Both Leica SL and Sony A7 III have Full frame sized 24.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
Another difference between these two cameras is that Leica SL'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 SL and A7 III sensor size comparison.
Sensor Size and Resolution Comparison image of Leica SL and Sony A7 III Cameras
Leica SL 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. Leica SL and Sony A7 III sensors have been tested by DxO and the results show that A7 III has a better overall score of 96, 8 points higher compared to SL's score of 88.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Leica SL
88
25.0 bits
13.4 Evs
1821 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
Leica SL
or the
Sony A7 III ,
including hyperfocal distance.
