I have read many places that for the best calibrated astrophotographs, you should be taking bias frames, dark frames, and flat frames.
But on a forum I read the following statement
You usually don't need to. DSLRs with CMOS sensors (as opposed to CCD) automatically take and subtract a bias frame every time an exposure is made. If they didn't, the noise would be horrendous.
Almost all current models of DSLR use CMOS sensors; some older Nikons used CCD.
Is this true? Does this mean that all the astrophotography literature I have been reading is either outdated, or just wrong?
Is there no point taking bias shots to subtract from my flat frames and light shots?
EDIT: I should clarify that a bias frame is not a dark frame. The quoted person went on to indicate that all CMOS sensors take a bias frame afterwards, and SOME have the option for take a dark frame, which is taken with the same shutterspeed as the light frame (bias frame is always taken with fastest shutter).