Both Nikon D40X and Canon 400D have APS-C sized 10.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Below you can see the D40X and 400D sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D40X and Canon 400D Cameras
As seen above, Nikon D40X has a 1.1x Larger sensor area than Canon 400D. 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 Nikon D40X and Canon 400D 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, D40X has scored 63, 1 points higher than 400D.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Nikon D40X
63
22.4 bits
11.4 Evs
516 ISO
Canon 400D
62
22.1 bits
11.0 Evs
664 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
Nikon D40X
or the
Canon 400D ,
including hyperfocal distance.
