convertible lenses

[scott russell]

The longest lens i have for 4x5 is 150mm. Is there a good place to start when looking for convertible lenses? Keh doesn't seem to have a lot. any recommendations?

[Gene McCluney]

While they might not call them "convertable" any Schneider Symmar (not Symmar-S) is a true convertable and you can find these readily. Be very sure that you have enough bellows for a "converted" lens. Your 150mm (if convertable) would be about a 300, and actually take more bellows than a non-converted 300mm. Look back thru the online lists of LF lenses and look for Schneider Symmar (and not "Symmar-S)

But if I were you, I would just look for longer focal length lenses, rather than convertable ones. They will be sharper than a converted lens.

[Walter Calahan]

How about http://cgi.ebay.com/Turner-Reich-Gundlach-triple-convertible-view-lens-f6-8_W0QQitemZ170231529688QQihZ007QQcategoryZ30076QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

or

http://cgi.ebay.com/TURNER-REICH-TRIPLE-CONVERTABLE-12-21-28-LENS-L-KNORS_W0QQitemZ330245858923QQihZ014QQcategoryZ15248QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

If your pockets are deep, there's this:

http://cgi.ebay.com/Nikon-Nikkor-T-ED-360mm-500mm-720mm-Triple-Con-Lens_W0QQitemZ380039025617QQihZ025QQcategoryZ30076QQssPageNameZWDVWQQrdZ1QQcmdZViewItem

But what do you want to do with longer glass.

You might simply need a 240 or 270 mm. Have you tried longer glass from a friend to see what fits your vision? I mean a quick drive out the Carroll County with a lunch stop at Baugher's might be in order. Their pie is excellent.

[lenser]

You also might search for either the Acuton or Caltar 215mm. They appear to be one and the same from Ilex and usually go for somewhere around $150 at the auction site. A great convertible lens with fine sharpness at every focal length.

[Jan Pedersen]

In addition to the 215/355 4.8 Acuton there is also a 150/247 4.8 Acuton both fine performers. the 150/247 covers 5x7 and is a bit more rare than the 215/355

[Turner Reich]

Find a TR 4x5 triple convertible.

[seawolf66]

May I suggest you go to the following web site and do some reading thru the vast booklets of lens this has to offer ; you will find that some mfg's state that their doppel or double anastigmat lens are convertable; I do not profess any knowledge on that subject; so go here cameraeccentric.com and have fun learning:

[jnantz]

you might poke around for a symmar 210/370.
it is a nice lens, as long as you have enough draw for the 370 part ..

[Ole Tjugen]

Here's a little table of Symmars with focal length of rear cell and minimum extension for infinity focus with the rear cell alone:

100 / 175 - 215
135 / 235 - 285
150 / 265 - 325
180 / 315 - 380
210 / 370 - 415
240 / 420 - 500
300 / 500 - 610
360 / 620 - 760

as you can see you need quite a lot more bellows draw with a converted lens than with a normal lens of the same focal length.

[Darryl Baird]

re: "240 / 420 - 500"

So my new 240/420 Symmar will require 1000mm of bellows to shoot 1:1?

That puts a tiny damper on my purchase :confused: ( but then again I really wanted the shutter for the 305mm G-Claron, so the Symmar lens is a bonus)

[sanking]

re: "240 / 420 - 500"

So my new 240/420 Symmar will require 1000mm of bellows to shoot 1:1?

That puts a tiny damper on my purchase :confused: ( but then again I really wanted the shutter for the 305mm G-Claron, so the Symmar lens is a bonus)

You can also use the Symmar convertible by leaving the front element in place and removing the rear. Performance will not be as good as when using the rear element, but you will need a lot less bellows draw.

Sandy

[Ole Tjugen]

No, a 240/420 Symmar will require 500+420mm extension to shoot 1:1 with the rear cell alone. And about 480mm with both cells, which is generally better.

Not even my 30x40cm camera has enough bellows for a tight headshot with a converted 360/620!

[Darryl Baird]

I went over to the Cameraccentric site and copied the Symmar brochure (what a god send that site is...!!!). Here's a quote:

The Schneider Symmar f/5.6 is of almost symmetrical design and permits excellent pictures to be taken at a close range, even up to an image scale of 1:1 (natural size).

If the distance between the lens and the subject is shorter still, the lens should be turned.

