Both Sony A7S II and Sony A7S III have Full frame sized 12.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the A7S II and A7S III sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A7S II and Sony A7S III Cameras
Sony A7S II and Sony A7S III have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture.
DxOMark Sensor Scores
At Camera Decision, we also look at Dxo Mark sensors when available as we think it is a good indicator of image quality.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony A7S II
85
23.6 bits
13.3 Evs
2993 ISO
Sony A7S III
85
24.2 bits
13.4 Evs
3900 ISO
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Sony A7S II
or the
Sony A7S III ,
including hyperfocal distance.
