Robert Walker & Laura Elliot in Strangers on a Train (1951, dir. Alfred Hitchcock)
In one of Hitchcock’s most famous shots, Strangers on a Train’s pivotal murder is seen as reflected in a pair of glasses. Hitchcock & his director of photography, Robert Burks, achieved this effect by placing a concave mirror on the floor and having the actress, Laura Elliott, stand next to it as she simulated slowly falling dead to the floor. Elliot’s reflection in the concave mirror as she fell was filmed and the shot was then printed onto the lenses of the glasses (scene on youtube here).