Both Sony RX1 and Sony A7 III have 24.0 MP resolution sensors but Sony RX1's sensor is Full frame (35.8 x 23.8 mm ) and Sony A7 III's sensor is Full frame (35.8 x 23.8 mm ).
Since Sony A7 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 RX1.
Below you can see the RX1 and A7 III sensor size comparison.
Sony RX1 and Sony A7 III 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. Sony RX1 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 RX1's score of 93.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Sony RX1 |
93 |
25.1 bits |
14.3 Evs |
2534 ISO |
Sony A7 III |
96 |
25.0 bits |
14.7 Evs |
3730 ISO |