Leica M9 has a
18.0MP Full frame (36 x 24 mm ) sized CCD sensor . On the other hand, Sony A1 has a
50.0MP Full frame (35.9 x 24 mm ) sized Stacked CMOS sensor and features Dual Bionz XR processor.
Sony A1's sensor provides 32MP more than Leica M9'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.
Another difference between these two cameras is that Leica M9'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 M9 and A1 sensor size comparison.
Sensor Size and Resolution Comparison image of Leica M9 and Sony A1 Cameras
Leica M9 and Sony A1 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 M9 and Sony A1 sensors have been tested by DxO and the results show that A1 has a better overall score of 98, 29 points higher compared to M9's score of 69.
Model
Overall
Color Depth
Dynamic Range
Low-light ISO
Leica M9
69
22.5 bits
11.7 Evs
884 ISO
Sony A1
98
25.9 bits
14.5 Evs
3163 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 M9
or the
Sony A1 ,
including hyperfocal distance.
