DD269693A1 - PHOTOOBJEKTIV WITH GREAT RELATIVE OPENING - Google Patents

Abstract

The large-aperture photo-objective for film and television cameras comprises, in the direction of the light, a convex meniscus lens L1, a convex cemented L2-L3, a concave meniscus L4, a concave cement L5-L6, a biconvex L7, and a convex cement L8-L9. An aperture diaphragm A is arranged between the meniscus lens L4 and the cemented element L5-L6. Fig. 1

Description

For this 2 pages drawings

Field of application of the invention

The invention relates to a camera lens with a large relative aperture and high light intensity, especially for film and Fernsehaufnahmekamei as for use in extremely low light conditions.

Characteristic of the known state of the art

There are known photographic recording objects with a relative aperture of 1: 1.2 and also of> 1: 1.0, which are constructed as a seven- and eight-lens systems (DD PS 146860, FR-PS 1386732 and US-PS 4621909).

Here, the strong growth of the Öffnungsfehlei s and the Isopianasiebodingung, as well as the further enlargement of all residual chromatic aberration to a significant increase in the aperture difference, whereby the relatively good image performance of such lenses at full relative aperture is much worse image performance at lower aperture values. This disadvantage could be eliminated by the use of aspheric surfaces as a construction element, but it has been bought with a very high production cost for the production of aspherical surfaces. Receptors with relative openings> 1: 1.0 are known in X-ray screen photography. Due to the function-related film guide on a lens belonging to the field lens, the focal length of these lenses are only small fractions of a millimeter in size, and thus these lenses are not applicable for film and television cameras.

Object of the invention

It is the object of the invention to overcome the disadvantages of the prior art and to provide a high-speed, high-quality high-value-value photo objective.

Explanation of the essence of the invention

The invention has the object zugiunde to provide a camera lens with a large relative aperture of 1: 0.95, which features an image circle diameter of about 16mm, at all f-numbers provides the same good image performance. In this case, the aperture difference should be <0.3% of the amount of execution focal length and an average value of the contrast transfer function D> 0.2 for white light at a spatial frequency of 3Γ lines / mm at an image height given by the 0.4 times the format diagonal is to be achieved.

According to the invention, this object is achieved in a large-aperture photographic lens of 1: 0.95, consisting of six links and nine lenses, arranged successively in the light direction along an optical axis, a convex meniscus lens, a convex cemented element consisting of a convex and a concave meniscus lens, a concave meniscus lens including an aperture stop with a downstream concave putty, a biconvex lens and another convex cemented member consisting of a concave and a convex meniscus lens, and the camera lens includes the following design data:

f = 1.0 = 1.7145 1: 0.95 = 0.1594 2σ "37.3 ° Y. = 40.50 radii = 11.6292 distances = 0.0245 η. _Γ1 = 1.1469 = 0.1672 = 51.98 r ₂ = 3.4582 d, = 0.0620 η, = 1.77491 = 32.00 r ₃ = 1.0199 ii = 0.0175 d ₂ r ₄ = 0.5712 d ₂ = 0.1631 n ₂ = 1.73444 = 32.00 r ₅ = 0.3961 d ₃ = 0.3890 n ₃ = 1.67764 = -0.4326 I ₂ = 0.0652 # 4 = 25.26 H = 24.3679 d ₄ = 0.2789 n ₄ = 1.67764 = 56.14 r » = -0.6365 I ₃ = 0.0041 $ r ₉ = 4,4657 d ₅ = 0.1684 n ₅ = 1.81262 = 51.98 fio = -1.1812 de = 0.0041 n ₆ = 1.66640 'Ί ι = 1.0515 I ₄ = 0.0824 = 36.09 = 0.8326 d ₇ = 0.1729 n ₇ = 1.73444 = 51.98 Γη = 7,3987 I ₅ Γΐ4 de n ₈ = 1.62410 Γίδ d ₉ n ₉ = 1.73444

Σ = 1.7587

where η is the Liiuan radius, d is the lens thickness, I is the lens pitches, n- is the refractive index, and the number is V, of the respective lens.

It is advantageous if the refractive indices of the first, second, fifth, seventh and ninth lenses have a value n,> 1.73.

For good color correction, it is advantageous if the refractive index difference in the kit following the aperture stop (A) is Δη,> 0.1.

