Both Nikon D750 and Sony A7 III have 24.0 MP resolution sensors but Nikon D750's sensor is Full frame (35.9 x 24 mm ) and Sony A7 III's sensor is Full frame (35.8 x 23.8 mm ).
Since Nikon D750'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 A7 III.
Below you can see the D750 and A7 III sensor size comparison.
Nikon D750 and Sony A7 III 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. Nikon D750 and Sony A7 III sensors have been tested by DxO and the results show that A7 III has a better overall score of 96, 3 points higher compared to D750's score of 93.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Nikon D750 |
93 |
24.8 bits |
14.5 Evs |
2956 ISO |
Sony A7 III |
96 |
25.0 bits |
14.7 Evs |
3730 ISO |