Double-Gauss lens
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The double Gauss lens consists of two Gauss lenses back to back.
In its most basic design it therefore consists of two positive meniscus lenses on the outside with two negative meniscus lenses inside them. The symmetry of the system and the splitting of the optical power into many elements reduces the optical aberrations within the system. There are many variations of the design. Sometimes extra lens elements are added. The basic lens type is one of the most developed and utilized photographic lenses.
[edit] History
In 1817 C F Gauss improved the Fraunhofer telescope objective by adding a meniscus lens to its single convex and concave lens design. Alvan Clark, in 1888 then took two of these lenses and placed them back to back to obtain the double Gauss design. The lens was named in honour of C F Gauss. The current design can be traced back to Paul Rudolph (physicist) of the Zeiss company in 1895 who used cemented doublets as the central lenses to correct for chromatic aberrations.
Later the design was developed with additional glasses to give high-performance lenses of wide aperture. The main development was due to Taylor Hobson in the 1920s, resulting in the f/2.0 Opic and later the Speed Panchro designs, which were licensed to various other manufacturers. The design forms the basis for many camera lenses in use today, especially the wide-aperture standard lenses used on 35 mm and other small-format cameras. It can offer good results up to f/1.4 with a wide field of view, and has sometimes been made at f/1.0.
