Leica X Vario has a
16.0MP APS-C (23.6 x 15.8 mm ) sized CMOS sensor . On the other hand, Leica X1 has a
12.0MP APS-C (23.6 x 15.8 mm ) sized CMOS sensor .
Below you can see the X Vario and X1 sensor size comparison.
Leica X Vario and Leica X1 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 Leica X1 has 32% larger pixel area (30.56µm2 vs 23.13µm2) compared to Leica X Vario, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.