"All the latest sony digicams, including 828, V1, V3, T1, T3, P150, all have very good, autofocus systems, and truly fast final shutter lags in the 0.010 range - much faster than any DSLR! The high end ones all take CF cards now too."
Faster than a digital SLR as well...hmmmmm. I think I'd wager on that!
Autofocus time in low light conditions is the real issue. Many cameras perform well topside and have negligible shutter lag; however, once submersed on a cloudy day they take forever to lock the focus.
BTW...how does one measure "true shutter lag"? It seems to me any test you ran would be rather subjective. Anything below .25 of a second would "subjectively" be considered negligible. I have older digicams where its measured in seconds and is noticable. In the newer ones, I've not noticed a real difference topside. Most of them that I've tested manually have a tendency to focus slower in low light. So, if you dive with a good focus light, you eliminate the issue altogether. My wife and I serve as each other's "focus light" while the other is enjoying the camera. Some other factors you should consider:
RAW capability and RAW write times. I have found adjusting the white balance post dive has been invaluable to saving a few photos. Write times of Super Fine, SHQ JPEGs is also a concern.
Complete manual mode - My SP-350 will allow me to do everything manually including the focus and strobe. BTW...by presetting everything including the subject distance in manual mode there is no shutter lag whatsoever.
Battery life - seems inconsequential but if you can shoot all day on one card and one set of batteries....that means no opening the camera on the boat between dives.
Housing availability - I agree with the Ike asessment stated on here.
Flash recharge time - again seems inconsequential but I're read that some cameras take as long as 6-10 seconds between shots just to recharge the internal strobe.
At the end of the day, there's a workaround for almost everything and your skill with any camera will trump almost everything else. When I need a good dose of humility, I simply look at some of Alex M's shots with a consumer digicam + internal strobe.
