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RE: [APML] Poor Blue in 400F?
That's still a nice shot. What gave the blue "halo"
around the brightest star? (Good thing I don't have to
know the names of stars to photograph them!). Shows
about the same amount of nebulosity I see in my
30-minute f/5.6 telephoto slides (I just looked at one
of those slides in the ol' $5 slide viewer to check!).
My 45-minutes shots show more. You have far more
detail in the nebulosity, of course (the Pleiades
aren't very big at 300-mm!) and the contrast on the
slides is less, naturally.
The Pleiades is one of those subjects I just never
seem to be able to quite get at prime focus, for one
reason or another. I need more equipment - like an
autoguider and maybe an LPS filter - to increase my
chances of success.
--- "Lane, Jason R" <jason.lane@navy.mil> wrote:
> Hi Alen,
>
> I just remember I had to stretch the contrast hard
> to bring up the blue for my 60-minute shot. I also
> did a shot of M42 which turned out fine using 400F,
> so I just figured Pleiades is a tough shot for the
> Provia. Since I took that shot, I've kind of gotten
> the impression from various sources that you ought
> to use E200 for blue nebulae. I've been wanting to
> go back and shoot Pleiades for a while now. Maybe
> I'll use this as an excuse to go back and do it, and
> shoot it under same conditions with both 400F and
> E200.
>
> I've still got my image floating around if you want
> to compare. I thought it was a 45-minute shot but
> the caption says 60-minutes. Fortunately the
> written word is much better than my memory. <g>
> You can probably calculate what the equivalent
> exposure at f/5 would be (mine was taken at f/6.3).
> The skies were approx mag 5.5.
>
>
http://www1.iwvisp.com/opticman/astroimages/Pleiades.html
>
> Uh, ignore the horrible framing and background
> gradient :)
>
> Cheers,
> Jason
>
> -----Original Message-----
> From: astro-photo-bounces@seds.org
> [mailto:astro-photo-bounces@seds.org]On Behalf Of
> Alen Koebel
> Sent: Monday, August 22, 2005 12:54 PM
> To: Discussion of Film Astrophotography
> Subject: RE: [APML] Poor Blue in 400F?
>
>
> 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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