Canon 20D has a
8.0MP APS-C (22.5 x 15 mm ) sized CMOS sensor . On the other hand, Canon 40D has a
10.0MP APS-C (22.2 x 14.8 mm ) sized CMOS sensor .
Below you can see the 20D and 40D sensor size comparison.
Canon 20D and Canon 40D 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. Canon 20D and Canon 40D sensors have been tested by DxO and the results show that 40D has a better overall score of 64, 2 points higher compared to 20D's score of 62.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Canon 20D |
62 |
21.9 bits |
11.0 Evs |
721 ISO |
Canon 40D |
64 |
22.1 bits |
11.3 Evs |
703 ISO |