Nikon D4s has a
16.0MP Full frame (36 x 23.9 mm ) sized CMOS sensor and features Expeed 4 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 D4s and E-M1 II sensor size comparison.
As seen above, Nikon D4s has a 3.8x 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
Both Nikon D4s and Olympus E-M1 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, D4s has scored 89, 9 points higher than E-M1 II.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Nikon D4s |
89 |
24.4 bits |
13.3 Evs |
3074 ISO |
Olympus E-M1 II |
80 |
23.7 bits |
12.8 Evs |
1312 ISO |