rdeloe
Well-known member
Schneider-Kreuznach sold the APO-Digitar 35mm f/5.6 in various housings, and in two models, the well known one being the later XL-102° in a Copal 0 shutter. Much less common is the L-88° version in a Schneider-Kreuznach electronic shutter that is screwed to a lens board for the Plaubel digital view camera system that was developed by Jenoptik, Plaubel and Schneider-Kreuznach and announced at Photokina in 2002.
UPDATE #3: The thread started with the assumption that the L-88 version and the XL-102 version were distinct. Then we put together evidence that suggested they might actually be the same. And then I found the data sheet for the L-88, and thanks to Rod's analysis, it's now clear that they are different optical formulations. To cut to the chase, jump ahead to this post in the thread and read from there: https://www.getdpi.com/forum/index....tar-35mm-f-5-6-l-88°-on-gfx.75891/post-904739 Long story short, the L-88 is close but not the same. It has a smaller image circle than the successor XL-102. However, the price for the larger image circle may be a very small reduction in sharpness in the XL-102, based on comparing the MTF charts posted below. The L-88 is still an excellent lens if you can get by with an image circle of 70mm.
Image from a Schneider-Kreuznach ad; thanks to Rod (@4x5Australian) for sharing.
There’s a good chance you didn’t know about the L-88 version because it’s not common, and doesn’t figure prominently in documentation. Everything I know about it I learned from Rod (@4x5Australian), who filled me in after I bought one thinking it was an XL.
The seller said it was an L-88° version in the ad; alas, the significance of the labelling simply didn’t register because I didn’t know there were two versions. Why does this matter? The L-88° version has a 70mm image circle, while the XL-102° that is beloved by many on this forum has a 90mm image circle.
The L-88 version is not a good choice for people using a medium format back that can take advantage of the 90mm image circle. However, on my F-Universalis plus GFX setup, I can only shift a 35 L or XL 8mm because the rear of the lens is inside the GFX mount. An 8mm shift needs a ~68mm image circle, so I couldn’t use the rest of the XL image circle anyway. That took the sting away from discovering that I had not purchased the lens I thought I had purchased.
The flange distance of this lens is very short, so the standards are close together. Nonetheless, there’s plenty of room for around 5 degrees of tilt and swing before the recessed lens board hits the frame. This set of images shows the lens centred at infinity (left), tilted as far as it will go (middle) and shifted as far as it will go (right). A copy of the XL I tried seems to have about the same flange distance, so it offers no advantage on a GFX and F-Universalis with Rotafoot setup when it comes to shift, tilt and swing.
The price was right for this copy because it’s an electronic shutter on a lens board for a digital view camera that doesn’t seem to have sold many copies. My plan was to remount the cells in a Copal 0 shutter. This is always a risky proposition because these wide technical lenses need to be adjusted properly for best results. I like a challenge, so I took the chance.
To remount it, I needed a shutter. The XL version is often found in a standard Copal 0 shutter. I didn’t want a Copal 0 because with a 35mm lens, the shutter cocking lever and the aperture overlap, making it fiddly to change the aperture. I chose a late Compur 0 shutter because the controls are spaced better. Fitting the front cell onto this Compur 0 shutter required removing a decorative plastic ring that surrounds the centre of the shutter.
#0 shutters are supposed to have a distance of 20mm between the mounting surfaces of the lens cells, but the design allows for -/+ 0.025mm on either side of that value. Some #0 shutters seem to exceed that tolerance. For example, my copy of the lens in a Schneider electronic shutter came with three shims that added 0.21mm. This was too much spacing for the donor shutter I used (a Compur 0 set up for a 100mm lens). Fortunately, a single 0.09mm shim produced optimum results wide open.
Unfortunately, there was an unexpected catch to closing up the spacing. With a single 0.09mm shim, the rear surface of the front cell is in the same plane as the shutter, meaning the shutter would not close. I don’t use the shutter in the Compur 0 housing, so this is not a problem for me. In my use, the shutter is locked open with the lever on the housing, and it stays open. However, someone who wanted to use this remounted lens with the shutter in the Compur 0 mount would not be able to do so.
The final step in this remounting process was calculating which of the positions on the scale that came with the lens was f/5.6. In the spirit of “close enough is good enough”, I did this by using my Pentax-A 645 35/3.5 to figure out the shutter speed at f/5.6 against a blank wall, switched to the 35 L and moved the aperture lever on the Compur 0 shutter until I matched the speed. The “temporary” label you see in the picture, above, is likely to remain on the shutter until it wears off… or I find a way to make a professional looking aperture scale.
