JP7055652B2 - Zoom lens and image pickup device - Google Patents

Description

The present invention relates to a zoom lens and an image pickup device, and more particularly to a zoom lens suitable for an image pickup device equipped with a solid-state image pickup element such as a CCD or CMOS, and an image pickup device provided with the zoom lens.

Imaging devices equipped with solid-state image sensors such as CCDs and COMS, such as single-lens reflex cameras, digital still cameras, video cameras, and surveillance cameras, are rapidly becoming widespread. Along with this, a zoom lens that can be used in an image pickup device equipped with a solid-state image pickup element such as a CCD or CMOS has been proposed (see, for example, Patent Documents 1 and 2).

Patent Document 1 describes, in order from the object side to the image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power including an aperture aperture, a third lens group having a positive refractive power, and a negative lens group. A zoom lens having a fourth lens group having an optical power, the distance between adjacent lens groups changing during zooming, and the third lens group moving during focusing is disclosed.

Further, Patent Document 2 includes a front group of negative refractive force and a rear group of positive refractive force, and the front group includes a first lens of negative refractive force, a second lens of negative refractive force, and a positive lens. The first lens and the second lens include a third lens of refractive power, the first lens and the second lens are meniscus lenses having a convex surface facing the object side, and the rear group has two lens units, and upon scaling, the rear group has two lens units. The distance between the front group and the rear group becomes narrower, the distance between the two lens units changes, the first lens unit consists of two sub-lens units and an aperture aperture, and the sub-lens unit on the image side A zoom lens having a focus lens group and having a variable or constant distance between two sublens units upon scaling is disclosed.

Japanese Unexamined Patent Publication No. 2016-75742 Japanese Unexamined Patent Publication No. 2017-122744

Since a digital camera can also shoot a moving image, high-speed autofocus processing corresponding to the shooting of a moving image is desired. In autofocus, first, a part of the lens group (focus group) is vibrated at high speed in the optical axis direction (wobbling) to create an out-of-focus state → an in-focus state → an out-of-focus state. Then, the signal component of a specific frequency band in a part of the image region is detected from the output signal of the image sensor, the optimum position of the focus group in the in-focus state is obtained, and the focus group is moved to the optimum position. In particular, in moving image shooting, it is required to continuously repeat these series of operations at high speed. Then, in order to perform wobbling, the focus group is required to have a small and light aperture as much as possible in order to enable the focus group to be driven at high speed.

Further, when wobbling is introduced, the size of the image corresponding to the subject changes during wobbling. This is mainly due to the fact that the focal length of the entire optical system changes due to the movement of the focus group in the optical axis direction. Further, since the focus group is always moved during wobbling, if the change in image magnification due to the fluctuation of the angle of view is large, the image always seems to be shaking, which causes a sense of discomfort. It is known that in order to reduce this discomfort, focusing should be performed with the lens group behind the aperture.

On the other hand, when designing a wide-angle zoom lens, if the regular group leading type is selected, the front lens becomes large, making it difficult to design a compact and lightweight zoom lens. In general, the first lens group of a zoom lens is larger than the other lens groups. Therefore, when a glass material having a high refractive index and a large specific gravity is used for the lens constituting the first lens group, the lens weight is increased and the weight is reduced. The design of the optical system becomes difficult. In addition, when a lens using a highly dispersed glass material is placed in the first lens group through which off-axis rays pass at a position far from the optical axis, it becomes difficult to correct chromatic aberration of magnification, and an optical system having high resolution is realized. Will be difficult.

The zoom lens disclosed in Patent Documents 1 and 2 is a negative group leading type and has a third lens group behind the aperture as a focus group, so that it is a compact lens suitable for wobbling during moving image shooting. However, since glass having a high refractive index and high dispersion is used for the negative lens arranged in the first lens group, the optical system cannot be expected to have high resolution.

It is an object of the present invention to provide a zoom lens that is compact, lightweight, and has high resolving power, while being suitably applicable to moving image shooting in order to solve the above-mentioned problems caused by the prior art. In addition, it is an object of the present invention to provide an image pickup device equipped with a zoom lens that is compact, lightweight, and has high resolution.

