Sigma SD1 has a
15.0MP APS-C (24 x 16 mm ) sized CMOS (Foveon X3) sensor and features Dual True II processor. On the other hand, Olympus SZ-16 iHS has a
16.0MP 1/2.3-inch (6.17 x 4.55 mm ) sized CMOS sensor .
Another difference between these two cameras is that Sigma SD1's sensor lacks anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the SD1 and SZ-16 iHS sensor size comparison.
Sensor Size and Resolution Comparison image of Sigma SD1 and Olympus SZ-16 iHS Cameras
As seen above, Sigma SD1 has a 13.7x Larger sensor area than Olympus SZ-16 iHS. 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
Sigma SD1
or the
Olympus SZ-16 iHS ,
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.