Fujifilm S2 Pro has a
6.0MP APS-C (23 x 15.5 mm ) sized CCD sensor . On the other hand, Pentax K-3 III Mono has a
26.0MP APS-C (23 x 15.5 mm ) sized BSI-CMOS sensor and features PRIME V processor.
Pentax K-3 III Mono's sensor provides 20MP more than Fujifilm S2 Pro'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 Pentax K-3 III Mono'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 S2 Pro and K-3 III Monochrome sensor size comparison.
Sensor Size and Resolution Comparison image of Fujifilm S2 Pro and Pentax K-3 III Mono Cameras
Fujifilm S2 Pro and Pentax K-3 III Mono 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 Fujifilm S2 Pro has 110% larger pixel area compared to Pentax K-3 III Mono, 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
Fujifilm S2 Pro
or the
Pentax K-3 III Mono ,
including hyperfocal distance.
