A compact objective lens with two lens groups (COMPACT OBJECTIVE LENS WITH TWO LENS GROUPS)

摘要

A lens system for a folding reflex camera was provided. (A) the first group on the object side of the iris of the system comprises (i) a positive refraction optics, (ii) an aspherical surface, (iii) a concave surface adjacent to the aperture, and (b) the second group at the image side of the aperture is comprised of a single positive component or a combination of a single positive component and at least one focusing element, said first group and said second group.;The system includes two or more elements in which at least one of the elements is made of plastic and the dispersion power is made of a different material. The system has only two plastic elements. The system can have only two plastic elements and, with a simple construction, can achieve a relatively flat field, relatively low distortion and excellent optical performance, which can at least partially correct the lateral chromatic aberration.