Sony a5100 has a
24.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Bionz X 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 a5100 and E-M1 II sensor size comparison.
As seen above, Sony a5100 has a 1.6x Larger sensor area than Olympus E-M1 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
At Camera Decision, we also look at Dxo Mark sensors when available as we think it is a good indicator of image quality.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Sony a5100 |
80 |
23.8 bits |
12.7 Evs |
1347 ISO |
Olympus E-M1 II |
80 |
23.7 bits |
12.8 Evs |
1312 ISO |