Canon 70D has a
20.0MP APS-C (22.5 x 15 mm ) sized CMOS sensor and features Digic 5+ processor. On the other hand, Canon 40D has a
10.0MP APS-C (22.2 x 14.8 mm ) sized CMOS sensor .
Canon 70D's sensor provides 10MP more than Canon 40D's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the 70D and 40D sensor size comparison.
Canon 70D 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
Both Canon 70D and Canon 40D 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, 70D has scored 68, 4 points higher than 40D.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Canon 70D |
68 |
22.5 bits |
11.6 Evs |
926 ISO |
Canon 40D |
64 |
22.1 bits |
11.3 Evs |
703 ISO |