duration application_number US 90995278 A description referring now fig1 through 4 there is shown an embodiment of the sound motion picture camera according to the invention designated by 1 is a housing of the motion picture camera the housing 1 has a cassette receiving chamber 1a in which a sound film cassette 2 is received and an image gate for exposure 1b opened in the chamber 1a the cassette 2 is a sound film cassette of the type as disclosed in u s pat no 3 858 968 and commercially available the sound film cassette 2 has an opening for exposure 2a and an opening for sound recording 2b when the cassette 2 is inserted into the chamber 1a the opening 2a is positioned at the image recording location of the chamber 1a facing the image gate 1b of the camera housing and the opening 2b is positioned at the sound recording location of the chamber 1a the sound film 3 contained in the cassette 2 is wound off from a supply spool provided in the cassette and wound up on a take up spool arranged coaxially with the supply spool after passing through the opening for exposure 2a and the opening for sound recording 2b the sound film 3 has a strip of magnetic recording material along one side on one surface of the film designated by 5 is a photo taking lens tube in which a photo taking lens system is arranged in a known manner through the lens system an image of an object is formed which is to be recorded on the sound film 3 located at the image recording location in the chamber 1a the operator can control a normally open type.