How do you measure the Dynamic Range of a Camera?

[ondebanks]

I'll probably get a spanking for asking this, but what do you make of the following DXO review of the IQ180? Either I'm not understanding something or I was just uninformed, but I thought the IQ180 had the highest DR of any camera, yet below they say it is less than some APS-C cameras.

"In term of dynamic range, the IQ180 also reaches the very high score 13.6 Evs, but still doesn’t beat the best APS-C sensors, like the Pentax K5 (14.1 Evs) or the Nikon D7000 (13.9 Evs)."

There is a very simple explanation for that: readout noise. At the frame rates demanded by photographers, none of the CCDs in MFDBs has readout noise remotely as low as the best CMOS sensors in APS-C or FF-DSLRs. Readout noise is the denominator in the dynamic range equation, so to significantly boost the DR, you "only" have to drop the readout noise (easier said than done!).

Let me ask folks here: Would you be happy the menu option of with a 5 sec/frame (not 5 frame/sec!) readout time on your MFDB? In many circumstances, I would, because clocking out the pixels at a slower frequency reduces readout noise. A 50% reduction might be the most one could hope for, and the resulting noise would still be around 3-4 times worse than the CMOS cameras, but it's a good start! That would improve both DR and high ISO performance.

Ray