I have a Calumet Pro Series wireless trigger, which seems to be a Calumet-branded Phottix Stratto 2.4GHz trigger set.
When using a 5D Mark III with a 100mm f/2.8L Macro, I get consistently a black bar at the bottom of the frame (maybe about one-fifth to one-sixth the vertical dimension of the frame) with the shutter at 1/200 (at f/2.8 ). At 1/160, the bar goes away.
I don't know whether bodies or lenses make a difference, but they appear to do so.
With a Rebel T3i and a 24mm f/1.4L II (at f/2.8 ), there is no bar at 1/200.
My flash unit is a 600EX-RT.
Any ideas as to what I'm missing or simply not seeing?