MACRO LENS WITH VARIABLE MAGNIFICATION Russian patent published in 2017 - IPC G02B15/16 G02B15/173 

FIELD: optics.

SUBSTANCE: lens has four groups of lenses. First and fourth groups are fixed and have positive optical power. Second and third groups have negative and positive optical power and can be moved. First group is made of single biconvex lens, gluing of biconvex lens and negative meniscus, facing object, and single negative meniscus, facing image. Second group is made of gluing of biconvex and biconcave lenses and second single biconcave lens. Third group is made of single biconvex lens and negative meniscus, convex side of which faces image. Fourth group includes front component of biconvex lens, glued with negative meniscus, convex side faces image, and rear component of meniscus in form of positive and negative menisci are glued together, convex side of which faces object, and single positive meniscus, convex side of which faces object.

EFFECT: technical result is high image quality in whole range of focal distance during capture with distances comparable with focal distance of lens.

1 cl, 8 dwg, 1 tbl