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View Full Version : Obscure 240 G Claron Spacing Question



Kevin Crisp
16-Feb-2015, 09:41
I picked up another one, in barrel mount as for enlarging. And I've read the chatter about some Schneider salesman saying that at some point they optimized these for distance. This one was made in 1985 more or less.

This one, unlike all the other ones I've seen, has two shims in the mount behind the front element. They measure .2 and .4 mm in thickness. So my questions are:

1. Why? Never seen this before.

2. If you were mounting it in a Copal 1 would you ditch the shims or use them?

My experience has been that slight changes in cell spacing don't make a noticeable difference in taking lenses unless the focal length is short, then it seems to matter quite a bit. But I could be wrong.

Thanks.

Kevin

Kevin Crisp
16-Feb-2015, 10:00
And I'll add that the overall length of the new one in the barrel mount is 54.19mm. I checked another one in a Copal 1 (screwed in from a barrel mount with no shims) and it is 53.6mm.

Will S
16-Feb-2015, 10:42
In my polaroid copal 1 shutter it is about 40mm from back to front if that helps. No shims that I can see but the front element is 25mm and the back 19, so there is about 6mm inside of the shutter between the two elements.

Dan Fromm
16-Feb-2015, 10:59
Polaroid Copal Press #1 shutters don't conform to the #1 standard; their tubes are longer than the standard.

Will S
16-Feb-2015, 13:14
Polaroid Copal Press #1 shutters don't conform to the #1 standard; their tubes are longer than the standard.

Interesting.. It was really easy to mount this lens in it. Is there a reason not to use that shutter? I know the aperture scale is off, but that's usual isn't it?

Bob Salomon
16-Feb-2015, 15:37
Interesting.. It was really easy to mount this lens in it. Is there a reason not to use that shutter? I know the aperture scale is off, but that's usual isn't it?

Not if you order a new set of scales or have a service center calibrate a set of scales.

Kevin Crisp
17-Feb-2015, 10:07
Thread hijacking aside, does anyone have experience with a 240 G Claron with spacers?

Peter De Smidt
17-Feb-2015, 10:40
My guess would be that the spacers are to optimize the lens for closeups. Assuming you plan to use it for general landscape work, you might test that out. Leave the spacers in. Focus on something at a common distance for you. You might want to use considerable movement to get as close to the edge of the circle of good definition as you can. Shoot a negative at F22. Now remove the spacers and re-mount the lens. Take the photo again. Develop and compare them. If one gives better performance, then go that way. If not, then for your uses the difference is not significant. Pick whatever you'd like. If you don't use the spacers, I'd keep them somewhere safe.

I've done that test with a copal press shutter an my 240mm g-claron. The spacing is a bit different from the barrel the cells came in, but for my uses the results are perfectly fine.

Steve Goldstein
17-Feb-2015, 11:05
There are two different versions of G-Claron, the earlier all-cemented one based on the Dagor design and the later one based on the Plasmat. They have different overall lengths in Schneider's literature. The Dagor version is listed with OAL of 48mm in a 1976 document, while the Plasmat version is listed as 53.5mm in both barrel (May 82) and shutter mount (1998); the latter matches pretty well with your measurements. Schneiders info suggests there was no difference in length between barrel and shuttered versions as they came from the factory, so someone must have added these spacers either advertently or inadvertently. I haven't seen a lot of G-Clarons, but don't recall any spacers. The only lenses I've ever heard of with a spacer that thick are the Computar/Graphic-Kowa 150mm and 210mm.

I'd be happy to take those spacer rings off your hands if you decide you don't want them. And shoot me an email if you want PDFs of the various Schneider literature I mentioned.