DE6606937U - WIDE ANGLE PHOTOGRAPHIC LENS - Google Patents

Description

Nippon Kogaku K. K. Nippon 66

Tokyo, Japan

Wide angle photographic lens

The invention relates to a wide angle photographic lens with a folcussing mechanism in the retrofocus lens type, whereby a corrective air gap for close-up features in of the positive convex lens group provided that eats is located behind the negative concave lens group, which forms the front part of the lens, and where the air / apalt enteprechena the change of the object distance by one predetermined amount is gradually changed to compensate for the change in the object aberration which occurs with the change the object distance occurs.

The wide-angle photographic lenses for a single-lens reflex camera with a short focal length require a back focal length of a certain minimum length, and therefore a lens type _v with a diffusing convex lens in the front part of the lens

'IF

group, for example a retrofocus lens type, is used. That Lens system of this type as a whole has strongly asymmetrical properties, as well as the further property that it behaves of the lens changes considerably when the object distance is small, and in the case of wide-angle photographic lenses with a focal length these effects get big because of the big picture «

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winkeis. Generally speaking, the correction of the lenses " error of a photographic lens with regard to infinite object distance will be carried out "but will serve" the system as a Rctrofocus type trained, eo are the changes of the Limaenf © hler, caused by the object distance, great. Wvjnn

ri nh ftf Mtilfr rta iifnntimnnn flpr JM aliQ. »ι-frt α tim ah dARtoaht umyjan u ^ u_ the properties of the picture deteriorate considerably and it is impossible to obtain a good β picture. On the other hand, if the close-up effects are improved by changing the constitution of the lens, the results obtained are worse when the object distance is greater or infinite. Such properties are the result of an imbalance in that the change in image curvature and antigmoidism is greater than the change in other aberrations. There is therefore a need for a wide-angle lens with short focal lengths in which these disadvantages are eliminated.

The object of the invention is to provide a wide-angle photographic lens to create which does not have the disadvantages mentioned and which is characterized in that the size of the aberration change, caused by the change in magnification, compensates uöd according to the size of the aberration at infinite Removal and the change of the vorstehecd mentioned

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Aberrations can be maintained, which according to the Object distance are different, and the lens is in excellent aberration state by performing the correction of the air gap according to the respective distances and the lens aberration correction mechanism coupled with the angle adjustment mechanism is to correct the aberration automatically, furthermore clear recordings from the distance infinite up to extremely small distances can be carried out and get the same effect as with removal indefinitely when taking close-up pictures and eventually shorten the close-up distance to extremely small values can be.

According to the invention, it is possible to always maintain excellent image generation properties, regardless of the object distance, by coupling the continuous rating "setting mechanism of the lens" with the " ¹ correction amount of the air gap. Since the light flow is largely parallel in the air gap to be corrected Therefore, even if the air gap is changed, there is practically little change affecting the F-number, back focus, focal length and the like, and are more than two air coils for correcting aberrations

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are suitable, present in the collecting convex Linaengruppe, thus it is possible to select a most effective air gap by accounting for the efficiencies. If there is no effective air gap in the collecting convex Lin-Ben group, thus it is possible to provide a suitable air gap by dividing the single-component lens in two Linßenglieder, like this one described below Äusfübrungsform 3 is shown. In addition to being able to take extreme close-ups or macro shots, it is also possible to shorten the close-up distance and increase the magnification because the Change in lens properties are small.

The invention thus relates to a wide-angle photographic lens of the retrofocus type with a focusing mechanism and is marked by suitably placing an air palto in the converging convex lens group that is behind the diffusing concave lens group covering the front part of the rietrofocus lens is located such that the light flux becomes parallel so that the condition

} bf - dv> 2fr

is fulfilled, where dv is the air gap, bf is the overall technology Lens groups between the object to be photographed and the

Air gap and denote the total focal length of the lineea group between the image and the air gap, and by gradual Changing the air gap dv by a predetermined amount in accordance with the change in the object distance by the To compensate for the change in lens aberrations caused by the change in the object distance.

The principle of the invention is explained below.

