Brass Knob on Petzvel / Darlot / etc

[StoneNYC]

I have not in the past really been interested in portrait images, but I've grown to really find them interesting and I was looking to maybe purchase an old portrait lens.

I'm trying to understand the differences, I'm not a lens designer and I don't understand the different lens design explanations like doublet etc., I understand that I can Google the different explanations but I don't understand how they translate into the "look".

I'm also trying to understand what the knob is for, since LF cameras of today have a bellows focussing system, I'm trying to understand if the knob on these old brass lenses are for focussing or something else?

Finally I'm trying to measure the value of a name brand Petzval, Darlot, or Voitlenger (spelling) over the B&L and no-name brass lenses.

I'm looking for something with character, furthermore I don't actually want TOO MUCH swirl, I find it dizzying and distracting, this is relative of course to my personal taste and degree, but I assume to lessen this I would need something that covered say 11x14 for my 8x10 to be more pleasant? Or an 8x10 lens design shot on 4x5? To lessen the swirl and edge changes while still giving an older lens look?

And we can't talk price now but I've been told there are no-name brands for $50 vs the $1,000+ versions? So when does decent lens optics overtake shiny brass on a shelf on the affordable scale?

And also understanding Petzal design vs Darlot, vs rectilinear vs hemispherical vs euryscope vs "portrait lens" vs whatever else there is. And how each differ in look, maybe with comparable examples?

It's a little confusing. I've spent days googling without a serous comparison so it's not like I haven't looked.

Thanks.

[Jim C.]

The knob on brass photographic lenses always seemed redundant to me since as you said, you can focus with the front and rear standards.
I have used it to fine focus on the ground glass rather than fiddling with the standards, that is if I can reach the knob :)
Some Petzval design lenses don't swirl, I have three, one has heavy swirlies ( Seroco 10" portrait ), very faint swirlies ( Darlot ) and a unknown brand
that has none, but a very nice soft bokeh.

Some of the terms you're asking are brand names ( Darlot for example ) versus a lens design ( Petzval ).

There's tons info here which is where I looked when I got " swirly fever" there are also examples, you can try Googling just this forum.

[jnantz]

http://en.wikipedia.org/wiki/List_of_lens_designs
http://en.wikipedia.org/wiki/Photographic_lens_design
http://en.wikipedia.org/wiki/Camera_lens

wendy o was in the plasmatics not to be confused with the lens type


are some wiki articles on different lens designs

some lenses have a defocus knob which is different ... and not used it to focus the lens ( rack/pinion system like jim mentions ).
they were used to move one of the lens groups / elements inside the brass barrel back and forth and are sometimes
numbered 1-6 - the wollensak vitax had a defocus knob ) some len designers stopped using the knob and had a ring
that was numbered and turned and pretty much did the same thing ( moved a group. ) you could move the group
and focus again if you wanted but that sort of defeated the purpose of the knob ...
i had a vitax ( sort of a petzval design ) and it had a knob which i didn't use very much. defocus systems
work best if you stop the lens down ( petzval lenses are sharp ) and they still allowed you to defocus the subject

jim galli's page has lenses and examples of what they can do / signature.
otherwise you might go to places like flickr or google and search with the lens type
and hope folks have that in the title or a tag.

often times you can get similar effects by front focusing a lens and shooting wide open
or unscrewing a group a quarter turn

[Jac@stafford.net]

[... snip good stuff ...] some lens designers stopped using the knob and had a ring
that was numbered and turned and pretty much did the same thing ( moved a group. )

Before I purge my old folders, I'll post two of the most particularly helpful posts regarding modifying lenses to get more soft focus, or to create it.

Mark Sawyer posted a suggestion that I applied to a F/4.5 14” Wollensak Velostigmat Series II. It allows us to screw the front element much further beyond the maximum of #5 softness. It is here (http://www.largeformatphotography.info/forum/showthread.php?56296-Wollensak-Velo-Diffusion-Ring&p=531043&viewfull=1#post531043). It was very easy to do.

Jim Galli writes of modifying a lens to be soft focus right here (http://www.largeformatphotography.info/forum/showthread.php?107284-Modifying-a-Wollensak-Velostigmat-7-1-2-quot-for-Soft-Focus&p=1067834&viewfull=1#post1067834).

[jnantz]

Before I purge my old folders, I'll post two of the most particularly helpful posts regarding modifying lenses to get more soft focus, or to create it.

