Schneider G-Claron internal spacer?

[Roger Hein]

I recently purchased another G-Claron (240mm - sn 14,350,XXX). I noticed on this lens there is a brass spacer/washer between the front cell and the copal shutter. My other 'clarons', also late models, don't have this spacer. I did a web search and am a bit confused. Some posters (referring to Docter lenses) say to remove the ring to optimize the lens for infinity, others say to remove it for 1:5 (or closer). Any idea which applies to the Clarons?

[Arne Croell]

For the Docter Apo-Germinars, the optimization for infinity is with the ring installed.

[lee\c]

Roger, I have a 210 and 305 mm G-Clarons and neither have a spacer and they seem to focus just fine anywhere I put them. I say try it with the ring and then try it without the ring.

good luck and tell us what the answer is.

leec

[Michael Mutmansky]

Roger,

I think, (although I'm not positive), that the spacer was installed by Schneider to optimize the lens for infinity. I was told by a Schneider representative that they started optimizing the in-shutter G Clarons to infinity in the early 90's, and it wouldn't suprise me if that's what they did to do it.

I don't think it will make a difference at all if you shoot with it stopped down much anyway. The optimization does permit the lens to operate better in the larger apertures at infinity, but most people shoot with these lenses smaller than f22, and I doubt there is any appreciable difference at that point.

---Michael

[sanking]

Roger,

I have a 240mm G-Claron, Serial # 14285974, in a Copal #1 shutter, and there is no spacer ring. My lens focuses fine and gives very sharp results.

My lens must have been made shortly before yours, so it is possible that your lens has been optimized for infininty and mine has not. I gather that Michael does not think that the spacer will make much differnce with the lens stopped down, and I agree, but just out of curiosity, can you measure the thickness of the spacer ring and let us know?

[Jim Galli]

I've never seen a spacer on a G-Claron so far. FWIW the Computar's and Kyvytar's that were factory mounted in shutter for view camera use instead of Process Camera use have a 1mm shim at the rear element.

[Roger Hein]

I did try 'viewing' on the gg to see I could tell any difference - not a chance. I'm sure Michael's correct - at infinity distances and f/45 the hair isn't worth splitting. Sandy, if I'm reading my caliper correctly the ring is 0.016" in thickness. Thanks for all the replies!

[Arne Croell]

For comparison, with the Apo-Germinar 300mm that I own the difference in performance between the lens with and without the ring is very, very subtle, and only visible at the edges of the field at really high magnifications (f/22). The ring thickness there is 0.7mm if I recall correctly. Of course the Apo-Germinar is a Dialyte type and the G-Claron a Plasmat type, so the effect of changing the spacing might be different for the lens types.