Quote:
Originally Posted by Shiraz
A few comments
Most cameras only have about 12 bits of effective resolution. They stretch the data to 16 bits, but the lower bits contain junk. A 12 bit DSLR that provides 12 bits of real data will produce just as many usable shades of grey as a 16 bit system that provides 12 bits of real data. The only chips that can get much better than 12 bits of real data will cost as much as 10 DSLRs.
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Interesting idea but not quite true. It does depend on the well depth and the gain used in the CCD. My ST10XME is 16 bit and I use it to do photometry. If the number of levels of grey was less I would not be able to measure the difference on brightness of 2 stars anywhere near as accurately. It is not just stretched data. Big CCD pixels have greater well depth so can be broken into many more individual levels.
I don't know about the noise level at very low signal but this is not where I measure the stars.