Setting the map scale automatically
Multimedia system:
Select View.
Activate 
Auto zoom.
Auto zoom. When the option is switched on, the map scale is set automatically depending on your driving speed and the type of road.
The automatically selected map scale can be changed manually. After a few seconds, this is automatically reset.
When the option is activated, no detailed display of the junction or a 3D image is shown in the navigation window during an upcoming driving manoeuvre.