ALEXANDRIA, Va., July 9 -- United States Patent no. 12,352,936, issued on July 8, was assigned to Canon K.K. (Tokyo).
"Optical system, lens apparatus, and image pickup apparatus" was invented by Makoto Nakahara (Tochigi, Japan).
According to the abstract* released by the U.S. Patent & Trademark Office: "An optical system includes a main optical system including an aperture stop, and a variable-magnification optical system configured to be removably inserted between the aperture stop and an image plane. A distance from a lens surface that is the closest to an object side in the main optical system to the image plane is constant before and after insertion and removal of the variable-magnification optical system. The main optical system incl...