Here we have a Leitz Summicron-R 50mm f/2. It received a full Cine-Mod which includes an 80mm front ring, an 80mm Duclos front cap, a seamless focus gear, and an aperture de-click. Additionally, the EF mount conversion was performed.
Now for a brief explanation about why "Canada" is engraved on this lens. In 1952 Ernst Leitz opened Leitz Canada in Midland, Ontario. It's also known as ELCAN (Ernst Leitz Canada). In 1947 lens designer Walter Mandler began working for Leitz in Germany before moving to the Canada location at its open. He continued working there until his retirement in 1985. Mandler is credited with the design of more than 45 Leica lenses, including the one in this post. Nowadays ELCAN is an optics and electronics company owned by the American defense contractor, Raytheon, that manufactures devices for civilian and military markets.