Both Sony A7 III and Sony A7 have 24.0 MP resolution sensors but Sony A7 III's sensor is Full frame (35.8 x 23.8 mm ) and Sony A7's sensor is Full frame (35.8 x 23.9 mm ).
Since Sony A7'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 A7 III and A7 sensor size comparison.
Sony A7 III and Sony A7 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
Both Sony A7 III and Sony A7 sensors have been tested by DxoMark. DxoMark 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. Of the two cameras that we are comparing, A7 III has scored 96, 6 points higher than A7.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Sony A7 III |
96 |
25.0 bits |
14.7 Evs |
3730 ISO |
Sony A7 |
90 |
24.8 bits |
14.2 Evs |
2248 ISO |