Zoom lens system for finite distance

Abstract

Abstract PURPOSE: To obtain a zoom lens system for finite distance having an about 1/10W 1/5-magnification range, by making a lens system, consisting of negative and positive lenses in two groups from an object side, meet prescribed requirements. CONSTITUTION: A lens system, consisting of two negative and positive groups of lenses, wherein the 1st group has positive, negative and positive arrangement as the negative lens group of oneWtwo negative lenses and the 1st group has the same arrangement as the positive lens group of two positive lenses, meet requirements as shown by inequalities (1)W(5). In those inequalities, M max and M min are the magnifications of the high-magnification and low-magnification sides, f max is the focal length of the entire system on the low-magnification side, f 1 , f 2 and r 2 , and n 1 are the focal length of the 1st lens group, the focal length and radius of curvature of the image-side surface of the 1st positive lens, and refractive index to a line (d); and Δl 1 and Δl 11 are variations of the 1st and 2nd lens group intervals, and n 111 and n 112 are indexes of refraction of the 1st and 2nd positive lenses in the 2nd lens group to a line (d). Consequently, a zoom lens system for finite distance has an about 1/10W1/5-magnification range. COPYRIGHT: (C)1982,JPO&Japio

Inventors

• 👤 Takayuki Ito

Bibliographic Details