Both Pentax KF and Nikon D750 have 24.0 MP resolution sensors but Pentax KF's sensor is APS-C (23.5 x 15.6 mm ) and Nikon D750's sensor is Full frame (35.9 x 24 mm ).
Since Nikon D750'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 KF.
Another difference between these two cameras is that Pentax KF'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 KF and D750 sensor size comparison.
Sensor Size and Resolution Comparison image of Pentax KF and Nikon D750 Cameras
As seen above, Nikon D750 has a 2.4x Larger sensor area than Pentax KF. 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 KF
or the
Nikon D750 ,
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.
