Olympus E-P1 has a
12.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor and features TruePic V processor. On the other hand, Sony A55 has a
16.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features Bionz processor.
Below you can see the E-P1 and A55 sensor size comparison.
As seen above, Sony A55 has a 1.6x Larger sensor area than Olympus E-P1. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in 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. Olympus E-P1 and Sony A55 sensors have been tested by DxO and the results show that A55 has a better overall score of 73, 18 points higher compared to E-P1's score of 55.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Olympus E-P1 |
55 |
21.4 bits |
10.4 Evs |
536 ISO |
Sony A55 |
73 |
23.0 bits |
12.4 Evs |
816 ISO |