DE2437560C3 - Very powerful semi-wide-angle lens - Google Patents

Description

83.826

F == 100
d _l 4.78 H ₁ Jv ₁ 1.55671 / 58.7

r ₂ 50.446 d ₂ 19.85
r ₃ 304.333 d ₃ 7.39

1.79952 / 42.3

^15th

r ₄ -203.478 d _A 0.24

r ₅ 46.739 rf _s 11.00 njv ₃ 1.80610 / 40.8

r _e 74,000 d ₉ 3.65

r ₇ 141.304 d, 7.11 «><1.68893 / 31.1 ^ao

r ₈ 43.465 J ₈ 18.33

r ₉ -64.330 rf, 3.28 « _s /» - ₅ 1.80518 / 25.4

r ₁₀ 93.478 rf ₁₀ 21.74 "" / v, 1.80610 / 40.8

r _u -62.391 J _n 0.22 »5

r ₁₂ 239.129 J ₁₂ 10.87 « ₇ / v, 1.78590 / 44.2

r ₁₃ -214.129

F ₁ = -239.8

Flj.3 = 90.8 ίΊ.2.3.4 = 458.6

2. Bright, consisting of seven lenses grouped into six lens elements Semi-wide angle lens with minimal aberration with a back focal length of > 0.77 F and an image field angle of> 48 °, characterized in that the following design data is available:

F = 100

T ₁ 107.532 dy 3.00 nJ _Vl 1.62280 / 56.9

r ₂ 57.140 di 10.01

r ₃ 115.150 d ₃ 8.01 njv _t 1.84100 / 43.2

r «2176.757 rf ₄ 0.19

r ₅ 43.056 rf ₆ 8.01 njv ₃ 1.84100 / 43.2

r _e 77.571 rf "3.00

r ₇ 81.911 rf, 9.01 njv _t 1.80518 / 25.5

r ₈ 34.393 rf ₈ 15.01

r "-43.535 d, 5.01" ₅ / v ₆ 1.75520 / 27.5

r ₁₀ 191.990 d ₁₀ 13.02 « _e / v _e 1.76200 / 40.3

r _n -53.548 rf _u 0.19

r ₁₂ 242.491 d _u 6.5i n, / v, 1.72000 / 46.0 r _l3 -115.616
F ₁ = -200.1
F ₁ .,., = 76.7

Λ.Ι.3.4 = ²⁸⁵ > 7

45 There are already bright lenses of the above-mentioned design with a large field of view known (DT-OS 17 97 435, example 6). However, this known lens has a number of disadvantages. On the one hand, the rear focal length is only relatively small, so that the known lens is practically unsuitable for use in single-lens reflex cameras in which sufficient space must be available for the mirror behind the lens. Another shortcoming of the known lens is that there is only a very low level of illuminance in the edge area of the image field. For the reasons mentioned above, the known lens is therefore only suitable for certain areas of application.

The invention is now based on the object of providing a semi-wide-angle object of the generic type to create that has a relatively large field of view and is also bright, as well as a sufficiently large one back focal length possesses to it also without difficulty for single lens reflex cameras to use to know.

According to the invention, the object is achieved by designing the semi-wide-angle lens of the type mentioned at the beginning Kind with the design data according to one of those listed in the characterizing parts of claims 1 and 2 Data tables solved.

The semi-wide-angle lenses according to the invention are therefore distinguished from the known lens in particular, that they have a sufficiently large rear focal length to also be used in single-lens reflex cameras to be able to use, in which for the movement of the mirror behind the Lens a relatively large amount of space is required. In addition, the lens according to the invention the focal length of the first lens is not too large, as it is in a range between F / 0.55 and F / 0.35, while the focal length of the known lens is F / 0.033. Finally, it must be taken into account that if the two lenses were calculated with a corresponding power, the known lens would only be very faint in the edge area of the image field. This is because of the reasons just mentioned well-known lens is also not in question for the areas of application for which the wide-angle lenses are usable according to the invention.

During the development of the objective according to the invention, the following equations were used went out:

F / 0.55> IF ₁ 1 <F / 0.35; F ₁ <0 (1)
F / 1.4 <F ₁ .,., <F / 0.9 (2)

F / 0.5 <F _112-3 . * <F / 0.15

47

> 35

The invention relates to bright lenses consisting of seven lenses combined to form six lens elements Semi-wide-angle lenses with minimal aberration and a back focal length of > 0.77 F and an angle of field of> 48 °.

