iOS
[assembly: ExportRenderer(typeof(Map3d), typeof(MapView3dRenderer))]
namespace MyApp.iOS.Renderers
{
public class MapView3dRenderer : MapRenderer
{
MKMapView _nativeMap;

 protected override void OnElementChanged(ElementChangedEventArgs<View> e)
 {
 base.OnElementChanged(e);
 if (e.NewElement != null && Control != null)
 {
            _nativeMap = Control as MKMapView;
 }
 }
 protected override void OnElementPropertyChanged(object sender, System.ComponentModel.PropertyChangedEventArgs e)
 {
 base.OnElementPropertyChanged(sender, e);
 if (_nativeMap == null)
 return;
 if (e.PropertyName == "VisibleRegion")
 UpdateCameraView();
 }
 void UpdateCameraView()
 {
 var target = new CLLocationCoordinate2D(50.890119f, 5.857798f);
 //Enable 3D buildings
        _nativeMap.ShowsBuildings = true;
        _nativeMap.PitchEnabled = true;
 // Attach the camera
 var camera = MKMapCamera.CameraLookingAtCenterCoordinate(target, 650, 60, 0);
        _nativeMap.Camera = camera;
 }
}

}

Android
// Create the camera
CameraPosition cameraPosition = new CameraPosition.Builder()
.Target(location)
.Tilt(45)
.Zoom(10)
.Bearing(0)
.Build();
// Convert to an update object
CameraUpdate cameraUpdate = CameraUpdateFactory.NewCameraPosition(cameraPosition);

// Attach the camera
map.MoveCamera(cameraUpdate); // map is of type GoogleMap