Leica M11 has a
60.0MP Full frame (36 x 24 mm ) sized BSI-CMOS sensor and features Maestro III 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.
Leica M11's sensor provides 35.4MP more than Sony A9 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 M11 and A9 Mark III sensor size comparison.
Sensor Size and Resolution Comparison image of Leica M11 and Sony A9 III Cameras
Leica M11 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 Leica M11 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, M11 has scored 100, 13 points higher than A9 Mark III.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Leica M11
100
26.3 bits
14.8 Evs
3376 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
Leica M11
or the
Sony A9 III ,
including hyperfocal distance.