x9cm is 101mm.

101*.2381 = 24mm

Nodda Duma
23-Nov-2014, 13:30
A 120 degree FOV should have a 4 stop fall off.

Take the cosine of the half-angle, raise that to the power of 4. Then take the natural log of that divided by the natural log of 0.5. That should give you the stop loss without vignetting.

Here's a brief writeup on illumination falloff. Read it if you have insomnia:

http://dougkerr.net/Pumpkin/articles/Cosine_Fourth_Falloff.pdf

Corran
23-Nov-2014, 13:32
OnF, you may be right, but since the actual IC of the lens isn't known, it's kind of hard to estimate. Plus differences in aspect ratio between the formats.

I just divided by 4, obviously, but who knows.

Old-N-Feeble
23-Nov-2014, 13:44
Corran, I agree that using the long edge of any film format, rather than the diagonal, is a better way to calculate normal FL for that format. I agree that 6x9cm (2:3 ratio) isn't a perfect match to 8x10in (4:5 ratio).

If we divide 75mm by the long edge of the image area of 8x10 inch (approximately 249mm) we arrive at .301. If we multiply the long edge of 6x9cm (84mm) by .301 we arrive at 25mm... still extremely wide and MUCH wider than either the 35mm Apo Grandagon and 38mm SAXL.

Like I stated earlier, I wouldn't buy a Hypergon but I'm sure some folks would because no other designs I'm aware of go that wide.

Teodor Oprean
23-Nov-2014, 14:27
Ideas for a lens design exploration:

Lens 1: classic Tessar optimized for 4x5

focal length = 180 mm
maximum aperture = f/8
coatings = double-coating on every glass surface

By how much would double-coating increase light transmission compared to single coating?

Would such a lens compare foavourably with a 150 mm f/5.6 Apo-Sironar (N or S) in relation to the 4x5 inch film size?

Would the performance of this Tessar change significantly if one were to tweak the maximum aperture up or down from f/8 (e.g. further down by a third of a stop from f/8 to f/9)?

----------

Lens 2: Start with the existing Sironar-N 240mm f/5.6 mounted in the heavy and huge Copal 3 shutter and reduce the maximum aperture until the lens fits comfortably in a much more portable Copal 1 shutter.

What would be the maximum aperture for that lens?

What would be a good guess for the smaller filter thread?

Would the image circle be affected in any sense?


Teodor

Lachlan 717
23-Nov-2014, 14:40
My suggestion of a large IC 180-200mm has the benefit of multi-format. It's usable for the smaller ULF where the only options are the Grandagon/SA/SSXL, and also for those 8x10 and smaller shooters wanting to use huge movements (architecture et al.. Not a whole lot of choice in this sector if you include large IC.

Mark Sawyer
23-Nov-2014, 14:43
Before getting too carried away with the Hypergon, we should consider whether Jason (or anyone) could make such a lens. It's a simple enough looking formula, but the curves are extreme, and the glass very thin. Wisner promised a new Hypergon a while back, but never made one. Even Goerz had trouble making them. But it would be cool... :)

Another lens that might be worth considering is a fast modern Dialyt, similar to the Celor or Dogmar. Those were popular before WWII, even though as uncoated lenses, they suffered from quite a bit of flare. Many lf photographers are using modern coated Dialyt process lenses (Artar, Ronar, Process Nikkor...) for their excellent resolution and out-of-focus rendering, but those are all f/9 or f/10 lenses. I can't think of any modern (coated) fast Dialyts...

Nodda Duma
23-Nov-2014, 15:29
Before getting too carried away with the Hypergon, we should consider whether Jason (or anyone) could make such a lens. It's a simple enough looking formula, but the curves are extreme, and the glass very thin. Wisner promised a new Hypergon a while back, but never made one. Even Goerz had trouble making them. But it would be cool... :)


I'll ask the shop.

Dan Fromm
23-Nov-2014, 16:19
Dumb question: is the 110 degrees measured diagonally? Horizontally?Diagonally. That's the convention.

