Tripod
Overview
 
A tripod is a portable three-legged frame, used as a platform for supporting the weight and maintaining the stability of some other object. The word comes from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 tripous, meaning "three feet". A tripod provides stability against downward forces, horizontal forces and moments about the vertical axis. The positioning of the three feet away from the vertical centre allows the tripod better leverage for resisting lateral forces.
Encyclopedia
A tripod is a portable three-legged frame, used as a platform for supporting the weight and maintaining the stability of some other object. The word comes from the Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 tripous, meaning "three feet". A tripod provides stability against downward forces, horizontal forces and moments about the vertical axis. The positioning of the three feet away from the vertical centre allows the tripod better leverage for resisting lateral forces. Tripods have the disadvantage of being heavy and bulky although they can be used with large equipment.

Etymology

First attested in English in the early 17th century, the word tripod comes via Latin
Latin
Latin is an Italic language originally spoken in Latium and Ancient Rome. It, along with most European languages, is a descendant of the ancient Proto-Indo-European language. Although it is considered a dead language, a number of scholars and members of the Christian clergy speak it fluently, and...

 "tripodis", genitive of "tripus", which is the romanization
Romanization
In linguistics, romanization or latinization is the representation of a written word or spoken speech with the Roman script, or a system for doing so, where the original word or language uses a different writing system . Methods of romanization include transliteration, for representing written...

 of Greek
Greek language
Greek is an independent branch of the Indo-European family of languages. Native to the southern Balkans, it has the longest documented history of any Indo-European language, spanning 34 centuries of written records. Its writing system has been the Greek alphabet for the majority of its history;...

 "τρίπους" (tripous), "three-footed", (gen. "τρίποδος" - tripodos), ultimately from "τρι-" (tri-), "three times" (from "τρία" - tria, "three") + "πούς" (pous), "foot". The earliest attested form of the word is the Mycenaean Greek ti-ri-po-de, written in Linear B
Linear B
Linear B is a syllabic script that was used for writing Mycenaean Greek, an early form of Greek. It pre-dated the Greek alphabet by several centuries and seems to have died out with the fall of Mycenaean civilization...

 syllabic script.

Cultural use

Many cultures, including the ancient peoples of China and Greece, used tripods as ornaments, trophies, sacrificial altars, cooking vessels or cauldrons, and decorative ceramic pottery. Sacrificial tripods were found in use in ancient China
China
Chinese civilization may refer to:* China for more general discussion of the country.* Chinese culture* Greater China, the transnational community of ethnic Chinese.* History of China* Sinosphere, the area historically affected by Chinese culture...

 usually cast in bronze but sometimes appearing in ceramic form. In prehistoric times, around 2500 B.C., these tripods were found in the northeast culture, near to the provinces of Hopei
Hebei
' is a province of the People's Republic of China in the North China region. Its one-character abbreviation is "" , named after Ji Province, a Han Dynasty province that included what is now southern Hebei...

 (in which Beijing is located), Shantung
Shandong
' is a Province located on the eastern coast of the People's Republic of China. Shandong has played a major role in Chinese history from the beginning of Chinese civilization along the lower reaches of the Yellow River and served as a pivotal cultural and religious site for Taoism, Chinese...

, and southern Manchuria
Manchuria
Manchuria is a historical name given to a large geographic region in northeast Asia. Depending on the definition of its extent, Manchuria usually falls entirely within the People's Republic of China, or is sometimes divided between China and Russia. The region is commonly referred to as Northeast...

. The people of this culture were ancestors of the Tunguses
Evenks
The Evenks are a Tungusic people of Northern Asia. In Russia, the Evenks are recognized as one of the Indigenous peoples of the Russian North, with a population of 35,527...

 and mixed with Paleo-Siberian
Paleosiberian languages
Paleosiberian languages or Paleoasian languages is a term of convenience used in linguistics to classify a disparate group of languages spoken in some parts of north-eastern Siberia and some parts of Russian Far East...

 tribes. They made pottery with basic forms which were long preserved in subsequent Chinese pottery, such as a tripod. They are often referred to as "dings
Ding (vessel)
A ding is an ancient Chinese cauldron with legs, a lid and two handles opposite each other. They were made in two shapes with round vessels having three legs and rectangular ones four....

" and usually have three legs, but in some usages have four legs.

The Chinese use sacrificial tripods symbolically in modern times, such as in 2005, when a "National Unity Tripod" made of bronze was presented by the central Chinese government to the government of northwest China's Xinjiang Uygur Autonomous Region
Xinjiang
Xinjiang is an autonomous region of the People's Republic of China. It is the largest Chinese administrative division and spans over 1.6 million km2...

 to mark its fiftieth birthday. It was described as a traditional Chinese sacrificial vessel symbolizing unity.

In ancient Greece, tripods were frequently used to support lebes
Lebes
The lebes was originally a type of ancient Greek pot, a deep bowl with a rounded bottom. It needed a stand, frequently a sacrificial tripod, to remain upright. In classical times a foot was attached, and it was typically used as a mixing bowl in food preparation...

, or cauldrons, sometimes for cooking and other uses such as supporting vases.

