Sony A7S vs. A77II XAVC-S Comparison
 

I own both cameras so I shot a quick comparison today. Download the master in ProRes LT to really pixel peep.

To make the playing field as level as possible I used the same lens on both cameras (with and LEA4 on the E-Mount) and also set the A7S to APS-C mode. This does not degrade the image of the A7S and it allows both to have similar focal lengths using the same lens. Picture profiles and other details are listed at the end of the video.

The A77II holds up surprisingly well against the A7S, especially considering the latter is more the 2X the price.