Re: Weird problem with M6 and infrared film

["joe b." <joe-b@xxxxxxxxxxxx>]

In message <199610310250.VAA15747@xxxxxxxxxxxxx>, Dan Cardish
<dcardish@xxxxxxxxxxxxx> writes
>Furthermore, the pattern only occures on a few frames, and takes the
>same shape in each one.  The band may be quite pronounced in one frame, but
>completely absent in the next, and when it does happen in two consecutive
>frames, the band starts over being 2 mm wide in the rightmost frame, after
>widening to 3mm in the left frame 

I can't help thinking this would be consistent with light somehow
leaking through the shutter according to how long that light was hitting
the shutter for each frame. There is no mirror in the M6, just a
rubberised cloth shutter, and light passing through the lens will be
hitting that shutter, so walking around outdoors in daylight without a
lens cap on may be allowing something through. It shouldn't happen, but
maybe the shutter is a bit worn. So here's a question- *do* you walk
around with no lens cap on the camera? (Well I do...) 
An experiment to test this would be quite simple- simply recreate the
problem in a controlled way to test it. Load IR film again, and in a
sunny situation give long times with the lens cap before exposing them
normally for an outdoor scene. Allow several minutes of light hitting
the shutter for each frame to recreate the possible "exposure" through
the shutter. In other words- recreate the hypothetical scenario of IR
leaking through the shutter while the lens cap is off, but note the
times of "cap off" duration and the frame numbers- AND- alternate long
"lenscap off" times with very short "lenscap off" times and this might
give the same result as you already got; the exposure difference
appearing as a diagonally slanted stripe on the negative, but only on
certain (numbered!) frames. 
-- 
joe b.

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Topic No. 26