Symmar 240mm F5.6 convertible to 420mm use?

Darryl Roberts · Jun 28, 2020

Hi,

Is the Symmar 240mm F5.6 convertible any good when using the 420mm element? Do you know the 420mm's image circle?

If I use the 420mm element, does the 240mm become the rear behind the lens board or do I just leave that off?

Thank you in advance for your knowledge.

Bob S · Jun 28, 2020

Not very good converted plus you need much more rail and bellows just to reach infinity and converting makes a much slower Lens. The front element is removed leaving the shutter exposed to dust, smoke, etc..

138S · Jun 28, 2020

Darryl Roberts said:
Hi,

Is the Symmar 240mm F5.6 convertible any good when using the 420mm element? Do you know the 420mm's image circle?

If I use the 420mm element, does the 240mm become the rear behind the lens board or do I just leave that off?

Thank you in advance for your knowledge.

IMO conversion is quite useable !!!! Of course some may think the counter.

Nominally you remove the front cell and then you use the green painted alternative aperture scale, if you instead remove the rear cell it will work, but the green aperture scale is not exact. The older Symmar convertible (Dagor type, until 1952) had three aperture scales: for the full lens, for the rear cell alone and for the front cell alone.

It has a similar image circle than the non converted lens, but illumination circle is much larger, so a compendium shade is recommended to avoid flare from all the light that will bounce in the bellows. If you use the compendium shade it has less flare than the full lens because it has half of the groups, being very contrasty.

The converted lens is as sharp in the center than the full lens, the corners will require stopping to f/22 or to f/32 to be well sharp, when stopped it is mostly as sharp than the full lens. If you shot portraits then corners are irrelevant so you may shot f/12 and you'll get a high quality smooth bokeh !! The conversion is a sound portrait lens...

Focus is an issue, the conversion has some "Focus Shift" (not the full lens), as you stop the less you may have to correct focus, so if you shot a landscape at f/22 then you should check focus at f/22, so you need a tight dark cloth, but if you are proficient you may also use this lens for landscape, but remember, you need a compendium shade and a tight dark cloth to focus at the shooting aperture to overcome focus shift.

The conversion can save you bellows extension if instead removing the front cell you remove the rear cell, this conversion is as good as the other and it requires less extension than the resulting focal.

I guess some people underrated the conversion because not being aware about the Focus Shift.

Those are the ratings C. Perez found for a Symmar convertible 150mm

Lp/mm before conversion, center-mid-corner, full lens 150mm

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

Lp/mm before conversion, center-mid-corner, half lens 240mm

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

This is practical DIY test, not a lab test, but it shows that the conversion is not that bad, in many shots you won't see any difference because real photograpy is about 3D scenes and many times not much is in perfect focus but in the DOF, so peak performance if not always important.

See this: https://www.kenrockwell.com/schneider/150.htm

So IMO it's quite useable if we overcome the limitations: compendium shade, stop at least f/22 for sharp corners, check focus again at the shooting aperture with a tight dark cloth.

If you use the 420mm for 4x5" (or even 5x7") you get easily sharp corners as you take more the image center, if you don't displace much the image center from the sheet center. This happens to me with the 360 converted to 620.

Quite easy, check it !!! You'll spend a sheet.

Here you have a 420mm conversion samples:

https://www.flickr.com/photos/denis...MQS-oVoy7b-s67ZVf-dDv9VR-7HG6wA-7HG6cy-dHaFqs

https://www.flickr.com/photos/denis...MQS-oVoy7b-s67ZVf-dDv9VR-7HG6wA-7HG6cy-dHaFqs

I've 4 Symmar convertibles.

Bob S said:
you need much more rail and bellows

Bob, if removing the rear cell then you need less bellows than regular, and shutter is protected, but aperture scale has to be recalculated.

Bob S said:
converting makes a much slower Lens.

Fuji Fujinon C 450 is f/12.5 and nobody complains much, anyway most LF shots are made beyond f/16, specially those in the 400mm range.

It is true that f/12 shows a dim image on the GG, but other 420 lenses won't be much faster, the problem of the conversion is that focus has to be checked again at the shooting aperture, so we need a tight dark cloth.

AgX · Jun 28, 2020

The plain Symmar is convertible. For the Symmar S Schneider explicetely did not advise such.

Nokton48 · Jun 28, 2020

Everything answered above. I concur.