Generally speaking, when the magnification changes “A photographic lens can be found when the object distance changes, as well as the aberration of the lens therefore, the lens characteristics deteriorate when taking pictures made outside of the standard magnification. The change is noticeable when using asymmetrical lenses. In particular, the change in the case of retrofocus lenses Astigmatism and the curvature of the image are very strong compared to the other aberrations. As a basic type of retrofocus lines it is known to collect an inverted Galilee telescope in front of the provide convex lens. Jis is. also known to be a dissipative concave lens to be provided in the vicinity of the front main plane of the main line in order to lengthen the back focus. In this case, the fanning out of the Lichtfluesee is done by a

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concave lens swelled by a convex lens of the inverted GsJLÜäi telescopes or through a convex lens that is arranged sufficiently far behind the concave lens, when the light flux arrives at the image plane, it eats into one changed convergent light flux. The Crt at which the light flux is changed to a convergent light flux also changes accordingly the structure of the jittery convex lens, but the The fact that the different flux of light converges in one Light flux is changed, means that a nearly parallel light-cast must be connected in the middle part. The air gap between the lenses, in which the light flow is almost parallel, hardly affects the F-number, spherical aberration and back focus of the lens, even if this air gap somehow should be changed, but it greatly affects the curvature of the BÜdkur and the antigma + ism. Therefore, if the correction of the air gap is carried out in such a direction that the change in Compensate for the aberration caused by the magnification! Can be done by selecting the air gap between the lenses with the appropriate properties, ee possible to stick the kigeos the Büdfläche: independent in practically the same state from the object distance. When the part where the light flux is parallel is not in a suitable one Air gap but lies in a lens, the above-mentioned

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imagined goal had been achieved by an air gap, which by dividing the lens into two parts with only one parallel A plane or a surface closely approximated to a plane will. On the other hand, it is through suitable choice of air pnltoa also possible to change the other aberrations, like

rration edsr Ccnis, ™ u

According to the invention, the correction of the aberration can be carried out by using an air gap in which the light flux passing through is calibrated according to the above principle is in a largely parallel state, and the most effective results are obtained when the following condition occurs can be fulfilled:

j bf - dv j ^> 2fr.

Here bf denotes the back focal length of the object side in front of the Air gap for aberration correction lens group, dv the air gap and the effective focal length behind the. Air gap on the lens group on the image side.

If the value! Bf - dv is greater, the light flux in the air gap can be better kept parallel. According to the usual System, the aberration is corrected by correcting it

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the air gap «*) between the concave lens of the front group |

and the positive convex lens group, but through the |

Correlation of the air gap, the light flux is divergent, and §

the influence on the F number, the spherical aberration, the f

The back focal length becomes too large, so that the usual systonx is not fully

In the following the invention is based on various, in the
Drawing illustrated embodiments described; it
demonstrate:

Fig. 1 is a sectional view of a first embodiment,
Fig. 2 shows the state of correction with infinite object

distance in terms of spherical aberration (a).
Astigmatism (b) and distortion (c),
3 shows the correction state at the limited magnification (0.114 x) in the same representation; j corresponds to FIG. 2,

Flg. 4 the state of corrosion at the limited magnification of (0.114 x) when the objective eat-;

i is corrected speaking of the invention, in the

same representation according to Flg. 2; j

Flg. δ a sectional view of a second embodiment
the wide-angle lens according to the invention;

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6 shows the state of correction for an infinite object distance looks at spherical aberration (a), accuracy (b), and distortion (c);

Pig. 7 the correlation condition at the limited magnification (0, 15 x) in the same Darst & Uttög according to JRg. Ö;

Fig. 0 shows the restriction on the limited magnification of (0.15 o). if there «objective srfin = dgemüß auekorregiort is in the same Representation according to FIG. 6,

9 is a sectional view of a third embodiment of the wide-angle lens according to the invention,

10 shows the state of correction of the lens at infinite object distance with regard to d * s £ spherical aberration (a), astigmatism (b) and distortion (c),

Fig. 11 shows the state of correction in the limited magnification of (0, 7 x) in the same representation corresponding to FIG. 10;

12 shows the correction state of the objective at the limited magnification of (Q, 01 s) when the objective is corrected according to the invention, in the same representation corresponding to FIGS

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13 shows an embodiment of the connection for shifting wipe the entire joint system and change the air gap at the same time the sixth lens LG and the seventh Lina ο L? according to the advance of the whole System for correcting lens aberrations.

1st embodiment

In this embodiment, the second air gap is also weak divergent behavior in the converging convex lens group used for correction. Fig. 1 shows this Example of such a lens, which with a focal length of IQO.0, a focal length bf = 157.6 and an angle of view of 2ß = 84 the numerical values identified in claim 2 where r ... are the radii of curvature, d. , .. the axial Lens thicknesses or air gaps and η ... the refraction indices of the individual lens glasses, all numbered consecutively from the object side.

