[APML] new member questions

["Cross, Timothy" <TCross@NRCan.gc.ca>]

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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