There are two common methods of defining and measuring hyperfocal distance, leading to values that differ only slightly. Some lenses have markings indicating the hyperfocal range for specific f-stops. For example, on the Minox LX focusing dial there is a red dot between 2 m and infinity when the lens is set at the red dot, that is, focused at the hyperfocal distance, the depth of field stretches from 2 m to infinity. Some cameras have their hyperfocal distance marked on the focus dial. Rudolf Kingslake wrote in 1951 about the two methods of measuring hyperfocal distance. Louis Derr in 1906 may have been the first to derive a formula for hyperfocal distance. Thomas Sutton and George Dawson first wrote about hyperfocal distance (or "focal range") in 1867. The hyperfocal distance has a property called "consecutive depths of field", where a lens focused at an object whose distance is at the hyperfocal distance H will hold a depth of field from H/2 to infinity, if the lens is focused to H/2, the depth of field will extend from H/3 to H if the lens is then focused to H/3, the depth of field will extend from H/4 to H/2, etc. The hyperfocal distance is entirely dependent upon what level of sharpness is considered to be acceptable. As the hyperfocal distance is the focus distance giving the maximum depth of field, it is the most desirable distance to set the focus of a fixed-focus camera.
In optics and photography, hyperfocal distance is a distance beyond which all objects can be brought into an "acceptable" focus. This lens is set to the hyperfocal distance for f/32 at a focal length of 100mm. The depth-of-field, and thus hyperfocal distance, changes with the focal length as well as the f/stop.
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