Here

F ₁ ... <

«"N,> 1.70
means:
': Focal length of the entire system,

Total focal length of lenses 1 to 1,

rear focus,

: Refractive index of the rf line of the z'-th lens,: Abbe number of the i-th lens,
: Radius of curvature of the λ-th lens,
: Surface distance or thickness of the yth lens.

The drawings show sectional images of the objectives according to the invention and their correction states shown.

It shows

F i g. 1 schematically a section through the objective according to claim 1,

F i g. 2 graphically depicts the curves of the spherical aberration (SA) and the deviation from the sine condition (SB) for the lens according to FIG. 1, ίο

F i g. 3 shows a section corresponding to FIG. 1 in the objective according to claim 2 and

F i g. 4 shows a representation corresponding to FIG. 2 in the lens of FIG. 3.

As the F i g. 1 and 3 show that the bright semi-wide-angle lenses according to the invention are correct, which have a relatively large field of view, in principle, have the same structure. It deals each is a lens with seven lenses, which are combined to six lens elements. The first lens 1 is a negative meniscus lens, the second lens 2 is a positive lens, the third lens 3 a positive meniscus lens and the fourth lens 4 a negative meniscus lens. The fourth Linde 4 is at a distance from the fifth and ace the following lenses, the diaphragm being provided between the fourth lens 4 and the fifth lens 5 can be. The fifth lens 5 is a negative lens cemented to the sixth lens 6. In the seventh lens 7 is a positive lens.

The objectives according to FIGS. 1 and 3 satisfy the aforementioned conditions (1) to (6).

In the case of the lens according to FIG. 1, the design data corresponds to that in the code of the Claim 1 contained data table available. The Seidel coefficients of this lens result from of table 1.

The lens of FIG. 3 corresponds to the design data the data table from the characteristic of claim 2. The Seidel coefficients result according to table 2.

Table 1 (Seidel coefficients for Fig. 1)

Lenses- S ₁ 0.390 S ₁ 0.100 S ₃ S, 0.427 S ₅ 0.116 flat 2 -3.768 0.444 0.026 -0.709 0.090 1 0.233 0.203 -0.052 0.146 0.280 2 0.226 -0.335 0.176 0.218 -1.062 3 1,578 0.231 0.497 0.955 0.145 4th 0.012 0.072 0.034 -0.603 -0.991 5 -0.109 0.285 0.441 0.289 1.189 6th -0.773 -0.421 -0.744 -0.939 -0.637 7th -0.761 0.573 -0.230 -0.693 0.847 8th 0.002 0.001 -0.431 0.000 0.001 9 1,895 -0.561 0.001 0.715 -0.261 10 -0.000 0.002 0.166 0.184 0.724 11th 1.321 -0.582 -0.193 0.206 -0.204 12th 0.247 0.013 0.257 0.196 0.237 13th -0.053 total

Aperture behind the eighth lens surface: 10.87.

Table 2 (Seidel coefficients for Fig. 2)

lenses S ₁ 0.190 S ₂ 0.118 S ₃ 0.073 S ₁ 0.357 S ₅ 0.266 surface -3,539 -0.054 -0.001 -0.672 -0.010 1 1.176 0.407 0.141 0.397 0.186 2 0.028 -0.086 0.266 0.021 -0.890 3 1.703 0.287 0.048 1.061 0.187 4th 0.006 -0.068 0.703 -0.589 -1.191 5 -0.027 0.144 -0.775 0.545 1.244 6th -0.910 -0.478 -0.251 -1.297 -0.814 7th -1.912 1.071 -0.600 -0.988 0.889 8th 0.006 0.006 0.006 0.001 0.007 9 1.447 -0.562 0.218 0.808 -0.398 10 -0.000 -0.007 -0.112 0.173 0.939 11th 1.904 -0.732 0.281 0.362 -0.247 12th 0.072 0.046 -0.003 0.178 0.166 13th behind the eighth lens area: 8.4. total cover

For this purpose 2 sheets of drawings

Claims (1)

Patent claims: 1. Bright, consisting of seven lenses grouped into six lens elements Semi-wide angle lens with minimal aberration with a back focal length of > 0.77 F and an angle of view of> 48 °, thereby marked that the following design data is available: