Olympus E-520 has a
10.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor . On the other hand, Panasonic S2 has a
14.0MP 1/2.3-inch (6.08 x 4.56 mm ) sized CCD sensor .
Below you can see the E-520 and S2 sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus E-520 and Panasonic S2 Cameras
As seen above, Olympus E-520 has a 8.1x Larger sensor area than Panasonic S2. 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
Olympus E-520
or the
Panasonic S2 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(Four Thirds 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.