Pentax K-1 II has a
36.0MP Full frame (35.9 x 24 mm ) sized CMOS sensor and features PRIME IV processor. On the other hand, Leica S2 has a
38.0MP Medium format (45 x 30 mm ) sized CCD sensor .
Another difference between these two cameras is that Pentax K-1 II'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-1 Mark II and S2 sensor size comparison.
Sensor Size and Resolution Comparison image of Pentax K-1 II and Leica S2 Cameras
As seen above, Leica S2 has a 1.6x Larger sensor area than Pentax K-1 II. 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-1 II
or the
Leica S2 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(Full frame versus Medium format),
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.