Afokales Weitwinkelvorsatzsystem

977,745. Supplementary objectives. K. VOCKENHUBER, and C. HAUSER. May 10, 1962 [May 10, 1961], No. 18078/62. Heading G2J. In an afocal wide-angle supplementary objective for objectives of different focal length, in particular for variable focal length objectives, with one negative and one positive cemented component, which are arranged in the manner of a reverse Galibean telescope, the positive component has two cemented surfaces, whereby the cemented surface near the following main objective has a positive refraction power, the second cemented surface has a negative refraction power and both cemented surfaces are concave towards the rear. Preferably, with a refractive index difference between lenses L4 and L5 of greater than 0.15 the value of r6 is not greater than 1/3 focal length of the positive component and, with a refractive index difference between lenses L3 and L4 of greater than 0. 07 the value of r5 is between “ and 1/5 of the same focal length. The negative component preferably comprises two lenses, the cemented surface having negative refractive power, surface r1 being plane or concave to the front with large radius of curvature and the value of r3 being at least equal to 2/3 the focal length of the negative component. Preferably, cemented surfaces join glass pairs in which both the refractive index and the AbbÚ Number of one lens is higher than the adjoining lens. Optical data are given for two examples.