Sony A9 II has a
24.0MP Full frame (35.6 x 23.8 mm ) sized Stacked BSI-CMOS sensor and features BIONZ X processor. On the other hand, Olympus E-M10 II has a
16.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor and features TruePic VII processor.
Sony A9 II's sensor provides 8MP more than Olympus E-M10 II's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the A9 Mark II and E-M10 II sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A9 II and Olympus E-M10 II Cameras
As seen above, Sony A9 II has a 3.8x Larger sensor area than Olympus E-M10 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.
DxOMark Sensor Scores
Both Sony A9 II and Olympus E-M10 II sensors have been tested by DxoMark. DxoMark scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Of the two cameras that we are comparing, A9 Mark II has scored 93, 20 points higher than E-M10 II.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony A9 II
93
25.0 bits
14.0 Evs
3434 ISO
Olympus E-M10 II
73
23.1 bits
12.5 Evs
842 ISO
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
Sony A9 II
or the
Olympus E-M10 II ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(Full frame 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.