To all,
I was wondering if those of you who are comfortable with shooting large format infrared film could comment on the need to incorporate a focus shift when exposing infrared film. The answers from previous posts have thoroughly confused me as the following have been recommened: 1) no need to use focus shift at all when using f16 to f32 because depfth of field compensates, 2) definitely use 1/100th of the lens' focal length and add that to the bellows extension, 3) no, use 0.0025% of the lens' focal length and add that to the bellows extension, 4) only need to use focus shift if shooting with a ratio of 1:10(2mm) to 1:1(4mm), and 5) no need to use focus shift when shooting with apochromatic lenses only, irrespective of the f-stop or focal length. Any clarification would certainly be appreciated.
thank you,
dan dumitru
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