Leica Q2 has a
47.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Maestro II processor. On the other hand, Leica Q3 Monochrom has a
60.0MP Full frame (36 x 24 mm ) sized BSI-CMOS sensor and features Maestro IV processor.
Leica Q3 Monochrom's sensor provides 13MP more than Leica Q2'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 similarity between these two cameras is that both Leica Q3 Monochrom and Leica Q2 sensors lack anti-alias (Low-Pass) filters. 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 Q2 and Q3 Monochrom sensor size comparison.
Sensor Size and Resolution Comparison image of Leica Q2 and Leica Q3 Monochrom Cameras
Leica Q2 and Leica Q3 Monochrom 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.
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
Leica Q2
or the
Leica Q3 Monochrom ,
including hyperfocal distance.