Please, can anyone explain what's the real difference between a Fast and Slow options in the menu?
I never noticed any difference in speed. Though that was present on the a700 too, but is it possible that in SLT models that means a change in PD and CD AF?

Doc, my experience tells me that the options are mislabeled. "Fast or Sharp" is far more descriptive.
My bird photography (typically very shallow DOF) keep rate is much, much higher with the Sharp (slow) setting.

Ditto for the A700.

Thanks, that's exactly what I thought.