However, many active posters here use other conventions, usually talk about the long edge. I disagree. If the lens doesn't cover the frame's diagonal it won't put good image in the corners.

Goerz claimed that the original Hypergon with fan covered 135 degrees with fan, 110 degrees without. An 20.5 mm 135 degree lens will just cover 100 mm, nominal 6x9's diagonal; not quite six stops down in the corners. See http://www.cameraeccentric.com/html/info/goerz_2.html

Steven Tribe
23-Nov-2014, 16:24
I don't think Goerz had too much problem in making them as the prices were very close to their other series.

The mount may be more difficult than the glass- see cross section.

Old-N-Feeble
23-Nov-2014, 16:28
Diagonally. That's the convention.

However, many active posters here use other conventions, usually talk about the long edge. I disagree. If the lens doesn't cover the frame's diagonal it won't put good image in the corners.

Goerz claimed that the original Hypergon with fan covered 135 degrees with fan, 110 degrees without. An 20.5 mm 135 degree lens will just cover 100 mm, nominal 6x9's diagonal; not quite six stops down in the corners. See http://www.cameraeccentric.com/html/info/goerz_2.html

Dan, I prefer to use the long edge of the film image to determine normal focal length but use the image diagonal to determine coverage needed. IMHO, "normal FL" and "minimal coverage needed" are not the same thing at all unless the image ratio is close to 1:1.25. I multiply the long edge by 1.25 to determine normal FL.

David Karp
23-Nov-2014, 16:28
David, such a lens already exists.
The Grandagon (non-N version) 115 is much smaller than the 120 Nikkor, covers 8x10 (barely) and comes in a Copal 1 shutter.
It is on the heavier side, like many Rodenstock lenses seem to be, but still at a manageable 550-ish grams.
Or did you mean something even smaller?

Took me a while to get back to this. As Ari and I discussed via PM, the 115mm Grandagons require those big 82mm filters to cover that large front element. The rear elements are big too. The Fujinons and Schneiders are similar. The 120mm Nikkor SW is 77mm. Something 67mm, preferably smaller if possible would be better for backpacking. Good 5x7 coverage with plenty of room for 4x5 (larger than the 120mm Angulon) is what I would love.

And the idea of a 4x5 triple convertible is intriguing. It would be great if it came with rear caps to protect each set of lens elements when removed from the shutter/barrel. It would also be cool if it came with an attachment, sort of like a filter step up ring, that could screw into the front of the shutter/barrel for easy attachment of filters when shooting with the rear element only.

Today I read the thread over on APUG. Fascinating.

Dan Fromm
23-Nov-2014, 17:02
Dan, I prefer to use the long edge of the film image to determine normal focal length but use the image diagonal to determine coverage needed. IMHO, "normal FL" and "minimal coverage needed" are not the same thing at all unless the image ratio is close to 1:1.25. I multiply the long edge by 1.25 to determine normal FL.

Fine, if you're speaking Feeblish. Most of us speak the common language.

Old-N-Feeble
23-Nov-2014, 17:11
Fine, if you're speaking Feeblish. Most of us speak the common language.

No need to be rude, Dan. I'm just expressing my opinion.

Nodda Duma
23-Nov-2014, 17:14
I'd thicken the lenses just so, grind the bottoms and sides flat (outside the clear aperture), blacken and bond into place with UV cure adhesive or RTV adhesive if weight / temperature/ vibration is an issue. Forget retainer rings.

The thickness to diameter ratio is crazy but not too bad. It'll see some flex under polish and add some fringes to the surface as a result, but since the design is nowhere near diffraction limited until stopped down real tight it's not what I'd consider an issue. Any shop experienced with hemispheric windows (ie many shops) can do those. You just can't block up more than 1 lens at a time on a polisher.


as for field of view: In my field (pun intended) we use the terms Horizontal FOV, Vertical FOV to specify. There's also iFOV (instantaneous, grain, or individual pixel FOV), HFOV (Half Field of View), Diagonal FOV. Field of Regard, WOI (Window of Interest), Window of Regard, AFOV for DVO (guess that one), numerical aperture, so on and so forth..

