Both Nikon Z6 III and Sony A77 have 24.0 MP resolution sensors but Nikon Z6 III's sensor is Full frame (35.9 x 23.9 mm ) and Sony A77's sensor is APS-C (23.5 x 15.6 mm ).
Since Nikon Z6 III's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Sony A77.
Below you can see the Z6 Mark III and A77 sensor size comparison.
Sensor Size and Resolution Comparison image of Nikon Z6 III and Sony A77 Cameras
As seen above, Nikon Z6 III has a 2.3x Larger sensor area than Sony A77. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in 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 Z6 III
or the
Sony A77 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(Full frame versus APS-C),
so compare them at the same framing rather than the same focal length.
Put the same focal length on the smaller sensor and it will show less depth of
field, not more, because it also crops tighter. The calculator shows the
full frame equivalent focal length for each body so you can match the framing.
