DE1087827B - Wide-angle enlargement lens - Google Patents

Description

The invention relates to a magnifying wide-angle lens, which consists of four members separated by air gaps, namely a collecting meniscus-shaped fore limb, two meniscus-shaped dispersing limbs, which enclose the diaphragm, the surfaces of these members delimiting the diaphragm space turn their hollow sides to each other and of two each Lenses of opposite refractive power cemented together are joined together, and from one collecting meniscus-shaped hind limb, with the hollow sides of all lens surfaces - including those of the Putty surfaces - facing the faceplate. . .. -.

It is well known that lenses of the triplet type and those known under the name Tessar were preferred Type used as magnifying lenses, but only for a small magnification range and a relatively small field of view a good and consistent one Had image quality and were corrected only for a relatively small spectral range. It five-lens enlargement systems in triplet variants have recently become known that meet the requirement a good image quality over the usual magnification range and the required The spectral range. These become known magnifying lenses are capable of z. B. in a Execution focal length of about 50 to 60 mm the negative format 24-3OnIm in the enlargement range reproduce from about 2 to 12; these lenses thus capture a normal angle of view to be addressed. Wide-angle magnifying lenses, on the other hand, have remained unknown until now.

The invention seeks to provide wide angle magnifying lenses whose field of view is expanded such that, for. B. with appropriate focal length of about 60 mm the negative format of 50 x 50 mm in the entire magnification range from 2 to. 12 is played. aside from that the image quality of the magnifying wide-angle lens according to the invention is so improved that the Thanks to the modern photo-taking lenses, the gain in image sharpness achieved even in the magnification the entire magnification range is retained and in which the error correction is extended Spectral area extends so that it can be used for both black and white enlargements and on the other hand, is made possible for color enlargements.

The invention also aims to create magnifying wide-angle lenses which, in their geometrical-optical Correction in spherical, astigmatic, comatic terms as well as in the distortion are so refined that they remove the field curvature that is still mostly attached to normal lenses, the especially in the magnification range 3 magnifying wide-angle lens

Applicant:

Agfa Aktiengesellschaft,

Leverkusen-Bayerwerk,

Kaiser Wilhelm Allee

Carl Baur, Baldham near Munich,

and Dr. Christian Otzen, Munich,

have been named as inventors

up to 1.5 would be felt as annoying, completely eliminate it. Prepares the elimination of the field curvature the entire magnification range even with the magnifying lenses with the usual angle of view already great difficulties, so they grow extraordinarily for a magnifying wide-angle lens strong. The invention is therefore based on the Gaussian type, which has become known for recording purposes, since at a lens type of a triplet variant as a magnifying wide-angle lens not the refined astigmatic and comatic correction over one like that large angle can be achieved, but above all the astigmatic shell displacements in triplet variants significantly larger when going through 12 to 2 times the magnification scale, than this is the case with the Gaussian type under certain conditions according to the invention. The invention is therefore based on a Gaussian type in which not only all lens elements, but preferably all six Lenses are meniscuses which are arranged around the diaphragm in such a way that the hollow sides of all lens surfaces facing the aperture.

The aim of the geometrical-optical correction in the case of the objectives of the structure described above is achieved according to the invention by the following construction principle. In order to largely eliminate astigmatism and coma in the magnification range from 1.5 to 12 times, above all certain designs of the inner cemented negative images are necessary and a certain dimension of the air gap I ₂ between them is necessary. The meniscus-shaped negative members arranged before and after the diaphragm have such deflections that the ratios of the radii of the glass-air surfaces (R ₅ and R ₆ ) closer to the diaphragm to those

009 588/208

of the more distant glass-air surfaces (E ₃ or E ₈ ) in the case of the negative element in front of the diaphragm greater than 0.70 and less than 0.75 and in the case of the negative element behind the diaphragm greater than 0.75 and less than 0.80, according to the mathematical relationships

0.70 <

0.75 <

R ₀

<0.75,

<0.80.

In addition, the differences in the corresponding radii of the respective negative link, ie [E ₃ -E ₅ I or IE ₈ -E ₆ I, 'should differ in absolute terms by a maximum of 0.02 /, according to the mathematical inequality

[IE ₃ -E ₅ I-IE ₈ -E ₆ I] ^ 0.02 /.

The axial air gap I ₂ in the diaphragm space is greater than 3.5 times and less than 4.5 times the difference between the absolute amounts of the radii E ₆ and E _{5 of} the surfaces delimiting it

3.5 [IE ₆ I-IE ₅ I] </ ₂ <4.5 [[E ₆ I-IE ₅ I].

The lens example shown below has

the features according to the claim. It is given for a focal length / = 1.0 and an aperture ratio of 1: 4. The radii are with E ₁ ... E ₁₀ , the axial ones

Lens thicknesses with ^ ₁ ... d ₆ , the axial air gaps with I ₁ ... / ₃ , the refractive indices of the glasses with W ₁ ... w ₆ , their Abbe numbers with V ₁ ... v ₆ denote

. net. The refractive indices refer to the wavelength of 587.6 ΐημ. The construction elements

ίο are numbered consecutively, in the direction of

the negative level too.

example

Magnification wide-angle lens 1: 4;
Lens focal length / = 1.0;

Lens corrected for the magnification interval 12 to 1.5.

