yayi60 wrote:
Thanks for your advice, but I'm not sure that you read my original post.. I do have a SB700, and it occurs with built in camera flash and the SB700, with difusser, without, with the flash on the camera or with the SB of the camera
As others have mentioned it looks like lens barrel. I have the same issue with a 18-200 on a Canon with the shorter focal lengths. Are you using a hood? If so take it off and see if it makes any difference. Move the speedlight way off of the camera like 6 to 12 inches and try to move it forward of the lens and see what happens.