Pentax K110D has a
6.0MP APS-C (23.5 x 15.7 mm ) sized CCD sensor . On the other hand, Nikon D500 has a
21.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor and features Expeed 5 processor.
Nikon D500's sensor provides 15MP more than Pentax K110D'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.
One other difference between these two cameras that is worth mentioning is that Nikon D500's sensor doesn't have an 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 K110D and D500 sensor size comparison.
Sensor Size and Resolution Comparison image of Pentax K110D and Nikon D500 Cameras
Pentax K110D and Nikon D500 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 K110D has 242% larger pixel area compared to Nikon D500, it has potential to collect more light on pixel level hence 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
Pentax K110D
or the
Nikon D500 ,
including hyperfocal distance.
