Sony A9 II has a
24.0MP Full frame (35.6 x 23.8 mm ) sized Stacked BSI-CMOS sensor and features BIONZ X processor. On the other hand, Nikon Z9 has a
46.0MP Full frame (35.9 x 23.9 mm ) sized Stacked CMOS sensor and features Expeed 7 processor.
Nikon Z9's sensor provides 22MP more than Sony A9 II'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 A9 Mark II and Z9 sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A9 II and Nikon Z9 Cameras
Sony A9 II and Nikon Z9 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.
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. Sony A9 II and Nikon Z9 sensors have been tested by DxO and the results show that Z9 has a better overall score of 98, 5 points higher compared to A9 Mark II's score of 93.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony A9 II
93
25.0 bits
14.0 Evs
3434 ISO
Nikon Z9
98
26.3 bits
14.4 Evs
2451 ISO
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
Sony A9 II
or the
Nikon Z9 ,
including hyperfocal distance.
