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litespeed
scholastic sledgehammer
Reged: 10/31/03
Posts: 953
Loc: Treasure Coast, FL
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Here is my first film astrophoto. I am hoping that one of the pros can point me in the right direction.
The photo pictured here has been heavily processed. The original was almost white (light blue). Almost completely washed out? Is this normal? I figured the background would be darker and that the stars would jump out more....
Shots were done at F/1.8, F2.8 and F/4. 5 and 10 minute exposures of each. Should I have run it up to F/8 or F/11? All the shots were washed out in about the same way.
Very dissapointing....
Thanks,
AJ
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AJ
Orion 127 SVP
TouCam
Canon 20D
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litespeed
scholastic sledgehammer
Reged: 10/31/03
Posts: 953
Loc: Treasure Coast, FL
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Here is the original. It may help to try to solve the problem?
Thanks,
AJ
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AJ
Orion 127 SVP
TouCam
Canon 20D
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Suk Lee
Post Laureate
Reged: 10/07/03
Posts: 4315
Loc: Pleasanton, CA
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AJ:
Pretty good for a first shot. Astro-photos are inherently low contrast, so the raw film/scan is never going to look good, it always takes a lot of processing.
Hey, you caught some of the nebulosity around M45!
I wouldn't shoot beyond f4 - f8/f11 is far too slow and you won't pick up much nebulosity.
10 minutes @ f1.8 is quite a long exposure under typical suburban light polluted skies - you probably washed out most of the stars with skyglow. 10 minutes @ f2.8 is the skyglow limit for my area. Your 10 minutes at f4.5 probably came out fine and will look good with processing practice.
I highly recommend Jerry Lodriguss' "Photoshop for Astrophotographers" which covers everything from how to evaluate your shot in the prescan, through proper histogram manipulations, color correction, and vignette removal.
http://www.astropix.com/PFA/PFA.HTM
Were you shooting slide or print film?
Keep going, you caught WAY more stars than I did on my first shot.
Suk
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http://www.siliconvalleyskies.com
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Suk Lee
Post Laureate
Reged: 10/07/03
Posts: 4315
Loc: Pleasanton, CA
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Which shot is that? You should scan the f4.5 shot at 16 bits depth (if your scanner can) and save as a TIF.
Your shot looks a little overexposed i.e. you picked up too much skyglow, but otherwise kind of representative of a film shot.
REALLY recommend Elite Chrome 200. Negative scanning adds additional complications because you can't evaluate the raw picture visually to see if your scan is getting the right information.
Suk
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http://www.siliconvalleyskies.com
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litespeed
scholastic sledgehammer
Reged: 10/31/03
Posts: 953
Loc: Treasure Coast, FL
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Suk,
Thanks.... Your a life saver. I was getting kind of bummed out over these shots.
Why save as a TIF? What DPI should I be scanning at? Those were at 600 DPI. I can go as high as 1200.
I used print film. Fuji 400. I got some Elite Chrome 200 slide film I'm going to try when the rain decides to leave.
Is the slide film ok to use?
Negative scanning?
AJ
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AJ
Orion 127 SVP
TouCam
Canon 20D
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Suk Lee
Post Laureate
Reged: 10/07/03
Posts: 4315
Loc: Pleasanton, CA
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AJ:
You should save as a TIF because it's non-lossy format. JPG compresses the picture by throwing away some of the information, and unfortunately, a lot of the subtle astro-info we want is the FIRST stuff JPG throws away!
You should be scanning at as high a resolution as your scanner can manage, since a 35mm frame is pretty small. Go for the 1200. You want to get as close as possible to the native resolution of the film, so that you're losing as little information as possible in the scan (4000 DPI is getting close).
IMHO the slide film is vastly superior to Fuji print film. Ironically, it's probably faster than the 400, for long exposures, because E200 has very little reciprocity failure.
If you want to send me a raw TIF to look at (it'll be BIG), send me a PM and I'll send you an e-mail address that can handle up to 10 Meg.
Suk
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http://www.siliconvalleyskies.com
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