Both Nikon D90 and Canon A1100 IS have 12.0 MP resolution sensors but Nikon D90's sensor is APS-C (23.6 x 15.8 mm ) and Canon A1100 IS's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since Nikon D90'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 Canon A1100 IS.
Below you can see the D90 and A1100 IS sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D90 and Canon A1100 IS Cameras
As seen above, Nikon D90 has a 13.3x Larger sensor area than Canon A1100 IS. 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
Nikon D90
or the
Canon A1100 IS ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(APS-C versus 1/2.3-inch),
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.
