Both Canon M6 and Pentax K-3 II have APS-C sized 24.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
One other difference between these two cameras that is worth mentioning is that Pentax K-3 II's sensor doesn't have an anti-alias (Low-Pass) filter. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moiré occurring in certain scenes.
Below you can see the M6 and K-3 II sensor size comparison.
Sensor Size and Resolution Comparison image of Canon M6 and Pentax K-3 II Cameras
As seen above, Pentax K-3 II has a 1.1x Larger sensor area than Canon M6. 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. Canon M6 and Pentax K-3 II sensors have been tested by DxO and the results show that K-3 II has a better overall score of 80, 2 points higher compared to M6's score of 78.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon M6
78
23.4 bits
12.6 Evs
1317 ISO
Pentax K-3 II
80
23.6 bits
13.6 Evs
1106 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
Canon M6
or the
Pentax K-3 II ,
including hyperfocal distance.
