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Old 08-04-2012, 01:27 PM
luigi
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Join Date: Jun 2010
Posts: 438
Quote:
Originally Posted by Terry B View Post
I would have thought that astro photos all have a very high dynamic range. The difference in brightness of stars compared to DSO objects is very high. As long as you are happy losing almost all of the colour data for stars then I suppose this is ok.
I'm also curious about the read noise.
When is the gain (or ISP amplification) applied?
I thought that the order was that each line of the ccd is read then the gain is applied. This would mean that the read noise is also affected by the gain.
The DSLRs use CMOS not CCD
You have a wonderful explanation here:
http://theory.uchicago.edu/~ejm/pix/...ise/#readnoise


Quote:
Originally Posted by trek1701 View Post
I’ve been told that you should use Liveview at least as possible (even though you need it to achieve actuate focus) because it increases noise, is this info correct???
Cheers Mark
This is true, live-view increases thermal noise. So I use it to focus, frame and then turn it off for the rest of the night.
After about 1 minute of live-view you need 8 minutes off for the sensor to be back at the temperature it started.
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