Hi Guys I have recently used what is supposed to be a fully compatable Sigma Flashgun on my Nikon D70, but the images are completely burnt out. It is the Sigma EF-500 DG ST NA - iTTL and the lens I was using at the time was the older trombone type 80-200 2.8 Af lens. Everything was on auto, so how come it didnt read the light right? I then removed that flash and used my integrated flash, which, apart from the redeye, did a good job. Can you help?