Re: [APML] new member questions

[Jerry Lodriguss <jerryapml@astropix.com>]

Hi Tim,

If this happened with different lenses and the stars were only in focus on 
the same corner, I would be more inclined to think it is some kind of 
problem with the camera body's lens mounting flange most likely. Much less 
likely would be a problem with the film pressure plate.

Taking the camera in and out of the cold might cause moisture to condense 
inside the camera, but that wouldn't affect images already taken. Moisture 
absorbed by the emulsion after taking the camera in wouldn't affect images 
taken after that either.  It's only when moisture is absorbed during the 
exposure that you will see film creep, and that is usually irregular across 
the frame. Just put the camera in a zip loc bag before you take it inside 
from the cold to prevent moisture forming on or in the body.

I think you might need to get the body checked by a repairman.

Jerry



At 01:30 PM 1/30/2004 -0500, you wrote:
>Hi there!  I have been taking piggyback shots for a number of months now
>with generally good results.  The last roll of prints that came back however
>all had a major problem: the star images were way out of focus across much
>of the field (to the point that their edges were defined by the aperture
>blades of the lens), but sharpened to near points towards one corner.  This
>was the case with all of the images.  Three different lenses were used for
>this roll, and all were set at infinity, but all of the prints (and
>negatives) show the same pattern, with the focusing improving towards the
>same corner.  I assume that this has to be due to the film buckling or
>something similar; the negatives show the same issue, so not related to
>processing.  The pictures were taken in very cold winter conditions over 3
>sessions, with the camera (OM-1) being returned indoors to a warm house in
>between.  I can understand that as the film warmed and cooled, it would pick
>up moisture and that could be a source for the problem, however I wouldn't
>expect the initial pics on the roll to exhibit the same issue in that case.
>Can anyone help me with this?
>
>Tim Cross
>Physical Scientist
>Community Energy Systems / Natural Resources Canada
>1 Haanel Drive, Ottawa, Ont. K1A 1M1
>Systèmes énergétiques dans les collectivités / Ressources naturelles Canada
>T (613) 996 4804 F (613) 947 0291
>Email tcross@nrcan.gc.ca
>
>
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