Schneider Symmar 180mm f5.6-315 f12 stuck front cell

[Pere Casals]

No worries, Pere; here's a story that will explain my comments better.
In 1985 I was newly-hired at Eastman Kodak Co. One of the lenses in the equipment cabinet there was a Schneider 180/5.6 'convertible' Symmar. I had wanted to use a long lens on my 4x5 camera, and it seemed that here was my chance. So I borrowed the lens for a weekend and took it out to the countryside. In my ignorance I removed the *rear* cell and made some pictures. When making contact proofs of the negatives, I found that they were of really poor quality, and gave up on the idea of the 'convertible' lens. (Remember that in those days there was no internet- and information was not easy to come by.) The lens did perform very well as a 180mm on the job; I had no complaints with it. I saved my money and eventually bought my long lens, a Nikkor-M 300/9.
Many years later, c.1999?, the question of convertible lenses came up again, and I realized my past mistake; I should have removed the front cell! So I thought to make a comparison, easy enough to do. And I learned a few things, back to my first point; that the (properly) converted Symmar did a good job, and that the Nikkor-M was superior to it. My test, with landscape subjects at infinity, photographed at small stops, replicated my own usual practice and can only be considered anecdotal. Certainly not a rigorous test...and the surprise was a happy one. But I found out what I needed to know, and have happily used my Nikkor-M ever since.

Hello Mark,

I'm a newcomer to LF, but as I've 4 convertibles of those I had to learn about it

IMO front cell alone should also perform well, as both cells are fully corrected, in fact early units also displayed the third focal (front cell only) in the face lettering. "Front cell only" configuration requires less bellow extension than normal, as principal points are displaced to the outer side of the board, this can be good for some field cameras.

Your 1985' (oh... one remembers a lot LF experiences !!!) soft result perhaps could be because focus shift. A single cell alone is not a very well corrected wide open, and best focus position depends on aperture, so if one focuses at /12 and then one stops to /32 we need to check focus again, with a really light tight cloth , or using bright points of the scene.

I suspect that a single cell alone has well corrected chromatic aberration even wide open, but spherical aberration is not very well corrected wide open. I think this because lens performace does not improve with a yellow filter, while we have focus shift than can be more related to the spherical corrections.

I've the 150 and the 210 that came with a gorgeous Norma, then I got another 210 for an stereo DIY project I've in course, and then I got a 360 because I'm interested in the 620 focal for 8x10.

Of course I agree that a "modern" Nikon or Sironar are technically superior (when not diffraction limited), at least because Multicoating... better microcontrast helps film resolving power !!

I got really impressed with what did a Nikon W 360 I borrowed... Anyway I feel that lens performance is not all, sometimes some technical slight defects of the lens may help...

Regards

[Robert Opheim]

I have had a 180mm / 312mm convertible Symmar lens since 1974. The convertible 312mm is not usable as a regular lens. It is very very soft - and does not carry much focus. The combination of the front and rear elements make a rather nice lens.

[Robert Opheim]

I have had a 180mm / 312mm convertible Symmar lens since 1974. The convertible 312mm is not usable as a regular lens. It is very very soft - and does not carry much focus. The combination of the two lens elements make a rather nice lens.

[Pere Casals]

I have had a 180mm / 312mm convertible Symmar lens since 1974. The convertible 312mm is not usable as a regular lens. It is very very soft - and does not carry much focus. The combination of the two lens elements make a rather nice lens.

I've a way different experience, I've the 150, the 210, and the 360 (Technika stamped), and I have had very decent results with the converted configuration, I tested that with CMS 20 film so lens behaviour is very well asserted. It is true that a single cell has focus shift and focus has to be checked again with lens stopped to the shooting aperture, not everybody knew that.

If you take a look to the Perez tests... http://www.hevanet.com/cperez/testing.html


You'll see that for the 265 conversion of the 150 he measured

f/16 48 48 23
f/22 48 48 33
f/32 42 42 38

So at f/22 one can only notice some slight softness at the far corners, and near no difference at /32.


Compare with measurement of the full 150 lens:

f/11 42 48 38
f/16 42 48 42
f/22 48 64 42

So conversion is a bit inferior in the corners but no that extremly far from regular configuration.

No skilled photographer can distinguish by eye if a practical negative is resolving 38 or 42 LP/mm, he needs a high contrast USAF 1951 pattern to say it, and a magnifier.

I concede that Perez test where practical tests and not lab tests, but anyway this a useful relative comparison.

Also it is well clear that most shooting conditions won't allow film to record more than 40 Lp/mm: TMX is a very sharp film, but only records some 50 Lp/mm for common textures, needing extreme 1:1000 microcontrast to record those extrange 200 Lp/mm.

So, to me, the converted configuration is not convenient (checking focus at /22 !!, and /12 max aperture), and of course there are better multicoated/faster choices, but a converted configuration does not limit a sound photographer ( I'm not one ): There is a fact, Ansel made the Moonrise with a single cell of the Cooke, a way worse convertible glass than the Symmar convertible.

[helios1014]

Hello all, just wanted to say thank you for the advice. I eventually tried the tape route and the cell came right off.

[Pere Casals]

Hello all, just wanted to say thank you for the advice. I eventually tried the tape route and the cell came right off.

Great !!! Simple solutions are the best ones !