Both Canon A3000 IS and Canon 1000D have 10.0 MP resolution sensors but Canon A3000 IS's sensor is 1/2.3-inch (6.17 x 4.55 mm ) and Canon 1000D's sensor is APS-C (22.2 x 14.8 mm ).
Since Canon 1000D'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 A3000 IS.
Below you can see the A3000 IS and 1000D sensor size comparison.
Sensor Size and Resolution Comparison image of Canon A3000 IS and Canon 1000D Cameras
As seen above, Canon 1000D has a 11.7x Larger sensor area than Canon A3000 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
Canon A3000 IS
or the
Canon 1000D ,
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.
