Pentax K100D S has a
6.0MP APS-C (23.5 x 15.7 mm ) sized CCD sensor . On the other hand, Fujifilm X-A3 has a
24.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor and features EXR Processor II processor.
Fujifilm X-A3's sensor provides 18MP 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.
Below you can see the K100D Super and X-A3 sensor size comparison.
Sensor Size and Resolution Comparison image of Pentax K100D S and Fujifilm X-A3 Cameras
Pentax K100D S and Fujifilm X-A3 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 297% larger pixel area compared to Fujifilm X-A3, 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 K100D S
or the
Fujifilm X-A3 ,
including hyperfocal distance.
