Both Nikon D40X and Nikon D3000 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 D3000 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D40X and Nikon D3000 Cameras
Nikon D40X and Nikon D3000 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 D40X and Nikon D3000 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 D3000.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Nikon D40X
63
22.4 bits
11.4 Evs
516 ISO
Nikon D3000
62
22.3 bits
11.1 Evs
563 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
Nikon D3000 ,
including hyperfocal distance.