Mark Sawyer posted a suggestion that I applied to a F/4.5 14” Wollensak Velostigmat Series II. It allows us to screw the front element much further beyond the maximum of #5 softness. It is here (http://www.largeformatphotography.info/forum/showthread.php?56296-Wollensak-Velo-Diffusion-Ring&p=531043&viewfull=1#post531043). It was very easy to do.

Jim Galli writes of modifying a lens to be soft focus right here (http://www.largeformatphotography.info/forum/showthread.php?107284-Modifying-a-Wollensak-Velostigmat-7-1-2-quot-for-Soft-Focus&p=1067834&viewfull=1#post1067834).

it has always amazed me how one can make
a 200+$ lens by modifying a 30$ lens ...

knowing these posts existed ...
i looked but came up empty :(
thanks for referring to them ... :)

- john

[Jac@stafford.net]

it has always amazed me how one can make
a 200+$ lens by modifying a 30$ lens ...

Oh, if only the lenses were $30.
.

[jnantz]

Oh, if only the lenses were $30.
.

lenses harvested off of folders are even less than that.
and sometimes they cover 4x5 without a hitch ;)

[CCHarrison]

Speed course:

1. The very first lenses for Dags were landscape lenses. Originals are super rare and slow (f16-f22). Popular 1839-1844 ish...
2. Petzval desigened lenses were made for portraits - fast (F3-F6) , sharp centers. 1842-1940 ish.... From 1840s to late 1860s about 95% of all images taken with a Petzval lens. Prices range from $ 50 to thousands....
3. Rapid Rectilinears came along late 1860s - med speed (F8) - good sharpness - ok for portraits - general use lens. Popular 1870-1920. In general much cheaper than Petzvals.

Read for an in depth article on Petzval lenses I wrote: http://antiquecameras.net/petzvallens.html This article also covers the development of other 19th century lens designs.

Good luck
Dan

[StoneNYC]

My head is now spinning... I've read so much I'm almost confused... Haha, so I understand a lot now except the Hemispherical lenses, and how they differ from Euryscopes.

Also, I wish one of our fine lens collector friends lived close, I would kill 5-10 sheets of 4x5 and 5-10 sheets of 8x10 just to compare all 5 (or so) of the basic design differences between the various styles of lenses, reading about the optics doesn't tell me about the look they give, I really need to actually see images not read about the lens element structures to know what is what (but now at least I understand a LITTLE more about optics, so thanks).

I'm just surprised there isn't someone who's used all these lenses on the exact same scene to compare the differences.

Thanks so far, this is all helping toward an end goal of a first bought inexpensive brass lens. It's looking like I'm leaning toward "views" and "hemispheric" mostly because of price, I DON'T want a portrait lens as I'm not into soft focus lenses in the center, I do like the idea of aberrations in the corners and sharp in the middle, but again a nice balance as Jim C. mentioned earlier the Darlot which is what I've been looking at, but which Darlot did you mean Jim?

Thanks.

[Nodda Duma]

it has always amazed me how one can make
a 200+$ lens by modifying a 30$ lens ...

knowing these posts existed ...
i looked but came up empty :(
thanks for referring to them ... :)

- john

The difference is about 2-3 hours' labor for a good machinist, including wages and overhead. It's also cheaper to paint a room yourself vs hiring a painter. It's not that much of a mystery.

[Jac@stafford.net]

Be prepared for a roller-coaster ride, Stone.

The very fact is that regardless of what you read, you will never know how a lens renders for you until you use it. Having a lot to write about means little.
.

[Jac@stafford.net]

The difference is about 2-3 hours' labor for a good machinist, including wages and overhead.

In my area, a good machinist is very difficult to find, and when you do find one, he's very expensive. Most 'machinists' today are really CNC machine operators who never knew the real thing.
.

[Will Frostmill]

Thanks so far, this is all helping toward an end goal of a first bought inexpensive brass lens. It's looking like I'm leaning toward "views" and "hemispheric" mostly because of price, I DON'T want a portrait lens as I'm not into soft focus lenses in the center, I do like the idea of aberrations in the corners and sharp in the middle, but again a nice balance as Jim C. mentioned earlier the Darlot which is what I've been looking at, but which Darlot did you mean Jim?

Thanks.

I've never found one for cheap, but I understand that there are "cheap-ish" petzval formula brass lenses made for early slide projectors (magic lanterns). Some modern, plastic, slide projector lenses also use the Petzval formula.

