C# and XAML. How to call the camera?

Question

XAML

Good day to all. I am new to this business and would like to learn from the pros how to call, for example, a camera or a calculator (or any other standard application on Windows Phone) by pressing a button, and how to call a third-party application (including those that are not installed on Windows Phone)?
private void button1_Click(object sender, RoutedEventArgs e)
{
// what should be written here to call the camera or another standard application???
}
PS I found something similar, but this is for windows phone 7, but I need it for 8 or 8.1, who can help ???
CameraCaptureTask
Launches the Camera application. Used to allow the
user to take a photo from within your application.
using Microsoft.Phone.Tasks;
private void Camera_Click(object sender, RoutedEventArgs e)
{
CameraCaptureTask camera = new CameraCaptureTask();
camera.Completed += new EventHandler(camera_Completed);
camera.Show();
}

Answer 1

For WP 8, use CameraCaptureTask too, no problems will arise, and if you are writing an application for WP 8.1, then FileOpenPicker.