Re: [Leica] Light leak not art

[Kip Babington <cbabing3@swbell.net>]

Dave -

This reminds me - just a bit - of a light leak problem I've diagnosed in
my IIIf and, to a lesser degree, an M6.  In my cases, it occurs during a
lens change in bright light.  As best I can tell, the tracks in which
the shutter curtains travel are not especially close fitting, and light
can sort of "wrap around" the top and/or bottom of the shutter curtain
when the lens is off.  Fogging is worst near the edges of the film,
fading out toward the middle, although there is a band of a millimeter
or two right at the upper and lower edges of the image that is not
fogged.

I figured out what the problem was by dedicating a roll of film to
testing specifically for this - take a shot or two, wind on, change (or
just remove) the lens with the opening exposed to bright light or open
sky, cap the lens and trip the shutter, wind on, take another shot,
etc.  Sometimes I changed the lens without winding the film on.  The
results were similar to what you've shown - a tapering fog on the frames
that were in the film gate when the lens was off.  (Remember that the
image is upside down, so the top of the picture was at the bottom of the
film gate -  if your camera hangs mostly vertical when you change lenses
I'd expect more light leakage at the bottom of the shutter.)

I learned that I need to be especially careful to shade the lens opening
when changing lenses on the IIIf and to do the change as quickly as
possible (without getting fumble fingered.)  The M6 is better, and
doesn't fog film as fast as the older model, but I still try to minimize
the time that there isn't a lens (or body cap) on the camera if there's
film in it.

Hope this helps.

Cheers,
Kip

Dave Hillman wrote, in part:
> 
> This 'fetching' result shows a problem I'm trying to understand, a light
> leak that I need to fix through repair or technique.
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