Both Ricoh G900 II and OM System OM-5 II have 20.0 MP resolution sensors but Ricoh G900 II's sensor is 1/2.3 inch (6.17 x 4.55 mm ) and OM System OM-5 II's sensor is Four Thirds (17.4 x 13 mm ).
Since OM System OM-5 II'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 Ricoh G900 II.
Below you can see the G900 II and OM-5 Mark II sensor size comparison.
Sensor Size and Resolution Comparison image of Ricoh G900 II and OM System OM-5 II Cameras
As seen above, OM System OM-5 II has a 8.1x Larger sensor area than Ricoh G900 II. 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
Ricoh G900 II
or the
OM System OM-5 II ,
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.
