on 15/07/2003 18:20, Moose at olymoose@xxxxxxxxxxxxx wrote:
> OK, I 've had a question for some time for you astrophotogs. In
> exposures measuring from 10s of minutes to hours, what difference does
> mirror lock-up make? Mirror, aperture and shutter crash-bang all damp
> down in maybe a second or 2. So out of all the light that makes up even
> a 2 min. exposure, less than 1 0s disturbed. How can that affect the
> image? None of that light which is in the wrong place, and a moving
> wrong place at that, will even register on the film.
>
> Moose
Of course Moose. Plain OM2 (preferrably black ones) are the best ones for
long exposure astrophotog. Battery drain is nonsense, how many times shall I
write this. BUT if you want to pic the moon or the Sun only, better go spot
metering. And if you want to picture remote galaxies or nearby planets
better use not 35mm film... Wish some time I will show you my southern sky
on Ektachrome100, Zuiko 21mm f3.5 @ f8, one hour plus exposure (exposure
comp +2 = ASA25) - and next day half dozen pics of a tree trunk. This was on
April, changed batteries on following February. OK, I'm not taking pictures
everyday, not even everyweek.
Hope someone teaches me how to calculate exact exposure time if I measure
the degrees of the star trails.
Fernando
Fernando.
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