PHOTOGRAPHIC TELEPHOTO LENS Russian patent published in 2017 - IPC G02B13/02 G02B9/64 

FIELD: physics.

SUBSTANCE: lens contains two lens groups. The first group consists of a positive meniscus with convexity toward the object, a negative meniscus with convexity to the object, a biconvex lens, a negative meniscus with convexity to the image, a negative meniscus with convexity to the object and having the ability to move along the optical axis. There is an aperture diaphragm between the first and the second lenses of the first group. The second group consists of a positive and a negative menisci with convexity to the object. In the first group, the fifth lens can move along the optical axis.

EFFECT: increasing the aperture while maintaining acceptable image quality in the visible and near IR ranges in the extended temperature range.

1 dwg, 1 tbl