Michael Caine explains the difference between stage and screen acting.

"The art of cinema acting is the exact opposite of stage acting. In the theatre you have to be as big and broad and loud as possible, even in the quiet scenes, which is a trick that only the best actors can pull off. Film acting, on the other hand, is about standing six feet from a camera in blazing light and not letting the tiniest bit of acting show. If you are doing it right you make it look very easy, but it takes a great deal of hard work to accomplish."