Both Pentax X90 and Nikon D2X have 12.0 MP resolution sensors but Pentax X90's sensor is 1/2.3-inch (6.08 x 4.56 mm ) and Nikon D2X's sensor is APS-C (23.7 x 15.7 mm ).
Since Nikon D2X'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 Pentax X90.
Below you can see the X90 and D2X sensor size comparison.
Sensor Size and Resolution Comparison image of Pentax X90 and Nikon D2X Cameras
As seen above, Nikon D2X has a 13.4x Larger sensor area than Pentax X90. 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.
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
Pentax X90
or the
Nikon D2X ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1/2.3-inch 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.
