The Sony A7S is the first camera to really beat the Canon 5D Mark III across the board at almost every level for both stills and video, especially the latter. The A7R did not have the video quality to rival the Canon, but the A7S is a different proposition altogether and raises the bar to another level, possibly signalling the end of DSLR domination in this area at the same time. I can think of no reason to shoot on stock Canon 5D Mark III video settings when you can shoot XAVC-S on the A7S.
