Nikon D500 has a
21.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor and features Expeed 5 processor. On the other hand, Pentax K100D S has a
6.0MP APS-C (23.5 x 15.7 mm ) sized CCD sensor .
Nikon D500's sensor provides 15MP more than Pentax K100D S's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Another difference between these two cameras is that Nikon D500'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 D500 and K100D Super sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon D500 and Pentax K100D S Cameras
Nikon D500 and Pentax K100D S have the same sensor sizes so they will provide same level of control over the depth of field when used with same focal length and aperture. On the other hand, since Pentax K100D S has 242% larger pixel area (61.08µm 2 vs 17.85µm 2 ) compared to Nikon D500, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.
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
Nikon D500
or the
Pentax K100D S ,
including hyperfocal distance.