[StoneNYC]

I've never found one for cheap, but I understand that there are "cheap-ish" petzval formula brass lenses made for early slide projectors (magic lanterns). Some modern, plastic, slide projector lenses also use the Petzval formula.

Thanks, yes I've seen those too, I'm less interested in a projection version, the Hemispheric Darlot brand lenses tend to go for less it seems but SOUND more like what I would want. Which is why I'm trying to figure out how it differs from other lenses, I'm understanding (and correct me if I'm wrong) that the Darlot Rapid Hemispheric is simply slower than the petzval? Like f/4 for the Hemispheric vs f/3.5? For a petzval which also will have more swirl, but will the Henispheric also have some swirl?

And then there's coverage because I want one to cover 8x10 for contact portraits. Though I'm open to starting out with a 4x5 lens if it's cheap enough for trial purposes I suppose.

[kintatsu]

I'm just surprised there isn't someone who's used all these lenses on the exact same scene to compare the differences.

I don't think he did them all on the same scenes, but Ansel Adams used a wide variety of lenses. He also kept meticulous notes. By looking at different images where the lens info is available, you can see some of the differences. A quick search for Adon and Ansel Adams came up with several images made with the Dallmeyer Adon lens, and similar results for Dagor. Also check out Edward Weston's stuff, he often noted things like that.

While you may not find all the types you're looking for, there is plenty of info to be found. Patience and InvestiGoogling, especially by using the terms and image search will help get you closer.

I don't know how much this helps, but I hope it provides something useful for you to go on.

[jnantz]

The difference is about 2-3 hours' labor for a good machinist, including wages and overhead. It's also cheaper to paint a room yourself vs hiring a painter. It's not that much of a mystery.

removing a spacer or unscrewing an element a little bit requires a machinest for 2-3 hours labor ?

[8x10 user]

What type of look are you going for? If you want the sharp in the center and soft in the edges look then get a petzval. If you are looking for something with an even field of sharp focus and smooth creamy bokeh then you want a different lens type. How much depth of focus do you want? The lenses with lower DOF and larger apertures sell for more then their less rapid counterparts. An F/5 petzval will be a lot more affordable then an F/3.5. For the smooth and even look then you might want to consider something like a Cooke Series II, Tessar, Heliar, Rapid Rectilinear (F/8), Extra rapid rectilinear (some euryscopes), a dagor, or even a soft focus lens when stopped down. The less rapid Cookes are more affordable and so are the versions without soft focus. Projection petzval lenses are the cheapest petzvals and have the same sort of look but with less features like soft focus and aperture control. Projection petzvals that cover formats above 4x5 are more rare. Petvals that cover 8x10 are quite large, especially large aperture versions. A modern option to look into would be the Cooke XVa.

[Emil Schildt]

a few choices...

[Emil Schildt]

more---

[Emil Schildt]

and...

[Emil Schildt]

lens names under each image...

[Tin Can]

Fantastic, just what we need a series visually explaining SF

Thank you!

[Jac@stafford.net]

removing a spacer or unscrewing an element a little bit requires a machinest for 2-3 hours labor ?

A girlfriend of mine, a spoiled rotten Princess, would call a mechanic to open a soup can. Her idea of natural childbirth was like, without makeup.
.

[Emil Schildt]

you're welcome -

just a few more of my favorites...

[goamules]

... Hemispheric Darlot brand lenses tend to go for less it seems but SOUND more like what I would want. Which is why I'm trying to figure out how it differs from other lenses, I'm understanding (and correct me if I'm wrong) that the Darlot Rapid Hemispheric is simply slower than the petzval? Like f/4 for the Hemispheric vs f/3.5? For a petzval which also will have more swirl, but will the Henispheric also have some swirl?

And then there's coverage because I want one to cover 8x10 for contact portraits. Though I'm open to starting out with a 4x5 lens if it's cheap enough for trial purposes I suppose.

Names are basically ways manufacturers came up with to try to differentiate their lenses. But a Darlot hemispherique rapide is just a Rapid Rectilinear. They used that name because they were french, and it sounded good. The rest of Europe called them Rapid Rectilinears or Aplanats. All the same design, and pretty much the same look.

