Both Olympus E-520 and Canon S90 have 10.0 MP resolution sensors but Olympus E-520's sensor is Four Thirds (17.3 x 13 mm ) and Canon S90's sensor is 1/1.7-inch (7.44 x 5.58 mm ).
Since Olympus E-520'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 S90.
Below you can see the E-520 and S90 sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus E-520 and Canon S90 Cameras
As seen above, Olympus E-520 has a 5.4x Larger sensor area than Canon S90. 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.
DxOMark Sensor Scores
Both Olympus E-520 and Canon S90 sensors have been tested by DxoMark. DxoMark scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Of the two cameras that we are comparing, E-520 has scored 55, 9 points higher than S90.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Olympus E-520
55
21.4 bits
10.4 Evs
548 ISO
Canon S90
46
20.2 bits
11.0 Evs
185 ISO
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
Canon S90 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(Four Thirds 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.