Dan Fromm
23-Nov-2014, 18:05
No need to be rude, Dan. I'm just expressing my opinion.

I've got to start using smileys. :) :) :)

Jason, in my little world numerical aperture is used only for microscope objectives. I can see it being used for stepper lenses too, but ain't no stepper lenses in my little world. Photographers who use only conventional cameras are usually puzzled by N.A.

Randy Moe
23-Nov-2014, 18:14
Nodda, most of us here recently watched a couple lens making films. Old ways.

Kodak Hawk Eye plant 50's. Here. (http://youtu.be/tpziDTklPs0)

And 90's Canon. Here. (https://www.youtube.com/watch?v=ovxtgj4SsiI)

Nodda Duma
23-Nov-2014, 18:57
Yep I've seen those. They are good stuff..lots of touch labor. It's too bad labor has gotten so expensive. That drove the push for automation in manufacturing and eventually labor-intensive processes offshore. The Kodak clip I got a private screening of from the vendor who bought the Kodak Optical Imaging Group.

Here's some more to watch. I've worked with all these vendors

http://www.rpoptics.com/Home/Resources/Videos/tabid/101/Default.aspx

http://www.lacroixoptical.com/videos
(If LaCroix video doesn't show up then google LaCroix optical video. Lots of good little snippets)

And then this How It's Made episode on JML Optical.

http://m.youtube.com/watch?v=F7-IfLe3-oo

Bernice Loui
23-Nov-2014, 21:27
Speaking of optics designers....

https://lh5.googleusercontent.com/-3xS8akIq9Uw/VHKzLDl116I/AAAAAAAAA1E/vsJKcv9zHrA/w800-h574-no/AlNaglerAsAKid.png

:rolleyes:
Bernice

StoneNYC
23-Nov-2014, 23:09
Question, and someone brought this up earlier and it gave me the idea, one of the most expensive things some of these wide-angle lenses is the center filter to compensate for falloff at the edges, for example my Schneider 150mm SS XL.

I have no center filter because the darn thing used costs $500-$700! So, would you be able to make a lower cost (like $100) center filter for these types of lenses? There are many made for 4x5 and 8x10 sizes that could use them.

Jim Jones
24-Nov-2014, 07:24
Homemade center filters are possible, if not really practical. For pinhole photography, I exposed film through the pinhole, developed it to a gamma of about 1, and mounted it at about one focal length in front of the pinhole. It could have also been mounted just in front of the focal plane. There are obvious problems in doing this to obtain quality images. Many films lack the smooth emulsion surface needed to avoid diffusion. The non-linear H-D curve of film used for the filter would cause uneven exposure. Perhaps carefully reducing the toe of the H-D curve with potassium ferricyanide would partly correct for this. Reflections from the center filter might cause ghosts and flare. The film is easily scratched and harder to clean than glass, although it could be mounted between coated optical flat glass filters to reduce this and some of the above listed problems. This project is best suited to those who delight in problem solving. For most people, it is more cost effective to get a temporary second job to pay for such a filter than to design, test, and fabricate one.

Nodda Duma
24-Nov-2014, 09:32
Homemade center filters are possible, if not really practical. For pinhole photography, I exposed film through the pinhole, developed it to a gamma of about 1, and mounted it at about one focal length in front of the pinhole. It could have also been mounted just in front of the focal plane. There are obvious problems in doing this to obtain quality images. Many films lack the smooth emulsion surface needed to avoid diffusion. The non-linear H-D curve of film used for the filter would cause uneven exposure. Perhaps carefully reducing the toe of the H-D curve with potassium ferricyanide would partly correct for this. Reflections from the center filter might cause ghosts and flare. The film is easily scratched and harder to clean than glass, although it could be mounted between coated optical flat glass filters to reduce this and some of the above listed problems. This project is best suited to those who delight in problem solving. For most people, it is more cost effective to get a temporary second job to pay for such a filter than to design, test, and fabricate one.

I was actually going to suggest something like this, although being an engineer I do find it much more interesting to DIY.

