Canon 5D MII has a
21.0MP Full frame (36 x 24 mm ) sized CMOS sensor and features Digic 4 processor. On the other hand, Leica SL3-S has a
24.0MP Full frame (36 x 24 mm ) sized BSI-CMOS sensor and features Maestro IV processor.
One other difference between these two cameras that is worth mentioning is that Leica SL3-S'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 5D MII and SL3-S sensor size comparison.
Sensor Size and Resolution Comparison image of Canon 5D MII and Leica SL3-S Cameras
Canon 5D MII and Leica SL3-S 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. On the other hand, since Canon 5D MII has 14% larger pixel area compared to Leica SL3-S, it has potential to collect more light on pixel level hence have less noise in low light / High ISO images.
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 5D MII
or the
Leica SL3-S ,
including hyperfocal distance.
