DE2430524C3 - Photographic lens - Google Patents

Description

The invention relates to a lens of the cemented element on the lens side of three lenses - both are lenses break down existing Tessar-type lens with convex lenses - a great value. Equal rear screen, its third lens element as a cemented element, these values are limited to 1.8 in order to achieve the development is. Avoid using special types of glass. this

In the case of photographic lenses of the Tessar type, with means that a deterioration in the refractive index of the rear aperture is generally assumed - the following conditions have been assumed:
the aberrations at large angles of view,

especially astigmatism and coma, 1,7 <«, <1.8 (3)

observed. Such lenses also have the 40 .., « , ..

Disadvantage of vignetting at large angles of view. !, / <«« <1.0 w

The invention is based on the object

Photographic lens of the Tessar type with rear For low-cost correction of the chromatic aberration indicate at which the aberrations are at ration for the two lenses of the cemented member large angles of view are well corrected. 45 low dispersion glasses selected so that

This Aufgare is made by the formation of the lens, in this regard, when developing the lens of the type mentioned at the beginning with the construction, the following condition is assumed
data solved according to the data table listed in the characterizing part of the claim. v ₃ , i> ₄ > 30 (5)

With the objective according to the invention, a 50

Unnetting of the steel cones with a large field of view The invention will now be explained with reference to the drawings

angle Hurch prevents the aperture, as the thickness explains in more detail,
of the respective lenses as well as the air gaps in the drawings shows

be kept as small as possible between the lenses. F i g. 1 is a schematic sectional view through the

In addition, during the development of the lens according to the invention,

correct lens under the following conditions: F i g. 2A to 2C Correction curves of the invention: −1.6 / < r ₃ < 1.2 / (1) 0.3 / <T ₁ <0.4 / according to the objective.

(2). By choosing the radius of curvature r _{a of} the object from F i g. 2A is the correction of the spherical

laterally lying surface of the second lens element. Aberration, from FIG. 2 B the correction of the astigma Condition (1) becomes a symmetry of extrism and from Fig. 2 C the correction of the directory axes spherical aberration achieved. Visible through the voltage.

Condition (2) is a good correction of the spherical- The Seidel coefficients of aberrations for

see aberration ensured and an overcorrection / = 1.0 are given in the table below, for the off-axis spherical aberrations. In this table, SI represents the spherical aberration prevents. 65 coefficient, SII the coefficient of the asymmetry

In order to prevent the Petzval sum from increasing (coma), 5IH is the coefficient of the astigmoid, the refractive indices N _{1 show} the first tism, P the Petzval sum and SV the lens _{element coefficient and the refractive index / J 4 of} the objects Distortion.

3 24 sn 30 524 P. 1.2664 4th SI -0.1498 -0.4960 SV 5.8731 -0.4747 5ΠΙ -0.2803 -0.0324 1 0.1899 3.2426 0.0038 -1.3229 -1.7254 2 -3.8093 -1.4759 1.1863 0.2339 2.5882 3 -8.2379 0.4777 -2.7602 0.1887 -0.2844 4th 0.5066 0.3531 -0.2644 0.6242 0.6453 5 3.2151 -2.2168 0.4505 0.2140 0.0250 6th 3.6394 -0.2437 0.0388 -1.2027 7th 1.3770 1.3503 0.0137 2 ' 0.0051

From the correction curves and the Seidel 15 objective while avoiding a vignettie aberration coefficient as well as from the above tion of the cone of rays at large angles of view The description shows that the image errors are favorably corrected with the diaphragm according to the invention.

Hiemi 1 sheet of drawings

Claims (1)

% Claim: ^f Tesiar-type photographic lens consisting of three Liosengliedero with rear diaphragm, the third lens element Ids is a cemented element, characterized by the numerical data listed in the following table: T ₁ = 0.348 4 = 0.110 / J ₁ = 1.78590 V ₁ = 44.24 * 2 = 0.888 <4 = 0.033 r ₃ = -1.436 d ₃ = 0.040 n ₂ = 1.67270 "2 = 32.10 r _t = 0.304 rf ₄ = 0 ^ 037 = 1.617 d _s = 0.023 W ₃ = 1.60717 = 40.34 _r = 0.281 d _e = 0.117 « ₄ = 1.75700 "4 = 47.89 r-, = -0.691 therein / denotes the focal length, T ₁ to r ₇ the radii of curvature of the lens, d _x to d _t the thicknesses or the distances between the lenses, It ₁ to n _t the refractive indices and V ₁ to v ₄ the Abbe numbers.