The present invention relates to a diaphragm for a photo or film camera lens assembly, or a photo or film camera, the aperture is the numerical aperture of elliptical shape (2; 2 '; 2 ") device to limit the (1; 1'; 1") a has and, at least in part, is fixed primary axis and the secondary axis of the apparatus, and the numerical aperture of an elliptical shape as a result, if the vertical alignment of the (2;; 2 '2 ") is known from the anamorphic lens aesthetic image characterized in that the effect is produced in the areas that are out of focus. in addition, the aperture may comprise a conventional diaphragm. openings in the elliptical shape is of a disc (1) having an opening of a fixed elliptical or linear It can be formed by; forming a diaphragm and thin sheet (1 ", 1 ') which can be moved at right angles to the main axis of the oval-shaped opening.