DE1279959B - Photographic or cinematographic lens with a large field of view - Google Patents

Description

Photographic or cinematographic The invention. regards a photographic or taking lens with large field of view performance cinematographic Taking lens with a large image angle performance that should be at least 90 °.

In the French patent specification 1316 250 a wide-angle lens is proposed in which two collecting members adjacent to the diaphragm, each consisting of three lenses of changing refractive power, are cemented in such a way that the refractive indices of the optical glasses increase from the diaphragm to both sides so that those of the two increase from the Lenses distant from the diaphragm are greater than 0.12 units larger than the lenses adjacent to the diaphragm; In addition, in the case of such an objective, there is a difference in the refractive index of at least 0.08 on the cemented surfaces connecting the outer lenses to the inner positive lenses of these members. These two collecting members are arranged upstream or downstream of a negative meniscus facing these collecting members with a larger air gap.

With the proposed lens, however, the overall length (= vertex height) about twice as large as the focal length of the system, which is when meeting high performance requirements - e.g. B. for the achieved light intensity of 1: 3.4 and a usable angle of view of 90 - requires relatively large lens thicknesses and diameters that reduce manufacturing costs such a lens strongly influence.

The invention is based on the object. with full maintenance or even increase the picture angle performance and good correction of all known Image errors by reducing the overall length by about 50 "J (, significantly smaller lenses to get a particularly economical production and smaller exterior Ensure dimensions, even if this results in a slight decrease in the opening ratio - according to the example to 1: 5.6 - is to be accepted.

This is achieved with the data tables according to the claims defined objectives according to the invention.

It is useful to have such a distribution of the refractive indices in the the negative lenses facing the two negative menisci on the one hand and in them on the other hand to provide adjacent biconvex lenses. that the conditions a) <8 and b) <8 are fulfilled. where the sum of the two is the front and rear, respectively The air gaps separating the meniscus from the internal collecting members are smaller than 30 "" the focal length of the system. In order to also fix the coma errors as far as possible such a dimensioning of the center thicknesses of the two diaphragm space is to be able to facing negative lenses in the two collecting members provided that the condition ds + d7 <0.03f 'is fulfilled, with the outer surfaces facing the diaphragm these lenses are too hollow after the diaphragm.

The latter measures - in conjunction with the Thickness dimensioning of the lenses - also the field curvature and the astigmatism fixed will.

The design data of the built according to the invention. Systems are specified for a focal length f '= 100 mm, in which - in accordance with the sectional view of the drawing - r, to r, 2 are the radii of the lenses L, to 1, s, and d, to d "mean their thicknesses and air gaps. The refractive indices of the optical glasses and their Ny values are given for the - yellow - d line of the spectrum.

Claims (1)

Claims: 1. A photographic or cinematographic lens with a large field of view consisting of four elements standing in the air, of which two collecting elements adjacent to the diaphragm each consist of a collecting lens comprised of two diverging lenses and are cemented in such a way that the refractive indices of the optical glasses from the diaphragm towards both Sides rise so that the two lenses distant from the diaphragm are greater than 0.12 units larger than the lenses adjacent to the diaphragm, and in addition, there is a difference in refractive indices of at least on the cemented surfaces connecting the outer lenses with the inner N: sitivlinsen of these members 0.08, each of the two collecting members with a larger air gap is preceded or followed by a negative meniscus facing these collecting members, characterized by the following objective data: f '= 100 mm s' = 68.46 mm r1 = +122.75 na I L1 dl = 7.04 1.46450 65.8 r2 = +25.49 d2 = 14.65 air r3 = +34.89 L2 d3 = 13.00 1.71700 47.9 r4 = +20.90 II L3 d4 = l6.48 1.61405 55.1 r5 = -21.48 L4 d 5 = 1.48 1.56138 45.3 r6 = +360.27 ds = 2.96 air (aperture space) r 7 = -1052.6l L5 d, = 1.48 l, 56883 56.0 r $ = +23.84 III L @ d8 = 14.27 1.61375 56.3 r9 = -16.29 h d9 = 12.89 1.70181 41.1 rlo = -34.74 d1 0 = 12.04 air r11 = -25.98 IV L8 d11 = 4.27 1.52015 63.6 r12 = -128.32 Id = 100.56 2. Lens according to the generic term of claim 1, characterized by the following lens data:. f '= 100 mm s' = 67.98 mm >'t = + 127.95 na I Lt dl = 7.17 1.46450 65.8 r2 = +25.24 d2 = 14.87 air r3 = +35.13 12 d3 = 15.42 1.71700 47.9 r4 = +20.56 II L3 d4 = 13.83 1.61405 55.1 r5 = -21.67 L4 d 5 = 1.10 1.56138 45.3 r6 = +361.41 d, = 2.95 air (aperture space) r 7 = -1056.86 L 5 d 7 = 1.10 1.56470 55.8 r $ = +23.95 III L, d8 = 14.45 1.61375 56.3 r9 = -16.46 L 7 d9 = 13.40 1.7018l 41.1 r10 = -34.95 d1 0 = 12.25 air r11 = -25.94 IV L8 d11 = 4.26 1.52015 63.6 r12 = -124.29 ; d = 100.80 Contemplated publications: German Patent No. 1,054,248;. Swiss Patent No. 310 552; French Patent No. 1316 250; U.S. Patent No. 2,845,845.