Both Sony A9 II and Leica SL have Full frame sized 24.0 MP resolution sensors so sensor size and resolution is not a differentiator between these two cameras.
One other difference between these two cameras that is worth mentioning is that Leica SL'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 A9 Mark II and SL sensor size comparison.
Sensor Size and Resolution Comparison image of Sony A9 II and Leica SL Cameras
Sony A9 II and Leica SL 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 Sony A9 II and Leica SL 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, A9 Mark II has scored 93, 5 points higher than SL.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Sony A9 II
93
25.0 bits
14.0 Evs
3434 ISO
Leica SL
88
25.0 bits
13.4 Evs
1821 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 II
or the
Leica SL ,
including hyperfocal distance.
