ALEXANDRIA, Va., Sept. 24 -- United States Patent no. 12,742,949, issued on Sept. 22, was assigned to SIGMA Corp. (Kanagawa, Japan).
"Imaging optical system" was invented by Ken Asakura (Kanagawa, Japan) and Noriyuki Ogasawara (Tokyo).
According to the abstract* released by the U.S. Patent & Trademark Office: "It is aimed at providing an imaging optical system which is small-sized and lightweight, has a small-sized and lightweight focusing unit, and is therefore appropriate for a small-sized and lightweight telephoto lens. An imaging optical system of the present invention includes, in order from an object side toward an image side, a first lens group G1 having a positive power as a whole, a second lens group G2 including a lens that move...