a compact catadioptric lens system with a widened field angle is disclosed and characterized in that the axial distance l between the main - mirror element and the sub - mirror element fulfills the following condition in relation to the diagonal length d of the rectangular focal plane on which the image is projected : 1 . 5d & gt ; l & gt ; 0 . 5d , and that the radius of curvature r 5 of the image side surface of the sub - mirror element and the radius of curvature r 6 of the object side surface of the same fulfill the following condition in relation to the focal length f of the system : ## equ1 ##