Hi Olaf, (and Ralf, just got the mail..)
thats right, stars(in contrast to planets of our solar system) cannot be
enlarged, they are real point sources in any, even very big, conventional
telescope. So, a starfield picture tells you a lot about the quality of your
lens. e.g. the 55/1,2 at full aperture showed all sorts of aberrations like
coma,low contrast etc and even poor quality in the middle. it had to be
stopped down to at least 2,8 to yield decent results. The 24/2,8 is quite
good wide open, my experience with the 50/1,8 is limited, i mostly used the
50/1,4 stopped down to 2,0 with good results. In contrast, my old schneider
xenon 50/1,9 on the Exacta performs very fine (ok, some vignetting) wide
open! As far as films are concerned, i have used kodak gold 1000 (grainy,
but still nice), Kodak and fuji 1600 negative with nice results, kodak 1600
slide and fuji ms100/1000(medium format)
Scotch crome only once(hard to get) . Ektachrome E200 for slides and superia
800 for prints seem to have a very high reputation among astrophotographers
now.
The rest has been said by Ralf, no objection!
Have fun
Rainer
-----Ursprungliche Nachricht-----
Von: owner-olympus@xxxxxxxxxxxxxxx
[mailto:owner-olympus@xxxxxxxxxxxxxxx]Im Auftrag von Olaf Greve
Gesendet: Dienstag, 26. Juni 2001 13:51
An: olympus@xxxxxxxxxxxxxxx
Betreff: RE: [OM] Taking pictures of Mars
Hi Ralf and Rainer (and others),
Then: I do remember having read something to the effect of that in this type
of photography the focal length of the lens is of hardly any influence to
the size of the stars as they show up in the pictures due to the enormous
distance there is between the earth and the stars, but how about stopping
down? What would be the most ideal apertures? Wide open? Stopped down 1
stop? f4/8/11? f16 perhaps?
Cheers and thanks for your answers!
Olafo
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