Macro lens

Abstract

A macro lens comprised of a front lens group of a retrofocus type and a rear lens group of which component lenses are aligned in the order from the closest to the subject. The front lens group includes a first lens of a negative meniscus lens having its convex surface projecting toward the object, a second lens of a positive lens having its one surface with greater curvature oriented toward the object, a third lens of a positive lens having its one surface with greater curvature oriented toward the object, a fourth lens of a negative lens having its concave surface with greater curvature oriented toward the imaging plane, fifth and sixth lenses of a junction lens in combination of a negative lens with a positive lens, the negative lens having its one surface with greater curvature oriented toward the object, across a space having an aperture stop, and a seventh lens of a positive lens having its one surface with greater curvature oriented toward the imaging plane, the rear lens group including an eighth negative lens and a ninth positive lens, the macro lens providing relations expressed as follows: 1.0<|F1|/Ft<1.3  (1) 4.0<|Fr|/Ft<6.0  (2) where F1 is a focal length of the first lens, Fr is the focal length of the rear lens group, and Ft is the focal length of the total optics of the.

Dependencies are inferred from the claim text.