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View Full Version : how to accurately focus view camera with IR film ?



freecitizen
17-Feb-2015, 21:59
My 4x5 cameras are a Speed Graphic with Optar 135mm lens and a Sinar Norma with lenses which I think came originally from a Linhof Technika ………. 65/8 Super Angulon, 135/5.6 Symmar and 210/5.6 Symmar.

I want to shoot with 4x5 Rollei IR400 sheet film using a R72 filter ( held in front of the lens ).

How do I focus correctly ? I know how to focus using a lens with distance scale and depth of field marked on the barrel such as on a rangefinder or SLR ….. but not with a view camera. After focusing normally and then placing the R72 filter in place, I expect I need to move the lens a little bit closer to the subject but do not know how much or how to measure it properly in the field.

The inherent narrower depth of field in large format makes focusing even more critical and I do not have APO lenses. I don’t want to just rely on depth of field by stopping down. I need to be able to nail the focus as I want it to be.

Any ideas are much appreciated ….

ic-racer
18-Feb-2015, 17:01
http://www.largeformatphotography.info/forum/showthread.php?40217-Focusing-LF-in-the-Infrared-Sprectrum