Both Olympus E-450 and Canon 40D have 10.0 MP resolution sensors but Olympus E-450's sensor is Four Thirds (17.3 x 13 mm ) and Canon 40D's sensor is APS-C (22.2 x 14.8 mm ).
Since Canon 40D'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 Olympus E-450.
Below you can see the E-450 and 40D sensor size comparison.
As seen above, Canon 40D has a 1.5x Larger sensor area than Olympus E-450. 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-450 and Canon 40D sensors have been tested by DxO and the results show that 40D has a better overall score of 64, 8 points higher compared to E-450's score of 56.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Olympus E-450 |
56 |
21.5 bits |
10.5 Evs |
512 ISO |
Canon 40D |
64 |
22.1 bits |
11.3 Evs |
703 ISO |