Schneider 240mm f9 G-Claron lens question

[John Wiegerink]

A while back I bought a 240mm f9 G-Claron to use on my 8X10 camera I'm refinishing. Since I was still refinishing the 8X10 camera I put the lens aside until I could try it on the camera. Well, I decided to try it on my 4X5 and then the 8X10. Well, to make a long story short I wasn't really happy with how the results looked. It just didn't seem to be as good as what I had heard from other folks. The lens is clean so I know that's not the problem. The only thing I can think of is that it is mounted in a Copal Press No. 1 instead of a regular Copal No.1. I'm beginning to think the distance between front and rear croups might be off. I checked the specs of the lens mounted in a regular copal No.1 and the total length is 53.5mm. I measured mine and it's short of that at 50.495mm. Could that difference in total length make that big of a drop in image quality? I guess my question is is if somebody out there has this lens in a regular Copal No.1 coulD they've so kind and measure the total length from front to rear and see if it is 53.5mm. If it is I'll then have to shim mine to get the image quality I'm hoping for. I know it has to be better than what I'm seeing from this.

 

[RalphLambrecht]

A while back I bought a 240mm f9 G-Claron to use on my 8X10 camera I'm refinishing. Since I was still refinishing the 8X10 camera I put the lens aside until I could try it on the camera. Well, I decided to try it on my 4X5 and then the 8X10. Well, to make a long story short I wasn't really happy with how the results looked. It just didn't seem to be as good as what I had heard from other folks. The lens is clean so I know that's not the problem. The only thing I can think of is that it is mounted in a Copal Press No. 1 instead of a regular Copal No.1. I'm beginning to think the distance between front and rear croups might be off. I checked the specs of the lens mounted in a regular copal No.1 and the total length is 53.5mm. I measured mine and it's short of that at 50.495mm. Could that difference in total length make that big of a drop in image quality? I guess my question is is if somebody out there has this lens in a regular Copal No.1 coulD they've so kind and measure the total length from front to rear and see if it is 53.5mm. If it is I'll then have to shim mine to get the image quality I'm hoping for. I know it has to be better than what I'm seeing from this.

Photrio has a lens desighner on board. It's forhim to answer. My guess is, the answer is 'Yes.".

 

[DREW WILEY]

What f-stop were you using, and what kind of view camera movements, if any? This lens should be exceptionally crisp with 4x5 format anywhere from f/11 to f/32, anywhere from 1:1 to infinity. With 8x10, you want to be more around f/22 to f/45 for optimal performance.

I only have experience with the Copal 1 shutter, so can't respond to the Press shutter issue. But any difference in spacing would make me suspicious.

 

[abruzzi]

3mm seems like a lot, it also seem unusual that there would be that difference. I've heard that some Compur #0 shutters with 90mm angulons were non standard, but I haven't heard of non standard spacing on anthing Copal 0 or 1 (3 of course has the 3 vs 3s issue.)

 

[John Wiegerink]

I tried just one holder two shots, one at f16 and one at f22. I used front rise to get near the edge/corner limit, but the overall image just didn't seem to have any great sharpness to it. I know this is single coated, but the scene would not have been hard on an uncoated lens even. I suspecting the spacing also. Or the fact that maybe somebody took it apart to clean and assembled it wrong. I've had that happen before, but those image results show much more than this. I thought the Copal Press shutter would have had the same specs measurement wise as a regular Copal shutter, but I could be wrong.

 

[Erik L]

Do you happen to have a regular copal 1 laying around you could swap and remeasure? Now you’ve got me worried as I have the same lens in a copal press as well…

 

[John Wiegerink]

Do you happen to have a regular copal 1 laying around you could swap and remeasure? Now you’ve got me worried as I have the same lens in a copal press as well…

Erik,
I'm going to dig into my bag of lenses and see if I have a Copal No.1 here with me. My problem is that most of my gear is down state at home and I'm back north at the cottage. I know I have one down state, but here?
How does your lens work for image quality? Are you using it on an 8X10 or 4X5?

