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A Split Focus Diopter is half convex glass that attaches in front of the camera’s main lens to make half the lens nearsighted. The lens can focus on a plane in the background and the diopter on a foreground element. In the 1970′s and 1980′s, Brian De Palma championed the use of this tool to enhance the visual and emotional experience of his films.
The Split Diopter allows for Deep Focus cinematography but requires much less light. It also delivers a distinctive look that blends sharp and out-of-focus imagery all in one frame. Subjects in both foreground and background can be kept in focus.