Both Sony RX1R and Sony A7 III have 24.0 MP resolution sensors but Sony RX1R's sensor is Full frame (35.8 x 23.9 mm ) and Sony A7 III's sensor is Full frame (35.8 x 23.8 mm ).
Since Sony RX1R'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.
Another difference between these two cameras is that Sony RX1R's sensor lacks 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 RX1R and A7 III sensor size comparison.
Sony RX1R 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. Sony RX1R and Sony A7 III sensors have been tested by DxO and the results show that A7 III has a better overall score of 96, 5 points higher compared to RX1R's score of 91.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Sony RX1R |
91 |
25.0 bits |
13.6 Evs |
2537 ISO |
Sony A7 III |
96 |
25.0 bits |
14.7 Evs |
3730 ISO |