I think sky conditions play more of a role than people think. I have shot it for 90min one night and the next the same time one was good the other had nothining. 61cm f7.5 rc
From: Alen Koebel <akoebel@rogers.com>
Reply-To: Discussion of Film Astrophotography <astro-photo@seds.org>
To: Discussion of Film Astrophotography <astro-photo@seds.org>
Subject: RE: [APML] Poor Blue in 400F?
Date: Mon, 22 Aug 2005 15:53:40 -0400 (EDT)
>Well, like I said, the last roll of 400F showed much
>more blue response. I shot the Pleiades on that roll
>too. Granted, I wasn't shooting with the same
>equipment that time - I was using a 300-mm telephoto
>at f/5.6. Not accounting for the effects of
>reciprocity failure (which works in this comparison's
>favor, actually) that should be equivalent to a
>36-minute exposure at f/5, assuming my math is right.
>My 30-minute exposure thus is a bit weak (and
>certainly very weak compared to the usual exposures
>people do for this object, I know - at least one hour
>sounds about right to me). But not weak enough to
>account for no nebulosity AT ALL (not even a hint!),
>given the amount I'm seeing on the 45-minutes f/5.6
>shots.
>
>Maybe atmospheric conditions explain it.The
>transparency wasn't great that night (although the
>seeing was superb).
>
> > Hi Alen,
> >
> > That sounds about right for 400F. At f/5, shooting
> > at Pleiades with 400F, 30 minutes is too short for
> > the reflection nebula to show up well. I've shot it
> > at f/6 for 45 minutes and haven't gotten much. What
> > I did get required a lot of histogram stretching to
> > be even half-decent. I'd say don't bother with
> > anything less than an hour exposure shooting
> > Pleiades with 400F.
> >
> > Unless they are actively trying to, developers at
> > the automated photo labs can't screw up slide
> > processing, and really can't screw up the negatives
> > either. What you see is what you got. Heck I take
> > mine to Wal-Mart to get developed and they turn out
> > just fine. Scan it and tinker, that gets you the
> > good results. :)
> >
> > Hope this helps,
> > Jason
> >
> >
> >
> > -----Original Message-----
> > From: astro-photo-bounces@seds.org
> > [mailto:astro-photo-bounces@seds.org]On Behalf Of
> > Alen Koebel
> > Sent: Friday, August 19, 2005 6:08 AM
> > To: APML
> > Subject: [APML] Poor Blue in 400F?
> >
> >
> > I just got some recent 400F slides developed and I
> > am
> > very disappointed with the blue response. For
> > instance, a 30 minute f/5 shot of the Pleiades
> > yielded
> > NO reflection nebula at all. What the..? I got
> > decent
> > blue response from the last roll of 400F and
> > certainly
> > more than this even from E200. Could the lab have
> > screwed up the processing? Tired chemicals? I tried
> > this supposedly very good lab for the first time on
> > the recommendation of a fellow APer, so I have to
> > wonder. The film itself was fresh (Dec 2006 expiry),
> > was kept refrigerated until the day I started using
> > it, didn't experience high heat and I had it
> > developed
> > a couple weeks after I took the pictures.
> >
> > You know, even if this isn't a lab problem, I've had
> > myt fair share of them (which is why I tried a new
> > one
> > this time). I'm tired of them compromising, and in
> > some cases ruining, my efforts. I think it's finally
> > time to take them out of the equation. I hate to say
> > it but next year it's goodbye to film for me and
> > hello
> > DSLR.
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> >
>
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