The side with the **engraving should always point in the direction of the greater direction,** regardless whether it is the subject or the image distance.
~~~~~~~~~~~~~~~~~~~~
OK, I'm trying to navigate (in my head) this concept, but I think there is some other "rule" that may apply. If I want to shoot with the rear element (aka the 420 conversion) and I'm closer to the subject than 36" or 920mm, I should put the rear lens element in the front...? (it doesn't have engraving, so it is now turned/reversed towards the film/bellows rather than the subject). Otherwise it remains in the rear as in the normal two-element usage.

I love this stuff, but I do wish I'd studied a bit more math and the technical stuff regarding lenses... too much fine art training. :p

[Ole Tjugen]

The rear cell alone isn't that optimised for anything, but it makes sense to reverse that too.

The 150, 180 and 210 are difficult to reverse, being in #1 shutters. The rest are easy - unscrew both cells, and mount each on the other side.

[Darryl Baird]

Ole, thanks. My "to test and to do" list just keeps getting longer everyday. :D

...keeps me out of (other) trouble I guess.

[Jim Galli]

Wollensak may have had some of the last and best classic convertibles. Their Raptar 1A came in many combinations and made it well into the single coated age. I have a lovely 4X5 5X7 version languishing waiting for me to use it. (I simply don't get the 4X5 out very often.) It is 8 3/4" f7.7 / 12 3/4" f12.5 / 20" f16 all snugged into a modern Rapax #1 shutter. Maybe Goldfield later today :cool: It's mate that came on the same day is a gorgeous 150 Heliar, also untested. Shame on me.

[scott russell]

I think the 210mm symmar is the perfect lens for me. I'm in the market for a 210 or 240 so the convertible part is just an extra plus. The longest rail i have is 21" so i wont quite get to a 1:1 with the lens, but i will definitely be able to focus closer than infinity on it. How exactly do you "convert" this specific lens? do you remove the back or front element, or reverse them?

[Ernest Purdum]

Scott, you screw off the front cell.

[Mark Sawyer]

Scott, the first thing you should do is see if you already have a convertable lens. Unscrew the front element of your 150mm and see if just the rear gives you an image at about twice the focal length. Any symmetrical lens is a convertable, and plasmats, probably the most common current design, are also convertable.

You'll want to do a test exposure to see if the resolution is acceptable, and you'll have to figure the new aperture scale, but that's not hard.

[scott russell]

the 150 I have is a symmar-s, so i don't think it would work, but i will try! I've noticed that the non-S symmars are all older, a lot of them are in compur shutters and seem to be more expensive. How do they differ from the S lenses besides the fact that one is convertible and one is not?

[Dan Fromm]

Scott, the -S is a major redesign. There've been many discussions about performance differences between various versions of the lenses that have been engraved Symmar. To the extent that there's a consensus, it is that the gain from the jes' plain Symmar (6/4 plasmat type, sold as convertible) to the -S is large enough to make the -S preferable and that the gain from the -S to the APO- is minimal.

If you want a longer lens, just get one.

Its been a while since I've read this thread from the beginning and I don't recall whether Ole Tjugen has pointed out that all Symmars are double anastigmats and can be used converted whether Schneider says so or not. If he hasn't, he should have.

[Ole Tjugen]

I haven't pointed that out - since that would also necessitate the usual caveats about performance as converted lenses. the short version is that some "double anastigmats" are better than others for conversions, and that there are some simple rules, and that there are exceptions to every rule. Oh - and that many double anastigmats, when converted, perform somewhat less well than a converted Rapid Rectilinear. Which leads to the statement that the best Aplanats (AKA Rapid Rectilinears, according to "common knowledge") are actually sharper in the center of the field than all but a very few anastigmats. Which opens up a whole new can of worms, and starts a debate that won't be over until easter. ;)

But for simplicity's sake, this picture (http://farm1.static.flickr.com/169/438377619_59565dccfc_b.jpg) was shot with a 150/265mm convertible Schneider Symmar, with the front cell removed.

:D

[BennehBoy]

So, are the APO lenses convertible?

[Ole Tjugen]

The rear cell of all double anastigmats will form an image; whether or not that image is of sufficient quality to qualify as "usable" is a subjective call.

[Mark Sawyer]

So, are the APO lenses convertible?

Depends on the apo lens. "Apo" just means apochromatic, a higher degree of color correction. Since tessars aren't convertible, apo-tessars won't be. Since plasmats are convertible, , apo-plasmats will be. With all the caveats Ole just pointed out.

