OSCAR SIMON ANASTIGMAT LENS SATZ DRESDEN with STRANGE Optical attachment

[Gsavino]

Hello to All,

I recently acquired a nice OSCAR SIMON ANASTIGMAT LENS (DRESDEN) in a casket box.
There are two actual lenses in there (#3 and #4 that can work independently, one slightly wider than the other- I haven't measured them yet but possibly one is a 130mm and the other a 180mm), a nice, small brass barrel with iris (stops marked from 0 to 7- what system would that be ? Zeiss ? I figured fully open- on zero- it must be roughly f6,3), two light yellow/orange filters, a removable back metal cone with threads (probably just to black out the optical path), and a strange device I had never encountered before. I'll try to describe it (also see attached photo): It fits the diameter of the lens barrel but has no threads, on one side there is a mirror surface and on the other side a small hole. If I shine a light on the mirror I do see a little bit of it coming through. What could be the intended use of this device? Does anybody have a copy of the printed instructions that this casket set contained when originally sold? I would be most grateful for any information you might be able to give me about this lens and particularly about the mirror cap/device.

Many thanks for your help
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[Bob Salomon]

It sounds like part of the cast from The Odd Couple.

The mirror with the small hole sounds like part of a mirror alignment device. It would also need a mirror on the copy board. Usually these are front surface mirrors.

[Gsavino]

Yes, I also thought about some sort of alignment device, but there is virtually no transparency in the mirror. Looking through the hole as I shine a very strong light through, it almost looks like an extinction meter, but I know it can't be. Also, for alignment purposes, I think it should have a thread to fix it in exactly the right position, instead it looks like it can only be placed temporarily on the lens, by keeping it there with your fingers. I am very intrigued.....

[Greg]

In the late 1970s we acquired a round opaque filter with a small central mirror. When copying large transparencies with a 120 or 4x5 camera, you placed it in front of the lens, and it was supposed to reflect a round image back down onto the transparency. The round circle of light that it reflected should fall in the center of the transparency indicating that the lens and transparency were parallel to each other. My memories of this "accessory" are that it didn't work as it was supposed to. It was selectively marketed to members of the BPA (Biological Photographic Association). But then I seriously doubt that what you have is the same.

[Gsavino]

Indeed, I think I have seen the devices you are describing, but this lens, (per vademecum) should be from the early 1900's, and that would explain also the color of the two filters that came with it (yellow and orange) perhaps due to the orthochromatic plates of the time. What I really cannot explain is why my device has no threads. That would seem to indicate that it was to only rested temporarily over the lens or the barrel. The mirror side, as you more or less see from the pic is not in great conditions but it still reflects despite the patina. I am really interested in understanding more about this lens as in the several decades I used LF equipment I never came across anything like this. BTW, the coverage seems to exceed 4x5, but could not do a proper test as all my equipment is pack as I am relocating.I understand there was an instruction sheet that came with this lens (It was mentioned in the only other identical one I saw being sold in the past) but surely it is nowhere to be found in the internet. I attach below three more photos, one of which reveals the amount of transparency of the mirror when shining a strong light into it.206231206232 206233

[Bob Salomon]

Indeed, I think I have seen the devices you are describing, but this lens, (per vademecum) should be from the early 1900's, and that would explain also the color of the two filters that came with it (yellow and orange) perhaps due to the orthochromatic plates of the time. What I really cannot explain is why my device has no threads. That would seem to indicate that it was to only rested temporarily over the lens or the barrel. The mirror side, as you more or less see from the pic is not in great conditions but it still reflects despite the patina. I am really interested in understanding more about this lens as in the several decades I used LF equipment I never came across anything like this. BTW, the coverage seems to exceed 4x5, but could not do a proper test as all my equipment is pack as I am relocating.I understand there was an instruction sheet that came with this lens (It was mentioned in the only other identical one I saw being sold in the past) but surely it is nowhere to be found in the internet. I attach below three more photos, one of which reveals the amount of transparency of the mirror when shining a strong light into it.206231206232 206233

You don’t need equipment to check the coverage. All you need is a darkened room and a large white mount board.
Point the lens, in one hand, out a window. Hold the mount board behind it in your other hand behind the lens. Move the board towards and away from the lens till you see a sharp image on the board. That will show you how big a circle the lens throws.
If you want this to be very sophisticated just draw formats on the board before darkening the room.

[Gsavino]

Thanks, I did that, and the lens covers 4x5 easily, possibly 5x7 as well. What I can't figure out is the sort of lens cap (not really a lens cap as it has no threads and doesn't fit snugly either) that has a mirror on one side and a hole on the other. (See pics above )