No, it will also lose the ability to second-curtain synch, contrast-control flash and auto zoom (obviously, since the 280T doesn't have a zoom head). The 280T also doesn't warn if the lens on the camera is too wide for the flash's coverage (i.e., if you zoom out beyond 28mm on a wide zoom).Question #1: Is the only function lost when using the Af 280t on the PZ1 the ability to focus in the dark (ie red sensor)?
I don't know enough about the hotshoe grip and sync cords to answer questions 2 and 3.
Joe
Guys I could probably do tests to answer my own questions but I suspect someone out there can answer them faster than I can do tests. I picked up AF 280t recently. I plan to use it primarily with the LX but I will also be using it with the PZ1.

