Sony A7S III has a
12.0MP Full frame (35.6 x 23.8 mm ) sized BSI-CMOS sensor and features Bionz XR processor. On the other hand, Leica M-Monochrom has a
18.0MP Full frame (36 x 24 mm ) sized Monochrome CCD sensor .
Leica M-Monochrom's sensor provides 6MP more than Sony A7S III'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 A7S III and M-Monochrom sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A7S III and Leica M-Monochrom Cameras
Sony A7S III and Leica M-Monochrom 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
Sony A7S III
or the
Leica M-Monochrom ,
including hyperfocal distance.
