Both Olympus E-P7 and Panasonic GX8 have Four Thirds sized 20.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Another difference between these two cameras is that Olympus E-P7's sensor lacks 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 E-P7 and GX8 sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus E-P7 and Panasonic GX8 Cameras
Olympus E-P7 and Panasonic GX8 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the 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
Olympus E-P7
or the
Panasonic GX8 ,
including hyperfocal distance.
