Both Pentax K-3 III Mono and Canon 6D MII have 26.0 MP resolution sensors but Pentax K-3 III Mono's sensor is APS-C (23 x 15.5 mm ) and Canon 6D MII's sensor is Full frame (35.9 x 24 mm ).
Since Canon 6D MII'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 Pentax K-3 III Mono.
Another difference between these two cameras is that Pentax K-3 III Mono's sensor lacks 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 K-3 III Monochrome and 6D MII sensor size comparison.
Sensor Size and Resolution Comparison image of Pentax K-3 III Mono and Canon 6D MII Cameras
As seen above, Canon 6D MII has a 2.4x Larger sensor area than Pentax K-3 III Mono. 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.
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
Pentax K-3 III Mono
or the
Canon 6D MII ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(APS-C versus Full frame),
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.
