Both Panasonic S5 II and Panasonic S1 have Full frame sized 24.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Another similarity between these two cameras is that both Panasonic S1 and Panasonic S5 II sensors lack anti-alias (Low-Pass) filters. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the S5 Mark II and S1 sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic S5 II and Panasonic S1 Cameras
Panasonic S5 II and Panasonic S1 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.
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
Panasonic S5 II
or the
Panasonic S1 ,
including hyperfocal distance.