Both Panasonic G5 and Pentax K-5 have 16.0 MP resolution sensors but Panasonic G5's sensor is Four Thirds (17.3 x 13 mm ) and Pentax K-5's sensor is APS-C (23.7 x 15.7 mm ).
Since Pentax K-5'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 Panasonic G5.
Below you can see the G5 and K-5 sensor size comparison.
Sensor Size and Resolution Comparison image of Panasonic G5 and Pentax K-5 Cameras
As seen above, Pentax K-5 has a 1.7x Larger sensor area than Panasonic G5. 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. Panasonic G5 and Pentax K-5 sensors have been tested by DxO and the results show that K-5 has a better overall score of 82, 21 points higher compared to G5's score of 61.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Panasonic G5
61
21.4 bits
11.6 Evs
618 ISO
Pentax K-5
82
23.7 bits
14.1 Evs
1162 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
Panasonic G5
or the
Pentax K-5 ,
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.
