Re: [APML] M35 (exposure times) + experiment

["Brian Larmay" <astrobri@ameritech.net>]

I thought about getting one of those awhile back but decided just to get the
Epson 1250 for scanning prints and it works pretty good.
I was skeptical enough to stay away from the slide aspect considering the
non dedicated slide option.
I still really cant judge those types of scanners, but I heard all sorts of
good things about them that they do a very good job scanning slides....I
just didnt  want to chance the astrophotos.

Ive gotta take a look at your site...whats the url?

Brian

> We could do that, and it would be interesting, but....
>
> The biggest caveat is scanner differences.  I have an Epson 2450,
> which is a flatbed with a transparency adapter.  It's a decent scanner
> and hard to beat if you need a flatbed and want the option for
> medium/large format negatives.  But my guess is that it doesn't get as
> much out of the shadows as a dedicated slide scanner.  I have an old
> shot of Cygnus that a local photo shop did a great job on.  It was
> horribly underexposed (4 min @ f/4) slide -> negative -> print
> conversion did a good job of drawing out the Milky Way and even the NA
> nebula.  I can't get much of anything out of my scanner.
>
>     bl> Ill post two later whe I get home from work just so that you
>     bl> can see what I get as far as an exposure of 7- 12 mins at f/4
>     bl> using E200 and provia 400F.  Yall can edit them and post your
>     bl> results..I hope even to learn some techniques that I might not
>     bl> have thought of to apply to my work.
>
> Well, I can tell you the procedure I generally use for my
> constellation shots---it's not really a secret :-)
>
>     o Crop and trim to remove any border from the scan.
>
>     o Level adjustment---move the black and white points to be at or
>       very near the darkest and brightest point of the scan.
>
>     o If there is any sky glow and if the photo does not include a
>       large amount of nebulosity, try a Gaussian blur or median filter
>       with a large radius as a synthetic "dark frame."
>
>     o Apply a mild unsharp mask.  Exact values will depend on the
>       photo and the scan resolution....
>
>     o Boost the mid-tones---can do either via "curves" for manual
>       control, or via PWP menu Transformations -> Gray -> Levels and
>       Color.
>
>     o Maybe mess with the saturation.  With PWP, this can be done at
>       the same time as the previous step.
>
>     o Go back and play with all the above until you're happy or can't
>       stand it any more.
>
>
>     bl> Just one question before I post these though....  Should I
>     bl> post these as tiffs or high res jpegs
>
> I've got 1.5 Mbs download speed, so I can tolerate as much as you are
> willing to allow for the download.
>
> regards,
>
> roland
> - -- 
>        PGP Key ID: 66 BC 3B CD
> Roland B. Roberts, PhD                             RL Enterprises
> roland@rlenter.com                            6818 Madeline Court
> roland@astrofoto.org                           Brooklyn, NY 11220
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