Quote:
Originally Posted by Shiraz
hi Richard. So your sub length is essentially limited by the thermal noise as the chip heats up during imaging - have i got that right? Dark calibration must be a pain if that is the case.
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Based on my interpretation of the test results I have seen you are correct - thermal noise is the limiting factor. I have dark masters taken at various temperatures, and do my best to match sub frames with the appropriate master (within the limits of practicality). My dark masters are typically 50 subs or more. My bias master has 100 subs.
Quote:
Originally Posted by Shiraz
Does the optimum sub length vary with ambient temp?
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Yes it does. As a rough approximation, optimal sub settings for me would be 4 mins ISO1600 in winter, 3-4mins ISO1600 in autumn/spring and probably 1-2mins in summer. Admittedly the first time I used this method of sub calculation was in May of this year, so I haven't had the opportunity to test it at ambient nighttime temps >20C