Olympus E-M1 has a
16.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor and features TruePIC VII processor. On the other hand, Olympus E-M1 II has a
20.0MP Four Thirds (17.4 x 13 mm ) sized CMOS sensor and features TruePic VIII processor.
One other difference between these two cameras that is worth mentioning is that Olympus E-M1 II's sensor doesn't have an 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-M1 and E-M1 II sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus E-M1 and Olympus E-M1 II Cameras
Olympus E-M1 and Olympus E-M1 II 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.
DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. It 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. Olympus E-M1 and Olympus E-M1 II sensors have been tested by DxO and the results show that E-M1 II has a better overall score of 80, 7 points higher compared to E-M1's score of 73.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Olympus E-M1
73
23.0 bits
12.7 Evs
757 ISO
Olympus E-M1 II
80
23.7 bits
12.8 Evs
1312 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
Olympus E-M1
or the
Olympus E-M1 II ,
including hyperfocal distance.
