Leica M9 has a 18.0MP Full frame (36 x 24 mm ) sized CCD sensor . On the other hand, Pentax 645D has a 40.0MP Medium format (44 x 33 mm ) sized CCD sensor and features Prime II processor.
Pentax 645D's sensor provides 22MP 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 similarity between these two cameras is that both Pentax 645D and Leica M9 sensors lack anti-alias (Low-Pass) filters. Removing anti-alias filter increases the sharpness and level of detail but at the same time, it increases the chance of moire occurring in certain scenes.
Below you can see the M9 and 645D sensor size comparison.
![Leica M9 vs Pentax 645D Sensor Size Comparison]()
Sensor Size and Resolution Comparison image of Leica M9 and Pentax 645D Cameras
As seen above, Pentax 645D has a 1.7x Larger sensor area than Leica M9. 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. Leica M9 and Pentax 645D sensors have been tested by DxO and the results show that 645D has a better overall score of 82, 13 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 |
|
Pentax 645D |
82 |
24.6 bits |
12.6 Evs |
1262 ISO |