In addition to his technical talents with the camera (he developed several special effects techniques), his use of perspective and skillful contrasts between light and dark are noteworthy. His main collaborators were the directors Urban Gad, Lupu Pick, Georg Wilhelm Pabst und Paul Wegener and among his most important accomplishments are the shots of the Doppelgänger in Wegener's Der Student von Prag (The Student of Prague) of 1913 and the moving camera shots in the films of Lupu Pick, particularly Sylvester (1923), which can be seen as anticipating the so-called "unchained camera" of Friedrich Wilhelm Murnau's The Last Laugh (1924).