Leica tried to preserve as much of the film-shooting experience as it could while gently introducing some of the benefits of shooting digital.
Shutter mechanism
Battery and SD card
As with other M cameras, you have to remove the bottom plate to get to the battery and SD card.
Shutter speed dial
This is a familiar friend.
ISO dial
This is the dial in its locked position. To turn it, you lift the dial. Since the dial tops out at ISO 6,400, to use the higher sensitivity values you have to map the "M" to a specific setting within the menus.
Simplified operation
Leica pruned the buttons on the left side by moving the ISO sensitivity control to the top, info to the button in the center of the navigation arrows. Drive modes are in the menu system.
Favorites
You can customize the location of up to two screens of settings.
Rangefinder angle of view preview
The lever on the side of the lens lets you preview what the field of view would look like if you had a different lens mounted.