Nikon D3100 has a
14.0MP APS-C (23.1 x 15.4 mm ) sized CMOS sensor and features Expeed 2 processor. On the other hand, Canon 500D has a
15.0MP APS-C (22.3 x 14.9 mm ) sized CMOS sensor and features Digic 4 processor.
Below you can see the D3100 and 500D sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D3100 and Canon 500D Cameras
Nikon D3100 and Canon 500D 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 Nikon D3100 and Canon 500D 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, D3100 has scored 67, 4 points higher than 500D.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Nikon D3100
67
22.5 bits
11.3 Evs
919 ISO
Canon 500D
63
21.7 bits
11.5 Evs
663 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 D3100
or the
Canon 500D ,
including hyperfocal distance.