Canon 40D has a
10.0MP APS-C (22.2 x 14.8 mm ) sized CMOS sensor . On the other hand, Nikon D700 has a
12.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Expeed processor.
Below you can see the 40D and D700 sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 40D and Nikon D700 Cameras
As seen above, Nikon D700 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
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 40D and Nikon D700 sensors have been tested by DxO and the results show that D700 has a better overall score of 80, 16 points higher compared to 40D's score of 64.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon 40D
64
22.1 bits
11.3 Evs
703 ISO
Nikon D700
80
23.5 bits
12.2 Evs
2303 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 D700 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(APS-C versus Full frame),
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.