In Fig. 1, the lens elements Ll, L2 and L3 form the diverging lens the front group, and lenses L4 through LS accomplish the convergence of the light flux as the main XSnse of the rear

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There are three air gaps in the main lenses, but d ₁ is the most suitable for carrying out the correction of the aberrations, and in this case the back focal length bf of the front group in front of the air gap, that is, the sectional width bf of the lenses L1 to L6, is equal to -268 .84, and the effective burning width for jjf from the air gap to the rear group L7, L-8 and L9 is -ί-102.65

bf - U ₁ = -277.76.

The absolute value is greater than 2fr. The course of the aberration of this objective is shown in FIG. 2 for the object distance infinitely. The aberration course at the magnification of 0.1.14 is shown in FIG. It can be seen that the astigmatism is large as shown in (b) and that the curvature is positive. If the air gap is changed according to the invention so that it is e.g. = 4.46, the aberration curve at the magnification of 0.114 becomes that shown in Fig. 4, and it is apparent that the correction has been made.

?. Execution forum

The first air gap, through which the light flux is made largely parallel, is used in the correction, FIG. 5 shows the execution oiness of such lens. A calculated one

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The embodiment has a focal length of f = 100.0, a back focus bf of 113.4 and an angle of view of 2S -

d ... and n. ... have the meaning given above

the values characterized in claim 3, where again r ....,

In Fig. 5, the lenses L1 and L2 form the diffusing system of the front group, and lenses L3 to L8 are the main converging lenses. There are three air gaps between the main lenses, namely d _{? J} d and d. provided, and in this execution form. the air gap d is used to correct the aberration. The focal length bf of the front group consisting of Ll to IA is equal to -? 062.48 and the effective focal length for the rear group is 93.72. So for bf - d _? -2077.10 the value, and the absolute value thereof is considerably larger than 2fr "The diagrams of FIG. 6 to show the S Aberrationsverlauf of the lens of this embodiment, wherein Fig. 6 shows the aberration at an infinite distance, and also the Fig. 7 the Aberration at 0.15 times magnification, and finally in FIG. 8 the aberration curve for the case that the air gap was corrected to the value d = 12, 22 in the manner according to the invention,

also at 0.15x magnification.

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3. Execution format

This is an embodiment in which a suitable air gap (in which the LichtQufi parallel we-i) does not exist, rather this happens in a lens, and is the first lens of the converging convexon line group separated into two parts, with the air gap correcting the Aberration is used. Fig. 9 shows an example of one

Such a lens, and a calculated exemplary embodiment has, for a focal length f = 100.0, a focal length bf = 133.6 and an image angle of 23-74, the elements characterized in claim 4, where again r ..., i. ... and n * ... which have meaning given above.

In Fig. 9, the lenses Ll and L2 form the diffusing system the front group, and the lenses L3 to L7 * the converging ones Main lenses. As can be readily seen, L4 and L5 are originally a lens, but in accordance with the invention is a suitable one Air gap required, so this lens has been divided into two parts. So it becomes the air gap d "between L4 and L5

used for correcting aberrations. The back focal length of the EUO Ll up to 1/4 existing front group has the value bf = -281.5, one thus obtains bf - d "= -282.3. The effective focal length of the rear group from L5 to L7 is fr - 90.8, the absolute value of

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bf - d is therefore more than three times fr. Fig. 10 shows the Abbrrationsverlaui of the lens in this AusführungsforiE at infinite distance, Fig. 11 shows the Aberrationsverlauf at a magnification of G, 07 and Fig. 12 shows the Aberrationsverlauf for the case that the air gap to the value d _n = 0.176 in is corrected in the manner according to the invention, also at a magnification of 0. Ö? times.

A comparison of FIGS. 11 and 1? immediately shows the effect of Correction.

13 shows an embodiment for shifting the entire lens system and for simultaneously changing the air gap between the lenses LG and L7 in order to correct the aberration of the lens system. According to FIG. 13, the lines Ll to L6 are held by a first lens mount 1, while the lenses L7 to L9 are held by a second lens mount 2. The first Linaunfaaaung 1 has a jiinstellgewinde 3, which cooperates with an adjusting ring 4, which in turn engages in a screw thread 5 of a stationary mount 6. The latter feat protruding BayoncttanschlüSEC 7. Slide first version 1 also has a composition thread h, which is in thread engagement with the second version 2. The latter has a head start

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IC

which is slidably guided in an axial groove 10 doa Stollring 4. A pin 11 on the rotating socket G engages in an axial groove 12 and is guided in it so as to be slidable. If the stud ring 4 is rotated, it is axially displaced and the first line setting 1 moves axially together rait the ring 4 without turning, Glsiciizäiti "" vsriijTslit dis —wsits i ^ ias ^ sii ^ ss "^" 3 " Πΐ ^ ¹ "x ** i & szssi- pensationsgewinde 8 and moves axially ind r» same direction as the first Linsenfassüng 1. Consequently, the whole lens system wei'den shifted, wherein the air gap between the lenses L6 and L7 corresponding to the "displacement doa lens system changes in such a way that the aberrations of the lens are corrected.

