Sony A550 has a
14.0MP APS-C (23.4 x 15.6 mm ) sized CMOS sensor and features Bionz processor. On the other hand, Pentax K-x has a
12.0MP APS-C (23.6 x 15.8 mm ) sized CMOS sensor and features Prime processor.
Below you can see the A550 and K-x sensor size comparison.
Sony A550 and Pentax K-x 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 A550 and Pentax K-x sensors have been tested by DxO and the results show that K-x has a better overall score of 72, 6 points higher compared to A550's score of 66.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Sony A550 |
66 |
21.9 bits |
11.8 Evs |
807 ISO |
Pentax K-x |
72 |
22.8 bits |
12.5 Evs |
811 ISO |