I can add filters to the list, but there's so much variability there in what would be needed that I'm not sure how they could be made for any sort of reasonable cost.

See these prices for 1" and 2" production versions:

http://www.edmundoptics.com/optics/optical-filters/neutral-density-filters/continuously-variable-apodizing-filters/3121

Old-N-Feeble
24-Nov-2014, 10:41
If you do add center filters to your list I suggest concentrating on 3x rather than 4x strengths because some lenses only require 3x and those needing 4x can easily get by with just 3x. Then I'd concentrate on filling the gaps for lenses that could use center filters but for which none are made in those sizes.

Jac@stafford.net
24-Nov-2014, 11:35
[...]I have no center filter because the darn thing used costs $500-$700! So, would you be able to make a lower cost (like $100) center filter for these types of lenses? There are many made for 4x5 and 8x10 sizes that could use them.

Possible alternative to center filter.

The following two links show pictures of a center filter over a Metrogon wide lens over 8x10 - a sky camera of sorts I built long ago from a Lockheed research camera. The images are not as illustrative as they could have been. Ignore where the star looks incomplete. That's from a shadow. The pictures show a deep red filter with a silver looking 'star' radiating from the center. (The filter does cover the lens which is smaller below the filter mount.) The material of the star was semitransparent. Look for these and other highly economical center filters in military surplus suppliers. Mine cost $4 each. They are about 4" to 5.25" across. If they work, then good. If they don't, you are out only a few dollars.

First here: http://www.digoliardi.net/skc/skc-filter-1.jpg
Second: http://www.digoliardi.net/skc/skc-filter-2.jpg

(The square reflected in one is a window in front of the lens.)

The camera in its working position here: http://www.digoliardi.net/skc/skc1.jpg

Randy Moe
24-Nov-2014, 12:52
Would an inkjet printed star filter on clear Pictorico work as center filter?

How about 3d printing a star?

StoneNYC
24-Nov-2014, 13:06
I was actually going to suggest something like this, although being an engineer I do find it much more interesting to DIY.

I can add filters to the list, but there's so much variability there in what would be needed that I'm not sure how they could be made for any sort of reasonable cost.

See these prices for 1" and 2" production versions:

http://www.edmundoptics.com/optics/optical-filters/neutral-density-filters/continuously-variable-apodizing-filters/3121

For some reason I was under the impression that the center filter we're only about three different versions, I guess I kind of assumed that it just depended on which copal shutter was used to fill the center hole gap, obviously I'm not a lens designer... LOL and I've only owned a 75 Grandagon-N green stripe which IMO didn't really need a center filter the falloff seemed to be very low, and the 150 SS XL which I'm told has much more noticeable falloff but I haven't used it enough yet to know for sure.

djdister
24-Nov-2014, 13:13
I don't understand how the star filter functions the same as a center ND filter - doesn't the star have a clear area in the very center of the lens? A center ND filter is just the opposite - it has its greatest ND effect in the very center of the lens. Just trying to understand what the star filter effect is for...


Possible alternative to center filter.

The following two links show pictures of a center filter over a Metrogon wide lens over 8x10 - a sky camera of sorts I built long ago from a Lockheed research camera. The images are not as illustrative as they could have been. Ignore where the star looks incomplete. That's from a shadow. The pictures show a deep red filter with a silver looking 'star' radiating from the center. (The filter does cover the lens which is smaller below the filter mount.) The material of the star was semitransparent. Look for these and other highly economical center filters in military surplus suppliers. Mine cost $4 each. They are about 4" to 5.25" across. If they work, then good. If they don't, you are out only a few dollars.

First here: http://www.digoliardi.net/skc/skc-filter-1.jpg
Second: http://www.digoliardi.net/skc/skc-filter-2.jpg

(The square reflected in one is a window in front of the lens.)

The camera in its service position here: http://www.digoliardi.net/skc/skc1.jpg

Jac@stafford.net
24-Nov-2014, 13:23
I don't understand how the star filter functions the same as a center ND filter - doesn't the star have a clear area in the very center of the lens? A center ND filter is just the opposite - it has its greatest ND effect in the very center of the lens. Just trying to understand what the star filter effect is for...

