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Old 29-03-2008, 10:37 AM
Craig_L
Craig

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Location: Adelaide, South Australia
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Canon 400D Noise and exposure length

Hi,
Just wondering whether it is better in terms of noise to shoot say 10 shots @ ISO 800 and 4 minutes exposure, or 20 @ ISO 1600 at 2 minutes? Will stacking double the shots, reduce the noise more than using half the number of shots at the lower ISO setting. Or the same between 400 and 800 ISO. Wonder if anyone has any thoughts on this.
Thanks,
Craig
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Old 29-03-2008, 12:28 PM
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JohnH
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Location: NSW
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Craig, there are reasons other than noise involved.
The first is this can you track without error for 4 mins or will your success rate be better with 2 min shots? If you can go with 4 mins then you will get better results with the lower iso, the Canon 20d I use is recommeded to be used at iso1000 - the lower iso seems to give better dynamic range but the major influence on noise is ICNR versus dark frame subtraction. For non-cooled DSLRs ICNR gives better results.

Have a look here also:

http://www.astrosurf.com/buil/eos40d/test.htm
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