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, Nikon D40X has a
10.0MP APS-C (23.7 x 15.6 mm ) sized CCD sensor and features Expeed processor.
Below you can see the D3100 and D40X sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D3100 and Nikon D40X Cameras
Nikon D3100 and Nikon D40X 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 Nikon D40X 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 D40X.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Nikon D3100
67
22.5 bits
11.3 Evs
919 ISO
Nikon D40X
63
22.4 bits
11.4 Evs
516 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
Nikon D40X ,
including hyperfocal distance.
