OK, there's something I don't seem to get: why doesn't aperture and film
speed affect exposure times for astro photos?
Time, I understand has no direct bearing on stars as they are moving
objects, and like firework bursts, exposure film as they move hence no
worries of overexposure. However, what about ambient light? There is
always SOME, which would theoretically (to my logic) fog the film after a
given time.
Here are some observations which may or may not be true as they are based
on print film (Fujicolor Superia 400) processed Fuji Premium with index
sheet.
On the index sheet, the astro photos do not show up. The frame is just
plain GREEN! The Index sheet was the first thing I pulled out (store was
closing in 2 mins), and gasped "NOOOO! I overexposed them!" Asked the
person. Someone else said "that's the proof sheet; look at the prints."
[are index prints done the same way as proof sheets? besides, i asked
for no corrections--but apparently they were corrected if the index
sheet and prints don't match up exposure-wise].
Prints come out OK. The last pix, taken with 28mm for 5 hours has some
fogging from surrounding lights (even with hood). The others, with the 50
and hood, are OK.
The 30sec exposure shows MANY stars...I mean LOTS and LOTS, much more than
what I can ever dream of seeing in the city. The longer exposures,
however, do not. What gives?
Asked them for film suggestion: anything goes. 800 for print, 100/200/400
for slide. doesn't matter either way.
So, can anyone answer my question (which, if you forgot, is the first line
up at the top ;-)).
Thanks,
/Acer "steppenwolf" Victoria
--
"In a minute there is time / For decisions and revisions which a minute
will reverse." --Eliot
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