Loupe
An optical loupe is a head worn magnifier. Worn like glasses, the loupe will magnify an image. It will NOT correct your vision. The amount of magnification depends on the curvature of the lenses and the lens spacing. Loupes are designed to meet specific magnification requirements and working distances.

From Wikipedia, the free encyclopedia

A loupe.A loupe (pronounced loop), is a type of magnification device used to see things one is looking at more closely. In this respect, they are simply a form of a modified microscope, allowing the user to be able to better apply the phenomenon of microscopy to his or her trade.

Contents
1 Commercial uses of loupes
1.1 Jewelers
1.2 Watchmaking
1.3 Photography
1.4 Printing
1.5 Dentistry
1.6 Geology
1.7 Entomology
1.8 Electronics
1.9 Tattooing
2 References

Commercial uses of loupes
Loupes are used in a number of diverse industries, notably the jewelry trade, watchmaking, photography, printing, dentistry, geology, and ophthalmology.

Jewelers
Jewelers typically use a monocular, handheld loupe in order to magnify gemstones and other jewelry that they wish to inspect. [1] A 10x magnification is good to use for inspecting jewelry.[1] A 10x loupe is the standard instrument used to determine a diamond's clarity grade in the gemological industry. While higher-power magnification devices may be used to examine the stone, inclusions (internal flaws) and blemishes (surface irregularities) are not factored into the stone's final clarity grade if they are small enough to be undetectable when the stone is examined under 10x magnification.[2]

Watchmaking
Loupes' are employed to assist watchmakers in assembling mechanical watches. Many aspects require the use of the loupe, in particular the assembly of the watch mechanism itself, the assembly and details of the watch dial (i.e. the "face"), as well as the formation of the watch strap and/or installation of precious stones onto the watch face.

Photography
Photographers use loupes to review, edit or analyze negatives and slides on a light table. Photographers using large format cameras also use a loupe to view the ground glass image to aid in focusing.

Printing
Offset and flexographic printing see frequent use of loupes in order to carefully analyze how ink lays on paper. Strippers use loupes in order to register film separations to one another. Pressmen use them to check registration of colors, estimate dot-gain, and diagnose issues with roller pressure and chemistry based on the shape of individual dots and rosettes.

Dentistry
A pair of dental loupes featuring in-lens magnification. There is an loupe light mounted on the bridge of the loupes and side shields (not shown) on the temples to protect a dentist's eyes from splatter.Many dentists will use loupes to better scrutinize the entities within their patients' mouths in order to make a better diagnosis, for example, to determine how far a crack proceeds along the surface of a tooth. Loupes are also used in order to perform on a more precise level; while dentists drill teeth on a millimeter scale, magnification can enlarge the dentists' view of the teeth, perhaps making it easier to inspect teeth for decay and/or see things that ordinarily would not be seen without magnification.
Specialties of dentistry, such oral surgery and periodontics, may benefit from the use of loupes as well. Even though they may be performing surgical procedures on the gingiva or bony structures of the oral cavity, the oral cavity is notorious for being a place containing small entities with limited access. Magnification can be very helpful when suturing a flap.
Because dentists use both of their hands while performing dental procedures, dental loupes are binocular and usually take on the form of a pair of glasses. Some dental loupes are flip-types, which take the form of two small cylinders, one in front of each lense of the glasses. Other types are inset within the lense of the glasses. A typical magnification for use in dentistry is 2.5x, but [dental loupes] can be anywhere in the range from 2x to 5x.
Together with proper access to the oral cavity, light is an important part of performing precision dentistry. Because a dentist's head often eclipses the overhead dental lamp, loupes may be fitted with a light source. This light source, emanating from in front of the loupes, cannot be blocked by the position of the dentists' head, and so provides for a continuous source of light during the extent of dental procedures. Loupe-mounted lights used to be fed by fiber optic cables that connected to either a wall-mounted or table-top light source, and often introduces a limiting range for the dentist, as he or she would be required to remain close to the wall or table, respectively. Additionally, the fiber optic cord can be damaged by excess flexing or crushing, such as would occur should the cord be rolled over by a chair. Newer models feature an LED lamp within the loupe-mounted light and an electric cord coming from either the conventional wall-mounted/table-top light source or a belt clip rechargeable battery pack. Options for loupe-mounted cameras and video recorders are also available.

Geology
The loupe (hand lens) is a vital geological field-tool used to identify rock's constituant minerals.

Entomology
Loupes are also popular among professional and amateur field entomologists for help identifying insects in field situations where a full-sized microscope is impractical, but the ability to observe small morphological characteristics is desired.

Electronics
This section may require cleanup to meet Wikipedia's quality standards. Please improve this article if you can. (December 2008)

For many soldering applications engineers and technicians will use a loupe to inspect a printed circuit board with small surface components on it.

Tattooing
Tattoo artist's use a Loupe to inspect the quality of their needle tips. They do this to ensure the least amount of damage possible to the skin surface.