Both Sony NEX-5R and Pentax K-5 IIs have APS-C sized 16.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
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 NEX-5R and K-5 IIs sensor size comparison.
Sony NEX-5R and Pentax K-5 IIs 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. Sony NEX-5R 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, 4 points higher compared to NEX-5R's score of 78.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Sony NEX-5R |
78 |
23.7 bits |
13.1 Evs |
910 ISO |
Pentax K-5 IIs |
82 |
23.9 bits |
14.1 Evs |
1208 ISO |