Both Nikon D3S and Nikon D2Xs have 12.0 MP resolution sensors but Nikon D3S's sensor is Full frame (36 x 23.9 mm ) and Nikon D2Xs's sensor is APS-C (23.7 x 15.7 mm ).
Since Nikon D3S's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Nikon D2Xs.
Below you can see the D3S and D2Xs sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D3S and Nikon D2Xs Cameras
As seen above, Nikon D3S has a 2.3x Larger sensor area than Nikon D2Xs. 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
Both Nikon D3S and Nikon D2Xs 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, D3S has scored 82, 23 points higher than D2Xs.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Nikon D3S
82
23.5 bits
12.0 Evs
3253 ISO
Nikon D2Xs
59
22.2 bits
10.9 Evs
489 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 D3S
or the
Nikon D2Xs ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(Full frame versus APS-C),
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.
