Abstract: An arrangement for projecting film pictures in which a system of lenses are provided on the side of a window facing the light source. A first mirror in the light beam projected by the lens system, forms an angle with the axis of the light beam. The first mirror is rotated about the axis of the light beam, and a second mirror is located in the light beam deflected by the first mirror, at a first rotated position of the first mirror. The plane of the second mirror forms an angle of substantially 45.degree. with the plane of the first mirror located in the first rotated position. A third mirror is located in a second rotated position of the first mirror in the light beam deflected by the first mirror. The plane of the third mirror forms an angle of substantially 45.degree. with the plane of the first mirror when located in the second rotated position.