It's not "simply slower than a petzval." A RR is the lens that replaced the Petzvals in a lot of portrait studios. They were used, along with Petzvals, for portraits for 30 years, until the better corrected Anastigmats came out. So that's the difference, a petzval, though the sharpest in the center, has a curved field, which makes things go out of foucs towards the edges. A RR does not, but still has other aberrations like astigmatism. The Zeiss designs around the mid 1890s corrected even that. Interestingly, though the anastigmats replaced the Rapid Rectilinears, which quickly became obsolete and were no longer made, they did not replace quality portrait Petzvals. Those continued to be made another 30 years. The RRs had no advantage over a Dagor, Tessar, or Protar. But the Petzvals did.

Individual RRs will have slightly different looks, but all have a fairly flat field, and usually are around F6 to F8. Slower than a Petzval, but with less concern that the edges would be out of focus, if shooting groups. Yet Petzvals don't have to go out of focus at the edges, if you use a long enough one. If a head and shoulder shot, with a studio background, and using a correctly sized Petzval, it will give a similar look as an RR, just have shorter depth of field. No swirls, no edge aberrations. But for 8x10 you'd need at least a 14" or 16" one. People today try to get by with 12" ones, or use foliage as a background. Hence, swirls.

You can review portraits shot by various lens on a lot of sites like here, and choose what look you want. Instead of what sound! https://www.flickr.com/groups/lf-portrait/

[Nodda Duma]

removing a spacer or unscrewing an element a little bit requires a machinest for 2-3 hours labor ?

Don't know what's involved. Just saying that paying someone to do something you can't or won't do yourself is never free. The difference just so happens to be exactly what someone is willing to pay.

[Nodda Duma]

In my area, a good machinist is very difficult to find, and when you do find one, he's very expensive. Most 'machinists' today are really CNC machine operators who never knew the real thing.
.

That's unfortunate. Most of the machinists I've worked with were old school machinists. I had the good fortune of learning my way around a shop under the tutelage of a Navy machinist with something like 40 years' experience (and no missing fingers).

Part of that experience included learning how colorful the English language can be when put to use by veteran Navy personnel. Unfortunately, the only thing that particular experience gets me now is in trouble with my wife when I forget that the kids are in hearing range! :D

[Jim C.]

My head is now spinning... I've read so much I'm almost confused... Haha, so I understand a lot now except the Hemispherical lenses, and how they differ from Euryscopes.

Also, I wish one of our fine lens collector friends lived close, I would kill 5-10 sheets of 4x5 and 5-10 sheets of 8x10 just to compare all 5 (or so) of the basic design differences between the various styles of lenses, reading about the optics doesn't tell me about the look they give, I really need to actually see images not read about the lens element structures to know what is what (but now at least I understand a LITTLE more about optics, so thanks).

I'm just surprised there isn't someone who's used all these lenses on the exact same scene to compare the differences.

Thanks so far, this is all helping toward an end goal of a first bought inexpensive brass lens. It's looking like I'm leaning toward "views" and "hemispheric" mostly because of price, I DON'T want a portrait lens as I'm not into soft focus lenses in the center, I do like the idea of aberrations in the corners and sharp in the middle, but again a nice balance as Jim C. mentioned earlier the Darlot which is what I've been looking at, but which Darlot did you mean Jim?

Thanks.

The Darlot I have is... well ... a Darlot, they didn't have model numbers other than what they are classed under in old catalogs,
it's a petzval design and 8" focal length. I didn't see much swirly on an 8X10 compared to the 10" Seroco lens I have, but I haven't had a chance
to test it with the waterhouse stops I made, if there are swirlies the waterhouse stops will probably dull the effect depending on the f stop.

Cameraeccentric's site is a great place to start by looking thru the old catalogs, Gandolfi posted some great examples,
I might relapse into brass fever again because of his pictures, and CCHarrison and Garrett gave a great explanation of the lens type/names
and what design style they are, you need to narrow down what you want and work from there.

[Jac@stafford.net]

I had the good fortune of learning my way around a shop under the tutelage of a Navy machinist with something like 40 years' experience (and no missing fingers).

I learned to weld from an old ex-Navy ship welder. Stick welding. Today welding is so different. It is good to get out our 115 year old cameras today, isn't it.
Best,
j

[jnantz]

Don't know what's involved. Just saying that paying someone to do something you can't or won't do yourself is never free. The difference just so happens to be exactly what someone is willing to pay.


i DO know what is involved, and have done it myself.
it didn't cost me very much time or money.

[Will Frostmill]

you're welcome -

just a few more of my favorites...

Okay, everybody go home now. Gandolfi has won the thread.

[StoneNYC]

Just wrote a lot and lost it all.. Ugh...

