SU1278769A1 - Photographic lens - Google Patents

Abstract

The invention relates to an optical instrument making and improves image quality. The lens is focused on the final shooting distances by moving the positive meniscus 1 facing the concavity towards the image. After the double-concave lens 2, the aperture diaphragm 6 is located. The third component is glued together from two double convex 3, concave flat 4 and flat convex five lenses. Lens 4 is made of a material with a lower refractive index than lenses 3 and 5, the cross-sectional spherical aberration of the lens does not exceed 0.05 mm, the astigmatic difference at the edge of the field of view is 0.5 mm. 1 hp f-ly, 4 ill. (L 00 O5 CD

Description

  127 The invention relates to optical instrument making, namely, to photographic lenses, and in particular, can be used in compact scale and scale nodal cameras with a frame format of 24 X 36 mm. The purpose of the invention is to improve the image quality. FIG. 1 shows the principle optical layout of a photographic lens; in fig. 2 is a graph of the frequency-contrast characteristic (MTF) dp of an infinitely distant object and points on the axis; in fig 3 - the same, in the meridional section for point of field at 19 m | fig 4, too, E in a salient cross section dd point half mm, in the lens, the first component is made as a single positive meniscus 1 facing the concavity of the image, the second one as a two-concave lens 2, the third positive component is glued together from two 3 convex, concave 4 and 5 lenses, in the AIR between the second and third components, aperture diaphragm 6 is located. Focusing on the final shooting distances is carried out by moving the first component ,. The lens has a focal length of 35 mm, a relative aperture ;; 2,8 s is calculated per frame: measure 24 X 35 mm. The length of the lens from the first surface to the film plane is 42.1 mm, the mass of optical components is 4.6 g. The lens aberrations are corrected for a wavelength of 5461 μm, the achromatization area is from 4358 μm to 6563 μm. The spherical aberration does not exceed 0.05 µm, the spot size for the field edge of -19 mm in the meridional section is not more than 0.04 mm, in the sagittal

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Claims (1)

44 About the cross section not more than 0.15 mm. Astigmatic difference at the edge of the field of vision 0.5 mm. Image quality characteristics are given for a shooting distance of infinity. For a shooting distance of 1.7 m, the characteristics have the best values. High image quality is confirmed by frequency-contrast characteristics (Fig. 2-4). The calculated photographic resolution, determined on the KN-1 film, is the intersection point of the MTF of the lens T (K) and the threshold contrast function of the film K (N) J for an infinite shooting distance of 63 mm5 in the center of the field of view () 27 and 32 mm respectively for aa; gittal and meridional sections, on the edge of the field of view (at 19 mm) are 34 and 26 Mi «i, respectively. Claim 1, A photographic lens containing three components, the first of which is a positive meniscus convex to the object, the second is a double-bent lens, the third is a positive glued one, about the fact that image quality, the third component is made of three lenses, the first and third of which are flat, and the second is negative, made of a material with a lower refractive index than positive lenses, and faces a greater curvature surface to the object. 2, the lens according to claim 1, tl l and mostly the fact that the radii of curvature r and r of the first component are chosen from the condition 4.6 5 - 5.4, T1 U 20 30 0 ff ig, .3 W 2S U) W N FIG.