Magnifying glass
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A magnifying glass |
A
magnifying glass, is a single
convex lens which is used to produce a
magnified image of an object. The
lens is usually mounted in a frame with a handle.
A magnifying glass works by creating a magnified
virtual image of an object behind the lens. The distance between the lens and the object must be shorter than the
focal length of the lens for this to occur.
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Magnifying glass on an arm lamp |
The framed lens may be mounted on a stand, keeping the lens at the right distance from the table, and therefore at the right distance from the object on the table. The latter applies if the object is small, and also if the height is adjustable. Some magnifying glasses are foldable (from the handle or stand).
A
sheet magnifier consists of many very narrow concentric ring-shaped lenses, such that the combination acts as a single lens but is much thinner. This arrangement is known as a
Fresnel lens.
A
loupe is a small magnification device used by
jewelers,
watchmakers, and other precision craftsmen. The magnification of jewelers' loupes for studying gemstones is 10x [
1].
The magnifying glass is an icon of
detective fiction, particularly that of
Sherlock Holmes.
Visually impaired people sometimes benefit from magnifying glasses and similar
low vision aids.
*
Burning-glass*
Eyeglasses*
Screen magnifier
