DE2342418C3 - Wide angle lens of the inverted telephoto type with a large aperture ratio - Google Patents

Description

JVj = 1.58913

N, = 1.67270

AT ₇ = 1.80518

W ₈ = 1.77250

IV, = - 1.77250

v, = 61.11
v. = 32.10

», = 25.43
y _t = 49.57

v _t = 49.57

back focal length = 1.4460

the permissible ranges of variation for the parameters of the individual lenses from the above numerical values for l / r: ± 5%, for d: ± 5%, for N: ± 0.03 and for l / v: ± 5%.

The present invention relates to an inverted telephoto type wide angle lens.

The invention is concerned with wide-angle lenses for a camera of the reverse telephoto type, which have a relative aperture ratio of up to 1: 2.0 and an angle of view of up to 80 °, and which are also designed so that the rear focal length is long enough to allow swiveling back quickly from a mirror in a single lens reflex camera.

In known wide-angle lenses of the type mentioned above, it is often unavoidable that the Image field curvature at the edge areas of the field of view is overcorrected, resulting in a remarkable Loss of image sharpness in the edge areas of the image leads. Especially when these well-known lenses are designed so that a further increase in the relative opening ratio with a short overall length is to be achieved, this disadvantage is particularly evident.

Another wide-angle lens of the type mentioned above is known from DE-PS 12 50153. However, this prior publication contains no suggestion, as is essential for such lenses larger relative opening or significantly smaller overall length is at least as good Correction as can be achieved with the lenses described there.

The present invention is therefore based on the object of providing a wide-angle lens of the type mentioned at the beginning To create type that has a larger relative opening or a smaller overall length than the known lenses.

This task is achieved by training the wide-angle lenses of the type mentioned above with the Design data solved according to the data tables listed in the characterizing part of claims 1 or 2. The drawings show sectional images of the two wide-angle lenses according to the invention.

F i g. 1 shows the first wide-angle lens according to the invention;

F i g. 2 shows the spherical aberration, the sine condition, the astigmatism and the distortion of the in FIG. 1 illustrated wide-angle lens;

F i g. 3 shows the second wide-angle lens according to the invention;

F i g. 4 shows the spherical aberration, the sine condition, the astigmatism and the distortion of the in FIG. 3 wide-angle lens shown.

In order to achieve the above-mentioned problem, the methods shown in FIGS. 1 and 3 according to the invention shown Wide-angle lenses developed whose lens systems contain eight lens elements. The first marked with I. The lens element is formed by a divergent meniscus, which is concave on the image side. That second lens element II is formed by a converging lens. The third lens member III is from a dispersing meniscus is formed, which is concave on the image side. The lens member IV is made up of a converging lens formed with a strongly curved surface on the object side. The lens member V is of a converging lens whose image-side boundary surface is strongly curved, is formed. The lens member VI is biconcave Lens formed, the Linsengüed VII of a collecting meniscus double lens, which consists of a diffusing lens and a converging lens is cemented together. The lens element VIII is finally of a biconvex lens. A diaphragm is inserted between the lens elements V and VI.

In this objective, which has eight lens elements, the symbols for the lens parameters have the following meaning:

/: the equivalent focal length of the entire system;

r: the radii of curvature of the individual lens surfaces;

d: the axial distances between the refracting ones

Surfaces;
JV: the indices of refraction;

v: the Abbe numbers.

It has been found that it is advantageous for the correction of the objectives according to the invention if iis meet the following conditions at the same time:

(1) 0.35 / << /, + </, + d _t <0.8 /

(2) 0.5 < \ r _u \ / r _M <2.0; r "<0

(3) 0.03 / << / "< 0.13 /

(5) v4 <35.0

(6) 2.0 <V ₁ - vy < 20.0

The data of the two objectives according to the invention are shown in Tables 1 and 3 below. These tables give the radii of curvature Γι to / · ,. of the individual Linscnfiäehcn, whereby

the minus sign means that the corresponding surface is concave towards the front, as well as the axial thicknesses O ₁ to i / _{16 of} the individual elements or the distances between the components formed by air, as well as the corresponding refraction

indices N ₁ to N, and the Abbe numbers V ₁ to v, of the individual lens elements. The numerical data in Table 1 corresponds to that in FIG. 1 lens shown. The aberration curves of this in FIG. The corrected lens shown in FIG. 1 are shown in FIGS. 2a,

ij 2b and 2c shown. The numerical data of the Table 3 corresponds to that in FIG. 3 lens, its aberration curves in the F i g. 4a, 4b and 4c are shown.

