A
rangefinder is a device that measures distance from the observer to a target, for the purposes of
surveyingSurveying or land surveying is the technique and science of accurately determining the terrestrial or three-dimensional space position of points and the distances and angles between them...
, determining focus in
photographyPhotography is the process, activity and art of creating still or moving pictures by recording radiation on a sensitive medium, such as a photographic film, or an electronic sensor...
, or accurately aiming a
weaponA weapon is a tool used to apply force for the purpose of hunting, attack, self-defense, or defense in combat.Weapons can be as simple as a club, or as complex as an intercontinental ballistic missile, and include those that damage individual or group morale.-Prehistoric weapons:Very simple weapon...
. Some devices use active methods to measure (such as
sonarSonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels. There are two kinds of sonar: active and passive. Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water...
,
laserA laser is a device that emits light through a process called stimulated emission. Laser light is usually spatially coherent, which means that the light either is emitted in a narrow, low-divergence beam, or can be converted into one with the help of optical components such as lenses...
, or
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
); others, available since the nineteenth century, measure distance using
trigonometryTrigonometry is a branch of mathematics that deals with triangles, particularly those plane triangles in which one angle has 90 degrees...
(stadiametric rangefinders and
parallax, or coincidence rangefindersA 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....
). They usually use a set of known distances or target sizes to make the measurement.
Rangefinders may be used by military or law enforcement snipers as a means of calculating the distance to the target to set up a perfect shot.
Discussion
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A
rangefinder is a device that measures distance from the observer to a target, for the purposes of
surveyingSurveying or land surveying is the technique and science of accurately determining the terrestrial or three-dimensional space position of points and the distances and angles between them...
, determining focus in
photographyPhotography is the process, activity and art of creating still or moving pictures by recording radiation on a sensitive medium, such as a photographic film, or an electronic sensor...
, or accurately aiming a
weaponA weapon is a tool used to apply force for the purpose of hunting, attack, self-defense, or defense in combat.Weapons can be as simple as a club, or as complex as an intercontinental ballistic missile, and include those that damage individual or group morale.-Prehistoric weapons:Very simple weapon...
. Some devices use active methods to measure (such as
sonarSonar is a technique that uses sound propagation to navigate, communicate with or detect other vessels. There are two kinds of sonar: active and passive. Sonar may be used as a means of acoustic location and of measurement of the echo characteristics of "targets" in the water...
,
laserA laser is a device that emits light through a process called stimulated emission. Laser light is usually spatially coherent, which means that the light either is emitted in a narrow, low-divergence beam, or can be converted into one with the help of optical components such as lenses...
, or
radarRadar is an object detection system that uses electromagnetic waves to identify the range, altitude, direction, or speed of both moving and fixed objects such as aircraft, ships, motor vehicles, weather formations, and terrain. The term RADAR was coined in 1941 as an acronym for RAdio Detection And...
); others, available since the nineteenth century, measure distance using
trigonometryTrigonometry is a branch of mathematics that deals with triangles, particularly those plane triangles in which one angle has 90 degrees...
(stadiametric rangefinders and
parallax, or coincidence rangefindersA 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....
). They usually use a set of known distances or target sizes to make the measurement.
Rangefinders may be used by military or law enforcement snipers as a means of calculating the distance to the target to set up a perfect shot. The rangefinder is not always the best option though, as it sends out a light source that may give away the snipers' position.
See also
- 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
- 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...
- 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...
External links
- http://books.google.com/books?id=7igDAAAAMBAJ&pg=PT35Range-Finding in the Army / How to use range-finders to get results: the erect and inverted types, Popular Science
Popular Science is an American monthly magazine founded in 1872 carrying articles for the general reader on science and technology subjects. Popular Science has won over 58 awards, including the ASME awards for its journalistic excellence in both 2003 and 2004...
monthly, February 1919, page 118-120, Scanned by Google Books]