SU1647491A1 - Optical system of cine camera - Google Patents

Abstract

This invention relates to professional cinematography. The purpose of the invention is to increase the periscopicity of the system, increase the luminosity and decrease the vignetting of the system. The optical system of the periscopic type filming apparatus for shooting on a 35 mm film contains a filming lens 1, mirror 2, team 3, the first wrapping system consisting of two groups 4 and 5 lenses, between which there is a three-lens afocal optical system 6

Description

The invention relates to professional cinematography, namely, film lenses for shooting films on 35 mm film.

The aim of the invention is to increase the periscopicity of the system, increase luminosity, decrease vignetting of the system.

The drawing shows the optical layout of a movie camera.

The device contains a replaceable node of movie lenses 1, mirror 2, team 3, the first reversing system consisting of two groups of 4 and 5 lenses, a three-lens afocal optical system 6 with a working aperture 7, the team 8, the second reversing system consisting of two groups of 9 and 10 lenses, mirror 11.

The device uses interchangeable film lenses 1 for shooting on 35 mm film: OKS 7-28-1 (f 28 mm, 1: 2), OKS 11-35-1 (ff 35MM, 1: 2) and OKS 1-50- 1 (g 50mm, 1: 2).

Groups 3 and 8 are double convex lenses located near the planes of intermediate images of the object and serve to align the entrance pupil of the filming lens 1 and the effective aperture 7 and direct the path of the rays of the wide oblique beams to the optical axis, which reduces the vignetting of the system with the smallest dimensions of the subsequent components of the system ,

The first and second reversing systems serve to rotate the image of the object and increase the periscopicity of the system,

Groups of lenses 4 and 5 of the first wrapping system consist of five lenses, the first two-convex lens glued to the second negative meniscus, the third negative meniscus, the fourth lens positive meniscus glued to the fifth double convex lens.

Lens groups 9 and 10 of the second reversing system consist of five lenses, of which the first two-convex lens is glued to the second negative meniscus, the third lens is the negative meniscus, the fourth is the positive meniscus, and the fifth is a two-bell convex lens.

The afocal system 6 consists of three single lenses, the first of which is flat-concave, the second positive meniscus, the third is a concave lens, with the curvature centers of the surfaces facing the aperture diaphragm 7 located between the first and second lenses.

Flat mirrors 2 and 11 are designed

for breaking the optical axis of the system and are involved in image rotation. As a result of the use of mirrors and inverting systems, an even number of turns over the images of the object and

film is obtained an image of the object, which is identical to the image after the movie lens 1. The image of the object given by the movie lens 1 is transmitted to the plane of film with a single magnification.

The device works as follows. The beam of rays from the object passes the filming lens 1 and the deflecting mirror 2 and gives a mirror image

an object in the plane of the collective 3. Next, the beam of rays passes through groups 4 and 5 of the lens and the optical afocal system 6 and gives an inverted image of the object near the collective 8, passes through a group of 9 lenses, a mirror 11 and a group of lenses 10 and after double wrapping the image (mirror 11 and second inverting system 9 and 10) an inverted image in the plane of the film. The change of the relative aperture and the limits (1: 3) - (1:22) is carried out by the acting diaphragm 7, and the aperture diaphragm of the filming lens 1 is fully open. Remote sensing is performed by moving a group 10. A part of the system, which includes components 1-11, can rotate 360 ° around the optical axis of the camera.

The optical system has a relative aperture of 1: 3, a focal distance f1 of 28.72 with an OKS lens 7-28-1, f 36.68 mm with an OKX lens 11-35-1 and f 49.29 mm with an OKS lens 1-50 -1 and rear vertex

focal length SF 41.65mm.

Thus, as a result of using the periscopic type of the two reversing systems and the frontal system with an aperture diaphragm inside it, the periscopicity of the system is increased (540 mm), the aperture ratio is increased to 1: 3, and the vignetting of wide oblique beams is reduced with satisfactory quality of the resulting lens. images.

Claims (1)

The invention The optical system of the film camera, comprising an objective lens, a collective lens, an inverting system consisting of two opposing groups of lenses, and elements for breaking the optical axis, is distinguished by the fact that, in order to increase the periscope of the system, increasing luminosity and reducing the vignetting of the system, an afocal optical system located in the air space between the lens groups of the reversing system, and the second reversing system, and the second The optical system consists of three single lenses, the first of which is flat-concave, the second is the positive meniscus facing the concavity of the object, and the third is the concave-plane lens, the curvature of the surfaces of which is directed between the first and second lenses, and the second the wrapping system consists of two opposing groups of lenses, each of which is made up of a two-convex lens, glued to a negative meniscus, a negative meniscus with a concavity facing to th positive meniscus facing the concavity to the image, and a biconvex lens.