One thing to add; you can improve optical performance a bit if you add a dark orange filter.

Try it Daryl and see! You may be pleasantly surprised.

removed account4 · Jun 28, 2020

the Schneider website used to have information about their convertible lenses in the info section
but since the website was rebuilt / upgraded its no longer there
you can probably get them to send you the info if you email them
https://schneiderkreuznach.com/en

I have a 210-370 convertible and have used it for years converted and love it. you sometimes have to refocus after you stop down because there maybe "focus shift". and sadly the focus nodes are well behind the lens so the converted lenses take an awful lot of bellows. that said they are usually sleepers and well worth the $$ spent.

have fun !
John

138S · Jun 29, 2020

jnantz said:
the converted lenses take an awful lot of bellows. that said they are usually sleepers and well worth the $$ spent.

Yes, but we can remove the rear element and using the conversion provided by using the front element alone, having shorter bellows than regular, but as mentioned we would need a new aperture scale or metering with a probe in the gg, becuase the front cell alone has no aperture scale for it.

Bellows extensions for the Symmar conversions, so OP would require a 500mm extension for the 420 conversion, to focus infinite, also 3m focus extension is provided, 590mm:

138S · Jun 29, 2020

Nokton48 said:
One thing to add; you can improve optical performance a bit if you add a dark orange filter.

Nokton, if you check the C. Perez tests he rates a symmar conversion with and without a yellow filter, finding no enhacement. This suggests that the flaws in the corners of the conversion when wide open may come more from spheric aberration than from CA, being the triplet cells well corrected for CA, as a bandpass filter don't solve the problem.

Anyway an orange filter may usually deliver a more contrasty image and usually a more sharp look, sure the orange delivers a very nice combination with the symmar !

Anyway as OP is a 4x5" user then there is no concern with the corners, the image circle at 40º is 287mm, but he only needs a 154mm circle to cover so he will only take the center-mid of the of the 420mm conversion, for him the 420 conversion will work mostly like the full lens, if not performing extreme shifts.

IMO those conversions are more interesting for the long focals, for the shorter focals we have many alternatives, but for example the 620 conversion for the 360 symmar is absolutely cool for 8x10" as it takes the center of the circle, and it even covers ULF in shutter.

neilt3 · Jun 29, 2020

jnantz said:
the Schneider website used to have information about their convertible lenses in the info section
but since the website was rebuilt / upgraded its no longer there
you can probably get them to send you the info if you email them
https://schneiderkreuznach.com/en

I have a 210-370 convertible and have used it for years converted and love it. you sometimes have to refocus after you stop down because there maybe "focus shift". and sadly the focus nodes are well behind the lens so the converted lenses take an awful lot of bellows. that said they are usually sleepers and well worth the $$ spent.

have fun !
John

Schneider might have dropped the information on lenses off their website , but it's still available here ;
http://web.archive.org/web/20160413...m/info/vintage_lens_data/large_format_lenses/

Other links include ;
http://web.archive.org/web/20160323174354/https://www.schneideroptics.com/info/vintage_lens_data/

http://web.archive.org/web/20020606223852/http://www.schneideroptics.com/info/ads_&_brochures/

AgX · Jun 29, 2020

The above data sheets only show that Schneider no longer hint at the lenses being convertible at the S range.
However in a written statement I got they explicetely advise not to convert the lenses from the S range.

removed account4 · Jun 29, 2020

138S said:
Yes, but we can remove the rear element and using the conversion provided by using the front element alone, having shorter bellows than regular, but as mentioned we would need a new aperture scale or metering with a probe in the gg, becuase the front cell alone has no aperture scale for it.

yes you can do this but what's the point ? a few mm less distance for infinity and tiny bit less or more FL, and a different aperture scale ? there really isn't that much of a savings and it is more of a PITA to not use the lens as designed, the focus node is still way off the. back and requires a long bellows. its not like the lens will magically require only 420mm of bellows to focus at infinity. you can remove the front or rear element from any lens and use it "converted" .. might as well use the Schneider as it was made to be used..

neilt3 said:
Schneider might have dropped the information on lenses off their website , but it's still available here ;
http://web.archive.org/web/20160413...m/info/vintage_lens_data/large_format_lenses/

Other links include ;
http://web.archive.org/web/20160323174354/https://www.schneideroptics.com/info/vintage_lens_data/

http://web.archive.org/web/20020606223852/http://www.schneideroptics.com/info/ads_&_brochures/

you rock ! I looked for 20 minutes or 1/2 hour yesterday and couldn't even get to the old website, this is great !
thank you !!

