Both Nikon D3S and Pentax K-r have 12.0 MP resolution sensors but Nikon D3S's sensor is Full frame (36 x 23.9 mm ) and Pentax K-r's sensor is APS-C (23.6 x 15.8 mm ).
Since Nikon D3S'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 Pentax K-r.
Below you can see the D3S and K-r sensor size comparison.
As seen above, Nikon D3S has a 2.3x Larger sensor area than Pentax K-r. 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 D3S and Pentax K-r 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, D3S has scored 82, 10 points higher than K-r.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Nikon D3S |
82 |
23.5 bits |
12.0 Evs |
3253 ISO |
Pentax K-r |
72 |
22.9 bits |
12.4 Evs |
755 ISO |