SU1742770A1 - Photographic telephoto lens - Google Patents

Abstract

Usage: in the optical instrument. SUMMARY OF THE INVENTION: A photographic telephoto lens contains yes components, the first of which is positive and includes single double-convex and double-curved lenses, and the second is negative and includes single negative and positive menisci that are facing the concavity of the image. Before the first component, a plane-parallel plate is inserted, on the second surface of which a film form is applied. Moreover, the optical powers of the first and second components are as follows: 1: 0.95, the optical powers of the first and second components of the first component are 0.534, -0.97 of the optical power of the first component, and the optical powers of the first and second lenses of the second component are 0.46, -0.85 of the optical power of the second component. Both lenses of the first component and the first lens of the second component are made of glass with a refractive index of more than 1.6 and an average dispersion coefficient of more than 60, and the second lens of the second component is made of glass with a refractive index of more than 1.7 and a coefficient of average dispersion of less than 30. 1 sludge . “To r

Description

This invention relates to an optical instrument, namely to telephoto lenses.

The achromatic telephoto lens is known, which contains two components separated by a diaphragm, the first of which is made in the form of a two-convex lens, an abnormal meniscus facing the object and a positive lens, and the second is in the form of a negative lens, a negative meniscus is introduced in the component, facing the concavity to the image, set at a distance (0.27-0.21) j os from the positive lens and made with an optical force. equal to (0.2-0-4) | 0b, in the second component a deux-convex lens is inserted, installed after the diaphragm with an optical power equal to (2.9-3.3) vol., with the positive lens of the first component being two-convex, the negative lens The second component is made biconcave with an optical power equal to (4.8-5.2) 0b, and the second component is mounted for movement along the axis.

But this lens does not provide the required image quality.

The closest to the invention is a telephoto lens containing a first positive, made of a double-convex lens and a meniscus with a concavity facing the object, and a second negative one, made of a single negative meniscus facing vogue M

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with a full component lens and a positive lens component, the positive lens of the second component is made in the form of a meniscus with a concavity to the image, a heavy flint, the negative meniscus of the second component is made of a supercrown crown, and the positive lens and a negative meniscus of the first component are made of flint and fluorite.

An unspecified telephoto lens has large gaoari gy and the picture quality is not good enough.

 The aim of the invention is to improve the image quality while reducing the distance from the pew surface of the object to the image plane.

The photographic telephoto lens contains the de-component, the first of which is positive and includes single two-convex and negative lenses, and the second is negative and includes single negative and positive menisci converted to the first component by a plane-parallel the plate, on the second surface of which the kinoforms are applied, the negative lens of the first component is made double-curved, and the negative meniscus of the second component faces the image concavity, and cal forces of the first and second components both include 1.0,95: optical powers of the first and second lenses of the first component was dissolved 0.534 - 0 97 of the first component of the optical power and the optical power of the first and second lenses of the second component was dissolved 0.46. -0.85 from the optical power of the second component, both lenses of the first component and the first lens of the second component are made of glass with a refractive index of more than 1.6 and the coefficient of average dispersion of more than 60, and the second lens of the second component is made of glass with a refractive index of more than 1, 7 and a coefficient of average dispersion less than 30.

In front of the two-convex lens of the first component, a plane-parallel plate with a film form is placed on the second surface in order to improve the correction of spherical aberration for a point on the axis. as well as for wide oblique beams of rays in the meridional and sagittal sections.

The ratio of the forces of the second and third lenses of the first component to 0.534, -0.97 of the optical power of the first component is chosen experimentally and provides correction for coma, distortion, and the pattern of curvature of the astigmatism image in the first component.

The negative lens of the first component is biconcave and provides the best correction of the spherical aberration of wide oblique beams of rays in the meridional and sagittal sections.

The negative meniscus of the second component faces the concavity of the image to better correct the image curvature and reduce the rear focal length of the lens.

The ratio of the forces of the lenses of the second component is 0.46, -0.85 of the optical power of the second component selected experimentally and provides coma, distortion, curvature of the image and astigmatism of the second component.

The ratio of the forces of the first and second components 1: 0.95 is also chosen experimentally and provides correction for the image curvature and astigmatism of the distortion of the entire lens, and also reduces the distance between the first surface and the image plane.

For chromatic correction

aberrations, image curvature and astigmatism, both lenses of the first component and the first component of the second component are made of glass with a refractive index of more than 1.6 and a coefficient of average dispersion of more than 60. and the second lens of the second component is made of glass with a showing refractive gel of more than 1.7 and coefficient average dispersion less than 30.

This photographic telephoto lens has the following image quality: the longitudinal spherical aberration for a point on the axis for the edge of the pupil does not exceed 0.1 mm, and in the area of 0.04 mm; transverse spherical aberration for a point on the axis of the main wavelength does not exceed 0.008 mm, and in the whole spectral range of 0.01 mm, the neisoplanasity coefficient does not exceed 0.03%; chromatism of position no more than 0.22 mm.

The wave aberrations for the point of the nz axis are (i):

Image curvature and astigmatism are equal, the field is 2128. i 0.103. z v. 0,096, Z s-Z t 0.007 mm: zone w- - 1 ° 451. 0.043. Z s 0.0-42. Z s-Z t 0.001 mm, the increase chromatism is equal to: the edge of the floor is 0.001 mm, the area is 0.001 mm.

It follows that this photographic telephoto lens has an improved image quality.

The drawing shows an optical circuit of a photographic telephoto lens.

The scheme includes the first 1 and second 2 components of a photographic telephoto lens.

The first component 1 consists of two double convex 3 and two double convex 4 lenses.

The second component 2 consists of a negative 5 and a positive meniscus, concavity facing the image.

Before the first component 1, a plane-parallel plate 7 is introduced, on the surface 8 of which a film form is applied.

The object for this telephoto lens is at infinity, so a parallel beam is incident on the photographic telephoto lens. The rays pass through the plane-parallel plate 7, the lenses of the first 1 and second 2 components completely fill the aperture diaphragm and create an image in the focal plane of the lens.

Example. A photographic telephoto lens with the following optical characteristics is calculated:

Focal distance mm500.0

Relative hole1: 5

Corner field, degree5

Zalny focal length, mm 198.5

Distance from first

0

five

0

five

0

five

0

lens surface

to the image plane, mm 375.0

Claims (1)

Invention Formula A photographic telephoto lens containing two components, the first of which is positive and includes single double-convex and negative lenses, and the second is negative and includes single negative and positive, facing concavity to the image, menisci, different in that. in order to improve the image quality while reducing the distance from the first surface of the lens to the image plane, a plane-parallel plate is inserted in front of the first component, on the second surface of which is applied kinoforms, the negative lens of the first component is bent-curved, and the negative meniscus of the second component faces concavity to the image, and The optical powers of the first and second components are 1: 0.95. The optical powers of the first and second lenses of the first component are 0.534–0.97 optical. The strengths of the first component and the optical powers of the first and second lenses of the second component are 0.46. -0.85 of the optical power of the second component, both lenses of the first component and the first lens of the second component are made of glass with a refractive index of more than 1.6 and the coefficient of average dispersion of more than 60. and the second lens of the second component is made of glass with a refractive index of more than 1.7 and the coefficient of average dispersion is less than 30.