Both Olympus SZ-31MR iHS and Olympus E-M10 III have 16.0 MP resolution sensors but Olympus SZ-31MR iHS's sensor is 1/2.3-inch (6.17 x 4.55 mm ) and Olympus E-M10 III's sensor is Four Thirds (17.4 x 13 mm ).
Since Olympus E-M10 III's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Olympus SZ-31MR iHS.
Below you can see the SZ-31MR iHS and E-M10 III sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus SZ-31MR iHS and Olympus E-M10 III Cameras
As seen above, Olympus E-M10 III has a 8.1x Larger sensor area than Olympus SZ-31MR iHS. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in 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 SZ-31MR iHS
or the
Olympus E-M10 III ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1/2.3-inch versus Four Thirds),
so compare them at the same framing rather than the same focal length.
Put the same focal length on the smaller sensor and it will show less depth of
field, not more, because it also crops tighter. The calculator shows the
full frame equivalent focal length for each body so you can match the framing.