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Claims (4)

PATENT CLAIMS 1. Retrofocus type wide-angle photographic lens with a focusing mechanism, characterized by a converging convex lens group behind a diffusing concave lens group, <fie on the side of the one to be photographed Object is located by providing an air gap within the converging convex lens group for extensive parallelization of light flux such that the condition j bf - dvj \. 2fr is fulfilled, where dv denotes the air gap, bf denotes the total focal length of the lens groups between the object to be photographed and the air gap and for the Gesanitbrenmveite of the lens groups between the image and the air gap, and by means of a device for successively changing the air gap by a predetermined amount corresponding to the Change the distance of the object to be photographed in such a way that the lens errors caused by changing the distance to the object are compensated. 660693710.1Z70 2. Lens according to claim 1, characterized by the following Data: focal length f = 100.0; Back focal length bf = 157 »6; Angle of view 2 [beta] = 84 [deg.] L2 L3 L4 L5 L7 L8 «+242.33 = + 8Ö, 55 - +382, 50 * -428, 13 = +119, 17 r _g = + 43.96 V = +106.11 r ₀ * -74.38 = -128.16 * -208.33 r = +140.96 = -562.50 ϊ ₁₃ = +112.50 r .. · -Ö9. 54 χ * r ₁₆ «-1666.67 L = 16.250 η, = 1.622§9 d ₂ = 28.250 d ₃ = 26, d ₄ = 0.417 d ₅ = 15.833 dg = 37, d _? a 20.833 d _g a 2, d _g = 10.417 d ₁₀ - 22, d ,. «8,917 d._ = 0.250 d _lg = 20.417 d ₁₄ "0, d _1R - 11.250 n_ β 1.6228 = 1.62041 n ₄ a I, 62004 n _g a ι, 7173g n _? = 1, 80518 W ₈ * 1.62041 ft _o «X, 74443 3. Lens according to claim 1, characterized by the following data: f «100, Oj Schnittweito bf» 113.4; Büdwinkol 2ß «62 ° T ₁ - + 321, lü 10.033 OO L2 L3 L4 L5 L6 L ·? LS '+138, 2 ~ 0.278 ^r 3 " ■ + 47, d_ ■
3 ü-111 ^Γ 4 ' + OfL V 31.111 r_ »
ö -152, 22, 778 ^r 6 ⁼ + 94, d ₆ « 29.167 ^r 7 ^a - 59, ^d 7 ^B 14.722 +107, d _g - 2,778 r ₉ = = -71, ^d 8 ⁼ 10.445 ^r io ^d 10 = 0.278 ^r n , 89 = 8.333 ^r i2 78 ^d 12 “0.278 ^r 13 44 ^d 13 = 6.945 ^r i4 78 44 92 75 72 a -305.56 = -1Oi 5, p L, 11 = -219.58 Ti ₁ «1.713 1.66755 ", 61464 !,. 7847 1, 74443 1.76684 = 1.744 660693710.1270 4. Lens according to claim 1 * characterized by the following Data: f »100.0; Sight focal length bf 133.6, Büt'winkel 2ß - 74 ° T ₁ »+ 380, 18 Ll dj »18.203 r ₂ = +10900.00 d ₂ - 0.703 r _o = +241.34 -479.03 r ₁₂ - - 61.58 r ₁₃ = +214.13 r ₁₄ = -203.05 * ₁₀ "6.274 Cl ₁₁ = 9.142 Q ₁₂ = 0.703 d _ls = 6.329 660693710.12 70 H ₁ - 1.65044 r = + 62.33 rl
"3 - 92 Si Ί "2" ** 65128 d ₄ = 4, , 120 Y * SL
"5 + S4, S4 ^d 5 922 <
3 * ^r 6 ⁼ -1170.84 ■ 21 ^d 6 , 80 72825 ^r 7 ⁼ -60.83 ^d 7 406 ^η _Λ ⁼ 1 # ^Γ 8 ⁼ OO = 0, d _s 879 72825 ^r 9 ⁼ OO = 1, ^d 9 406 ⁿ 5 ^{= lj r} io = +110.83 ■ »1.6583 = 1.5163