I have a D70 and I am using my old Metz BCT4 flash. I wanted to see that the photograph must be cut in shutter speeds faster than 500 but it didnot. Then I made an experiment. With 50 mm 1:1.2 lens I set the aperture to 1.2. I set the flash power to M that means it will deliver the maximum light. And took my son's picture from 2 meters distance. The result was a white screen. I started to increase the speed to 640 and so. First pictures started to come speeds around 4000 and I have clear photographs at shutter speed of 8000!!!. I told this to one of my professional photographer friend who suses a Nikon D1. He told me that this is against the nature of the camera. Yes it is I also know that but he saw it and performed the same experiment with his D1 using my flash and he could go up to shutter speed of 16000. This is the experience that we could not find an answer. I am planning new experiments to prove the syncronization speed. Does anybody have an answer to it or knows something about the situation.