FOUR-ELEMENT LENS Russian patent published in 2017 - IPC G02B9/20 G02B15/16 

FIELD: photography.

SUBSTANCE: invention can be used as a photographic lens. Lens consists of two components. First component comprises two single lenses – plane-convex, by convex side facing object space, and concave with concave side facing object space. Second component is in form of glued convex-concave negative meniscus, by convex side facing object space, and a biconvex lens. Between refraction indices n₁, n₂, n₃, n₄ of first, second, third and fourth lenses, respectively, for D spectral line ratios are met 1.5<n₁=n₄<1.6, 1.6<n₃<1.7, 1.6<n₂<1.7, n₃<n₂. Air gap between components of lens varies from 0 to 0.4 ƒ’, where ƒ’ is focal distance of whole system, wherein image quality in center remains unchanged.

EFFECT: technical result is high aperture ratio, wider angular field in object space and possibility of portrait photography with variable artistic perception of photography.

1 cl, 2 dwg, 2 tbl