UV/IR Cut Filter w/ Film?

[Honus]

I just purchased a 28mm Biogon, primarily for use on my R-D1 (as an equiv. 42mm). The R-D1 suffers from IR contamination, albeit not as dramatically as an M8, but it is there nonetheless. I will also be using the lens with my M6, and don't wish to be screwing the filter on and off.

I am under the belief that using the filter with b&w negative or color positive film will not effect the image significantly by eliminating IR. Am I correct or delusional?

I'm also not too keen with having a pink lens on the front of my camera, but so be it.

 

[Sonnar Brian]

The filtering of the IR and UV is not a problem.

I've read that some users get a cyan cast towards the edges of photo's. I've never had a problem using a hot-mirror filter on my full-frame Nikon E3 or film SLR's. Keep an eye on it for the full-frame M6 with shorter back-focus distance than my cameras.

Also, Hot Mirror filters do just that- they are mirrors on the front of your camera that reflect deep read and IR away from it. Watch they they do not reflect into your field of view. I use mostly Macro lenses and telephoto's. A 28mm lens on a full-frame camera is more likely to pick up the reflection.

and if you are photographing cats and dogs, expect them to start chasing the reflection from the hot mirror filter.

 

[keithwms]

A hot mirror filter shouldn't be noticeably coloured, except the multicoating may give a slight hue. I have one such flter that appears very slightly greenish, an I take this to be from the multicoating.

Anyway, the question of whether it will affect film is hard to answer definitively: it dpeends what film we are talking about. Some "see" out past the reds, some don't. For most it should be fine, but you just have to take the cutoff curve of the filter and overlay it on the film's sensitivity curve to get a definitive answer! All filters cut into your spectral sensitivity somewhat, the question is how much.

Generally, having a filter permanently mounted on a lens, particularly a wide one, is not a good idea in my opinion, too much risk of flare etc. I know this is not what anyone wants to hear, but it is so. On the other hand, taking it on anf off all the time might be riskier to your output!

 

[Sonnar Brian]

May depend on the cutoff of the filter, but mine can cast a red reflection that would rev up the chase instinct.