Compact afocal attachment for use with photographic objectives

摘要

A compact convertible photographic objective that is separable into two working components consisting of a front substantially afocal component that can be rotated or translated laterally into or away from a coaxial position with a rear component which normally is fixed in position on an assigned optical axis. Movement of the front component into coaxial alignment with the rear component increases the focal length of the combination so that the two components can be used for telephoto purposes.