Quote:
Originally Posted by Alchemy
A few things I'm not used to,
Dark shot noise ? Is this the bias frame ?
Light flood.... Never done that, or even heard of anyone here doing it, however given the 8300 chip had a 400 sec for -25 , I might have to lower my temp somewhat.
Mine runs to -50 of ambient , fortunately nights here generally aren't over 20 too often. So -30 is doable on most nights.
Lots to consider there, thanks for the replies from all.
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well obviously if you haven't heard of it there are things that are commonly done that you need to learn how to do.. or at least understand what they do and decide if it is appropriate for your usage.
The Cassini and Galileo probes both had light flood to manage RBI. it is implemented in FLI ML and PL cameras too.
Except for FLI and to a lesser extent Apogee, no one else that I am aware of implements light flood. These camera companies are in denial as to the issues associated with RBI and it is a very real phenomenon observed in ALL KAF series sensors: with some significantly worse than others.
Dark shot noise is completely unrelated to bias frames. It is the noise you get by virtue of a non-zero signal level (average) in dark frames. It is numerically equal to the square root of the number of electrons in the frame.
So 100 electrons per pixel of average dark signal level means you have 10 electrons of dark shot noise. This is random noise like read noise. so you manage it by averaging many frames together. For dark signal you can do one better and that is by cooling... so you can make it smaller in a per frame basis by cooling or you can average many frames together to 'beat it down' (like read noise).
When you take 4x the frames then you get to reduce the noise by a factor of two....
sounds like some of you guys could benefit from my basic lecture series of the basics of electronic imaging... noise sources, management thereof and how to get high SNR images and how to tell when good enough is good enough!
Keep in mind that if you are imaging something faint where read noise is a consideration, then dark shot noise will also be a consideration and if you cannot run as cold as you would like to keep the dark shot noise less than the read noise, you may be better off to reduce your exposure time and take more exposures....
this stuff isn't terribly complicated but there are a few basics that I cover in my lecture series that I think anyone that is serious about imaging ought to know... sort of like the basics of how an internal combustion engine works and the importance of lubrication, gearing and tires by way of analogy....