The Canon S II was produced from October 1946 during the company's name change.

The first units of the S II, also the rarest, bear the engraving of the old company name: SEIKI KOGAKU. Seiki Kogaku Kenku Sho (Precision Optical Research Institute) was founded in November 1933 by two enthusiastic friends: Goro Yoshida, "the inventor," and Saburo Uchida, the businessman. They were soon joined by a few associates, including Takeo Maeda, who held positions as sales director, chief engineer, and design advisor. Maeda, an exceptional individual, played a significant role in the company's success, eventually becoming its President in 1974.

The initial units are equipped with retractable Seiky Kogaku Serenar lenses: a 1.5/50 mm, a 2/50 mm, and a 3.5/50 mm coupled with a rangefinder, and two non-retractable lenses, a 4/13.5 cm, and a 4/20 cm, uncoupled. Some of the very first S II models were equipped with retractable Nikon 5 cm lenses.

The company was renamed CANON CAMERA COMPANY Ltd on August 15, 1947. "Canon" was then engraved on the camera bodies and lenses, which became the famous Canon Serenar lenses. Manufacturing techniques were improved, and the quality of both cameras and lenses became impeccable. The durability, precision, and technical innovations of this Canon family were quickly recognized, leading to immense commercial success.

The S II is the first mass-produced Canon. Compared to its predecessors, it is revolutionary as the first Japanese camera to offer a combined and coupled rangefinder viewfinder. In its Canon version, it is the first to have a standardized mount with a rangefinder measurement roller. It is offered with standard lenses with rangefinder cams.

The total number of S II units produced is 7,550, of which approximately 70% are Canon versions. The serial numbers range from 15,000 to approximately 18,000 for Seiky Kogaku models and from 15,700 to 23,375 for Canon models. The majority of interchangeable lenses (Canon version) are in the 39mm Leica screw mount and coupled to the rangefinder.

Production of the S II ends in June 1949, with a few very small likely re-fabrications in 1950 and even 1952. These productions often involve hybridization (S II Hybrid). Similar to Leica and our national Foca, many units were later modified by the addition of a flash sync socket.