Double Gauss and Near Symmetric Types

This type of lens was derived from a telescope objective originally designed by C. F. Gauss (Kingslake 1951). It is one of the basic forms of anastigmatic photographic lenses and consists of a nearly symmetric arrangement of elements about a central stop. Surrounding this stop are two achromats with the flint element facing the stop (Brandt 1956), such that its surface is concave toward the stop. It can be well corrected over a large aperture and moderately large field of view.