[Leica] Fogging film during lens changes

[54moggie at embarqmail.com (Robert Lilley)]

I am relatively newbie to the Leica world and I've been going crazy trying
to figure out what gives with my screw mount Leica stuff.  Various frames on
a roll would be fogged seemingly at random.  I thought it was my Leica IIIa
body or the Summicron 50mm as it always seemed to happen around the use of
that lens.

I changed Leica bodies to the older Leica II and did a test roll with all my
Leica lenses and figured it out.  It's not the lenses or the bodies; it's in
the lens changes.  Apparently Leica shutter curtains are susceptible to
stray light.  Sure enough, every time I changed lenses the last frame shot
got another dose of fogging light whilst the next frame shot with the new
lens was fine.  Of course it always happened around use of the Summicron -
it wasn't the Summicron, it was the shot just before the change back that
got fogged.  Called Sherry Krauter, noted Leica repair person and she said,
"Oh, yea, you didn't know that - happens with all the screw mounts and M's!?
I said, "Why doesn't this happen with Japanese cameras, etc?" and she
shrugged (imagined), "That's just the way it is".

Being a longer time Exakta user I voiced my woe to that group and got the
following reply:

"I was using my Version 1 Varex IIa last week for an entire cartridge and I
used four different lenses. I don't know how many changes it was, but it was
more than three or four because I was using my 80mm Biometar most of the
time. It was the "user" lens and I switched to a 35mm and a 100mm and a
150mm. The mirror was up all the time when I was changing the lenses, of
course, and it was extremely bright sunlight, and I had no fogging.  In fact
I have never had fogging except when there was a sprung back or bad
weather-stripping on a camera requiring it.  Considering all the
photojournalists and other professionals who used Leicas switching lenses
all the time, I can't imagine they put up with this fogging business
changing lenses. Although that is my conjecture.  But it seems like we would
have read about it if it was an inescapable fact of cloth focal plane
shutters without instant return mirrors."

 

I have to agree with the above and wonder if this is something that can be
corrected as both of my Leica bodies are screw mount and pre-war.  Newer
bullet proof curtains?!   What say you all?  Thanks for your time.   

 

Rob