Quote:
Originally Posted by rally
Glen,
Why would you not need darks at -10C ?
Rally
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Rally, testing my Rcheshire and myself on our cold finger cooled Canons showed that below 0C there was no noise apparent on long exposure darks taken with these cameras ( comparisons between Darks of 5 minute duration and Offset bias frames shot a 1/4000th of s second, reveal no difference - noise cease to be an issue at those temperatures for these cameras). Of course you need the modification and temperature controller system to hold the sensor at that temperature with little variance. Hence, dark stacking is no longer required, offset bias frame stacking is still necessary for hot pixel detection and elimination. Once you build a library of offset bias frames of different durations that you commonly shoot at, you can stop shooting them as well.
I do still maintain a dark and offset library that has been shot at -10C at my common sub durations but generally don't use the darks anymore.
For full detais on Canon Cold Finger modifications and temperature control system build see Rcheshire's thread on Cold Finger Modification here on IIS.
Here:
http://www.iceinspace.com.au/forum/s...d.php?t=132498
and here:
http://www.iceinspace.com.au/forum/s...d.php?t=136524