Hi Greg
After your comment I fired off an e mail to QSI (I have a QSI 683). Their reply:
Ulrich,
Kodak doesn't publish full well capacity figures for the HSR and Output Register on the KAF-8300, but we have been able to determine effective values through Photon Transfer analysis. Well depth of the HSR is about 37,000 e-. Well depth of the OR is about 55,000e-. Low gain on the 683 is set to 1.1e-/ADU to maximize the dynamic range of the Output Register.
Take a look at this Knowledge Base article for a bit more detail about how this relates to Flats.
http://store.qsimaging.com/kb_results.asp?ID=28
Regards,
Kevin
Essentially while 2 X 2 binning is able to collect 100,00 photons only 55,000 can be read through the output register.
Ulrich