Both Olympus E-PM1 and Canon G15 have 12.0 MP resolution sensors but Olympus E-PM1's sensor is Four Thirds (17.3 x 13 mm ) and Canon G15's sensor is 1/1.7-inch (7.44 x 5.58 mm ).
Since Olympus E-PM1's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Canon G15.
Below you can see the E-PM1 and G15 sensor size comparison.
As seen above, Olympus E-PM1 has a 5.4x Larger sensor area than Canon G15. 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
Both Olympus E-PM1 and Canon G15 sensors have been tested by DxoMark. DxoMark 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. Of the two cameras that we are comparing, E-PM1 has scored 52, 6 points higher than G15.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Olympus E-PM1 |
52 |
21.0 bits |
10.3 Evs |
499 ISO |
Canon G15 |
46 |
19.9 bits |
11.5 Evs |
165 ISO |