RE: [APML] To Push or Not To Push

["Thomas W. Earle" <twade@bmi.net>]

Wei-Hao,

>What you said is generally correct, if it is based on the
assumption that the photographer
>also decreases the exposure time when he decides to push the film.

I'm probably the only person decreasing their exposure times to
compensate for the push process.  I guess, I have too much of a
"landscape photographer" in me.  In terrestrial photography, when
you push a film you always adjust the exposure downward depending on
how many stops you push.  Apparently this isn't the case in
astrophotography.  It seems that not compensating for the push would
produce blown-out highlights.  Just to make sure I have the
technique right.  Too reach a background sky limit of 21.0
magnitudes per arc-second I have to expose E200 130 minutes at
F/4.0.  This long exposure does not take into consideration any of
the push process.  I then tell the lab to push the film 1-stop
anyway.  Right?  It just seems to me that the base fog would be
abnormally bright and you would begin to lose your highlights,
especially with brighter objects.  

Wade


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