SU1647504A1 - Optical system of cine camera with continuous film movement - Google Patents

Abstract

The invention relates to optical instrumentation and can be used in cinema cameras with priemennoy compensation and continuous motion of the film. The purpose of the invention is to increase the field of view and improve image quality by eliminating the chromatic shift of the image. In the optical system of the camera, lens 1 builds an image of the object in the intermediate plane 20 of the image. The reversing system 3 transfers the image of the object to the plane 21. The reversing system consists of the first 4 and second 5 lens units and component 7. 1 sludge.

Description

The invention relates to optical instrumentation, in particular to high-speed movie cameras with continuous movement of film.

The aim of the invention is to increase the angle of field of view and improve image quality by eliminating the chromatic shift of the image.

The drawing shows a schematic optical diagram of a movie camera.

The proposed optical system of the movie camera consists of a lens 1, a prism compensator 2, a wrapping system 3. The wrapping system 3 contains two lens units 4 and 5 located on opposite sides of the image of the aperture diaphragm 6 of the lens, and a lens component 7 located near the plane ^{L of the} image of the aperture aperture 6, made in the form of a single flat-concave lens, concavity facing the subject.

The first lens unit 4 is made of four components. The first component 8 is glued from a biconcave lens 9 and a biconvex lens 10, the second biconvex lens 11, the third positive meniscus 12 convex to the object, the fourth 13 is glued "from a biconvex lens 14 and. biconcave. lens 15. The component 8 is made with positive optical power, and the component 13 is made with negative optical power.

The second lens unit 5 is made of. four components. The first 16 and second 17 components are the negative and positive menisci, convex to the image, the third 18 and fourth 19 are plano-convex lenses, the convexity of the image. one to another. The drawing also shows the planes of the intermediate image 20 and the film channel 21.

The optical system of the movie camera works as follows.

The lens 1 projects the image into the intermediate image plane 20, located in front of the prism compensator 2, the compensator shifts the image along the axis by the value h ^{_1 R} = - d _k , where R is the displacement of the axial beam along the optical axis;

h is the refractive index;

from! K is the thickness of the prism compensator, and the wrapping system 3 transfers the image to the plane 21 of the film channel with an increase of 1, 67 * ·.

A necessary condition for calculating the optical system of a movie camera to obtain high image quality is the introduction of a specific coma value (nonplanarism) equal to 0.01 for the output aperture of the shooting lens 03 = 0.2 (which corresponds to aperture ratio 1: 2.5) into the components located to the prism compensator, and exactly the same value, but with the opposite sign, to the components located after the prism compensator, to the wrapping system.

To correct the chromatic shift in the optical system, the specific values of the increase in chromaticity are introduced into the components located before and after the prism compensator. In the 'component after the prism compensator - the wrapping system, the value of the increase in chromatism is introduced, equal to. = -0.195 mm. An increase in chromatism equal to & ϊχρ = 0.11 mm is introduced into the component up to the prism compensator, in this case, into the shooting lens, taking into account the increase in the wrapping system.

The increase in the wrapping system is 1.67 ^. This allows you to reduce the size of the system, increase both the input angular field of view, and linear, determined by the frame size. An intermediate image is formed by the input lens in front of the prism compensator. The location of the prism compensator closer to the first lens of the wrapping system allows you to use the face of the prism compensator as a shutter, killing adverse rays.

The proposed camera system provides high image quality within the full angle of rotation of the prism compensator in the spectral range of β - • (0.48-0.64) microns. Example. When calculating the optical system of a movie camera, the following characteristics were obtained: focal length of the optical system of a movie5 apparatus f * = -50 mmj focal length of a shooting lens f = 30 mm, relative aperture 1.0: 2.5, field of view angle 2W = 32 ^e * increase in 1,662 systems; focal length of the first lens of the wrapping system f ^{, =} 39.66 mm, relative aperture 1.0: 2.5, field of view angle 25 °; focal length of the second lens of the wrapping system f * = 65.92 mm, relative aperture> 1: 4, field of view angle 25 ^e .

Claims (1)

SUMMARY OF THE INVENTION Optical system of a movie camera with continuous motion of a film containing a lens, a prism compensator, wrapping a system of two lens blocks, each of which contains four components, and a lens component located between the lens blocks, the first component being positive in the first lens block the meniscus facing concavity to the object, the second biconvex lens, the third - 10 .1647504 * false meniscus facing the convex to the object, the fourth negative meniscus, reversed convex to the object, in the second lens unit the first component is the negative meniscus facing the concavity to the object, the second is the positive meniscus facing the concavity to the object, the third and fourth positive lenses, characterized in that, in order to increase the angle of field of view and improve quality image by eliminating the chromatic shift of the image, in the first lens unit of the wrapping system, the first component is glued from a biconcave and biconvex lens, the fourth from a biconvex and two ovognutoy lenses in the second lens unit relaying system of the third component 'is formed as a plano-convex lens, the fourth - in the form of convex-lens plos25 Coy and lens component - in the form of a single concave-flat lens.