Both Olympus E-5 and Nikon D300S have 12.0 MP resolution sensors but Olympus E-5's sensor is Four Thirds (17.3 x 13 mm ) and Nikon D300S's sensor is APS-C (23.6 x 15.8 mm ).
Since Nikon D300S'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 Olympus E-5.
Below you can see the E-5 and D300S sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus E-5 and Nikon D300S Cameras
As seen above, Nikon D300S has a 1.7x Larger sensor area than Olympus E-5. 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
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. It 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. Olympus E-5 and Nikon D300S sensors have been tested by DxO and the results show that D300S has a better overall score of 70, 14 points higher compared to E-5's score of 56.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Olympus E-5
56
21.6 bits
10.5 Evs
519 ISO
Nikon D300S
70
22.5 bits
12.2 Evs
787 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-5
or the
Nikon D300S ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(Four Thirds versus APS-C),
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.
