DEO0003857MA - - Google Patents

Description

FEDERAL REPUBLIC OF GERMANY

Registration date: September 27, 1954. Advertised on May 9, 1956

GERMAN PATENT OFFICE

The invention relates to a changing system intended to use the first two in general Lins'en of a photographic three-lens triplet lens lying in front of the diaphragm, which is the the object shown in reduced size are facing, and that with the third standing behind the panel Lens of the triplet together a lens of the same focal length, but longer focal length, compared with that of the original triplet.

Such systems have been proposed several times. They consist of a cement, the object facing collecting part of meniscus shape, the - in the sense of the light direction with reduced Illustration - a divergent lens follows. Close behind this is the aperture and the end of the System forms the third lens of the triplet. Add further suggestions after the collection section another collecting single meniscus. With regard to the focal ratio and image quality, however, these older proposals are not satisfactory. 2c

The reason for this is the knowledge on which the present invention is based that the third lens of the triplet as a collective link of this basic lens must have the highest possible Nü value, while when combined with the interchangeable link, the one a; longer focal length, this third lens of the

609 514/232

O 3857IX / 42 h

Triplet with the divergent lens of the close in front of it

'Change system together should more or less clearly form the negative link of a telesystem that

■. must be at least approximately free of color defects.

. 5 It follows that for this the converging lens is a

ci ;. as low as possible, Nu has to show. The present Invention externally uses the known design of such changing systems and just solves it described contradiction of the conditions with the

ίο existing glasses by adding for the third lens of the Triplets presuppose a glass whose Nu value is below 50, and at the same time, according to the invention, the divergent lens of the Weehselsystem standing close in front of it has a comparatively low refractive power - taken in absolute terms - which is smaller than that which is just as absolute taken Brecrnaaft, the middle lens of the is original triplets; The telesystem character ■ of the combination is therefore only weakly pronounced, and imaging performance and debugging is preferred in the cemented collection part placed.

According to the invention, for this purpose the glasses of the lenses forming it must have Nu values, their ratio is at least 2. Otherwise the chromatic correction is not possible, since, moreover, the

_{Ä The} cement surface must be kept so flat that astigmatic and comatic error correction can be carried out without severe zone errors. Accordingly, it is one of the characteristics of the invention that this putty surface, which is hollow against the receiving object, has a radius that is at least i, 2 times the burning

. .. width of the whole, combination makes up. In order to be able to use this putty surface for the mentioned and Sufficient correction for astigmatic errors.

to have opportunities, must be the difference in the refractive index both glasses at least 0.10, but preferably 0.15 to 0.20.

Taking into account this correction condition • and a ratio of the focal length of the combination system to that of the original triplet between 1.3 as a practically interesting value and 2 as a value still to be realized, but preferably of about 1.65, the refractive power and distance condition for the cemented collecting part has a radius facing the object of not more than 32 ° / ₀ and an air space between this collecting part and the following diverging lens of not more than 25% of the combination focal length.

The data of the original triplet for the focal ratio 1: 2.8, based on the focal length 100, are for example (Fig. 1):

36.96 903.7 r _s = - 65.25 ^ ₄ = ■ + 37.52 r _& = + 158.6 »" Β - - 454O s' = 82.62; Bildwi 609 514/232

d ₁

d ₂

kd ₃

6.66

9.33

1.51

10.55

6.26

1.6667 / 48.4
1.7174 / 29.5
1.6667 / 48.4

The changing system according to the following. Data replaces the first two lenses of this triplet and has a focal length of 163.3 ^{un (i,} for the same distance s' = 82.62 ι at an opening ratio: 4.5 and a field angle of about 34 · ^0, the following data ( Fig. 2):

r [= + 52.43 -: - ■ .-

ra ■ =. - 199.7

r ^ = + 423.2

^ 4 = ~ 36.4

r ^ = + _59; ok

<^ Η - = - + 158.6

A = ^ ₆ = - 45.40

iZ {= 22.44 1.6204 / 60.3

di = 1.87 1.8052 / 25.5

/ i = 36.5

d ' _% = 1.0 1.6080 / 46.2

^ = 6.86

^ - d ₃ = 6.26 1.6667 / 48.4

In particular, the subject of the invention, a changing system according to this data, in arbitrary units or fractions or multiples thereof were measured, whereby individual curvatures of the lenses to + 5 ° / ₀ of the reciprocal of focal length of the Ursprung-, loan triplets, individual thicknesses and spacings to ¹ O ⁰ Zo this focal length, individual refractive indices may differ by ± 0.02 without departing from the scope of the invention.

Claims (4)

Patent claims: 1. Exchange system, which is intended to replace the first two lenses of a three-lens photographic lens of the triplet type, facing the object depicted in reduced size, in such a way that, together with the third lens of this triplet, it results in a lens with a longer focal length but the same focal length, and which consists of a cemented collecting part facing the object and a divergent lens following at a greater distance, characterized in that the refractive power of this divergent lens, taken in absolute terms, is smaller than the refractive power of the replaced divergent lens of the original triplet, but that its refractive power together with that of the third lens of the triplet, the Nü value of which is less than 50, is negative, and furthermore, at an amount between .i, 3 times and 2 times the combination focal length compared to that of the original triplet, the outer radius of the collecting part facing the object between 28 and 32 ° / ₀ , the Air space between the collecting part, and _{y is} the diffusion lens between 20 and 25 ° / ₀ is the combination focal length. 2. Exchange system according to claim 1, characterized in that the difference in the refractive index O 3857IX / 42 h in the collecting part of colliding glasses is at least 0.10, the ratio of their Nu values is at least 2, and that the radius of the cemented surface of the collecting part is at least i, 2 times the focal length of the combination. 3. Exchange system according to claims 1 and 2, characterized by the following data including the remaining third lens of the original triplet, understood in any length units or parts or multiples thereof, with individual curvatures of the lens surfaces by ± 5% of the reciprocal focal length of the original triplet, individual Thicknesses and distances of e.g. 10 ° / ₀ from this focal length, the refractive indices can deviate by ± 0.02: r [ = + 52.43 ' < = - 199.7 ^ = + 423.2 < = - 36.4 ή = + 59.1 ° »ί = + 158.6 ri, = - 45.40 d [= 22.44 4 = 1.87 A = 36.5 d ' ₃ = 1.0 4 = 6.86 1.1. - = 6.26 1.6204 / 60.3 1.8052 / 25.5 1.6080 / 46.2 1.6667 / 48.4 1 sheet of drawings © 609 514/232 5. 56