I'm setting up to (hopefully) shoot some IR film, and I'm hoping that someone might be able to help me here, or point me to a thread or webpage that I simply haven't found...
Question: What internal infrared light exists in the 645N? Will any present affect IR film?
After searching off and on for a few days, I finally called Pentax to simply ask whether or not there were any internal IR sources in the camera...frame counter, data imprinting, etc. I think they were taken aback by a question about a film camera. Now, I didn't get a conclusive answer, but I did learn the following:
- The 645N uses "some internal infrared" but they didn't know the actual wavelength, or really even where it came from.
- Pentax doesn't test with IR film, so they aren't sure if any IR light will affect IR film, or not.
- The 75mm f2.8 lens has an IR focus shift mark, which may or may not be a holdover from earlier lenses...i.e. it may never have been officially tested with infrared, since Pentax doesn't test with IR film. Arg!
I've also heard that the frame counter is NOT infrared, and that the data imprinting is not a factor with films in the 750nm range. I'm planning to shoot 820nm film, and I haven't seen much information on that in the 645N. I know the safe thing to do is to step back to a totally manual camera, but I really want to use the bigger format.
Any help is much appreciated. I suppose if nothing else, I can waste a few dollars.