Lenses

thumb|A Burning glass|burning apparatus consisting of two [[biconvex lens]]

transparent structure in the eye

compact composite lens

thumb|right|250px|A collection of different types of eyepieces.

optical instrument corrected for dispersion at 2 wavelengths

type of optical lens used to increase the focal length of an optical system

optical element that gathers light from the object being observed and focuses the light rays to produce a real image

piece of rock crystal

thumb|270px|right|Chromatic aberration of a single lens causes different wavelengths of light to have differing focal lengths. An apochromat, or apochromatic lens (apo), is a photographic or other lens that has better correction of chromatic and spherical aberration than the much more common achromat lenses.

lens, mirror or mirror-lens optical system

lens whose surface profiles are not portions of a sphere or cylinder

image artifact produced by scattered or flared light within a lens system

lens with a thickness that is negligible

large convex lens that can concentrate the sun's rays onto a small area, heating up the area and thus resulting in ignition of the exposed surface

optical device

lens which focuses light into a line

Spherically symmetric gradient-index lens

type of lens made up of two simple lenses paired together

technique used to increase the resolving power of a microscope

compound lens consisting of three single lenses

type of lenses

thumb|Diagram of Axicon and resulting Bessel Beam An axicon is a specialized type of lens that has a conical surface. An axicon transforms a laser beam into a ring shaped distribution. They can be convex or concave and be made of any optical material. The combination with other axicons or lenses allows a wide variety of beam patterns to be generated. It can be used to turn a Gaussian beam into a non-diffractive Bessel-like beam. Axicons were first proposed in 1954 by John McLeod.

A superlens, or super lens, is a lens which uses metamaterials to go beyond the diffraction limit. The diffraction limit is a feature of conventional lenses and microscopes that limits the fineness of their resolution depending on the illumination wavelength and the numerical aperture (NA) of the objective lens. Many lens designs have been proposed that go beyond the diffraction limit in some way, but constraints and obstacles face each of them.

EnChroma are a brand of color corrective lenses designed to address the symptoms of red–green color blindness. Studies have shown that these lenses can alter the appearance of colors, but they do not restore normal color vision, and generally agree that they do not allow the wearer to see "new" colors.

obsolete Fresnel lens used in lighthouses

thumb|A microlens array used in a spectrograph

single-lens magnifying glass