Both Olympus E-M10 II and Pentax K-5 IIs have 16.0 MP resolution sensors but Olympus E-M10 II's sensor is Four Thirds (17.3 x 13 mm ) and Pentax K-5 IIs's sensor is APS-C (23.7 x 15.7 mm ).
Since Pentax K-5 IIs'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 Olympus E-M10 II.
One other difference between these two cameras that is worth mentioning is that Pentax K-5 IIs'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-M10 II and K-5 IIs sensor size comparison.
As seen above, Pentax K-5 IIs has a 1.7x 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
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-M10 II and Pentax K-5 IIs sensors have been tested by DxO and the results show that K-5 IIs has a better overall score of 82, 9 points higher compared to E-M10 II's score of 73.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Olympus E-M10 II |
73 |
23.1 bits |
12.5 Evs |
842 ISO |
Pentax K-5 IIs |
82 |
23.9 bits |
14.1 Evs |
1208 ISO |