Quote:
Originally Posted by Shiraz
offset 21, 1x1 bin. Craig's article is great, but it deals with getting the best dynamic range in CCD subs. The 1600 allows you to trade off some dynamic range if you wish to use very short subs or get vanishingly small read noise for NB - something CCDs cannot readily do.
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Hi Ray,
I am not sure how you concluded that from Craig's article. The gain and offset had a procedure to be set to keep the resulting images within the 65535 levels that 16 bit gives. Its not dependent on exposure length but setting what the sensor will record without loss of data.
So you are saying shorter exposures at higher gain may clip dynamic range but you get better read noise with the higher gain settings?
Just out of interest what are the read noise values for this camera at different gain settings. is that known? I have read figures from 1.6 to 3.6.
Which by the way in CMOS world is quite high. I should look for it but I did read a test of the Sony A7r2 BSI 42.4mp full frame sensor read noise at some ISO levels as .3 electrons. This makes sense as OMD cameras are often reported by owners as noisy even at low ISO. The point here is not to take anything away from the ASI1600 as its a new paradigm and way cleaner than CCDs but more imagine one of those Sony full frame BSI babies in a cooled body like the ASI? Wow.
But this camera is 12 bit? Or is it 12 bit output but 16bit internal processing? (For example Sony A7 cameras output is 12 bit sometimes depending on features activated but the processing pipeline is 14 bit).
How many levels is 12 bit is 4096 levels of brightness.14 bit is 16384 levels of brightness.
Greg.