Editing Lens (section)

{{short description|Optical device which transmits and refracts light}}
{{Other uses|Lens (disambiguation)}}<!--No, this dablink is not superfluous. Some of the listed other uses of "lens" are ambiguous with "lens (optics)".-->

{{Use dmy dates|date=December 2013}}
[[File:Double-lens burning apparatus, Ehrenfried Walther von Tschirnhaus, Kieslingswalde (today Slawonice, Poland), c. 1690 - Mathematisch-Physikalischer Salon, Dresden - DSC08133.JPG|thumb|A [[Burning glass|burning apparatus]] consisting of two [[biconvex lens]]]]
A '''lens''' is a transmissive [[optics|optical]] device that focuses or disperses a [[light beam]] by means of [[refraction]]. A [[simple lens]] consists of a single piece of [[transparent material]], while a [[#Compound lenses|compound lens]] consists of several simple lenses (''elements''), usually arranged along a common [[Optical axis|axis]]. Lenses are made from materials such as [[glass]] or [[plastic]] and are [[Grinding (abrasive cutting)|ground]], [[Polishing|polished]], or [[Molding (process)|molded]] to the required shape. A lens can focus light to form an [[image]], unlike a [[Prism (optics)|prism]], which refracts light without focusing. Devices that similarly focus or disperse waves and radiation other than visible light are also called "lenses", such as [[microwave]] lenses, [[electron lens]]es, [[acoustic lens]]es, or [[explosive lens]]es.

Lenses are used in various imaging devices such as [[telescope]]s, [[binoculars]], and [[camera]]s. They are also used as visual aids in [[glasses]] to correct defects of vision such as [[Near-sightedness|myopia]] and [[Far-sightedness|hypermetropia]].