Fitting g claron into compur shutter?

[Tomasz Segiet]

Hello there,

I have a question; I have an old compur shutter (F Deckel Munchen) , and a enlarger-mount G-claron 240 that I would like to mount in it. The threads are ok, that is, both elements screw in, but not as close as in the enlarger mount. Is there any way to do something with it? Or maybe the difference in spacing between elements is not a problem?

I'd be grateful for advice. Thanks in advance!

Tomasz

 

[PHOTOTONE]

Have you tried putting the lens/shutter combination on a camera and looking at the image on the ground glass? That should tell you what you want to know. Maybe shoot a test sheet.

 

[Richard Kelham]

If the spacing between the front and rear lens cells is wrong then the quality of the image will suffer. A modern Compur (or Copal, Prontor) shutter should have the correct thickness for your lens cells, though you will still have to calibrate the aperture scale.


Richard

 

[Roger Hicks]

Dear Tomasz,

Measure the front-rear separation (overall length front-to-back) on the G-Claron or get it from the Schneider web-site. Shim the shutter to give the same -- but bear in mind that the optimum separation for enlarging may not be the optimum separation for photography at infinity.

Cheers,

Roger (www.rogerandfrances.com, where you'll find free information on how to do it if you hunt around, but some people have apparently complained that I'm promoting a commercial site by giving away free information. I'd post a direct link but I can't make 'em work)

 

[PHOTOTONE]

Dear Tomasz,

Measure the front-rear separation (overall length front-to-back) on the G-Claron or get it from the Schneider web-site. Shim the shutter to give the same -- but bear in mind that the optimum separation for enlarging may not be the optimum separation for photography at infinity.

Cheers,

Roger (www.rogerandfrances.com, where you'll find free information on how to do it if you hunt around, but some people have apparently complained that I'm promoting a commercial site by giving away free information. I'd post a direct link but I can't make 'em work)

Roger, I don't think he can "shim" the elements closer, only to make the distance wider. He stated in the OP that the elements don't go as close as they do in the barrel mount.

 

[Roger Hicks]

Roger, I don't think he can "shim" the elements closer, only to make the distance wider. He stated in the OP that the elements don't go as close as they do in the barrel mount.

Dear Photone,

Whoops! Misunderstood. Read it, but it didn't sink in. The fact that it was after dinner (sherry, pignons and Spanish ham beforehand, then a vin gris with the tartiflette) may account for this...

You can sometimes alter the shutter thickness by undoing the locking screw on the 'star' on the front, screwing the 'star' in a bit (1 full turn = 1/10mm, normally), then re-inserting the locking screw. Worth trying, anyway. Also worth checking the normal front-to-back length on the Schneider site. That's how I got MUCH better performance out my my G-Claron that had prevously been re-shuttered in a too-thick shutter.

Cheers,

R.

 

[kirkfry]

I had a similar problem with 210 mm G-claron. It would not screw completely in due to a ridge on the shutter down where the back of lens element seated.

Never solved the problem. :-(

K

 

[Harrigan]

You should be commended for checking the spacing. Most people just slap them in the shutter and start shooting. I have checked g-clarons in the past and found the spacing in shutter to be different than in barrel. The same goes for the graphic kowa lenses which do thread right into the shutter, yet the spacing is not perfect. Close is good enough for some people I guess.

The other optical concern, according to my phd optical lens design guru is the position of the aperture is very important and if not placed in the optical center of the lens could effect coverage. The optical center may not be the physical center and some shutters have off center apertures while some are centered.

 

[Tomasz Segiet]

Dear all,

Thanks for you kind advice. I think I would not attempt to fiddle with the shutter, as I my skills in this field *may* be too poor... But the remark about the optimum spacing for taking vs for enlarging is interesting. I will experiment with inserting some sort of spacers into the enlarger mount on the lens. Fortunately, I have an old behind-the-lens copal shutter that I can use with this lens.

Thanks once more and good photography to you!