Both Canon SD970 IS and Casio EX-100 have 12.0 MP resolution sensors but Canon SD970 IS's sensor is 1/2.3-inch (6.17 x 4.55 mm ) and Casio EX-100's sensor is 1/1.7-inch (7.44 x 5.58 mm ).
Since Casio EX-100'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 SD970 IS.
Below you can see the SD970 IS and EX-100 sensor size comparison.
Sensor Size and Resolution Comparison image of Canon SD970 IS and Casio EX-100 Cameras
As seen above, Casio EX-100 has a 1.5x Larger sensor area than Canon SD970 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 SD970 IS
or the
Casio EX-100 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(1/2.3-inch versus 1/1.7-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.
