Both Canon M and Leica M9 have 18.0 MP resolution sensors but Canon M's sensor is APS-C (22.3 x 14.9 mm ) and Leica M9's sensor is Full frame (36 x 24 mm ).
Since Leica M9's has a larger sensor area with the same resolution, this means that it also has a larger pixel area hence better light collecting capacity for a given aperture compared to Canon M.
One other difference between these two cameras that is worth mentioning is that Leica M9'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 M and M9 sensor size comparison.
Sensor Size and Resolution Comparison image of Canon M and Leica M9 Cameras
As seen above, Leica M9 has a 2.6x Larger sensor area than Canon M. Larger sensors give photographer more control on the depth of field and blurry background compared to smaller sensor when shot in 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. Canon M and Leica M9 sensors have been tested by DxO and the results show that M9 has a better overall score of 69, 4 points higher compared to M's score of 65.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Canon M
65
22.1 bits
11.2 Evs
827 ISO
Leica M9
69
22.5 bits
11.7 Evs
884 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 M
or the
Leica M9 ,
including hyperfocal distance.
One thing to watch when comparing these two: they have different sensor sizes
(APS-C versus Full frame),
so compare them at the same framing rather than the same focal length.
Put the same focal length on the smaller sensor and it will show less depth of
field, not more, because it also crops tighter. The calculator shows the
full frame equivalent focal length for each body so you can match the framing.
