Leica Q-P has a
24.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Maestro II processor. On the other hand, Nikon D3X has a
25.0MP Full frame (35.9 x 24 mm ) sized CMOS sensor and features Expeed processor.
Below you can see the Q-P and D3X sensor size comparison.
Sensor Size and Resolution Comparison image of Leica Q-P and Nikon D3X Cameras
Leica Q-P and Nikon D3X 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
Leica Q-P
or the
Nikon D3X ,
including hyperfocal distance.