In order to solve the above-mentioned problems and achieve the object, the zoom lens according to the present invention includes a first lens group having a negative refractive power and a second lens having a positive refractive power arranged in order from the object side. It consists of a group, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power, and by changing the distance on the optical axis of each lens group, the wide-angle end to the telephoto end. The third lens group is moved along the optical axis to perform focusing, and the condition expression shown below is satisfied.
(1) νd1n ave ≧ 67.5
However, νd1nave indicates the average value of the Abbe numbers of all the negative lenses included in the first lens group.

According to the above invention, it is possible to provide a compact, lightweight zoom lens having high resolving power, which is also suitable for moving images.

Further, the image pickup apparatus according to the present invention is characterized by including the zoom lens and an image pickup element that converts an optical image formed by the zoom lens into an electrical signal.

According to the above invention, it is possible to provide an image pickup apparatus provided with a zoom lens which is compact and lightweight and has a high resolving power.

According to the present invention, it is possible to provide a compact, lightweight zoom lens having high resolving power, which is also suitable for moving images. Further, it has the effect of being able to provide an image pickup device equipped with a zoom lens that is compact, lightweight, and has high resolution.

It is sectional drawing along the optical axis which shows the structure of the zoom lens which concerns on Example 1. FIG. It is a diagram of various aberrations of the zoom lens which concerns on Example 1. FIG. It is sectional drawing along the optical axis which shows the structure of the zoom lens which concerns on Example 2. FIG. It is a diagram of various aberrations of the zoom lens which concerns on Example 2. FIG. It is sectional drawing along the optical axis which shows the structure of the zoom lens which concerns on Example 3. FIG. FIG. 3 is an aberration diagram of the zoom lens according to the third embodiment. It is sectional drawing along the optical axis which shows the structure of the zoom lens which concerns on Example 4. FIG. It is a diagram of various aberrations of the zoom lens which concerns on Example 4. FIG. It is sectional drawing along the optical axis which shows the structure of the zoom lens which concerns on Example 5. FIG. FIG. 3 is an aberration diagram of the zoom lens according to the fifth embodiment. It is a figure which shows one application example of the image pickup apparatus provided with the zoom lens which concerns on this invention.

Hereinafter, preferred embodiments of the zoom lens and the image pickup apparatus according to the present invention will be described in detail.

The zoom lens according to the present invention is a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a negative refractive power arranged in order from the object side. And a fourth lens group having a positive refractive power. Then, the first to fourth lens groups are moved along the optical axis, and the distance between the first to fourth lens groups on the optical axis is changed to change the magnification from the wide-angle end to the telephoto end. Further, the third lens group is moved along the optical axis to perform focusing.

The zoom lens according to the present invention adopts a configuration in which four lens groups having negative, positive, negative, and positive refractive powers are arranged in order from the object side. In a zoom lens, the aperture of the first lens group tends to be larger than that of the other lens groups. Therefore, in the present invention, by making the first lens group a negative group, the aperture of the first lens group can be kept small, and the optical system can be made smaller and lighter. Further, by setting the first lens group as a negative group, it becomes easy to secure the angle of view on the wide-angle side.

Further, by setting the second lens group as the positive group, the diameter of the light flux incident on the third lens group can be reduced. By setting the third lens group as the focus group, wobbling with a small change in angle of view becomes possible with a lens group having a small diameter and light weight, so that a zoom lens that can be suitably applied to movie shooting can be realized. ..

In addition, in the zoom lens according to the present invention, it is preferable that the following conditional expression is satisfied when the average value of the Abbe numbers of all the negative lenses included in the first lens group is νd1nave.
(1) νd1n ave ≧ 67.5

The conditional expression (1) is an expression that defines the range of the average value of the Abbe numbers of the negative lenses included in the first lens group. When a lens using a highly dispersed glass material is placed in the first lens group through which off-axis rays pass at a position far from the optical axis, it becomes difficult to correct chromatic aberration and it becomes difficult to realize an optical system having high resolution. Become. Therefore, in the present invention, by adopting a negative lens having a small dispersion that satisfies the conditional equation (1) in the first lens group, it becomes possible to satisfactorily correct chromatic aberration of magnification and axial chromatic aberration. , It is possible to realize an optical system having high resolution.

The lower limit of the conditional expression (1) is preferably set to be 67.7 or more, more preferably 68.0 or more. The upper limit of the conditional expression (1) is preferably set to 95.0 or less, more preferably 85.0 or less.