UPDATE #3: The thread started with the assumption that the L-88 version and the XL-102 version were distinct. Then we put together evidence that suggested they might actually be the same. And then I found the data sheet for the L-88, and thanks to Rod's analysis, it's now clear that they are different optical formulations. To cut to the chase, jump ahead to this post in the thread and read from there: https://www.getdpi.com/forum/index....tar-35mm-f-5-6-l-88°-on-gfx.75891/post-904739 Long story short, the L-88 is close but not the same. It has a smaller image circle than the successor XL-102. However, the price for the larger image circle may be a very small reduction in sharpness in the XL-102, based on comparing the MTF charts posted below. The L-88 is still an excellent lens if you can get by with an image circle of 70mm.
Image from a Schneider-Kreuznach ad; thanks to Rod (@4x5Australian) for sharing.
There’s a good chance you didn’t know about the L-88 version because it’s not common, and doesn’t figure prominently in documentation. Everything I know about it I learned from Rod (@4x5Australian), who filled me in after I bought one thinking it was an XL.
The seller said it was an L-88° version in the ad; alas, the significance of the labelling simply didn’t register because I didn’t know there were two versions. Why does this matter? The L-88° version has a 70mm image circle, while the XL-102° that is beloved by many on this forum has a 90mm image circle.
The L-88 version is not a good choice for people using a medium format back that can take advantage of the 90mm image circle. However, on my F-Universalis plus GFX setup, I can only shift a 35 L or XL 8mm because the rear of the lens is inside the GFX mount. An 8mm shift needs a ~68mm image circle, so I couldn’t use the rest of the XL image circle anyway. That took the sting away from discovering that I had not purchased the lens I thought I had purchased.
The flange distance of this lens is very short, so the standards are close together. Nonetheless, there’s plenty of room for around 5 degrees of tilt and swing before the recessed lens board hits the frame. This set of images shows the lens centred at infinity (left), tilted as far as it will go (middle) and shifted as far as it will go (right). A copy of the XL I tried seems to have about the same flange distance, so it offers no advantage on a GFX and F-Universalis with Rotafoot setup when it comes to shift, tilt and swing.
The price was right for this copy because it’s an electronic shutter on a lens board for a digital view camera that doesn’t seem to have sold many copies. My plan was to remount the cells in a Copal 0 shutter. This is always a risky proposition because these wide technical lenses need to be adjusted properly for best results. I like a challenge, so I took the chance.
To remount it, I needed a shutter. The XL version is often found in a standard Copal 0 shutter. I didn’t want a Copal 0 because with a 35mm lens, the shutter cocking lever and the aperture overlap, making it fiddly to change the aperture. I chose a late Compur 0 shutter because the controls are spaced better. Fitting the front cell onto this Compur 0 shutter required removing a decorative plastic ring that surrounds the centre of the shutter.
#0 shutters are supposed to have a distance of 20mm between the mounting surfaces of the lens cells, but the design allows for -/+ 0.025mm on either side of that value. Some #0 shutters seem to exceed that tolerance. For example, my copy of the lens in a Schneider electronic shutter came with three shims that added 0.21mm. This was too much spacing for the donor shutter I used (a Compur 0 set up for a 100mm lens). Fortunately, a single 0.09mm shim produced optimum results wide open.
Unfortunately, there was an unexpected catch to closing up the spacing. With a single 0.09mm shim, the rear surface of the front cell is in the same plane as the shutter, meaning the shutter would not close. I don’t use the shutter in the Compur 0 housing, so this is not a problem for me. In my use, the shutter is locked open with the lever on the housing, and it stays open. However, someone who wanted to use this remounted lens with the shutter in the Compur 0 mount would not be able to do so.
The final step in this remounting process was calculating which of the positions on the scale that came with the lens was f/5.6. In the spirit of “close enough is good enough”, I did this by using my Pentax-A 645 35/3.5 to figure out the shutter speed at f/5.6 against a blank wall, switched to the 35 L and moved the aperture lever on the Compur 0 shutter until I matched the speed. The “temporary” label you see in the picture, above, is likely to remain on the shutter until it wears off… or I find a way to make a professional looking aperture scale.
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I paid less than the cutoff for the lens itself, but I had to buy a Compur 0 shutter that had another lens in it. And then shipping and taxes. If I had a donor #0 shutter lying around, that would have saved me some money. All in all it's still a lot less than the going rate for XL in Copal 0 shutters.