 

[reddesert]

Measuring the overall length of a lens doesn't tell you everything, because it depends on the mechanical length of the lens cells, and that could change during the history of manufacture without changing the optical design. Further, there are two different types of G-Clarons, Dagor and plasmat designs, so if you compare the length of one type to the length of the other type, you'll probably get different answers. What you could do is remove the lens cells from the shutter, and measure the thickness of the shutter from mount thread to mount thread to see if it matches the usual Copal. While doing this you can inspect the lens cells for any issues, haze, etc.

There's a link somewhere on LFPF about how to distinguish the two types of G-Clarons.

A shot-in-the-dark question is whether the lens has focus shift - I don't think a G-Claron should, but it might if it were spaced incorrectly. If it does, you need to refocus after stopping down to the taking aperture.

 

[GregY]

John, I had a 240 G Claron that i used on my 5x7 & it was flawless....& sharp. I was never disappointed in the results. Good luck sorting out the mounting/ shutter issue

 

[Erik L]

I’m using it on 8x10 and it is fine for my needs. It doesn’t blow me away with biting sharpness but the resolution seems good. I just stuck the cells in the barrel that it came from and it measures the same as when it’s in the copal press. Might there be a shim that your not seeing to account for the different measurements you seeing?

 

[John Wiegerink]

I’m using it on 8x10 and it is fine for my needs. It doesn’t blow me away with biting sharpness but the resolution seems good. I just stuck the cells in the barrel that it came from and it measures the same as when it’s in the copal press. Might there be a shim that your not seeing to account for the different measurements you seeing?

Eric,
I was just going by the specs/measurements supplied by Schneider of 53.5mm in length. Eric, did you have a measurement in mm's of the length of your barreled lens? Is it close to 53.5mm?

 

[DREW WILEY]

You can get a tiny bit of resolution loss way out toward the corners of an 8x10 exposure using this lens. But I'm talking about some pretty big enlargements before this becomes evident. Keep in mind that for critical work, especially expensive 8X10 color film intended for big print sizes, I always use precision adhesive film holders, which keep the film flat and in focus to a degree conventional holders simply can't.

 

[John Wiegerink]

A shot-in-the-dark question is whether the lens has focus shift - I don't think a G-Claron should, but it might if it were spaced incorrectly. If it does, you need to refocus after stopping down to the taking aperture.

That is something I never thought to check on this lens, but it's possible. I guess I'm just going to have to do a process of elimination with this one. I think I'll ask it out to the length Schneider says it's suppose to be and try it. If that works I'll shim it. If it doesn't I'm going to check to see if it was assembled properly or I should say reassembled. I'll figure it out one way or the other, because I want results like GregY posted.

 

[John Wiegerink]

You can get a tiny bit of resolution loss way out toward the corners of an 8x10 exposure using this lens. But I'm talking about some pretty big enlargements before this becomes evident. Keep in mind that for critical work, especially expensive 8X10 color film intended for big print sizes, I always use precision adhesive film holders, which keep the film flat and in focus to a degree conventional holders simply can't.

Drew,
I don't think I was coming close to the limit on the corners even. It almost looks to me that it has a very weak fog filter or soft focus filter on it. Maybe it is focus shift? I'll check it out more in the morning with I have some daylight.

 

[Erik L]

Eric,
I was just going by the specs/measurements supplied by Schneider of 53.5mm in length. Eric, did you have a measurement in mm's of the length of your barreled lens? Is it close to 53.5mm?

John I get 53.086mm in both barrel and copal press. However my caliper is not the most accurate but the barrel and copal press measure the same.

 

[Dan Fromm]

As has already been mentioned, two design types were sold as G-Clarons. Dagor type and plasmat type. 240/9 G-Clarons of both types were made to fit Compur #1 shutters, tube length 20.0 mm. Both cock-and-shoot and press #1s have the same tube length. Copal #1s conform to the Compur standard.

John, you looked up total length for the plasmat type 240 G-Claron. My Schneider documentation agrees with yours, total length 53.5 mm. If I read Schneider's documentation for the dagor types correctly, the 240/9 dagor type G-Claron's is 48 mm.

Is your shutter a Polaroid-Copal #1 Press? Its been decades since I measured, but IIRC that shutter's tube length is longer than the #1 standard 20 mm.

 

[John Wiegerink]

John I get 53.086mm in both barrel and copal press. However my caliper is not the most accurate but the barrel and copal press measure the same.

