I recently tried taking some Christmas lights photos with my 4T, using ASA
800 film. While taking the shots (in AUTO mode), it seemed like the
exposures were too short, and when the film came back, most of the frames
were severely underexposed - except for a few which I shot using the "B"
setting and timed myself external to the camera. I then started fiddling
with the camera, firing off some shots with lens cap in place (film loaded,
of course). I found that, at the ASA800 setting, the exposures were running
8-10 seconds at f/2.... shifting to ASA400 resulted in 3 minute exposures!
Thinking the contacts might be dirty I ran the selector back and forth a few
time, and then seemed to get the long exposures at a number of ASA settings.
When I repeated the experiment a day or so later, it was back to short
exposures at ASA800, long at ASA400. Seems that the camera doesn't like the
800 setting! Anything below 400 seems to work OK. Anyone have any
suggestions? Could there be a bad spot on the encoder or whatever, or
persistent dirty contacts? Are there any other experiments I can try to
narrow things done a bit? I did do a 'dark current' check - at ASA 3200 and
f/2 (but lens capped), the meter read 1/4 second, which the list archives
suggests is about right. I did find that even at ASAS25, the longest
exposure the camera will deliver is 3 minutes, not the 4 minutes everyone
seems to claim. Do I need to worry about light entering through the eyepiece
during auto exposure, or does the mirror completely block off any stray
light during exposure?
Lots of questions! Hope someone has some suggestions..... Thanx in
advance.
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