[BennehBoy]

Well it's a 150 APO Symmar, I guess I can just remove the front element and try it. I have a 300/5.6 but it's VERY heavy, and presumably also convertible since it's also a symmar?

[Bob Salomon]

Well it's a 150 APO Symmar, I guess I can just remove the front element and try it. I have a 300/5.6 but it's VERY heavy, and presumably also convertible since it's also a symmar?

So are all old Sironar lenses. But Rodenstock recommended removing the rear cell to convert. This would also protect the shutter.

[Mark Sawyer]

So are all old Sironar lenses. But Rodenstock recommended removing the rear cell to convert. This would also protect the shutter.

Hmmm, isn't it preferable to have the aperture in front of a single-cell lens rather than behind it? This is how Rodenstock built the Imagon...

[Dan Fromm]

Mark, the general rule is that the manfacturer knows best. And yes, the other general rule is that single cells perform a little better with the diaphragm in front.

Cheers,

Dan

[Mark Sawyer]

Mark, the general rule is that the manfacturer knows best. And yes, the other general rule is that single cells perform a little better with the diaphragm in front.

Cheers,

Dan

The single cells performing better with the aperture up front complies with the laws of physics. The manufacturers knowing best complies with the manufacturers' law of manufacturers knowing best. And manufacturers aren't stupid like me...

Who to believe? I'd like to hear Rodenstock's rationale. Maybe it doesn't really make much difference with some lenses, so it's better to protect the shutter. No judgement here, just wondering...

Mind you, if it's not symmetrical, it could be a triple convertible, so it would make a difference in the focal length. But even there, it's generally accepted that the front cell is put behind the aperture.

Cheers, Dan!

[Peter K]

Mark, as I've mentioned before
http://www.largeformatphotography.info/forum/showthread.php?t=37689#8, a front aperture invents barrel distortion and a back aperture pincushion distortion. Normaly distortion comes together with spherical abberation. To correct this most simplets in box cameras where equipped with front apertures. Also the rear part of a Symmar is spherical undercorrected. But the front part of the Sironar is spherically overcorrected. This is the reason the old Sironar uses a rear diaphragm.

This is known since the sixties of the 19th century, described in the distortion theory by R. H. Bow and Th. Sutton. (Sutton was the inventor of the water filled panoramic lens.)

BTW the Imagon was made by Staeble. He was a realy good lensmaker but not a good businessman. So Rodenstock buyed his workshop, his knowledge and the Imagon. The Imagon is spherically undercorrected, so it needs a front aperture to avoid pincushion distortion. So two benefits are coming together: the correction of distortion and one can better handle this Imagon sieves.

Have fun

Peter K

[Mark Sawyer]

Thank you, Peter! This is why I love this forum, I'm always learning!

[Dave Brown]

I bought a Turner-Reich a few years ago, and I never use the thing - I can't figure out how to get the top down.

Seriously, I don't use it much. It gives me a nice selection of longer focal lengths, but if I'm not using my 300 (for 8x10) I generally find I want something shorter. For 4x5 my "normal" lens is a 135 Symmar; I just don't use it as a 235. I fact, these days, the 135 pretty much lives on the 4x5 and the 6 1/4 lives on the 8x10; I've learned to live with one focal length for each camera.

[scott russell]

You also might search for either the Acuton or Caltar 215mm. They appear to be one and the same from Ilex and usually go for somewhere around $150 at the auction site. A great convertible lens with fine sharpness at every focal length.

You know where i can get some info on the caltar 215 lenses? the ones i'm seeing are 4.8 and i'm wondering how much they cover and what they convert to...

[Mark Sawyer]

You know where i can get some info on the caltar 215 lenses? the ones i'm seeing are 4.8 and i'm wondering how much they cover and what they convert to...

It's one of my "standard" sharp lenses for 8x10, and covers with "modest" movements, but sharp to the corners. I'd guess a sharp image circle of 340mm, needing 312mm to cover. It converts to a nice 14"/360mm, and has a factory aperture scale for both focal lengths. I prefer mine to my 210mm gold rim Dagor, which is probably worth four times as much.

[seawolf66]

So are all old Sironar lenses. But Rodenstock recommended removing the rear cell to convert. This would also protect the shutter.


Question how does one tell if they have an older Sironar that can be used convtable like! F5.6 150mm serial #8783605 ?

[lenser]

Scott,

I turned to Google and finally found the following info and a lens chart for large format in general.

