Both Canon 550D and Sony HX10V have 18.0 MP resolution sensors but Canon 550D's sensor is APS-C (22.3 x 14.9 mm ) and Sony HX10V's sensor is 1/2.3-inch (6.17 x 4.55 mm ).
Since Canon 550D'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 Sony HX10V.
Below you can see the 550D and HX10V sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 550D and Sony HX10V Cameras
As seen above, Canon 550D has a 11.8x Larger sensor area than Sony HX10V. 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 550D
or the
Sony HX10V ,
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.
