Olympus E-M5 has a
16.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor and features TruePic VI processor. On the other hand, Pentax K20D has a
15.0MP APS-C (23.4 x 15.6 mm ) sized CMOS sensor .
Below you can see the E-M5 and K20D sensor size comparison.
Sensor Size and Resolution Comparison image of Olympus E-M5 and Pentax K20D Cameras
As seen above, Pentax K20D has a 1.6x Larger sensor area than Olympus E-M5. 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-M5 and Pentax K20D 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-M5 has scored 71, 6 points higher than K20D.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Olympus E-M5
71
22.8 bits
12.3 Evs
826 ISO
Pentax K20D
65
22.9 bits
11.1 Evs
639 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-M5
or the
Pentax K20D ,
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.
