Sony A7S II has a
12.0MP Full frame (35.6 x 23.8 mm ) sized CMOS sensor and features Bionz X processor. On the other hand, Sony A7 III has a
24.0MP Full frame (35.8 x 23.8 mm ) sized BSI-CMOS sensor and features Bionz X processor.
Sony A7 III's sensor provides 12MP more than Sony A7S II'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.
Below you can see the A7S II and A7 III sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A7S II and Sony A7 III Cameras
Sony A7S II 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 A7S II and Sony A7 III sensors have been tested by DxO and the results show that A7 III has a better overall score of 96, 11 points higher compared to A7S II's score of 85.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony A7S II
85
23.6 bits
13.3 Evs
2993 ISO
Sony A7 III
96
25.0 bits
14.7 Evs
3730 ISO
Sensor size sets the circle of confusion, so it drives how much depth of field each
of these bodies gives you at a given aperture. You can calculate it exactly for the
Sony A7S II
or the
Sony A7 III ,
including hyperfocal distance.
