Was messing around today with the Zeus and a TT5/AC9 and got these results. You'll notice the bottom of the frame is lighter in all the shots above x-sync. I didn't post all the shots but I got great results at all power settings, not just full power. I'm going to have to go mess around with this and a real subject now.
I was kind surprised by the results as I shoot with Elinchrom 600Rxs and a Ranger with S heads and don't get near the results due to the shorter flash duration. In fact, I don't shoot the Ranger above a 250th. The 600Rxs I'll shoot to 500/800.
