RU1800430C - Photographic objective - Google Patents

Abstract

Field of application: the invention relates to optical instrumentation, in particular to photographic lenses. SUMMARY OF THE INVENTION: A photographic lens consists of six components; the first is a positive meniscus facing concavity to the image, the second and third are negative menisci facing concavity to the image, the fourth is a double convex lens, the fifth is a double convex glued lens, the gluing radius of which is turned concavity to the space of objects, the sixth is a single two a convex lens, the aperture diaphragm being located between the fourth and fifth components, the distance between the third and fourth components being 1.32 f /, where f is the focal length of the lens. 1 ill.

Description

The invention relates to optical instrumentation, and specifically to photographic optics.

The purpose of the invention is to increase the angular field while improving image quality.

The goal is achieved in that the photographic lens, consisting of six components, the first of which is the positive meniscus facing the concavity to the image, the second is the negative meniscus facing the concavity to the image, the third is the meniscus facing the concavity to the image, and the fourth is the positive lens the fifth is a glued positive lens including a biconvex lens, the sixth is a single biconvex lens, the aperture diaphragm being located between the fourth and fifth components, the third component m represents a negative meniscus,

the fourth is a biconvex lens; the fifth, the component is made in the form of a biconvex lens, the gluing radius of which is turned by the concavity to the space of objects, the distance between the third and fourth components being 1.23 f, and the distance between the fourth and the fifth component is 1.32 f, where f is the focal length of the lens.

The third component of the photographic lens is a negative meniscus for correcting image curvature and astigmatism, and serves to increase the angular field.

The fourth component is in the form of a single biconvex lens to provide aberration correction for a wide oblique beam of beams, as well as coma.

The fifth component is made in the form of a biconvex lens, the gluing radius of which is turned by concavity to the space

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objects, provides the correction of chromatic aberrations, especially position chromatism, spherical aberration of the third and higher orders for a point on the axis, as well as spherical aberration in inclined beams of rays in the meridian and sagittal sections.

The distance between the third and fourth components of 1.23 f and the distance between the fourth and fifth components of 1.32 f are chosen experimentally and allow correcting image curvature and astigmatism, distortion, and also to whom.

The proposed photographic lens has the following aberration

- transverse spherical aberration for a point on the axis in the entire spectral range does not exceed 0.0677 mm. For the main wavelength, the longitudinal spherical aberration does not exceed 0.057 mm, and the transverse - 0.018 mm (at the extreme point);

- the chromatism of the position is equal to: the edge of the pupil is 0.095 mm; zone - 0.030 mm;

- image curvature and astigmatism are equal to:

O) 45b; Z, 33 mm; Z, 087 MM; Zs-, 246 mm,

 fifteen ; Z, 181 mm; Zs-OJSI mm; ZS-Z (0.050 mm;

- chromatism magnification: edge margin - 0.01 mm; zone - 0.012 mm.

The resolution of the lens is for a point on the axis 50 lines / mm with a contrast of 0.64, at the edge of the field - 50 lines / mm with a contrast of 0.2.

The invention is illustrated in the drawing, which gives an optical diagram of a photographic lens: 1 -positive meniscus facing concavity to the image space; 2 and 3 - negative menisci facing concavity to the space of images; 4 - double convex lens; 5 - aperture diaphragm; 6 - a double convex lens glued from a double convex lens 7 and a negative meniscus 8; 9 - single double convex lens.

This lens is photographic, therefore the object is at infinity, and a parallel beam of rays is incident on the lens. The rays pass through the first four components 1-4, completely fill the aperture diaphragm 5, which determines the aperture ratio of the system. Then, the rays pass successively through the following lenses 6 and 9 and in the focal plane of the lens, located at a distance of SF 35.83 mm from the last surface of the lens, form an image of the object.

As a specific embodiment, a photographic lens with the following characteristics is calculated:

Focal Length 20 mm

Angular field 90 ° Rear focal length 35.83 mm Relative aperture 1: 2.8 Lens length 101.9 mm. An important advantage of a photographic lens is the increased angular field, which is 90 °, a high relative aperture of 1: 2.8, and good image quality. The back focal length and lens dimensions give

the ability to use it in a SLR camera.

Claims (1)

SUMMARY OF THE INVENTION A photographic lens containing six components, the first of which - a single lens, the second and third - negative menisci facing concavity to the image -, the fourth - two convex lens, fifth - double-glued positive lens, consisting of a two-convex lens and a negative meniscus, and a sixth is a positive lens, the aperture diaphragm being located between the fourth and fifth components, characterized in that, for the purpose of increasing the angular field while improving image quality, the first lens is made in the form of a positive meniscus, facing a concavity to the image, the fourth component is single and the sixth, in the form of a single biconvex lens, with the distance between the third and fourth components being 1.23 f, and the distance between the fourth and fifth components being 1.32 f, where f is the focal length of the lens.