DE2321806C3 - Telephoto lens - Google Patents

Description

iZ ₂ = 4.43

(Z ₃ = 5.19 H ₂ = 1.48749 ι · ₂ = 69.8 iZ ₄ = 1.77 n ₃ = 1.76182 i- ₃ - = 26.5 iZ ₅ = 14.91

20th

4 =

H ₄ = 1.66998 ι ₄ = 39.3

(I ₁ = 14.70

^25th

c ₇ = 17.670

c ₈ = 33.946

i / ₈ = 2.52 H ₅ = 1.80518 ι · ₅ = 25.4 c, = 62.394
F = I: 3.5
/ = 100

2, " = 18"

9 = 0.87 ^M

Denote therein

C ₁ to Cq are the radii of curvature of the associated lens surfaces,

(Z ₁ to (Z ₈ the thicknesses of the lenses or the air gaps between them, ^i:>

H, to H _{5 are} the refractive indices of the corresponding lenses,

ι ·, up to C ₅ the Abbe numbers of the lenses, / the focal length,

in the field angle and 'i the telephoto ratio.

2. Telephoto lens according to the preamble of claim 1, characterized by the following design data:
c, = 50.727

(Z ₁ = 3.18 H ₁ = 1.62041; ■, = 60.2

C ₂ = '/

(Z ₂ = 5.81
/ ·., = 30.358

4 ^r >

A ₃ = 4.84 H ₂ = 1.48749 v ₂ = 69.8 (Z ₄ = 2.26 H ₃ = 1.76182 r ₃ = 26.5 (Z ₅ = 19.25

(Z ₆ = 1.84 n ₄ = 1.67790 ι ₄ = 55.3 (Z ₇ = 13.42

50

C ₄ = -551.36

C ₅ = 65.822

c "= 51.530

C ₇ = 17.371

C ₈ = 32.302

(/ "= 2.12 H ₅ = 1.78472 r ₅ = - 25.6 c ₉ = 52.334
F = 1: 4
/ ■ = 100
2 ... = I2 "
P = 0.85

Denote therein

/ Ι to Ci, the radii of curvature of the associated The invention relates to a telephoto lens with a positive meniscus lens, one of a positive and a positive meniscus double lens consisting of a negative lens, a negative meniscus and a positive lens.

Telephoto lenses of this type, as they are known for example from DE-AS 12 51 971, have in the front lens group and lenses closely spaced in the rear lens group.

The present invention has for its object, using in larger Absland to specify a compact telephoto lens with a large aperture ratio for standing lens elements, in which the aberrations are well corrected.

This task is achieved by designing the telephoto lens according to the characterizing part of claim 1 or the data tables listed in the characterizing part of claim 2 solved.

According to this, the telephoto lens, which consists of lens elements arranged only with a larger air gap, has on the object side only convex and on the object side only concave lens surfaces standing in the air, which enables a good correction of the image errors with a large aperture ratio and a low telephoto ratio.

When developing the telephoto lens, the observance of the following conditions has resulted from those listed below
grasslands

(1) (Z ₇ > 0.12 f,

(2) 0.25 f <- Ir- < c

(3) 0.25 f <\ Jr _H < r "<2 / '

(4) π, - H ₂ > 0.05, & (n, - H ₂ )
Inscribed therein

Reasons as essential

- (/ 71 <0.1
1.2 / ■

<0.1

iZ _{5 is} the air gap between the second and third

Lens member,
cl _{n is} the air gap between the third and fourth

Lens member,
C _{4 is} the radius of curvature of the cemented surface of the cemented element forming the second lens element and
c ₆ , c ₇ and c _8, respectively. C ₁ , the radii of curvature of the third

and fourth lens element forming single lenses,
H ₂ and n. \ The refractive indices of the lenses forming the kilt member and
/ the focal length of the lens.
The condition (1) fulfilled by the lens system according to the invention ensures a favorable correction of the chromatic aberration and the off-axis aberrations. If condition (1) is not met, that is, if (Z ₇ <0.12 / or | (/ ₅ - d-, \ b5> 0.1 /), it becomes impossible to correct astigmatism and asymmetry errors with a small telephoto ratio In addition, it becomes difficult to compensate for the aberrations over the entire angle of view

Condition (1) also serves to minimize the color magnification error, that is, lateral chromatic aberration and spherical aberration, for each wavelength in conjunction with the other conditions. Condition · 2) is used to reduce the telephoto ratio and to correct spherical aberrations and extra-axial aberrations in a favorable manner. In order to reduce the telephoto ratio, it can be advantageous if 0.25 f> Ir ₁ , but off-axis aberrations have an unfavorable effect. When Ir ₁ > r _b , the telephoto ratio cannot be made small. In addition, in the case of r _b > 1.2 /, sufficient compensation for asymmetry errors cannot be achieved, and it becomes impossible to correct asymmetry errors even if other factors are changed.

