Anyone Using 600EX-RTs on a 5D2?
It's very functional, more than the manual states. One thing you can't do is groups, which restricts you from mixing manual and ETTL flash modes in one shot. HSS is there, even on remote radio control, although the manual states otherwise. It will sync to 1/200, where the manual says half this speed (or twice the time). Since you can't do the modern groups, you are stuck with A, B, and C like before, ratios for ETTL, and power levels for manual. If you only have two or three of them, big deal. These are great.