The Canon rangefinders of the late 1940s and early 1950s are Leica-compatible screw-mount cameras. Many were brought to the U.S. by servicemen who bought them while visiting Japan during the Korean War. Typically they were mounted with a 50mm Serenar (later, Canon) lens. Many of them can still be used, and are similar in function to the Leica III. The top speed is 1/500. Some models are flash synchronized, using Canon's side-rail synch contacts. The lens mount is compatible with all standard Leitz M39 mount lenses