Both Pentax K-3 and Nikon D7100 have APS-C sized 24.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Another similarity between these two cameras is that both Nikon D7100 and Pentax K-3 sensors lack anti-alias (Low-Pass) filters. 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 K-3 and D7100 sensor size comparison.
Pentax K-3 and Nikon D7100 have the same sensor sizes so they will provide same level of control over the depth of field when used with 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. Pentax K-3 and Nikon D7100 sensors have been tested by DxO and the results show that D7100 has a better overall score of 83, 3 points higher compared to K-3's score of 80.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Pentax K-3 |
80 |
23.7 bits |
13.4 Evs |
1216 ISO |
Nikon D7100 |
83 |
24.2 bits |
13.7 Evs |
1256 ISO |