I was given this external flash (refer to thread title) a while back and after spending about an hour with it when I first received it I gave up even trying to get it to work. Keep in mind, I don't have the manual to the flash either. Recently, my interest was sparked after trying to shoot one of the local community college's volley ball games and having to sacrifice a lower iso and a lower aperture for better lighting. I've spent some time with it again just fiddelling around with it and had some luck but have come far from perfect. It seems if I use above an f10 aperture I receive an error on my camera. It also seems very inconsistent with the exposure I get from it. If I let the external flash sit long enough while "on," it seems to totally fry my pictures. As if the flash unit is charging and blowing a whole charge on one flash... After doing some research, I figured out the function of a couple of settings on the flash. Their's a switch that says "N, S1, S2." I now know that s1 and s2 are for single and double internal flash syncing but am still lost as to what "N" means. But can anyone tell me why it's giving me an error on my camera? P.S. Sorry if I'm missing any vital information needed for an answer. I'll be happy to give any more information needed.