DE2102600C - Wide angle photographic lens - Google Patents

Description

Field angle 2w di = 63 ° "1 Relative aper'ur = 1: 2.8 156.014 d ₂ 5.27. ' 1.56883 V ₁ 56.0 44,446 d ₃ 35.939 «3 1.61272 v _a 58.6 132,405 d _t 23,430 «4 1.60717 v ₃ 40.3 525.813 rfs 0.567 «5 1.62299 v _4th 58.1 95.025 5.560 "β 1.66998 v ₅ 39.3 215.930 Of 0.425 «7 1.58144 v ₆ 40.7 66,409 21.076 1.6516 v ₇ 58.5 -99.887 6.666 -69.351 rfio 2,496 46.690 you 6.808 1005,378 rf » 2,496 42.055 12.765 -56.691

where (each starting on the object side with / = 1.2 ...)

fi = focal length of the respective lens;

/ ■ {= radius of curvature ^A tr surfaces of the respective lens;

di - thickness of the respective lens or of the air gap between the lenses;

/ Jf = refractive index of the glass of the respective lens with respect to the J line;

Vi = Abbe number of the glass of the respective line.

2. Lens according to the preamble of claim 1 with the following numerical data:

/ = 100

Field angle rfi 2κ> = 63 ° "l Relative Aperture = 252.639 d _t 5.111 «2 1.56883 V ₁ 56.0 45.028 d ₃ 35.778 «3 1.61772 V ₁ 49.8 128.350 German 20,833 "4 1.60342 v ₃ 38.0 1299,453 ds 0.444 «5 1.62041 r ₄ 60.2 96.058 d » 5.556 1.6727 V ₅ 32.1 225.911 0.417 '' '7 1.58144 v _e 4OJ 71.833 you 19.917 1.6516 v ₇ 58.5 -107.814 rfe 8,361 -69.322 rfio 2.5 52.258 rf .. 6,944 740.983 rf « 2.5 218.769 12.77b -56.236

The invention relates to a photographic wide-angle lens with several separated by air gaps Lenses whose first lens on the object side is a negative meniscus lens and whose lens is at a relatively large distance arranged second lens has low refractive power and large thickness and its image-side lens of two lenses cemented together.

Such an objective, which consists of five members, is known. However, with him are the aberrations Not sufficiently well compensated over the entire field of view. It also occurs when it is fully open Show a reflection spot.

The invention is based on the object of avoiding these disadvantages of the known lens and to create a lens that has a large relative aperture and has a wide field angle, while the rear focal length of the lens is sufficient erosion is maintained and in which the aberrations are over

the entire field of view is compensated extraordinarily well so that a high resolving power is achieved.

This object is achieved by an objective with the Munerischen "Oaten of claim 1 or 2.

The rear focal length of the entire system is 0.9 to 1. 25 times the lens focal length.

The objective of the present invention is as follows Conditions met:

0.5 Ι / ,! </ ₂ <5.0 | Λ |

0.25 f <d _t

0.15 / <d ₃ < 0.3 /

0.5 / <| r _e | <2.5 /

rf ₈ + rfio <0.2 /

| n, -n, | > O ₁ OJi,

where (each starting on the object side with If the thickness rf _{3 of} the second lens is too small w, rJ

ι = 1, 2 ...) the non-axial astigmatism becomes large. Hence i.iu.i

the thickness rf, satisfy the following conditions: /, = focal length of the respective lens element; Q \ 5 f <d ₃ <0.3 f.

= Thickness of the respective lens element or the ^ _{0n the} radius of curvature of the rear surface o->

Air gap between the lens elements; fourth lens becomes too small, the coma grows, ins!

= Refractive index of the glass of the respective io special the chromatic coma, noticeable. who

Lens element with respect to the rf line; on the other hand, the radius of curvature of the rear

Suppress coma and astigmatism, m.

If the diffusing power of the first lens is large 15 the radius of curvature r _{8 of} the rear skin <. ■■

is made, the amount of peripheral light in the fourth lens grows enough under the following conditions,

Edge zone of the image field, and the rear focal section - 0 5 f <r \ <\ <2.5 /.

wide becomes long. But if the force of destruction '. , ..... ...

is too large, the spherical aberration grows, the occurrence of the coma is suppressed, true-

Coma, the chromatic aberration of magnification and the amount of peripheral light increases when the Luitspaitc

and the like strongly. Therefore, if the spherical aberration and d ₁₀ are made small. Therefore it is necessary

tion is compensated by the behind the first iich that the air gaps d _H and J _{10 of} the following Ii

Lens close to the aperture of the lens suffice:

Lens group, the non-axial aberrations increase J _{8 r} d _l0 < 0.2 /. like the curvature of field. Therefore the compen- 25

The fourth to sixth lenses are from the so-called:

is arranged near the first lens. However, if the Tessar type. Hence the off-axis astigmatism

Compensation lens group too close to the first lens effectively compensated by increasing the UiIk--

(n _e - / J ₇₎ is arranged, which Focalschnittweite necessarily Renz, the prede between the refractive index

wise short, and the compensation for the coma is 30 ren lens and that of the posterior lens of the image-sidei

difficult. Therefore, the air gap d ₂ between the last link. Therefore, it is necessary that the Uittc

first lens and the following second lens in the limit (n _a -n ₇ ) the following condition is satisfied:

rich of d ₂ > 0.25 / can be kept. i " _g _" ₇ | > 0.05.

This can reduce the spherical aberration for the. second lens compensated extremely effectively 35 In the drawing, the lenses are after the mistake. The coma, however, is represented by the second lens. It shows

in turn creates and stun: the quality of the lens. F i g. 1 a longitudinal section through the lens

In order to avoid this error, the relationship between the objective lens according to the invention,

between the refractive power of the first lens and that of FIG. 2 different aberration curves of the object

second line is kept within the following limits according to claim 1,

den: F i g. 3 different aberration curves of the serious

0.5 I / i | <Λ <5.0 I / J. objective according to the invention according to claim 2.

1 sheet of drawings

Claims (1)

Patent claims: 1. Wide-angle photographic lens consisting of six optical members, the first of which, the The limb facing the object consists of a negative meniscus lens, the second limb of which is relatively larger Distance follows and! consists of a positive lens of low refractive power and great thickness, the third and fourth member is a positive lens, the fifth member consists of a biconcave lens, the sixth Link is positive and consists of two lenses cemented together and its cemented surface towards the object is hollow, where the rear focal length is 0.9 to 1.25 times the lens focal length, g e indicates by the following numerical data: / = 100