Firearms

On firearms, tripods are commonly used on machine guns to provide a forward rest and to reduce motion from recoil. Machine guns are capable of firing long continuous bursts of fire, but at the cost of increased recoil (which decreases accuracy), and increased weight (machine guns are heavier in order to absorb the stresses of prolonged fully automatic fire). The tripod permits the operator to rest the weapon on the ground and thus the gun feels lighter to the shooter and accuracy is increased.

Tripods are generally restricted to heavier weapons where the weight would be an encumbrance. For lighter weapons such as rifles, a bipod
Bipod
A bipod is a support device that is similar to a tripod or monopod, but with two legs. It provides significant stability along two axes of motion .-Firearms:...

 is more common.

Usage

Tripods are used for both motion and still photography to prevent camera movement and provide stability. They are especially necessary when slow-speed exposures are being made, or when telephoto lenses are used, as any camera movement while the shutter is open will produce a blurred image. In the same vein, they reduce camera shake, and thus are instrumental in achieving maximum sharpness. A tripod is also helpful in achieving precise framing of the image, or when more than one image is being made of the same scene, for example when bracketing the exposure. Use of a tripod may also allow for a more thoughtful approach to photography. For all of these reasons a tripod of some sort is often necessary for professional photography. In relation to film/video, use of the tripod offers stability within a shot as well as certain desired heights. The head of a Film Camera Tripod allows free flowing movement with which you can easily track a subject or pan left/right as well as tilt up and down. The use of a tripod within film/video is often a creative choice of the Director.

Construction

For maximum strength and stability, as well as for easy levelling, most photographic tripods are braced around a centre vertical post, with collapsible telescopic legs. To further allow extension, the centre post can usually extend above the meeting of three legs. At the top of the tripod is the head, which includes the camera mount (usually a detachable plate with a thumbscrew to hold the camera). The head connects to the frame by several joints, allowing the camera to pan
Panning (camera)
In photography, panning refers to the horizontal movement or rotation of a still or video camera, or the scanning of a subject horizontally on video or a display device...

, tilt and roll. The head usually attaches to a lever so that adjustments to the orientation can be performed more delicately. Some tripods also feature integrated remote controls for a camera, though these are usually proprietary to the company that made the camera.

Surveying

A surveyor's tripod is a device used to support any one of a number of surveying instruments, such as theodolite
Theodolite
A theodolite is a precision instrument for measuring angles in the horizontal and vertical planes. Theodolites are mainly used for surveying applications, and have been adapted for specialized purposes in fields like metrology and rocket launch technology...

s, total station
Total station
A total station is an electronic/optical instrument used in modern surveying. The total station is an electronic theodolite integrated with an electronic distance meter to read slope distances from the instrument to a particular point....

s, level
Dumpy level
A dumpy level, builder's auto level, leveling instrument, or automatic level is an optical instrument used to establish or check points in the same horizontal plane...

s or transits.

Usage

The tripod is placed in the location where it is needed. The surveyor will press down on the legs' platforms to securely anchor the legs in soil or to force the feet to a low position on uneven, pock-marked pavement. Leg lengths are adjusted to bring the tripod head to a convenient height and make it roughly level.

Once the tripod is positioned and secure, the instrument is placed on the head. The mounting screw is pushed up under the instrument to engage the instrument's base and screwed tight when the instrument is in the correct position. The flat surface of the tripod head is called the foot plate and is used to support the adjustable feet of the instrument.

Positioning the tripod and instrument precisely over an indicated mark on the ground or benchmark requires techniques that are beyond the scope of this article.

Construction

Many modern tripods are constructed of aluminum, though wood is still used for legs. The feet are either aluminum tipped with a steel point or steel. The mounting screw is often brass or brass and plastic. The mounting screw is hollow to allow the optical plumb to be viewed through the screw. The top is typically threaded with a 5/8" x 11 tpi screw thread. The mounting screw is held to the underside of the tripod head by a movable arm. This permits the screw to be moved anywhere within the head's opening. The legs are attached to the head with adjustable screws that are usually kept tight enough to allow the legs to be moved with a bit of resistance. The legs are two part, with the lower part capable of telescoping to adjust the length of the leg to suit the terrain. Aluminum or steel slip joint
Slip joint
A slip joint is a mechanical construction allowing extension and compression in a linear structure.-General forms:Slip joints can be designed to allow continuous relative motion of two components or it can allow an adjustment from one temporarily fixed position to another. Examples of the latter...

s with a tightening screw are at the bottom of the upper leg to hold the bottom part in place and fix the length. A shoulder strap is often affixed to the tripod to allow for ease of carrying the equipment over areas to be surveyed.

Astronomy

The astronomical tripod is a sturdy three-leg stand used to support telescopes or binoculars, though they may also be used to support attached cameras or ancillary equipment. The astronomical tripod is normally fitted with an altazimuth
Altazimuth mount
An altazimuth or alt-azimuth mount is a simple two-axis mount for supporting and rotating an instrument about two mutually perpendicular axes; one vertical and the other horizontal. Rotation about the vertical axis varies the azimuth of the pointing direction of the instrument...

 or equatorial mount
Equatorial mount
An equatorial mount is a mount for instruments that follows the rotation of the sky by having one rotational axis parallel to the Earth's axis of rotation. This type of mount is used for astronomical telescopes and cameras...

to assist in tracking celestial bodies.
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