Retrofocus wide-angle lens

Abstract

A retrofocus wide-angle lens includes a first lens group of negative refractive power, a diaphragm, and a second lens group of positive refractive power. The first lens group includes an object-side lens group, a middle lens group, and an image-side lens group. The object-side lens group includes a plurality of negative lens components and a positive meniscus lens component with its convex surface on the image side. The middle lens group satisfies a particular focal length condition and includes a negative lens component at the object side. The image-side lens group includes a negative lens element and a positive lens element. The first and second lens groups include lens elements of opposite refractive power that are made of anomalous dispersion glass so as to provide chromatic aberration correction and to compensate for variations in refractive index with temperature change that would otherwise cause the focal length to vary with temperature.

Dependencies are inferred from the claim text.