Best approach for repro work where size reduction is required?

[Pere Casals]

You don’t reverse it.

Bob, are you sure ?

By reversing we also reverse the ray tracing, so if we reverse the lens then we geometrically invert the value for the optimal magnification. With x1 it would not have an effect, but the benefit it should be clear for the x2. Think that enlarger lenses are usually reversed for macro, because of that.

http://extreme-macro.co.uk/reversed-enlarger-lenses/
https://web.archive.org/web/20170218...larger-lenses/

[Bob Salomon]

Bob, are you sure ?

By reversing we also reverse the ray tracing, so if we reverse the lens then we geometrically invert the value for the optimal magnification. With x1 it would not have an effect, but the benefit it should be clear for the x2. Think that enlarger lenses are usually reversed for macro, because of that.

http://extreme-macro.co.uk/reversed-enlarger-lenses/
https://web.archive.org/web/20170218...larger-lenses/

Yes, the D is not an enlarging lens!

[Pere Casals]

Yes, the D is not an enlarging lens!

We discussed that before... D stands for Duplication, I know, but we have the x1 and the x2 lenses. D x2 is not duplication but for enlarging to x2.

Anyway, I've to correct that the x2 lens has not to be reversed, because x2 is for projecting, not for taking the image, recommending -0.8 to -0.4 magnification in a camera.

For the APO Rodagon N catalog says "Magnification range: -0.05 … -0.5" so magnification in this case in the camera sense.

[Duolab123]

It's really easy with a real process camera. The magnification / reduction is marked on a big scale hooked to the aperture of the lens. No fiddling with exposure times, once you have a good time established. Bottom line. That Claron will do anything you want it to do . Look up lens extension in a old Kodak master photoguide or on line plug in your numbers and go. Have fun. If I had room I would have a nice horizontal process camera. When you think of cut and paste, remember that it was literally cut and paste in the day.

[kendolinator324058943]

Your G-Claron will do just fine at 1:2. Heck, it'll do fine at infinity as well. Doremus

Are you saying that it would be possible for a 10x reduction in size with my G-Claron 150mm lens? Like if I wanted to reduce a four-foot-long poster to an 8x10 negative? Or would I need a larger lens like a 355mm? Thanks you all are so knowledgeable.

[Doremus Scudder]

Are you saying that it would be possible for a 10x reduction in size with my G-Claron 150mm lens? Like if I wanted to reduce a four-foot-long poster to an 8x10 negative? Or would I need a larger lens like a 355mm? Thanks you all are so knowledgeable.

That's just taking a full frame photo of your poster. Easy-peasy. The G-Claron will perform just fine. You should be far enough away from your original with 150mm that spherical distortion at the corners should not be a problem. The only reason to go to a longer lens would be if that were a problem, e.g., if objects appear "stretched" at the corners and edges. That is a function of angular projection and the distance the camera is from the subject.

Best,

Doremus

[kendolinator324058943]

That's just taking a full frame photo of your poster. Easy-peasy. The G-Claron will perform just fine. You should be far enough away from your original with 150mm that spherical distortion at the corners should not be a problem. The only reason to go to a longer lens would be if that were a problem, e.g., if objects appear "stretched" at the corners and edges. That is a function of angular projection and the distance the camera is from the subject.

Best,

Doremus

Ok thanks again Doremus. Can you recommend the sharpest 8 x 10 film that will pick up the most detail? Someone else referred me to X-ray film. What is usually used in process camera work?