Both Nikon Z8 and Nikon D850 have Full frame sized 46.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
One other difference between these two cameras that is worth mentioning is that Nikon D850'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 Z8 and D850 sensor size comparison.
Nikon Z8 and Nikon D850 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.
DxOMark Sensor Scores
DxOMark is a benchmark that scientifically assesses image quality of camera sensors. It scores camera sensors for color depth (DXO Portrait), dynamic range (DXO Landscape) and low-light sensitivity (DXO Sports), and also gives them an overall score. Nikon Z8 and Nikon D850 sensors have been tested by DxO and the results show that D850 has a better overall score of 100, 2 points higher compared to Z8's score of 98.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Nikon Z8 |
98 |
26.3 bits |
14.2 Evs |
2548 ISO |
Nikon D850 |
100 |
26.4 bits |
14.8 Evs |
2660 ISO |