MAGNIFYING GLASSES [Magnifiers]: Variety

MAGNIFYING GLASSES (Magnifiers) - Variety

(Wikipedia excerpt: ..."...A magnifying glass [MG] is a convex lens—usually mounted in a frame with a handle—that is used to produce a [M] image of an object. A [MG] can also be used to focus light, such as to concentrate the Sun's radiation to create a hot spot at the focus for fire starting. A plastic Fresnel lens sold as a TV-screen [M] . Evidence of [MG] exists from antiquity. The [MG] is an icon of detective fiction, particularly that of Sherlock Holmes.

An alternative to a [MG] is a sheet magnifier, which comprises many very narrow concentric ring-shaped lenses, such that the combination acts as a single lens but is much thinner...")