Pentax KF has a
24.0MP APS-C (23.5 x 15.6 mm ) sized CMOS sensor and features PRIME MII processor. On the other hand, Samsung NX300 has a
20.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor and features DRIMe IV processor.
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 NX300 sensor size comparison.
Sensor Size and Resolution Comparison image of Pentax KF and Samsung NX300 Cameras
Pentax KF and Samsung NX300 have almost the same sensor size, so neither of them has any significant advantage over the other in terms of providing control over depth of field when used with the 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
Samsung NX300 ,
including hyperfocal distance.