Optical Design Will Wilon 4,5/105

I have picked up a Will Wetzlar Wilon 4,5/105 enlarging lens in the bay together with a lens turret. I have not been able to find any information on the optical design of this lens. Does anybody have any details?

RauschenOderKorn said:

I have picked up a Will Wetzlar Wilon 4,5/105 enlarging lens in the bay together with a lens turret. I have not been able to find any information on the optical design of this lens. Does anybody have any details?

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..with that combination of aperture and focal length it's most likely to be a Tessar.

Neil Grant said:

..with that combination of aperture and focal length it's most likely to be a Tessar.

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+1

Thanks for your thoughts. I also suspect it is a 4-lenses Tessar type.

The only information in the internet - which I was able to find - was a "rumor" that the lenses were cheaply made, plastic and had a kind of squarish aperture. None of that is true with the glass I have, it is extremly solid with a full-metal barrel and the iris of the aperture has 16 elements and makes a perfectly round circle.

I can't help on design info, or much else, but I do have a lens of the same brand - mine is a 50mm f/4.5. I got mine in the 60s, and it was considered "old" then, whatever old means. It came from our high school camera club moderator, either as a gift or very cheap. He knew I didn't have a 50mm lens at home (my dad had a hobbyist darkroom), so passed it on when he got a better lens. It had a small chip on edge of an element, but he said just stop down a little and it would be as good a lens as I would ever need. (Fwiw, he had a used Leica M-series, and I believe a Leitz enlarger, so I always presumed it would be very good quality - I just don't know for sure.)

I never did ever use it as the mounting threads were way too small for the available lens boards. I can't imagine it would be nearly as good as the lenses I have today, but who knows? Like yours, it has many blades in the iris (I didn't count them), and seems all metal. Testing it has been on my "list of things to do someday" since I got it.

I have disassembled the lens for cleaning today. Unfortunately the glasses are in poor condition and cleaning marks, a little haze and damage to coating surely will affect the optical quality.

The lens is actually a 135mm lens, not a 105mm as stated above. It is definitely a Tessar design, 2 elements in two groups in the front and and 2 elements in one group behind the aperture.

RauschenOderKorn said:

I have disassembled the lens for cleaning today. Unfortunately the glasses are in poor condition and cleaning marks, a little haze and damage to coating surely will affect the optical quality.

The lens is actually a 135mm lens, not a 105mm as stated above. It is definitely a Tessar design, 2 elements in two groups in the front and and 2 elements in one group behind the aperture.

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Thanks for the confirmation