John

harlequin · Jun 29, 2020

I happen to have this lens, probably manufactured in late 60’s early 70s
When converting (using rear element only) the focal length does become 420mm.

On my 8x10 camera I find using a deep yellow filter does help as does f22-f32 which seems to be “ sweet spot” for this Schneider optic.

When doing portraits, yes a good dark cloth as it’s a dim image for focusing, the rear element gives a slightly less contrasty image as opposed to the lens fully configured with both elements in place (240mm). Which is just fine for portraits, I have not experienced the focus shift, or I haven’t noticed....I don’t think there is much room for camera movements on 810 with just rear element, someone please correct me if I am mistaken...

Enjoy the lens, the experimentation is worth it, a luminous 8x10 negative with bokeh and all the trimmings!

Be Safe!
Harlequin

138S · Jun 30, 2020

jnantz said:
and sadly the focus nodes are well behind the lens so the converted lenses take an awful lot of bellows.

jnantz said:

yes you can do this but what's the point ? a few mm less distance for infinity and tiny bit less or more FL, and a different aperture scale ?

Click to expand...

John, if you complain about the additional 80mm "awful lot of bellows" for a 420mm focal, then using the front cell solves that. It is true that you have measure the new scale...

138S · Jun 30, 2020

harlequin said:
the rear element gives a slightly less contrasty image as opposed to the lens fully configured with both elements in place (240mm). Which is just fine for portraits

What I found is that, with rear element alone, with a compendium shade contrast is high, as flare comes from the insanely large iillumination circle illuminating the bellow inside.

harlequin said:
I don’t think there is much room for camera movements on 810 with just rear element, someone please correct me if I am mistaken...

You are right, no room... The 500 and 620 symmar conversions have room for 8x10", but not the 420, this is for far landscapes. Anyway for portraiture there we may have room, circle size increases as we focus close, and anyway illumination circle is very big, so if our corners are Out of Focus then a lot of room is there.

harlequin said:
Enjoy the lens, the experimentation is worth it, a luminous 8x10 negative with bokeh and all the trimmings!

+1, of course the conversion has its limitations, but's way worth to experiment with.

AgX · Jun 30, 2020

138S said:
What I found is that, with rear element alone, with a compendium shade contrast is high, as flare comes from the insanely large iillumination circle illuminating the bellow inside.

But in general bellows (in their zig-zag state) are considerd very good light baffles.

138S · Jun 30, 2020

AgX said:
But in general bellows (in their zig-zag state) are considerd very good light baffles.

There are situations where bellows are very defective light baffles, when bellows are compressed or very extended.

At 500mm extension you may have bellows quite extended, in that situation you have a tunnel reflecting 10% the light or more depending on the angle, with a single reflections a ray end on the film.

With very compressed bellows (Using a Nikon SW 120 in my CAMBO 4x5") the bends of the bellows also form a tunnel... with scarce light baffling.

The illumination circle of the 420mm conversion may be 600mm, the vast majority of the light ends in the bellows, and you may have sun out of the framing but hitting the bellows.

Well, this is quite easy... maesure it !!! In my experience many times it has way more effect using a compendium shade than using a multi-coated lens instead a single coated one.

removed account4 · Jun 30, 2020

138S said:
John, if you complain about the additional 80mm "awful lot of bellows" for a 420mm focal, then using the front cell solves that. It is true that you have measure the new scale..

I didn't complain just stated it as a fact. I have used the front cell from my 210/370 ( I didn't bother with a new scale but winged it ) and while my Toyo had 445mm of bellows draw I still was not able to focus at infinity just like the rear cell, it took well over 450mm, even with the front cell. I needed a "top hat lens board" which I didn't waste my money on, so in some (rare?) cases it is 6 of one 1/2 dozen of the other. I've used the lens converted on a 5x7 camera with a longer bellows, no issue and the few mm difference didn't add up to much. my uneducated and uninformed guess is the lens in question the OP is talking about will require good amount of bellows probably closer or more than to 500mm ( at infinity a ton more if used to shoot portraits ) with the front cell and more for the rear cell, and it makes me question if measuring a new scale, a tedious process, is worth it if one wants to save a few mm ? these symmar convertibles are notorious for requiring an excessive amount of bellows ( plasmat design convertibles? ) and the OP would be better advised to use it unconverted, unless he has an exceptionally large bellows on his 4x5 camera, or use it on a large format camera that typically has long bellows, like a 5x7 camera with a reducing back ( plentiful and cheep these days ). these converted lenses throw a pretty large image circle and have no trouble covering a 5x7 sheet of film too. at least to me using the lens differently than Schneider optics had intended doesn't seem to make much sense, many people already complain about focus shift and poor image rendering used as intended and using the "other cell" is just more fuel to the convertible-haters'-fire. much of what is discussed on this website and other photography websites where people like to tap into discussions about technique and equipment tend to not make much sense to me.
ADAD ||YMMV

