Archived posting to the Leica Users Group, 1997/05/26
[Author Prev] [Author Next] [Thread Prev] [Thread Next] [Author Index] [Topic Index] [Home] [Search]Joe Berenbaum wrote: > I've been meaning to use my M6 for black and white IR but haven't done > > so > yet; I seem to use colur IR in that and b&w IR in a Rollei 35 so far. > But > now I'm curious. > > Also I'm curious what lens/es you were using when you got this effect. > > I have one suggestion; assume the most likely explanation, which IMO > is that > the shutter that is leaking IR between exposures and set out to prove > or > disprove it by shooting pictures that will (or are likely to) show the > > effect on the first half of a film as you did before, and then > religiously > use a lenscap between exposures on the remainder of the film whilst > continuing to shoot pictures that you think are likely to show this > effect. > If the phenomenon only appears on the first half, you will have some > evidence to suggest that the shutter was leaking IR light. > > Joe: > Many thanks to Eric, Joe, Colin, Bill and Stephen for your valuable > comments regarding the problem I am having with infra red film in my > M6. I will try a roll of i-r against plain blue sky, (of which we have > plenty here in Queensland) using various apertures, and using the lens > cap between exposures for some of the film. > Another test I will conduct is to leave the camera for varying times > with lens cap off, then wind on without exposing the film and see if > the film is affected. This will test for the penetration of the blind > by i-r light. If I see the offending circle on the supposedly > unexposed film, we will know that the blind is the problem. > > Joe, you asked which lenses I used. It was both the Summicron 35/2 > and Summicron 50/2. As I said, the offending aperture was f11 and > f16. Rob Heyman Brisbane Australia.