Fujifilm X-T100 has a
24.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor . On the other hand, Nikon Z30 has a
21.0MP APS-C (23.5 x 15.7 mm ) sized CMOS sensor and features Expeed 6 processor.
One other difference between these two cameras that is worth mentioning is that Nikon Z30's sensor doesn't have an 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 X-T100 and Z30 sensor size comparison.
Sensor Size and Resolution Comparison image of Fujifilm X-T100 and Nikon Z30 Cameras
Fujifilm X-T100 and Nikon Z30 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 Nikon Z30 has 16% larger pixel area (17.85µm 2 vs 15.37µm 2 ) compared to Fujifilm X-T100, it has larger pixel area to collect light hence potential to have less noise in low light / High ISO images.
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
Fujifilm X-T100
or the
Nikon Z30 ,
including hyperfocal distance.