Samsung NX500 has a
28.0MP APS-C (23.5 x 15.7 mm ) sized BSI-CMOS sensor and features DRIMe 5 processor. On the other hand, Fujifilm X-T100 has a
24.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor .
Another difference between these two cameras is that Samsung NX500's sensor lacks anti-alias (Low-Pass) filter. 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 NX500 and X-T100 sensor size comparison.
Samsung NX500 and Fujifilm X-T100 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 Fujifilm X-T100 has 16% larger pixel area (15.37µm2 vs 13.18µm2) compared to Samsung NX500, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.