Paul C. Buff, Inc. Technical Forum

It's a known quirk w/ Canon's 5D FF body....a good number of them do *not* hit their max sync speed. How Canon manages to do this w/o a lot of irate customers exchanging their bodies I have no idea :roll:

If you watch Zach Arias' initial onelight workshop at CreativeLive, he also mentions it happens to his 5D and I'm sure he didn't make any mistakes. I think he mentioned he runs 1/125 shutter speed in the studio...

Just to clarify a point for the original poster -

When you use strobes, the shutter speed has essentially no effect on your exposure. Shutter speed is only relevant with continuous light sources. If you are shooting at a relatively small aperture, the ambient light won't contribute anything to the exposure and shutter speed is irrelevant. You'll know if you take a shot without the strobes turned on and get a pure black frame. Lit with strobes, f/11 at 1/10 will look identical to f/11 at 1/100 and action-stopping will be determined by the duration of the flash - not shutter speed.

If you are blending ambient light with strobes, then shutter speed will affect the ambient contribution only. Aperture and ISO will affect both ambient and strobes.