YI M1 has a
20.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor . On the other hand, Panasonic GF8 has a
16.0MP Four Thirds (17.3 x 13 mm ) sized CMOS sensor and features Venus Engine processor.
Below you can see the M1 and GF8 sensor size comparison.
YI M1 and Panasonic GF8 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 Panasonic GF8 has 27% larger pixel area (14.21µm2 vs 11.16µm2) compared to YI M1, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.