Eric,
Thank you so much for that measurement. I now know where to start in the process of elimination. For some strange reason my Press No.1 must have a short flange on one side or both. Like reddesert suggested this could cause focus shift among other things. It's a good place to start anyway. Thanks again!

 

[DREW WILEY]

These lenses wouldn't exhibit any focus shift unless they represent an early dagor style retrofitted into a shutter, rather than the typical later in-shutter plasmat version. If in doubt, simply focus at f/11 instead of wide open.

 

[reddesert]

John, one can't infer that the shutter is too short without measuring the shutter. Read Dan Fromm's post #16. For all we know, you have a Dagor-type G-Claron mounted in a shutter that is too long rather than too short.

I think it should be possible to tell whether one has a Dagor or Plasmat type by counting the reflections in an individual cell (front or back) - two strong reflections in a cell would be a Dagor, four strong is a Plasmat. That's just an inference as I have never had or touched the Dagor type.

 

[John Wiegerink]

As has already been mentioned, two design types were sold as G-Clarons. Dagor type and plasmat type. 240/9 G-Clarons of both types were made to fit Compur #1 shutters, tube length 20.0 mm. Both cock-and-shoot and press #1s have the same tube length. Copal #1s conform to the Compur standard.

John, you looked up total length for the plasmat type 240 G-Claron. My Schneider documentation agrees with yours, total length 53.5 mm. If I read Schneider's documentation for the dagor types correctly, the 240/9 dagor type G-Claron's is 48 mm.

Is your shutter a Polaroid-Copal #1 Press? Its been decades since I measured, but IIRC that shutter's tube length is longer than the #1 standard 20 mm.

Dan,
I was going to PM you even before I posted this thread, but figured you'd chime in with some help. My lens is a Plasmat since the ser. no. is 13336602 and it has 52mm filter threads. While I was just over on the Large Format forums page looking for answers I read that a fellow there had one in a Copal Press no.1 and when he removed the front group it had two shims. Mine is in a non-Polaroid Press shutter so maybe it's missing the two shims? All I know is it's short of the 53.5mm Schneider says it's suppose to be. Good as place to start as any I guess. I'll just unscrew the front group to reach the 53.5mm mark and see what happens.

 

[GregY]

John, one can't infer that the shutter is too short without measuring the shutter. Read Dan Fromm's post #16. For all we know, you have a Dagor-type G-Claron mounted in a shutter that is too long rather than too short.

I think it should be possible to tell whether one has a Dagor or Plasmat type by counting the reflections in an individual cell (front or back) - two strong reflections in a cell would be a Dagor, four strong is a Plasmat. That's just an inference as I have never had or touched the Dagor type.

Are the filter sizes different? I know on the 210, my G-Dagor is 40.5.... the plasmat is 49mm...

 

[John Wiegerink]

Are the filter sizes different? I know on the 210, the G-Dagor is 40.5.... the plasmat is 49mm...

Yes, mine is 52mm and a Plasmat and the Dagor is smaller, I think 46mm?

 

[DREW WILEY]

There's also the possibility of cobbled together mismatched front and rear cells.

 

[Steve Goldstein]

Yes, mine is 52mm and a Plasmat and the Dagor is smaller, I think 46mm?

Schneider's product literature says 46mm for the Dagor version, 52mm for the Plasmat.

 

[Ian Grant]

Photrio has a lens desighner on board. It's forhim to answer. My guess is, the answer is 'Yes.".

It has at least 3.

When Schneider sold off surplus stock Xenar, G-Claron, Centre filters. etc, in the early 2000s, they stated that their Copal mounted G-Claron lenses were optimised for use to Infinity. Essentially that meant different spacing to the copy camera barrel mount lenses.

In an article on post WWII CZ LF lenses, one Apo Tessar has a surprisingly large maybe 1cm spacer to convert between Macro/Copy use and normal Infinity.

The 90mm f6.8 Angulon has a bad reputation, well those under the 5 million serial number. The late Dean Jones of Razzle Dog Polaroid conversion fame realised that the issue was actually the batch of Compur #0 shutters used. The tube size was often out of tolerance, too long, he re-machined to the correct tolerance and suddenly a poor lens became sharp.

So yes, spacing can be critical.

Ian