The silver star portion is the filter. The central area does not have a clear area. The star admits less light, increasing light transmission gradually towards the edges. IOW, it acts like a center filter.

Edit: Oh! I think I know what gave the impression that the center was clear. The second picture shows a spot there. That is really the shutter aperture. :)

The shutter: http://www.digoliardi.net/skc/skc-shutter-b.jpg

alanbutler57
25-Nov-2014, 09:29
Hello and a belated welcome Nodda,
I have more general questions for a lens expert. There is an older thread here about focusing soft focus lenses, which, of course, fall into different design categories.

So, what lens designs have asymmetrical DOF?

I've read the meniscus like the old Kodak portrait has most of it's DOF behind the point of focus for example. But what about Imagon type lenses (I actually use a medium format Mamiya 150SF sometimes on 4x5) and always wonder, should I focus on the eye, on the tip of the nose, center the face and crop etc.?

I understand that design relies on spherical aberration, so does this mean the point of critical focus should always be as close to the optical axis as possible?

This may all be old hat to most here, but I've shot relatively few LF images so far.

Thanks,

Sal Santamaura
25-Nov-2014, 10:24
...Here are the specifications for what I'd like to see you design and have made. Focal length 225mm. Corrected for near infinity. Image circle at least 350mm, preferably 400mm. "Circle" defined as edge sharpness near what it exhibits at the center, i.e. not just "illumination" circle. Virtually no falloff when centered on wholeplate film (260mm diagonal), and not much more near the circle's edge. Almost no field curvature or focus shift. Fits in a Copal 1. Speed f/x, where x is as small numerically as you can make it and still fit in the Copal 1 while meeting all other specifications*. Weight with shutter not more than 500g. All elements multicoated...Recently posted in another thread:


http://www.largeformatphotography.info/forum/showthread.php?116042-Banner-Peak-and-Thousand-Island-Lake&p=1191315&viewfull=1#post1191315

The 225mm I requested seems pretty close to 9 inches. :) Same film format too. Good enough for Adams, good enough for me. :D

*Added to quoted post so it reflects subsequent clarifying post.

Dan Fromm
25-Nov-2014, 12:11
So, what lens designs have asymmetrical DOF?

PMFJI. DoF's symmetry has nothing to do with lens design and everything to do with CoC selected, aperture chosen, focal length and focused distance. At infinity DoF is considerably asymmetrical, infinitely longer behind the plane of best focus than in front of it. At very near distances ("macro") DoF is very nearly perfectly symmetrical.

Write yourself a DoF calculator in Excel and try it out.

Mark Sawyer
25-Nov-2014, 12:25
Soft lenses are a little different from conventional lenses, as the aberrations (usually spherical) mean there's a secondary image focus spread behind the focal plane. As you close the aperture, things sharpen up more behind than in front, because that's where the soft image is coming into focus. That's why the Kodak Portrait Lens fits those instructions, lots of spherical aberration making a sharp image behind the focal plane. With sharp lenses, Dan's right, it's symmetrical.

Ari
25-Nov-2014, 12:45
Jason, I was wondering about your 165 proposal on APUG: what about a triple convertible that covers 8x10 in FLs of 165, 330 and 460 (roughly), and would fit in a modern shutter?
Useful for 4x5, 5x7 and 8x10 shooters. One lens to rule them all.

Nodda Duma
25-Nov-2014, 13:12
Hi Ari,

Somewhere in that thread I reported what the F.L.'s of the front and rear lens groups themselves are. Dig through and see if those are acceptable. I need to update those values for the final incarnation but they should be close.

I also have noted the request for multiple focal lengths in a lens set. The multiple f.l.'s is an interesting concept... it's a 3x spread in focal length which can be addressed by a classical zoom design (although I have a much cooler idea forming in my head than the LF equivalent of a typical 35mm zoom lens ).

I'm hoping to finish out the compilation of requests and start a poll thread for the next project after the 165mm f/6.3 sometime during the Thanksgiving holiday.