Both Canon 40D and Nikon D200 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 40D and D200 sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 40D and Nikon D200 Cameras
As seen above, Nikon D200 has a 1.1x 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
At Camera Decision, we also look at Dxo Mark sensors when available as we think it is a good indicator of image quality.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon 40D
64
22.1 bits
11.3 Evs
703 ISO
Nikon D200
64
22.3 bits
11.5 Evs
583 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 40D
or the
Nikon D200 ,
including hyperfocal distance.
