Both Olympus E-M5 III and Olympus PEN-F have Four Thirds sized 20.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the E-M5 Mark III and PEN-F sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus E-M5 III and Olympus PEN-F Cameras
Olympus E-M5 III and Olympus PEN-F 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-M5 III
or the
Olympus PEN-F ,
including hyperfocal distance.
