Pentax K20D has a
15.0MP APS-C (23.4 x 15.6 mm ) sized CMOS sensor . On the other hand, Sony A35 has a
16.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Bionz processor.
Below you can see the K20D and A35 sensor size comparison.
Sensor Size and Resolution Comparison image of Pentax K20D and Sony A35 Cameras
Pentax K20D and Sony A35 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 K20D and Sony A35 sensors have been tested by DxO and the results show that A35 has a better overall score of 74, 9 points higher compared to K20D's score of 65.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Pentax K20D
65
22.9 bits
11.1 Evs
639 ISO
Sony A35
74
23.3 bits
12.7 Evs
763 ISO
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Pentax K20D
or the
Sony A35 ,
including hyperfocal distance.