The Caltar in it's 215mm form covers an image circle of 301mm and with rear element only for 375mm it covers 468mm so 5x7 and 8x10 with ease. Again, I've been delighted with the sharpness at all focal lengths.

Tim

[scott russell]

that's more than enough for a 4x5. does it fit in a standard copal 3 sized hole?

[lenser]

Scott,

Mine is in the original Ilex #3 which I recently had Carol Millier (Flutotscamerarepair.com) completely CLA. It works like a charm and other than the slight inconvenience of using a bi pole flash sync attachment instead of a PC, I'm perfectly happy with it and have dead on exposures.

The Ilex is the same shutter (in several different sizes) that most, if not all, of the great commercial Ektars were mounted in.

You might contact someone like S.K.Grimes to check on what other shutters would work with these cells, but keep in mind that the original comes with the multi focal length f stop scale already mounted and a new shutter would have to have a new one made and installed at a premium over the cost of the already very expensive new shutter. Plus, you may have to have special shims made for the cells to fit, adding much more to the cost.

An extremely good CLA for the Ilex only cost me $50.00 from Carol.

The 215mm Caltar was also branded as the Acuton and Acutar from Ilex and there were other focal lengths made. Google Acuton or Acutar or 215mm Caltar and you'll discover several different references, some of which show some charting of focal lengths.

Cameraeccentric.com also has quite a bit of information about the early Ilex lenses, but I did not see anything as late as the convertibles. Go to his (Seth) site and click on the info button. Then scroll down the page to the three or four Ilex covers. Click on those and they open to the entire document.

Just to say it, I use eight different lenses on my 4x5's and more for my 8x10's and 5x7's. The 215mm Caltar is one of my favorites.

Tim

[lenser]

Sorry, Scott.

I had a duh moment and didn't thoroughly read your post. I thought you were asking about the shutter instead of the mount hole.

I'll measure mine tomorrow and send the dimensions.

Tim

[Jan Pedersen]

It's one of my "standard" sharp lenses for 8x10, and covers with "modest" movements, but sharp to the corners. I'd guess a sharp image circle of 340mm, needing 312mm to cover. It converts to a nice 14"/360mm, and has a factory aperture scale for both focal lengths. I prefer mine to my 210mm gold rim Dagor, which is probably worth four times as much.

It is a nice lens but i still prefer my 210 dagor over the 215 Acuton.
I have attached a page from a Burke & James catalog from the sixties showing the Caltar, acutar and Acuton models available.

[Bob Salomon]

Question how does one tell if they have an older Sironar that can be used convtable like! F5.6 150mm serial #8783605 ?

It would be engraved SIRONAR on the lens. Not Sironar N or Apo Sironar. Just plain old SIRONAR.

[seawolf66]

It would be engraved SIRONAR on the lens. Not Sironar N or Apo Sironar. Just plain old SIRONAR.
Thanks Bob and yes it just says Sinonar on the outsides edge of the lens : Thanks again;

[scott russell]

I came across a symmar 180/315 convertible in a copal shutter that i might end up buying. It seems to be the best fit for my lens selection right now. I have a nikkor 120sw and a symmar-s 150mm. If i added a 180/315 to the kit i could probably leave the 150mm at home and be set for most situations. is that a good price for that lens?

[scott russell]

So i looked up the size for the ilex 3 shutter that the caltar-s 215mm comes in, and it appears to be a little over 50mm. where can i find a lens board with this size hole, or get one drilled?

[lenser]

Any competent machinist will work on the metal boards, same on a wooden one, but a carpenter could also do the wooden one for you.

[Gene McCluney]

It should be mentioned, that those lenses that were "promoted" as being convertable are normally mounted in shutters that have multiple f-stop scales, showing the effective f-stop for the single cell, as well as the complete lens. Symmar's have this, Symmar-S lenses do not...even though they "could" be used "converted" with lesser quality.

[Kevin Crisp]

Scott: If you are buying the 180/315, check to make sure the front and rear rim threads are OK. They often need a disassembly when you buy them to clean out haze and if the threads are wrecked you have a real problem. Also, since the front rim was shiny on these (chromed, I think) some people painted the rims black and that will also prevent in many cases disassembly for a simple cleaning of the haze. There are a ton of these out there, they are great lenses, keep looking until you find a really clean one without these issues. The really late ones are in Copal shutters, but the Compur is a fine shutter and I wouldn't avoid a nice one just because it has a Compur shutter if it is working or needs only a CLA. Price? 180-225 for a nice one.