Nikon Z8 has a
46.0MP Full frame (35.9 x 23.9 mm ) sized Stacked CMOS sensor and features Expeed 7 processor. On the other hand, Canon R1 has a
24.0MP Full frame (36 x 24 mm ) sized Stacked CMOS sensor and features Digic X processor.
Nikon Z8's sensor provides 22MP more than Canon R1's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Below you can see the Z8 and R1 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon Z8 and Canon R1 Cameras
Nikon Z8 and Canon R1 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.
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
Nikon Z8
or the
Canon R1 ,
including hyperfocal distance.