Having a weird problem today...hopefully this is the correct forum. Was taking some test shots to figure out my lighting for some photos tomorrow, and I keep getting half the photo way over-exposed while the other half is correct. On testing, I find: 1) It's always the top half of the sensor, regardless of how the camera is oriented or positioned 2) It only happens when using the studio flash, regardless of how that flash is positioned. I don't see it if I only use my 430EX. I don't see it if I put the camera on auto. 3) I get the same problem with several different lenses, different shutter speeds, different apertures, with or without a lens hood. Any ideas?