Pentax K-5 IIs has a
16.0MP APS-C (23.7 x 15.7 mm ) sized CMOS sensor and features Prime II processor. On the other hand, Sony A77 II has a
24.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Bionz X processor.
Sony A77 II's sensor provides 8MP more than Pentax K-5 IIs's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Another difference between these two cameras is that Pentax K-5 IIs's sensor lacks 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 K-5 IIs and A77 II sensor size comparison.
Pentax K-5 IIs and Sony A77 II 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
At Camera Decision, we also look at Dxo Mark sensors when available as we think it is a good indicator of image quality.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Pentax K-5 IIs |
82 |
23.9 bits |
14.1 Evs |
1208 ISO |
Sony A77 II |
82 |
24.4 bits |
13.4 Evs |
1013 ISO |