Quote:
Originally Posted by Shiraz
And then there is read noise .....
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Good one Ray,
Yes - I know I am preaching to the converted
But its still possible my point is missed - especially when we are talking about faint detail in low photn count areas of our images
If we have for simplicity -10e read noise and the levels of faint Ha signal is only from very low (say 1e) through 10e and say up to -20e
Then the signal to noise ratio goes from 1:10 (meaning no useful data) through 1: up to 2:1 - add shot noise, dark noise, and all the other possible noise its still a fairly sad situation for useful data . . . - but this is using up the first 4 to 5 bits of our 10-14 bits of data !
Now if we have a -1e read noise camera (and all other things being equal) then the situation becomes 1:1 through to 10:1 and up to 20:1
This is vast improvement improvement in signal quality and will thus produce an image that is (at least for the faint data) not just 20% better but more likely 1000% better
So who cares about an increase in Quantum efficiency of 20 or even 40% when these sorts of gains can arise by low read noise cameras.
Anyone care to analyse this better than my rough numbers