Kazimierz Prószyński (4 April 1875 – 13 March 1945), born in Warsaw, Poland, was a Polish inventor active in the field of cinema. He patented his first film camera, called Pleograph (in Polish spelling: Pleograf), before the Lumière brothers, and later went on to improve the cinema projector for the Gaumont company, as well as invent the widely used hand-held Aeroscope camera.