Hi! I actually killed my d600. I've debated sending it for the 50 to have it looked at or buy a sb700. I would like two, to use as you suggested but the expense is just too much right now. I'm not sure how I did my sb600 in but it will not flash. I think i identically left my camera on continuous shoot mode, not giving the Sb600 time to catch up. Lesson learned. Ugh.