The superachromat or superachromatic lens was first conceived and developed by
Maximilian Herzberger
Maximilian Jacob Herzberger (7 or 17 Mar 1899, Berlin, Germany — 9 Apr 1982, New Orleans, United States)[lens
A lens is a transmissive optical device which focuses or disperses a light beam by means of refraction. A simple lens consists of a single piece of transparent material, while a compound lens consists of several simple lenses (''elements''), ...](_blank)
. The color shift curve of a superachromat is a
quartic, meaning that in theory four separate colors can be brought to
focus
Focus, or its plural form foci may refer to:
Arts
* Focus or Focus Festival, former name of the Adelaide Fringe arts festival in South Australia Film
*''Focus'', a 1962 TV film starring James Whitmore
* ''Focus'' (2001 film), a 2001 film based ...
in the same plane, while simultaneously correcting
spherical aberration
In optics, spherical aberration (SA) is a type of optical aberration, aberration found in optical systems that have elements with spherical surfaces. Lens (optics), Lenses and curved mirrors are prime examples, because this shape is easier to man ...
and field aberrations. This near-perfect correction of
chromatic aberration
In optics, chromatic aberration (CA), also called chromatic distortion and spherochromatism, is a failure of a lens to focus all colors to the same point. It is caused by dispersion: the refractive index of the lens elements varies with the wave ...
is highly beneficial in film and digital
multi-spectral photography
Photography is the art, application, and practice of creating durable images by recording light, either electronically by means of an image sensor, or chemically by means of a light-sensitive material such as photographic film. It is employed ...
, as a superachromat can focus
near-infrared
Infrared (IR), sometimes called infrared light, is electromagnetic radiation (EMR) with wavelengths longer than those of Light, visible light. It is therefore invisible to the human eye. IR is generally understood to encompass wavelengths from ...
energy in the 0.7 to 1.0 micrometer wavelength band in the same
focal plane as visible light, eliminating the need for refocusing. Unfortunately, due to the limited selection of optical glasses and
partial dispersion properties, superachromats must be manufactured with costly
fluorite glass
Fluorite (also called fluorspar) is the mineral form of calcium fluoride, CaF2. It belongs to the halide minerals. It crystallizes in isometric cubic habit, although octahedral and more complex isometric forms are not uncommon.
The Mohs sca ...
es and to very tight tolerances.
{{clear, left
See also
*
Photographic lens
A camera lens (also known as photographic lens or photographic objective) is an optical lens or assembly of lenses used in conjunction with a camera body and mechanism to make images of objects either on photographic film or on other media capab ...
*
Achromat
An achromatic lens or achromat is a lens that is designed to limit the effects of chromatic and spherical aberration. Achromatic lenses are corrected to bring two wavelengths (typically red and blue) into focus on the same plane.
The most comm ...
*
Apochromat
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.
Explanation
Chromatic aberration is the phenomenon of differen ...
References
*Herzberger, M., and N. McClure
''The design of superachromatic lenses'' ''Appl. Opt.'' 2, pp. 553–560 (June 1963).
*N. v. d. W. Lessing
''Selection of optical glasses in superachromats'' ''Appl. Opt.'' 9, 1665–1669 (1970).
External links
Photographic lenses