Imaging lens

摘要

The present invention is directed to an imaging lens with an optical system that comprises the foremost lens group closest to an object and of positive refractivity, the succeeding middle lens group, and the rearmost lens group closest to an image plane and of negative refractivity where the middle lens group, having the first, second, and third lens subgroups disposed in series, is moved axially along the optical axis for focusing, and the foremost lens group includes at least three or more convex lens pieces and a single concave lens piece and meets predetermined requirements defined in formulae. The imaging lens has a quality image stabilizing system in which a light-weight lens piece(s) is moved in directions perpendicular to the optical axis.

主权项

1. An imaging lens with an optical system comprising the foremost lens group closest to an object and of positive refractivity, the succeeding middle lens group, and the rearmost lens group closest to an image plane and of negative refractivity; the middle lens group, with the first, second, and third lens subgroups disposed in series, being moved axially along the optical axis for focusing;
the foremost lens group having at least three or more convex lens pieces and a single concave lens piece; the imaging lens with the optical system meeting the requirements as defined in the following formulae:
(Rn1−Rn2)/(Rn1+Rn2)<0  (1)nd1<1.6,vd1>67.5  (2)55