Canon 1D X III has a
20.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Digic X processor. On the other hand, Sony A9 III has a
24.6MP Full frame (35.6 x 23.8 mm ) sized Global Shutter sensor and features BIONZ XR processor.
Sony A9 III's sensor provides 4.6MP more than Canon 1D X III'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.
One other difference between these two cameras that is worth mentioning is that Sony A9 III's sensor doesn't have an 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 1D X MIII and A9 Mark III sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 1D X III and Sony A9 III Cameras
Canon 1D X III and Sony A9 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
Both Canon 1D X III and Sony A9 III 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, 1D X MIII has scored 91, 4 points higher than A9 Mark III.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon 1D X III
91
24.2 bits
14.5 Evs
3248 ISO
Sony A9 III
87
24.1 bits
13.0 Evs
3224 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
Canon 1D X III
or the
Sony A9 III ,
including hyperfocal distance.
