I have noticed that when using my 300D with my 580EX in high-speed sync mode I get a grossly over-exposed band on the left in portrait orientation or on the top in landscape orientation. Here are three samples frames showing this shutter or flash problem. The body is a 300D with about 50000 frames shot during its lifetime. Considering how the two curtains operate in high speed sync I suspect the problem may be caused by bad shutter timing caused by a worn out shutter. Has anyone else seen that before ? Any idea what it might be ?