There is very little difference between the performance and image quality of the M10, M10-P and M10-D. The main difference is the handling and the approach to (digital) photography. Leica stresses the fact that the M10-D has the most quiet shutter release of any Leica rangefinder camera and enables un-conspicuous photography. I used a dedicated sound meter to check this claim and compared the noise of the M10-D with a number of other cameras (M3, M7, M-A, M8.2, M 246 and Canon L1) The distances were 10cm and 1 metre. The shutter speeds were 1/4, 1/60, 1/250 and 1/1000. I used the dB-C . All camera used the same lens and the analog models were additionally fitted with a film cartridge to fill the hollow space of the body. The loudest camera was the Canon L1. The M10-D was indeed the most quiet. The mechanical braking has been presumably replaced by an electronic one.
The complete shutter sound consists of two distinct components: the (softer) release of the first curtain and the (louder) braking of the second curtain. When using faster speeds, both sounds merge into one complex sound level.
Normal conversation level peaks at about 60 dB-A and the urban sound scape varies between 56 and 95 dB-A with an average of 73 dB-A. Even the loudest camera would be below the normal sound level on the street for un-conspicuous recording. Only when taking pictures in a very quiet library the sound would be detected.
The second important characteristic of the M10-D is the lack of the monitor which is supposed to emulate the idea of an analog camera where you also cannot check the results immediately. My first impression after using the camera for over a week is different. The fact that the M10-D has an adjustable ISO speed feature and an electro-magnetic shutter release button gives a non-analog experience. Add the fact that you do need to rewind the film and with the knowledge that after 36 exposures you do not have to load another cartridge which give you a digital experience. The acid test of the analog workflow is the proper exposure and the choice of developer and development time. This connection is not existent when walking the digital path. Proper exposure is much less critical because of the latitude of the sensor and the power of the software.
In my second part I will comment on this feature and also the use of the Leica Fotos App.
The noise patterns were recorded with Adobe Audition. The study of these recorded signals takes some time and needs the consultancy of an expert