The permissible tolerances with regard to the varia-

The range of the objective parameters from the values given in both examples is ± 5% for the inverse value of the radius of curvature (l / r), ± 5% for the thicknesses or distances (d) , ± 0.03 for the refractive index and ± 0.03 for the dispersibility

»5 (l / v) ± 5%.

Table 1
/ = 1

r, = 1.7090

r _t = 0.8800

r, = 2.5246

r ₄ = -9.0518

r _s = 1.3704

r, = 0.4995

r, = 1.1928

/ ·, = 3.4759

γ, = 3.6293

r _I0 = -0.8696

r _n = -0.8850

r "= 1.5573

r _w = -1.4292

r ₁₄ = 2.0409

r _u = -0.7961

r "= 3.2359

r "= -23112

relative aperture: 1: 2

d _x = 0.0707

d _t = 0.2743

d, = 0.1646

J ₁ = 0.0661

d _t = 0.0536

J ₁ = 0.2571

J ₇ = 0.0821

J ₁ = 0.0357

J, = 0.6179

J ₁₀ = 0.1536

J ₁₁ = 0.0611

J ₁₁ = 0.1036

d _a = 0.0357

J ₁₁ = 0-654

J ₁₅ = 0.0036

J ₁₁ = 0.1361

rear mullions ■■

2ω = 76 °

JV ₁ = 1.64328
N ₁ = 1.58913
JV ₁ = 1.65100
JV ₁ = 1.75520
N ₁ = 1.67790
JV ₁ = 1.62004

JV, = 1.80518
JV, = 1.77250

JV, = 1.77250
= 13346

v _s = 47.85
r _t = 61.11
_n = 56.15
ν «= 27.51
r, = 55.33
U = 36.25

r ₇ - 25.43
», = 49.57

*, = 49.57

Tabel

Area coefficient of the objective 1

No.

II

Ul

1 L 3 4 5 6 7 8 9

10

11th

12th

13th

14th

15th

16

17th

Table 3 / = I.

r, = 1.4927 r, = 0.7418 r, = 1.4464 r _t = 27.1473 r _t = 1.1989 r, = 0.4236 r ₇ = 1.2905 r ₈ = 34.2692 r, = 24.0238 r "= -0.7445 'n = -0.9866 r" = 1.6820 r _w = -1.1886 * i "= -3.9876 r" = -0.7141 r "= - 8.6313 r "= -1.4720

0.0477 0.0376 0.0296 0.2291 0.2039 -1.0121 0.1834 -0.0332 ■ -0.4448 0.0867 0.1958 0.1149 0.0675 0.1468 0.1258 0.0002 -0.0016 0.0161 0.0410 -0.5569 0.1465 0.0957 0.0625 0.2877 0.2287 -10.7936 1.5168 -0.2131 -0.7893 0.1409 4.5474 0.5541 0.0675 0.3607 0.0522 -0.2371 -0.1907 -0.1534 -0.1238 -0.2229 0.2206 0.1837 0.1529 0.1113 0.2200 8.5241 -2.5711 0.7755 0.4646 -0.3740 -5.9891 1.6225 -0.4395 -0.4325 0.2362 -0.6955 -0.5679 -0.4637 -0.2458 -0.5794 0.0154 -0.0223 0.0323 -0.3121 0.4059 -0.1189 -0.0646 -0.0350 -0.0050 -0.0217 3.0533 -0.3932 0.0506 0.5475 -0.0770 -0.0027 -0.0104 -0.0404 0.1347 0.3646 2.7356 -0.5173 0.0978 0.1886 -0.0542 0.6376 -0.0304 -0.0261 0.1587 0.1786

relative aperture: 1: 2.8

d _x = 0.0563 d _x = 0.1336 d _t = 0.1542 d, = 0.0704 d _t = 0.0423 d _t = 0.2714 rf, = 0.0648 d _% = 0.0423 </ , = 0.3358 d _u = 0.1070 d _n = 0.2268 d _a = 0.0507 </ "= 0.0338 d _lt = 0.1183 d _a = 0.0042 d _u = 0.0901

2 ω =

tf, = 1.66672

N, = 1.62041

N ₁ = 1.67790

N ₁ = 1.80518

/ V, = 1.58913

N, = 1.67270

N ₁ = 1.80518 N, = 1.77250

N ₃ = 1.77250

back focal length = 1.4460

v, = 48.32 v _t = 60.27 v, = 55.33 v _t = 25.43 v, = 61.11 r, == 32.10

τ, = 25.43 *, = 49.57

τ, = 49.57

Table 4

Area coefficient of the lens 2

No.