138S · Jun 30, 2020

jnantz said:
these symmar convertibles are notorious for requiring an excessive amount of bellows ( plasmat design convertibles? )
ADAD ||YMMV

Well, for the 420 conversion in particular you need additional 80mm more bellows, not a drama when you depart from 420.

If wanting to play the long focal game the as solution is a monorail, with a Norma, an F or a bare Cambo SC you have no limitations, you add as many bellows as you want. Not much aditional weight if you carry a F with extended bellows and with the 420mm converted lens that weights nothing, and if you also carry the front cell then you have another focal for little more weight. A field camera with a tele may weight similar, the Nikon T 360mm weights 800gr.

For long focals better to get long bellows. If you have to extend too much the bellows of a field camera then you have a tunnel reflecting a lot to the sheet, so you should carry a compendium shade to avoid insane flare if lens circle is large, the MC does not prevent that kind of flare....

jnantz said:
at least to me using the lens differently than Schneider optics had intended doesn't seem to make much sense

John, how you can say that ? You are the man developing with Robusta when film is specifically intended to be developed with the exclusive soup manufacturer says !!!

... you craft amazing images until I know !!!

IIRC, Jim Gally makes amazing images with the single front element stripped from the front cell of the convertibles, no manufacturer can tell us how to get some fun

jnantz said:
the convertible-haters'-fire.

Of course conversions have some technical limitations, but they have no creative limitations, creative limitations are in the photographer.

That "haters'-fire" is... funny...

"For instance, Ansel Adams used a Cooke triple convertible for some of his most famous images according to an article by Gordon Hutchings in View Camera magazine, July/August 2004. Ansel used the 19" (480 mm) component for "Aspens, Northern New Mexico," 1958; both components to get 12" (300 mm) for "Clearing Winter Storm, Yosemite National Park," 1940; and the 23" (580 mm) component for "Moonrise, Hernandez, New Mexico," 1941. Enough said?" (Ken Rockwell)

No doubt that those symmar convertibles are well better than the glass used by Adams. Usually we don't need better glass than Adams, what we usually need (me at least) is learning quite a bit from those masters around.

Well, Ansel Adams made his most famous image with a single cell of his convertible, so... it's the indian and not the arrow, isn't it ?

removed account4 · Jun 30, 2020

138S said:
Well, for the 420 conversion in particular you need additional 80mm more bellows, not a drama when you depart from 420.

If wanting to play the long focal game the as solution is a monorail, with a Norma, an F or a bare Cambo SC you have no limitations, you add as many bellows as you want. Not much aditional weight if you carry a F with extended bellows and with the 420mm converted lens that weights nothing, and if you also carry the front cell then you have another focal for little more weight. A field camera with a tele may weight similar, the Nikon T 360mm weights 800gr.

For long focals better to get long bellows. If you have to extend too much the bellows of a field camera then you have a tunnel reflecting a lot to the sheet, so you should carry a compendium shade to avoid insane flare if lens circle is large, the MC does not prevent that kind of flare....

John, how you can say that ? You are the man developing with Robusta when film is specifically intended to be developed with the exclusive soup manufacturer says !!!

... you craft amazing images until I know !!!

IIRC, Jim Gally makes amazing images with the single front element stripped from the front cell of the convertibles, no manufacturer can tell us how to get some fun

Of course conversions have some technical limitations, but they have no creative limitations, creative limitations are in the photographer.

That "haters'-fire" is... funny...

