Both Pentax K-50 and Sony A580 have APS-C sized 16.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the K-50 and A580 sensor size comparison.
Pentax K-50 and Sony A580 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. Pentax K-50 and Sony A580 sensors have been tested by DxO and the results show that A580 has a better overall score of 80, 1 points higher compared to K-50's score of 79.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Pentax K-50 |
79 |
23.7 bits |
13.0 Evs |
1120 ISO |
Sony A580 |
80 |
23.8 bits |
13.3 Evs |
1121 ISO |