III

1 0.0722 0.0569 0.0448 0.2680 0.2466 2 - 1.8412 0.1753 • -0.0167 -0.5392 0.0529 3 0.6206 0.1775 0.0508 0.2647 0.0902 4th -0.0001 -0.0009 -0.0166 -0.0141 -0.5401 5 0.1792 0.1245 0.0864 0.3370 0.2940 6th -16.0951 1.3993 -0.1217 -0.9537 0.0935 7th 5.7642 1.3557 0.2238 0.3456 0.1122 8th -0.0273 -0.0606 -0.1348 -0.0130 -0.3284 9 0.0273 0.0575 0.1212 0.0154 0.2878 10 9.8713 -2.6717 0.7231 0.4979 -0.3305 Π -5.3357 1.6095 -O.4S55 -0.-K.V6 Ο-Μ 12th -1.2512 -0.8855 -0.6267 -0.2391 -0.6127 13th 0.0458 -0.0531 0.0615 -0.3753 0.3635 14th -0.1180 -0.0620 -0.0326 -0.0026 -0.0185 15th 3.9041 -0.4442 0.0505 0.6103 -0.0752 16 -0.002 -0.0020 -0.0238 0.0505 0.3165 17th 5.2503 -0.6196 0.0731 0.2963 -0.0436 Σ ■ from left, 0664 -0.0635 -0.0230 0.1412 0.1777 For this 2 Sheet drawings

Claims (1)

n 2342418 * rf, = 0.1646 2 - ± 5%, for N: ± 0.03 and for l / v: db be 5%. 2 ω = 80 °; 47.85 1 1 r, = 1.1928 N ₁ = 1.64328 ν, = Type of inverted telephoto lenses, characterized in that 1 Patent claims: rf, = 0.0661 JV, = 1.66672 ν, = 1. Wide-angle lens from 1 "^{r> = 3} * ⁴⁷⁵⁹ Inverted telephoto lens type, relative aperture: 1: 2.8; the following design data having: d _s = 0.0536 61.11. / = i; I r, = 3.6293 relative aperture: 1: 2; characterized in that it N ₁ = 1.58913 v _t = rf, = 0.0563 ι-, = 1.7090 H d _t = 0.2571 N ₁ = 1.62041 ν, = ir _l0 = -0.8696 d ₁ = 0.0707 2 ω = 76 °; rf, = 0.1336 r, = 0.8800 rf, = 0.0821 56.15 i r "= -0.8850 rf, = 0.2743 N ₁ = 1.65100 »·, = rf, = 0.1542 r, = 2.5246 rf, = 0.0357 N ₁ = 1.67790 'V ₃ = I r "= 1.5573 d _t = 0.0704 r ₄ = -9.0518 § rf, = 0.6179 27.51 Ι Ίι = -1.4292 ^N AT ₄ = 1.75520 V ₄ = d _t = 0.0423 r _s = 1.3704 i rf ,, = 0.1536 N _A = 1.80518 v ₄ = I r _u = 2.0409 rf, = 0.2714 r, = 0.4995 rf i = 0.0611 55.33 I r _u = -0.7961 N ₅ = 1.67790 v _f = </ ₇ = 0.0648 I. rf i = 0.1036 I r "= 3.2359 rf, = 0.0423 1 rf i = 0.0357 36.25 I r ₁₇ = -2.3112 Af, = 1.62004 ν, = ti / </, ₄ = 0.1654 <f, ₅ = 0.0036 25.43 N ₇ = 1.80518 v ₇ = rf ,, = 0.1361 49.57 N ₁ = 1.77250 ν, = back focal length = 49.57 Nt = 1.77250 ν, = = 1.3346 numerical ί being the permissible ranges of variation for the parameters of the individual lenses from the above I values for l / r: ± 5%, for d it following if 2. Wide-angle lens from I design data has: ■ X r _x = 1.4927 48.32 r, = 0.7418 I T ₁ = 1.4464 60.27 % % r _t = 27.1473 1 I r = 1.1989 55.33 r, = 0.4236 r, = 1.2905 25.43 r, = 34.2692 (Continuation of the table above) / = 1;
r, = 24.0238
r ₁₀ = -0.7445
r _n = -0.9866
r "= 1.6820
r " = -1.1836
r "= -3.9876
' r _is = -0.7141
r "= 8.631
Fi ₇ = -1.4720. .-. relative aperture: 1: 2.8; d _t = 0.3358 d ₁₀ = 0.1070 d _n = 0.2268 d _lt = 0.0507 d ₁₃ = 0.0338 d _lt = 0.1183 d _JS = 0.0042 d _lt = 0.0901 2 ω = 80 °;