Both Pentax K-70 and Nikon D3200 have APS-C sized 24.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Another difference between these two cameras is that Pentax K-70'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-70 and D3200 sensor size comparison.
Sensor Size and Resolution Comparison image of Pentax K-70 and Nikon D3200 Cameras
Pentax K-70 and Nikon D3200 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 K-70
or the
Nikon D3200 ,
including hyperfocal distance.