CdS according to the invention photographic lens draws in its execution focal length of an image circle diameter of 16mm fully.

The residual aberrations are reduced to a minimum and at full relative aperture and at smaller f-numbers even without the application of aspherical surfaces an equally good image performance is achieved, it is economically and manufacturing advantageous if we can dispense with the use of aspherical elements in camera lenses.

Ausführungsbäispiel

The invention will be explained in more detail below using an exemplary embodiment. In the drawing show

Fig. 1: the lens sectional image of the photo lens and

2 to 4 are graphs of the white light contrast transfer function at a spatial frequency of 30 lines / mm and relative openings of 1: 0.95; 1: 2.8 and 1:11 in the three azimuths 0 °; 45 ° and 90 ° above the image height.

In the case of the photo objective shown in the lens section in FIG. _1, a convex meniscus lens L ₁ with the radii η and r ₂ and the thickness d is provided as the front lens. It follows in the direction of light at a distance I _1, a convex cemented L ₂ -L ₃ , which consists of a convex meniscus lens L ₂ with the radii r ₃ and r ₄ and the thickness d ₂ and a concave meniscus lens L ₄ with the radii r ₄ and r ₅ and the thickness d ₃ consists. This cemented element L ₂ -L _{3 is} followed at a distance I _{2 by} a concave meniscus lens L ₄ with the radii r _e and r ₇ and the thickness d ₄ . At a distance of I ₃ follows a concave cemented L ₅ -L ₅ , consisting of a biconcave lens L ₆ with the radii r ₈ and r ₉ and the thickness d ₆ and a bikonkexen lens L ₆ with the radii r, ₀ and r _r and the thickness d _e . An aperture diaphragm A is arranged in the space between the meniscus lens L ₄ and the cemented component L ₅ -U. Narli dor biconvex lens L ₆ is in

Distance I ₄ a biconvex lens L ₇ with the radii T) ₁ and r, ₂ and the thickness d ₇ arranged. This lens L ₇ follows at a distance I ₆ a Kittglied L ₈ -L ₉ , which consists of a concave meniscus lens L ₈ with the radii r »and r _u and the thickness d ₈ and from a convex Meniscus lens L ₉ with the radii ru and Γιβ and the thickness d _{9 is} composed. Particularly favorable is the photo lens with a relative aperture 1: 0,9b through the use of high refractive glasses with a Refractive index n,> 1.73 in five optical groups, which the lenses Li; L ₂ ; L ₆ ; L ₇ and L ₈ include, designed to provide a

evenly good picture performance over the entire field of view and at all f-numbers is achieved. For the color correction, a refractive index difference Δη,> 0.10 is favorable in the lattice elements L ₅ -L ₈ and L ₈ -Lg following the aperture stop.

The illustrated favorable properties of the camera lens are achieved when the individual lenses in claim 1

given values for the radii, distances and for the n, - and γ, values are realized.

In Fig. 2, the values of the contrast transfer function (KÜF!) For white light at a spatial frequency of 30 lines / mm are shown in Figs Azimuths 0 ° (solid line), 45 ° (short dashed line) and 90 ° (long dashed line) above image height for a relative Opening 1: 0.95 shown. FIG. 3 shows the course of the KÜF for a relative opening 1: 2.8 and FIG. 4 for an opening 1:11.

Claims (3)

A large aperture photographic lens of 1: 0.95 consisting of six links and nine lenses, characterized by successively arranging along an optical axis in the light direction, a convex meniscus lens (L ₁ ), a convex cemented lens (L ₂ -La), consist of a convex and a concave meniscus lens, a concave meniscus lens (L ₁ ), with a downstream concave cemented element (L ₅ -L ₆ ) an aperture diaphragm (A) monohydrate, a biconvex lens (L ₇ ) and a another convex cemented element (L ₈ -L ₉ ) consisting of a concave and a convex meniscus lens and in that the photographic lens comprises the following construction data: where η is the lens radius, d, the lens seria thickness, Ij the lens pitches, n · the refractive index and tf, the Abbe number i? _{e of} the respective lens. 2. A photographic lens according to claim 1, characterized in that the refractive indices of the first, second, fifth, seventh and ninth lens have a value n _e > 1.73. 3. Photo objective according to claim 1 and 2, characterized in that the refractive index difference in the aperture diaphragm (A) following cemented elements Δη _β > 0.1.