A rangefinder is a device that measures distance from the observer to a target, for the purposes of surveying
See Also: Public Land Survey SystemSurveying or land surveying is the technique, profession, and science of accurately determining the terrestrial or three-dimensional position of points and the distances and angles between them...

, determining focus in photography
Photography is the art, science and practice of creating durable images by recording light or other electromagnetic radiation, either electronically by means of an image sensor or chemically by means of a light-sensitive material such as photographic film...

, or accurately aiming a weapon
A weapon, arm, or armament is a tool or instrument used with the aim of causing damage or harm to living beings or artificial structures or systems...

. Some devices use active methods to measure (such as sonar
Sonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels...

, laser
A laser is a device that emits light through a process of optical amplification based on the stimulated emission of photons. The term "laser" originated as an acronym for Light Amplification by Stimulated Emission of Radiation...

, or radar
Radar is an object-detection system which uses radio waves to determine the range, altitude, direction, or speed of objects. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, weather formations, and terrain. The radar dish or antenna transmits pulses of radio...

); others measure distance using trigonometry
Trigonometry is a branch of mathematics that studies triangles and the relationships between their sides and the angles between these sides. Trigonometry defines the trigonometric functions, which describe those relationships and have applicability to cyclical phenomena, such as waves...

 (stadiametric rangefinders and parallax, or coincidence rangefinders
Coincidence rangefinder
A coincidence rangefinder is a type of rangefinder that uses mechanical and optical principles to allow an operator to determine the distance to a visible object....

). These methodologies use a set of known information, usually distances or target sizes, to make the measurement, and have been in regular use since the 18th century.


Rangefinders may be used by military or law enforcement snipers as a means of calculating the distance to the target in order to set up a "perfect shot". The laser rangefinder is not always the best option though, as it sends out a light source that may give away the snipers' position.


A rangefinder camera is a camera fitted with a rangefinder which allows the photographer to measure the distance to the subject and thus take photographs that are in sharp focus.


Rangefinders are also used for surveying in forestry. Special devices with anti-leaf filters are used.

Virtual reality

Since the 1990s, rangefinders have been used in virtual reality
Virtual reality
Virtual reality , also known as virtuality, is a term that applies to computer-simulated environments that can simulate physical presence in places in the real world, as well as in imaginary worlds...

 systems to detect operator movements and locate objects.

See also

  • Bradley A. Fiske
  • Rangefinder camera
    Rangefinder camera
    A rangefinder camera is a camera fitted with a rangefinder: a range-finding focusing mechanism allowing the photographer to measure the subject distance and take photographs that are in sharp focus...

  • Stadimeter
    -Overview:A stadimeter is an optical device for estimating the range to an object of known height by measuring the angle between the top and bottom of the object as observed at the device. It is similar to a sextant, in that the device is using mirrors to measure an angle between two objects but...

  • Laser rangefinder
  • Ultrasonic ranging module
    Ultrasonic ranging module
    An Ultrasonic ranging module, also called a range finder, is a small device that sends out an ultrasonic sound via a transducer, and since the sound has a very high frequency, a frequency that we can not hear, it bounces off objects pretty easily. Its main job is just to record the time it takes...

  • Macrometer
    A macrometer is an instrument for measuring the size and distance of distant objects. Distant in this sense means a length that can not be readily measured by a calibrated length. The optical version of this instrument used two mirrors on a common sextant...

  • Dazzle camouflage
    Dazzle camouflage
    Dazzle camouflage, also known as Razzle Dazzle or Dazzle painting, was a camouflage paint scheme used on ships, extensively during World War I and to a lesser extent in World War II...


  • Army Test and Evaluation Command, Aberdeen Proving Ground Maryland (1969) Laser Rangefinders Ft. Belvoir Defense Technical Information Center, U.S. Army, Ft. Belvoir, Virginia, 20 pages (early history of the use of lasers in rangefinders)
  • Gething, Michael J. (1993) Airborne Weapons: A Defence Handbook: A compilation of articles from Defence magazine over the last five years, charting the development of Airborne Weapons since 1987 Cardiff Publishing Company, Englewood, Colorado, ISBN 1-881289-11-7, 44 pages
  • Infantry and Cavalry School (1905) Notes on rangefinders, compasses and on contouring with the Scale of Horizontal Equivalents (series: Infantry and Cavalry School Lectures 1902-1910) Staff College Press, U.S. Army, Fort Leavenworth, Kansas, , 35 pages


  • Photographic and Imaging Manufacturers Association (1999) American national standard for photography (optics) : rangefinders and other focusing aids – performance specifications (revision and redesignation of "ANSI PH3.619-1988" as "ANSI/PIMA IT3.619-1998") American National Standards Institute, New York, , 14 pages
  • Hicks, Roger and Schultz, Frances (2003) Rangefinder: Equipment, History, Techniques Guild of Master Craftsman, Lewes, United Kingdom, ISBN 1-86108-330-0


  • Ehlert, Detlef; Adamek, Rolf and Horn, Hans-Juergen (2009) "Laser rangefinder-based measuring of crop biomass under field conditions" Precision Agriculture 10(5): pp. 395–408
  • Infantry and Cavalry School (1905) Notes on rangefinders, compasses and on contouring with the Scale of Horizontal Equivalents (series: Infantry and Cavalry School Lectures 1902-1910) Staff College Press, U.S. Army, Fort Leavenworth, Kansas, , 35 pages
  • Whitehouse, J. C. (2005) "Further considerations of defocus rangefinders" Transactions of the Institute of Measurement and Control 27(4): pp. 297–316

Virtual space

  • Ward, A.; Jones, A and Hopper, A. (1997) "A New Location Technique for the Active Office" IEEE Personal Communications 4(5): pp. 42–47
  • Werb, J. and Lanzi, C. (1998) "Designing a positioning system for finding things arid people indoors" IEEE Spectrum 35(9): pp. 71–78

External links

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