Anyone see anything like this before? My first thought is a flash sync problem but usually you see 1/4 of the frame dark not a dark line like that. Also if the shutter got stuck wouldn't the frame from that point on be darker? It was the only picture like that out of the entire wedding. I hate wired stuff like this that I can't explain. Also I have a 5D3 and it is like this on both cards so I don't think it is a card problem. Maybe a glitch when the camera wrote to the cards? So the other question is if the camera has two card slots does it write the image to both cards separately or does it write to one card and copy from one card to the other? I would hope they don't do that because it it would negate the usefulness of two card slots.