3D-Kraft put the SONY A7R II and Sony A7S camera side by side on a shoot to see the difference if any on how both the cameras handle low light.
They have set the cameras differently for their needs, for their test. So it’s not an exact side by side comparison.
Please check out their write up on the low light test they performed on the two A7 Sony series cameras HERE.
Bonus video, check out the Sony A7R II camera up in the air from 3D-Kraft:
Recorded with Sony A7R II camera using internal 4K XAVC-S full frame mode.