Optical aberration is a phenomenon that occurs when the shape of an image formed by a componet of an optical system, such as a lens or mirror, is distorted or not perfectly focused. This can occur for a variety of reasons, including the limitations of the optical system itself, the properties of the medium through which the light is passing, and the wavelength of the light being used.

 

There are six main types:

astigmatism

chromatic aberration (a problem restricted to lenses)

coma

distortion

field curvature

spherical aberration

 

Optical aberration can be corrected using a variety of techniques, including the use of multiple lenses or mirrors, the use of special coatings on the surfaces of the lenses or mirrors, or the use of specialized software to correct the image digitally. In some cases, it may be necessary to use a combination of these techniques to achieve the desired level of image quality.

 

See also aberration of starlight.