hiding from a reflection

[minor muppetz]

In a lot of movies and TV shows, there are scenes where a mirror or reflection is shown. What I want to know is, how can a camera man and additional film crew not be seen in the mirror?

I do know that there are windows that are only clear from one side, and tinted from the other. Does the camera man stand behind one of these windows? Of course, most of the time if a character is looking at it's reflection the background is not black.

 

[MGov]

You and a friend stand in front of a mirror.

Now you take a few steps to one side until you can't see yourself in the mirror anymore but can still see your friend in the mirror.

Now you're the camera.