Ej = + 0.69237
ao E ₂ = + 2.30294

E ₃ = + 0.30231

<Z ₂ = 0.09844 «3 = 1.63980 i> ₃ = 34.6

i, = 1.69895 v, = 30.1

It was also found that with the above-described design of the negative members and their spacing from one another, the largely uniform course of the correction is retained when the magnification is changed from 1.5 to 12 times if the radii Ej and R _{10 of} the outer lens surfaces differ by at most 0.03 f , ie

[IE ₁ I- [E ₁₀ I] <0.03 f.

The chromatic image quality above that required for color and black and white enlargements According to the invention, the spectral region is achieved in that the lenses are located in front of the diaphragm Lens halves consist of glasses whose refractive indices for the yellow light (587.6 ΐημ) of the condition

0.05 <U ₁ -

<0.10

suffice, and the refractive indices for the glasses of the lenses of the lens half lying behind the diaphragm the condition

.0.00 <k -

<0.05

meet and also for the dispersion of the glasses the Abbe numbers V ₁ , V ₂ , v _s , V ₁ , v _s , v _{e have the} following relationship:

0.7 <

<3.0.

^ = 0.06254% = 1.71700 ^ = 47.9 ^ = 0.00993 « ₂ = 1. 63930 v ₂ = 45.0

Z ₂ = 0.26074 M _g = 1.69350
<2 ₄ = 0.02647 w _e = 1. 72342
d ₅ = 0.09844
/ ₃ = 0.00877
d ₆ = 0.07875

By fulfilling these conditions at the same time, it has been possible to provide a magnifying wide-angle object in which the error correction is carried out so far and uniformly that the image performance that the lens has at full opening is hardly increased by stopping down . This success is all the more highly valued because the refinement of the correction in geometrical-optical as well as chromatic terms over the wide spectral range and the elimination of the image field curvature in the entire magnification range succeeded in a better quality over the very expanded image field than was possible for the usual field of view of a normal magnifying lens was previously known. E ₄ = + 3.30882
as ^ ₅ = + 0.22275

E ₆ = -0.28679

E ₇ = -7.94117
E ₈ = -0.36579

E ₉ = -7.78648

^ "= - 0.69237

The drawing shows the section through a lens according to the example. The aperture is indicated by BB. The negative plane is marked with N, the positive plane with P.

Claims (4)

Patent claims: 1. A magnifying wide-angle lens consisting of four members separated from one another by air gaps, namely a collecting meniscus-shaped front member, two meniscus-shaped dispersing members that enclose the diaphragm, the surfaces of these members delimiting the diaphragm space facing each other with their hollow sides and each two cemented lenses of opposite refractive power are joined together, and from a collecting meniscus-shaped rear element, the hollow sides of all lens surfaces - including those of the cemented surfaces - facing the diaphragm, characterized in that for the meniscus-shaped negative members surrounding the diaphragm space _{(^ 2) the following radius relationships} are valid: 45 55 a) 0.70 <- = A. <0.75, b) 0.75 <-§- <0.80, E ₈ c) [| E ₃ - E ₅ | - IE ₈ - E _e |] <0.02 · f, and the size of the axial air gap I ₂ by the relationship d) 3.5 · [| Ε ₆ | is specified. 4.5. [| E _e 2. Magnifying wide-angle lens according to claim 1, characterized by the simultaneous fulfillment of the conditions:. e) 0.05 <[^ _ f) 0.00 < g) 0.7 <- ίο for the wavelength 587.6 πιμ and V ₁ . .. ν _β mean their Abbe numbers. 3. Magnifying wide-angle lens according to claims 1 and 2, characterized by the fulfillment of the additional conditions for the radii (R ₁ and R ₁₀ ) of the lens outer surfaces h) Since ₁ I- | 22 _ω |] <Ο, Ο3 · Λ 4. Magnifying wide-angle lens according to claims 1 to 3, characterized in that ■ 3.0, the refractive powers - ^ - each by at most O ₂ I. the refractive indices of the glasses 15 The lens thicknesses (d) and the air gaps (/) each deviate by a maximum of ± 0.02 / from the values shown in the following numerical example: ^ = + 0.69237 · / + 1.03557 // R.
^ = 0.06254 · / W ₁ = 1.71700 V ₁ = 47.9 i? ₂ = + 2.30294 · / -0.31134 // /! = 0.00993 · / ^W 2 = 1.63930 v ₂ = 45.0 i? ₃ = + 0.30231 · / + 2.11472 // £, = 0.09844 · / ⁿ 3 = 1.63980 v ₃ = 34.6 R ^ + 3.30882 · / + 0.00015 // ώ ₃ = 0.01324 / ⁿ i = 1.69895 Vi = 30.1 i? ₅ = + 0.22275 · / -2.87228 // / ₂ = 0.26074 · / ⁿ 5 = 1.69350 v ₅ = 53.4 R ₆ =, -0.28679 · / -2.43715 // d ₄ = 0.02647 / W ₆ = 1.72342 v ₆ = 38.0 R ₇ = -7.94117 · / + 0.00069 // i ₅ = 0.09844 / i? ₈ = -0.36579 · / +1.89590 // Z ₃ = 0.00877 / R ₉ = -7.78648 · / -0.09291 // Cf ₆ = 0.07875 / R ₁₀ = -0.69237 / + 1.04485 // where the radii are given with R ₁ ... R ₁₀ , the axial lens thickness with S ₁ ... d ₆ , the air gaps with I ₁ ... I ₃ in units of the lens focal length / and the refractive indices of the glasses for the wavelength 587.6 ηιμ with W ₁ ... W ₆ and their Abbe numbers with V ₁ ... v _e . 1 sheet of drawings > 009 588/208 8.60