Both Panasonic GF7 and Panasonic GX850 have Four Thirds sized 16.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
One other difference between these two cameras that is worth mentioning is that Panasonic GX850's sensor doesn't have an anti-alias (Low-Pass) filter. 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 GF7 and GX850 sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic GF7 and Panasonic GX850 Cameras
Panasonic GF7 and Panasonic GX850 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 GF7
or the
Panasonic GX850 ,
including hyperfocal distance.