Condition (3) is mainly used to correct the chromatic aberration and the off-axis aberrations favorably. If 1.3 r ₈ > r _y , the color magnification error is unbalanced as soon as the telephoto ratio is made small. For / · <,> 2 /, it becomes difficult to correct stray light caused by asymmetry errors.

Condition (4) is used to correct the spherical aberration and off-axis aberrations favorably. When / I ₃ - Ji ₂ <0.05, the zonal spherical aberration is large and it also becomes difficult to correct asymmetry errors. If I / 4! > (113 - / I ₂ ) // 0.1 /, it becomes difficult to remove the scattered light caused by asymmetry errors for each wavelength.

The subject matter of the invention is explained in more detail below with reference to the drawings.

It shows j ^r )

F i g. 1 is a schematic sectional view through a telephoto lens according to the invention,

F i g. 2a to 2d Correction curves of a first objective according to the invention,

3a to 3d correction curves of a second Lens according to the invention.

The first lens has the data listed in Table I below:

Table 1

/ ·, = 45.297

r ₂ = 355.454

r, = 29.103

/ _{X 5} = 74.890

/ ■ "= 79.258

ί /, = 4.40 / ι, = 1.62041 ι ·, = 60.2

(I ₂ = 4.43

50

</., = 5.19 / ΐ ₂ = 1.48749 ι · ₂ = 69.8

ί / ₄ = 1.77 η, = 1.76182, ·., = 26.5

(Z ₅ = 14.91

4 = 1.79 / I ₄ = 1.66998 ι · ₄ = 39.3

Γη = 17.670 d-, = = 1.80518 '• s = 25.4 = 50.727 4th ch - Table 2 = 1.62041 ι ·, = 60.3 = 100 r _a = 33.946 (I ₈ - = ~ f. .. = 12 " (U - = 3.18 / ι, = 0.85 r ₉ = 62.394 = 30.358 i /, = = 5.81 = 1.48749 v ₂ = 69.8 1 : 3.5 / = 100 the below in = -551.36 ¹ U - = 4.84 H ₂ = 1.76182 1-3 = 26.5 2 ( ., = 18 " Table 2 listed data on: = 0.87 = 65.822 = 2.26 H ₃ The second = 14.70 Γι = 51.530 = 19.25 = 1.67790 r ₄ = 55.3 = 2,52 n _etc. r ₂ 17.371 U ₁ - = 1.84 / I ₄ f ₃ 32,302 ί / ₈ = = 13.42 = 1.78472 v ₅ = 25.6 '4 52,334 = 2.12 / i ₅ Lens points '5 '"(, Denote therein r ₇ ^r 8 1 : / 2r Ii

T ₁ to r _{9 are} the radii of curvature of the lens surfaces,

(/, to i / g the thicknesses of the lenses or the distances between this one

H ₁ to / I _{5 are} the refractive indices of the lenses and

r, until i ' _{5 are} the Abbe numbers of the lenses,

α is the telephoto ratio.

The F i g. 2a to 2d show the correction curves of the first telephoto lens according to the invention. The F i g. 3 a to 3d show the correction curves of the second telephoto lens according to the invention.

The correction curves of both telephoto lenses result in an outstanding correction state compact, bright telephoto lenses thanks to the low telephoto ratio.

For this purpose 2 sheets of drawings

Claims (1)

Patent claims: 1. Telephoto lens with a positive meniscus lens, one of a positive and a negative Lens consisting of a positive meniscus double lens, a diffusing meniscus and one positive lens, characterized by the following construction data: C ₁ = 45.297
r ₂ = 355.454
c, = 29.103
c ₄ = '/ ■
C _{5 to} 74.890
r _fl = 79.258 Lens surfaces, (I ₁ to d _{n are} the thicknesses of the lenses or air spaces between them, «Ι to n _{s are} the refractive indices of the corresponding lenses, j) to i> _{s are} the Abbe numbers of the lenses, / the focal length, 01 the field of view angle and P is the telephoto ratio. 10 Cl ₁ = 4.40 / J ₁ = 1.6204! . ·, = 60.2