Olympus E-M1 has a
16.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor and features TruePIC VII processor. On the other hand, Sony A58 has a
20.0MP APS-C (23.2 x 15.4 m ) sized CMOS sensor .
Below you can see the E-M1 and A58 sensor size comparison.
As seen above, Sony A58 has a 1.5x Larger sensor area than Olympus E-M1. 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-M1 and Sony A58 sensors have been tested by DxO and the results show that A58 has a better overall score of 74, 1 points higher compared to E-M1's score of 73.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Olympus E-M1 |
73 |
23.0 bits |
12.7 Evs |
757 ISO |
Sony A58 |
74 |
23.3 bits |
12.5 Evs |
753 ISO |