Basically "thanks Jim"

Also. Gandolfi!!! Amazing! Ok, The fact that you might have used movements and your skill level in general not withstanding, the following are in order of most liked to least liked of the lenses, anything I don't list I have no interest in whatsoever.

Petzval3
U-heliar
Ilex Paragon
Aplanat (16x20)
Ilex Paragon (11x14)
Petzval

So I'm not sure what the difference is between the "U-heliar" and the "heliar240" but the U-heliar was more what I was thinking and the heliar240 was a beautiful image but too the sharpness lasted too far to the edge and the depth of field was too great for what I was looking for.

Not sure if the two ilex paragons are the same or different, but both are pleasant.

The aplanat is really interesting however it's 16x20 and wondering if it only looks sharp because of the size but could actually be unsharp on a smaller camera like my 8x10? But I do kind of like the Aplanat look.

Ultimately the Petzval3 image is what I'm looking to achieve I think.

I don't know how the Petzval designs differ but the petzval4-hermagis was not at all to my liking for what I want to achieve.

The Verito is a classic look and though it would be nice to have as an option, not what I'm currently looking for, but if I were going for soft focus that would be my choice.

I did kind of like the Eidoscope look as it fits my wants to a degree but it seems still a bit soft in the center. Hard to tell on a cell phone screen and with these new image size limits.

The Cooke 3.5, dallmeyer landscape, duplouich, kodak305, kronarette, all hold no appeal for me, the Plasticca was kind of neat, but not really what I want either and again if I were to do soft focus I guess at least I can be sure the Verito is the lens for me for that.

So, can you tell me more about the ...

Petzval3, Ilex Paragon, Aplanat, and U-heliar please?

It would be interesting to see how much these lenses might be similar and I acknowledge I may be fooled by the skill of the photographer in this small sampling, but it certainly helps a LOT, and I'm very grateful! :)

[Nodda Duma]

i DO know what is involved, and have done it myself.
it didn't cost me very much time or money.

I'm not sure what the cost difference between the $30 and $200 lens would be then.


edit: Wait a minute.. . THIS is the conversation you got worked up about? You do understand we're just having an idle conversation, right? Not everyone on the internet is out to get you. :)

[Mark Sawyer]

I'm not sure what the cost difference between the $30 and $200 lens would be then...

$170!

BTW, here's my old tutorial on how to desharpify a Velostigmat:

http://www.largeformatphotography.info/forum/showthread.php?57385-Velostigmat-Series-II-Info-and-Images

[8x10 user]

It might be helpful to know if the soft focus was "turned on" for the Cooke and Universal Heliar pictures.

[jnantz]

I'm not sure what the cost difference between the $30 and $200 lens would be then.


what i am suggesting is it doesn't take a machinest to unscrew a lens group and remove a spacer
as you seem to be suggesting. it doesn't take much time. i can't imagine why anyone would pay someone for 2-3 hours of work
to ... unscrew a lens. but then again a fool and his money ... and all that

[Emil Schildt]

So, can you tell me more about the ...

Petzval3, Ilex Paragon, Aplanat, and U-heliar please?

It would be interesting to see how much these lenses might be similar and I acknowledge I may be fooled by the skill of the photographer in this small sampling, but it certainly helps a LOT, and I'm very grateful! :)

Petzval3 was my oldest Petzval, made by Ross of London (ca 1850+) - ca 300mm on a 4x5 film. Very sharp and nice lens indeed!

Ilex Paragon (both with the same lens) with soft set on 5 (full) - I think it is similat to the more common Wollensak velostigmat SF lens. Good part is, you can choose the degree of softness with that one.

U-heliar is the Universal Heliar - a favorite of mine. Also here there's a soft focus option (here set on 5 again), but if you want less soft, you can... (not cheap I fear)

Aplanat or RR has been described earlier - you can find them ealisy and cheap - if you get a longish one for your 4x5, then the DOF will seem more shallow... Nice lenses!

(AS 8x10 user asks, the Cooke also have a choice of softness or not - here it is as soft as possible, but if you chose a "sharp" setting, that's what you'll get...

[Steven Tribe]

........... the Cooke also have a choice of softness or not - here it is as soft as possible..........


This restriction on the Cooke softness only applies to the later models ( including those with the spectacles!). The early models, apart from being about 35% lighter, have a "screw out" mechanism which continues until the barrel separates.

A good machine shop would be able to split the barrel of an ordinary series II Cooke and add a couple of threads.