Olympus was established in October 1919 by Takeshi Yamashita in Shinjuku, Tokyo, Japan. Olympus initially specialized in microscopes and thermometers and currently owns a majority share of the world market in gastro-intestinal endoscopes. In 1936, Olympus introduced its first camera, the Semi-Olympus I. The first innovative camera series from Olympus was the Pen, launched in 1959. The half-frame format, allowing 72 pictures of 18 × 24mm format on a standard 36 exposure roll of film, made Pen cameras compact and portable for their time. In 2012, the company announced it would focus on Mirrorless interchangeable-lens cameras, commonly known as digital mirrorless cameras.