Sony A9 III has a
24.6MP Full frame (35.6 x 23.8 mm ) sized Global Shutter sensor and features BIONZ XR processor. On the other hand, Sony A9 has a
24.0MP Full frame (35.6 x 23.8 mm ) sized Stacked BSI-CMOS sensor and features BIONZ X processor.
Another difference between these two cameras is that Sony A9 III'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 A9 Mark III and A9 sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A9 III and Sony A9 Cameras
Sony A9 III and Sony A9 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 A9 III and Sony A9 sensors have been tested by DxO and the results show that A9 has a better overall score of 92, 5 points higher compared to A9 Mark III's score of 87.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony A9 III
87
24.1 bits
13.0 Evs
3224 ISO
Sony A9
92
24.9 bits
13.3 Evs
3517 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 A9 III
or the
Sony A9 ,
including hyperfocal distance.
