Robert Reeves has an excellent web sight on wide field astrophotography.
The link below covers tests he did on print and slide film. One way to
overcome reciprocity failure is to "hyper" the film. This can be difficult
and dangerous depending on the method used. If you search his web site you
will see that you can get some great shots, using off the shelf film, with
exposures of 15 minutes or more.
His book is also very good.
Hope this helps,
Joe
http://www.connecti.com/~rreeves/filmtest.htm
-----Original Message-----
From: owner-olympus@xxxxxxxxxxxxxxx
[mailto:owner-olympus@xxxxxxxxxxxxxxx]On Behalf Of Olaf Greve
Sent: Tuesday, June 26, 2001 6:07 AM
To: olympus@xxxxxxxxxxxxxxx
Subject: [OM] Taking pictures of Mars
Hi,
At present we are blessed with a magnificent view of Mars, and it's present
in an ideal location for taking pictures from my attic. It was mentioned to
me that using a telecope that gives roughly a 30X magnification (note that
the word "magnification" is probably not correct in this context, basically
what I refer to, is the amount of times the angle of view is cut in halve in
respect to a 50mm lens (which roughly gives us a normal view)) would allow
one to see some details of Mars. This sounded strange to me, as it seemed to
me that Mars shows way too small to be able to reveal details at such a low
level of magnification. Nonetheless, I decided to go for it, so yesterday I
borrowed the Manfrotto tank tripod from work again, then I dashed off to the
pro-lab to buy a roll of Provia 100F (new shipment coming in soon ;) ),
stacked 3(!) 2x teleconverters between the OM-4Ti and my 300/4.5 to get an
effective 2400/36 tele-bazooka and had some fun spying on non-suspecting
neighbours (just kidding of course ;) ). Anyway, come nightfall, Mars should
up lovely again in bright yellow, so I decided to go for it, I spent a few
minutes finding the planet in the viewfinder of the camera, and what I
feared was indeed the case, at 48X magnification Mars did not show up bigger
than a needle's head in the viewfinder. It goes without saying that I didn't
bother wasting expensive Provia 100F on this, but I was surprised to see
that (with a 2-13 screen) the viewfinder image was a lot brighter than I had
expected. I feared having to use the dreaded 1-12 FS I have (and with which
by no means I'm big friends), but the 2-13 worked fine (even though the
center of the screen blacked out, of course).
Now a few questions:
-I decided to push the Provia 100F to 400 ASA, as it was mentioned to me
that this gives better results than simply using the 400 ASA Provia F film.
Does anyone know if this is true? Does Provia 100F perform really well when
pushed two stops? Also, which high speed slide film do you guys recommend?
-What type of magnification would be needed in order to get a, say, frame
filling shot of Mars? Obviously this falls well within the telescopical
range, but I'm wondering just what type of magnification would be needed.
-Did any of you shoot pictures of Mars using telescopes? Acer? Matt? Anyone
else?
-I have to admit never having paid much attention to threads dealing about
this topic, but what is the exact reason again that people tend to use an
OM-1 for this type of photography, is it purely due to the MLU feature?
Also, I have an OM-40, an OM-2n and an OM-4Ti myself, which would be the
better one for taking shots using a telescope (if possible at all with these
cameras), the OM-2n or the OM-4Ti? Or should I simply use my father's OM-1
for such shots (not that I have a telescope, nor the proper adapters,
neither rotating mounts, but I'm wondering nonetheless).
Thanks in advance for any and all replies, and I hope some of you guys had
better luck at taking pictures of it, and that perhaps if you did, you can
share it with the group.
Cheers!
Olafo
BTW: When pointing the set-up at the moon (which was just going behind some
trees :( ), I got a lovely frame-filling viewfinder. I will perhaps take
some shots of this type soon, but the problem is that one of the converters
is a really cheap Vivitar simple MC 2xA (the others are the Vivitar 2xA
matched for the 70-150mm lens, and the Oly 2xA). Perhaps it's better to
remove the cheap converter...
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