DE1063826B - Asymmetrical photographic or cinematographic lens with a large field of view - Google Patents

Description

GERMAN

The invention relates to an asymmetrical photographic or mnematographic lens of large size Angle of view performance and with a back focus that is greater than the total focal length of the system.

Such lenses usually consist of a multi-part system part on the south side with a collecting refractive power and a diffusing system part facing the longer beam distance, which two objective parts by a big one. Are separated from each other. By fulfilling the requirement that the Back focus is greater than the focal length, such systems are preferably z. B. for use in Reflex chambers. suitable because the necessary deflection means between the lens and the image plane Require appropriate space, which is difficult to achieve especially when it comes to a lens small focal length.

Such systems are already known in which the front dispersing system part consists of two negative MeniskengHedern consists, with a non-cemented single lens one of two lenses with opposite refractive power Existing limb follows, in which the collecting part faces the anterior meniscus and the cemented surface is bent hollow to this side and which part of the system from the collecting part on the south side is separated by an air gap which is greater than the focal length of the entire system.

The invention was based on the object of this fundamental compared to known wide-angle lenses To bring about a strong increase in performance, on the one hand by considerably shortening the focal length - and corresponding expansion of the usable Büdwinkel -, but on the other hand by extending the Back focal length. These demands are difficult to implement in their legal contradiction. About that In addition, the optical performance should be improved without increasing the cost of lenses and lentil leather especially with a view to correcting the distortion well.

These and other requirements could be realized within the meaning of the invention by dimensioning the air gap separating the two negative menisci in the front part of the system so that it is greater than 60 ° / ₀ , but less than 75% of the focal length of the overall system.

For the elimination of Komarestfehlern in a lens according to the invention it is also specified that the air gap between the positive member facing the front system part and the one following it The negative element of the system part on the south side, made up of a total of four individual springs, serves as a panel space and that it is greater than 14% but less than 18% of the focal length of the overall system. That made of two lenses opposite refractive power cemented negative link in the asymmetrical photographic or a cinematographic lens with a large field of view

Applicant:
ISCO Optische Werke GmbH, Güttingen

Rudolf Solisch ₁ Göttingen,
has been named as the inventor

The system part on the south side is designed in such a way that there is a very large difference in the refractive index of more than 0.25, which leads to an extensive stretching of the two astigmatic shells can be.

Numerical example
Aperture ratio 1: 4; f = 100.0; s' = 152.3 r _x = + 223.49

r ₂ = + 127.27

r _R =

L ₁

+ 583.69

- 290.71
+ 96.90
+ 135.46

- 310.90

+ 42.59

r ₁₀ = + 43.20
T ₁₁ = - 28.26
r ₁₂ = - 34.86
r _ls = - 189.77
T _li = - 51.68

d _x = d ₂ = d ₃ = d _i = d ₅ =

da =

r * =

14.13 1.4989 65.2

68.64 air gap

39.97 1.6989 30.1

14.13 1.5014 56.5

119.11 air gap

8.08 1.7387 28.2

d ₇ = 16.15 air gap (aperture space)

d ₈ = 10.50 1.4707 67.2

d ₉ = 3.63 1.8069 25.5

d ₁₀ = 9.29 air gap

d _n = 4.85 1.7603 26.5

d ₁₂ = 0.40 air gap

d ₁₃ = 18.98 1.6385 55.5

909 608/206

Claims (3)

The above numerical example, in accordance with the drawing, explains the structure of a system according to the invention with the relative aperture ratio: 4 and an angle of view of more than 80 °. Here T1 to r14 denote the radii of the lenses L1 to ls, (I1 to d13 the thicknesses and air gaps, nd the refractive axes for the yellow line of the spectrum of the glasses used and ν {- Ny) the Abbe's numbers of the same. The negative member L2 / L3 following the anterior meniscus L1 is constructed from two opposing lenses in such a way that the converging part faces the anterior meniscus and the cemented surface is hollowed towards this side. The refractive index for the positive part i2 of this cemented element is 1.6989, that for the negative lens 1.5014; the difference in the refractive index in the putty r4 is 0.1975, which is greater than 0.15 as required. The air distance d% separating the two front lens elements L1 and LJL3 is - based on the focal length f = 100 - 68.64, and is therefore between 60 and 75% of the focal length of the overall system. According to the numerical example, the air gap H1 between the lens elements Li and L5 [LS in the rear system part II has a length of 16.15, ie, as required, is between 14 and 18% of the focal length of the overall system; it also serves as a screen space. The lens element LJLe in system part II is made up of glasses such that there is a refractive index difference of 0.3362 on the cemented surface r8; it is therefore greater than 0.25 according to the invention. All the requirements for creating a system according to the invention are thus met. Patent claims: 1. Unbalanced photographic or cinematographic lens with high field of view and with a back focus that is greater than the total focal length of the system, consisting of a multiple articulated image-side system part collecting refractive power and one of it by an air gap that is greater than the focal length of the overall system, separated front, composed of two negative meniscus members in such a way that the member facing the longer beam length consists of a non-cemented lens, the following member of two Lenses of opposite refractive power exist, in the latter the converging part facing the anterior meniscus and the cemented surface is curved hollow to this very side, whereby on this cemented surface there is a refractive index difference of more than 0.15, characterized by such a dimensioning of the two negative menisci (L ₁ or L ₃ , L _i ) in the front system part (I) separating air gap (d ₂ ) that it is greater than 60%, but less than 75% of the focal length of the overall system. 2. Asymmetrical photographic or cinematographic lens with large viewing angle performance according to claims 1 and 2, characterized in that the air gap (d ₇ ) _{between the positive member (L 4} ) facing the front system part (I) and the negative member (L ₅ , L ₆ ) of the image-side system part (II) made up of a total of four individual elements serves as a diaphragm space and that it is larger than 14%, but smaller than 18% of the focal length of the overall system. 3. Unbalanced photographic or cinematographic lens of large viewing angle performance according to claims 1 and 2, characterized by such a structure of the two lenses (L ₅ , L ₆ ) of opposite refractive power cemented, the front KollegHed (L ₄ ) in the image-side system part (II) following Negative member that on the cemented surface (r ₉ ) in this there is a very large difference in refractive index of more than 0.25. Considered publications:
French patent specification No. 1 097 478. 1 sheet of drawings © 909 608/206 8.