Canon 1D X III has a
20.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Digic X processor. On the other hand, Canon 40D has a
10.0MP APS-C (22.2 x 14.8 mm ) sized CMOS sensor .
Canon 1D X III'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 1D X MIII and 40D sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 1D X III and Canon 40D Cameras
As seen above, Canon 1D X III has a 2.6x Larger sensor area than Canon 40D. 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 Canon 1D X III 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, 1D X MIII has scored 91, 27 points higher than 40D.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon 1D X III
91
24.2 bits
14.5 Evs
3248 ISO
Canon 40D
64
22.1 bits
11.3 Evs
703 ISO
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Canon 1D X III
or the
Canon 40D ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(Full frame versus APS-C),
so compare them at the same framing rather than the same focal length.
Put the same focal length on the smaller sensor and it will show less depth of
field, not more, because it also crops tighter. The calculator shows the
full frame equivalent focal length for each body so you can match the framing.
