Sony A7R III has a
42.0MP Full frame (35.9 x 24 mm ) sized BSI-CMOS sensor and features Bionz X processor. On the other hand, Sony A7 IV has a
33.0MP Full frame (35.8 x 23.8 mm ) sized BSI-CMOS sensor and features Bionz XR processor.
Sony A7R III's sensor provides 9MP more than Sony A7 IV's sensor, which gives a significant advantage in real life. You can print your images larger or crop more freely.
On the other hand, please keep in mind that Max sensor resolution is not the only determinant of resolving power. Factors such as the optical elements, low pass filter, pixel size and sensor technology also affects the final resolution of the captured image.
Another similarity between these two cameras is that both Sony A7 IV and Sony A7R III sensors lack anti-alias (Low-Pass) filters. 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 A7R III and A7 IV sensor size comparison.
Sony A7R III and Sony A7 IV 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 A7R III and Sony A7 IV 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, A7R III has scored 100, 3 points higher than A7 IV.
Model |
Overall |
Color Depth |
Dynamic Range |
Low-light ISO |
Sony A7R III |
100 |
26.0 bits |
14.7 Evs |
3523 ISO |
Sony A7 IV |
97 |
25.4 bits |
14.7 Evs |
3379 ISO |