Leica X1 has a
12.0MP APS-C (23.6 x 15.8 mm ) sized CMOS sensor . On the other hand, Ricoh GR II has a
16.0MP APS-C (23.7 x 15.7 mm ) sized CMOS sensor and features GR Engine V processor.
Below you can see the X1 and GR II sensor size comparison.
Leica X1 and Ricoh GR II 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.