"For instance, Ansel Adams used a Cooke triple convertible for some of his most famous images according to an article by Gordon Hutchings in View Camera magazine, July/August 2004. Ansel used the 19" (480 mm) component for "Aspens, Northern New Mexico," 1958; both components to get 12" (300 mm) for "Clearing Winter Storm, Yosemite National Park," 1940; and the 23" (580 mm) component for "Moonrise, Hernandez, New Mexico," 1941. Enough said?" (Ken Rockwell)

No doubt that those symmar convertibles are well better than the glass used by Adams. Usually we don't need better glass than Adams, what we usually need (me at least) is learning quite a bit from those masters around.

Well, Ansel Adams made his most famous image with a single cell of his convertible, so... it's the indian and not the arrow, isn't it ?

well -- its good you are able to fix the long bellows problem but it was the OP who asked the questions about the lens how it was intended to be used &c. he never came back after the first post. no clue if the OP has the same cameras as you or the same ability to cobble together stuff so it solves the problems that arise from not using lenses as the optics makers intend. no one has any idea if the OP is into perfection / perfect images, like the many people seek perfection.. perfectly exposed zone system type negatives coupled with papers that they enlarge or contact print on to give rich full tonal range 3D looking images.

yes Jim has published extensively about modifications he has made with lenses &c. but he is a soft focus enjoyer, no one knows if the OP wants images that are full of aberrations and issues that might drive a west coast school f64 type to the local asylum.

regarding the triple convertible saint Ansel used well you don't need to look far in the photrio archives to find people hating on triples, you know, unless they are the modern cooke triple that costs like $7,000 that was well made and had all the "issues" vintage triple convertibles were often riddled with issues. vintage triples often are placed with quality issues. that said, I regularly use a wollensak 1a (triple) and love it, but then again as mentioned previously my working methods would probably have a f64 type hauled away in the twinkie mobile in a shirt with the long arms that tie off in the back to be left in a rubber room. ( or they might suggest *I* need to be taken away )
total agreement about creativity &c. but some people like things to be "just so". and to be honest we don't really know what side of the road the OP is standing...

regarding the coffee. .. it works as well or better than the manufacturers concoctions and in 6 months when the supply chain is broken and no one is able to process film in their favorite chemistry, I'll be roasting coffee in my driveway ..
YMMV

138S · Jun 30, 2020

jnantz said:
, unless they are the modern cooke triple that costs like $7,000 that was well made and had all the "issues" vintage triple convertibles were riddled with excised.

Well, some people buy motivated a lot because of hype, others have more other criterions... this is complicated to explain, a bit like with cars...

it is true that a non convertible lens may have an advantage for the manufacturing. In that case some aberrations may get more undercorrected or more overcorrected as inter-cell spacing is modified by a bare shim in the front cell, probably this easily increases the proportion of the samples that are technically excellent. Also, by removing the requisite that both cells have to be individually well corrected the designer has more possibilities to correct better some aberrations...

...and also convertible lenses were a drawback for the industry, if not shoothing much with the converted focal then the limitations in the conversion were not a big issue, perhaps ruining an additional sell.

Anyway in my experince those conversions are specially interesting for the long focals, (if we have bellows) for 8x10" the 500mm and the 620mm conversions are super attractive, add that they come for free. In particular I'm amazed with the 620mm conversion from a Technika stamped 360, the 8x10" corners are tack sharp even when well open at f/16 because the center-mid is taken, personally I don't feel the need to get a Fujinon C at all... Of course a Pro would have preferred another lens, no doubt... The thing I learned is that I need the compendium shade because the illumination circle is insanely big and this generates flare, with the shade it is surprisingly contrasty.

I'm curious about the real technical performance that this 620 conversion delivers, this is something I want to measure for 8x10", it cannot be bad.

Nokton48 · Jun 30, 2020

Darryl our OP has a 4x5 Norma and a 5x7 Conversion kit. The Norma can be extended infinitely.

I have all the convertible chrome Symmars, it will be interesting to try them converted, particularly the two really big ones. I will test them with 8x10 as I have time. I will test them against my fairly complete collection of Apo Ronars. I'd like to find the 800mm and 1000mm ones that don't cost the Moon..............

138S · Jun 30, 2020

Nokton48 said:
it will be interesting to try the converted, particularly the two big ones. I will test them with 8x10 as I have time.

You may have a beautiful surprise !!! Those conversions are the powerful ones.

Let me suggest to measure flare with and without compendium shade, you should find that the conversion is very contrasty with the shade, well more than the full lens as it was two groups only.

Symmar 240mm F5.6 convertible to 420mm use?

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