How (and when) properly initialize camera in Windows Phone 8.1 (RT) - windows-phone-8

Question

I'm writing simple WP app, that can work with images stored in a device or image taken by a camera right in my app. I'm maybe confused with navigation and camera initializing. There is a MainPage in the app where are buttons to select camera or library. Camera button just navigates to the CameraPage like this:
private void CameraButton_Click(object sender, RoutedEventArgs e)
{
...
this.Frame.Navigate(typeof(CameraPage));
}
And then I initialize camera in CameraPage OnNavigatedTo:
protected async override void OnNavigatedTo(NavigationEventArgs e)
{
...
cameraCapture = new CameraCapture();
PreviewElement.Source = await cameraCapture.Initialize(Dispatcher);
await cameraCapture.StartPreview();
...
}
And CameraCapture initialization:
public async Task<MediaCapture> Initialize(CoreDispatcher dispatcher)
{
var cameraID = await GetCameraID(Windows.Devices.Enumeration.Panel.Back);
// Create MediaCapture and init
mediaCapture = new MediaCapture();
await mediaCapture.InitializeAsync(new MediaCaptureInitializationSettings
{
StreamingCaptureMode = StreamingCaptureMode.Video,
PhotoCaptureSource = PhotoCaptureSource.VideoPreview,
AudioDeviceId = string.Empty,
VideoDeviceId = cameraID.Id
});
mediaCapture.VideoDeviceController.PrimaryUse = Windows.Media.Devices.CaptureUse.Video;
this.dispatcher = dispatcher;
var maxResolution = mediaCapture.VideoDeviceController.GetAvailableMediaStreamProperties(MediaStreamType.Photo).Aggregate((i1, i2) => (i1 as VideoEncodingProperties).Width > (i2 as VideoEncodingProperties).Width ? i1 : i2);
await mediaCapture.VideoDeviceController.SetMediaStreamPropertiesAsync(MediaStreamType.Photo, maxResolution);
imgEncodingProperties = ImageEncodingProperties.CreateJpeg();
return mediaCapture;
}
The problem is - when I tap on the CameraButton on my MainPage, the app freezes on the MainPage until camera isn't initialized and then is the CameraPage loaded. What is the best approach to deal with this? Should I just move content from CameraPage to MainPage (so initialize camera on the MainPage and take a photo here)? Or there is a better way - like some event on the CameraPage? Tapping another button on the CameraPage to initialize camera would be so annoying for both me and user :)