dictates what particular lens focal length would be used in order to achieve a desired viewing angle. Smaller sensors or film gauges will require an overall range of shorter focal lengths to achieve any desired viewing angle than larger sensors or film gauges. Because depth of field is a characteristic of lens focal length (in addition to aperture and focus distance setting), it is easier to achieve a deep-focus look with a smaller imaging sensor or film gauge. For example, a 40mm lens will give a 30-degree horizontal angle of view in the Super35 format. To achieve the same viewing angle with a 1/2" 16:9 sensor, you would need a 13mm lens. A 13mm lens inherently has much more depth-of-field than a 40mm lens. To achieve the same depth of field with a 40mm lens would require a very small aperture, which in turn would require far more light, and therefore time and expense. Some filmmakers make deliberate use of the deep-focus capabilities of digital formats. Miami Vice (Michael Mann, 2006), a movie that was shot digitally early in the conversion from film to digital formats, made use of this capability. Cinematographer Dion Beebe commented: We also decided that there were attributes of HD technology we liked and wanted to exploit, like the increased depth of field. Because of the cameras' chip size (2/3"), they have excessive depth of field that we decided not to fight, but rather utilize. Split-focus diopter In the 1970s, directors made frequent use of the split-focus diopter. With this invention it was possible to have one plane in focus in one part of the picture and a different plane in focus in the other half of the picture. This was and still is very useful for the anamorphic widescreen format, which has less depth of field. A split 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. A split diopter does not create real deep focus, only the illusion of this. What distinguishes it from traditional deep focus is that there is not continuous depth of field from foreground to background; the space between the two sharp objects is out of focus. Because split focus diopters only cover half the lens, shots in which they are used are