Fall off with wide angle lensgreenspun.com : LUSENET : Large format photography : One Thread
I have a used Calumet view camera, Series 400, with a bellows draw of 10", (measured from film plane to lens. I don't know if this is the correct way of measuring.) My only lens is a CaltarII-N 90 mm, f:6.8. My prints are darker toward the middle and lighter around the outsides of the print. Is this what is known as falloff? Is there anything that can be done about it? I'll appreciate any help I can get. I'm just getting started in large format & find it rather frustrating. Joe Stanek
-- Jose Stanek (email@example.com), March 14, 1998
What you are seeing is light falloff as you suspect. Three ways around it. First, get a center filter(Calumet can give you a lot of info on these). Second, work in the darkroom with judicious dodging and/or burning to even things out. Third, shoot only scenes with very dark edges, such as in grottoes and caves. For most of us the third option doesn't work too well though. But try shooting at f/22 or so and a lot of the falloff will even out, tho maybe not enough for some subjects.
-- Dan Smith (firstname.lastname@example.org), March 18, 1998.
What you have is falloff, but I don't think it is from your camera lens. You say the prints are darker in the center and lighter around the outsides of the print. If you have falloff from the camera lens it should be the opposite. The prints should get darker at the outer edges because the negative would be thin at the edges. What does your negative look like? I think your problem is in your darkroom. It might be from the enlarger lens you are using. If the focal length of your enlarger lens is too short you will get the results that you described. There is another possibility is if you are using a condenser enlarger. If the condensers are adjustable they may not be set properly for the lens you are using. Good Luck.
-- Larry Gard (email@example.com), March 19, 1998.
I think you should look at your film processing techniques, also. Could be that you are not getting even agitation....more on the edges than in the center of the film. Frank
-- Frank Armstrong (firstname.lastname@example.org), March 26, 1998.
I agree with Frank (above). I had the same problem when attempting to use a daylight tank with sheet film. What are your processing techniques? I finally made myself some developing tubes with pvc and they are working very well. Erik Ryberg
-- Erik Ryberg (email@example.com), April 04, 1998.