Further, in the zoom lens according to the present invention, it is preferable that the following conditional expression is satisfied when the maximum value of the refractive index of the negative lens included in the first lens group is nd1n max.
(2) nd1n max ≦ 1.80

The conditional expression (2) is an expression that defines the range of the maximum value of the refractive index of the negative lens included in the first lens group. Generally, the first lens group of a zoom lens is larger than the other lens groups. Therefore, when a glass material having a high refractive index and a large specific gravity is used for the lens constituting the first lens group, the lens weight increases and the weight is reduced. It becomes difficult to realize a flexible optical system. Therefore, in the present invention, by adopting a negative lens having a small refractive index that satisfies the conditional expression (2) in the first lens group, a glass material having a small specific gravity is used in the first lens group having the largest optical system. Since it will be used, it will be easier to design a lightweight optical system.

The lower limit of the conditional expression (2) is preferably set to 1.44 or more, more preferably 1.49 or more. The upper limit of the conditional expression (2) is preferably set to 1.75 or less, more preferably 1.72 or less.

Further, in the zoom lens according to the present invention, when the focal length of the first lens group is f1 and the focal length of the second lens group is f2, it is preferable that the following conditional expression is satisfied.
(3) 0.75 ≤ f2 / | f1 | ≤ 1.70

The conditional equation (3) is an equation for defining the range of the ratio of the focal length of the second lens group to the absolute value of the focal length of the first lens group. By satisfying the conditional equation (3), the refractive power of the second lens group with respect to the first lens group can be made appropriate, the overall length of the optical system can be shortened while maintaining good resolution performance, and the size is small. , It becomes possible to realize a zoom lens having a high resolution.

If it falls below the lower limit in the conditional expression (3), the refractive power of the second lens group with respect to the first lens group becomes too strong, the correction of spherical aberration becomes excessive, and a zoom lens having high resolution can be realized. It will be difficult. On the other hand, if the upper limit is exceeded in the conditional expression (3), the refractive power of the second lens group with respect to the first lens group becomes too weak, the overall length of the optical system is extended, and it becomes difficult to realize a small zoom lens. ..

The lower limit of the conditional expression (3) is preferably set to 0.80 or more, more preferably 0.90 or more. The upper limit of the conditional expression (3) is preferably set to 1.60 or less, more preferably 1.50 or less.

Further, in the zoom lens according to the present invention, when the focal length of the first lens group is f1 and the focal length of the third lens group is f3, it is preferable that the following conditional expression is satisfied.
(4) 1.50 ≦ f3 / f1 ≦ 2.70

The conditional expression (4) is an expression for defining the range of the ratio of the focal length of the third lens group to the focal length of the first lens group. By satisfying the conditional equation (4), the refractive power of the third lens group with respect to the first lens group can be made appropriate, the overall length of the optical system can be shortened while maintaining good resolution performance, and the size is small. , It becomes possible to realize a zoom lens having a high resolution.

If it falls below the lower limit in the conditional equation (4), the refractive power of the third lens group with respect to the first lens group becomes too strong, the correction of spherical aberration becomes excessive, and a zoom lens having high resolution can be realized. It will be difficult. On the other hand, if the upper limit is exceeded in the conditional equation (4), the refractive power of the third lens group with respect to the first lens group becomes too weak, and the amount of movement of the third lens group during focusing increases, so that the total length of the optical system becomes full. It becomes difficult to realize a small zoom lens.

The lower limit of the conditional expression (4) is preferably set to 1.60 or more, more preferably 1.65 or more. Further, the upper limit of the conditional expression (4) is preferably set to 2.60 or less, more preferably 2.45 or less.

Further, in the zoom lens according to the present invention, when the focal length of the first lens group is f1 and the focal length of the fourth lens group is f4, it is preferable that the following conditional expression is satisfied.
(5) 1.90 ≤ f4 / | f1 | ≤ 4.20

The conditional equation (5) is an equation for defining the range of the ratio of the focal length of the fourth lens group to the absolute value of the focal length of the first lens group. By satisfying the conditional equation (5), the refractive power of the fourth lens group with respect to the first lens group can be made appropriate, and the overall length of the optical system can be shortened while maintaining good resolution performance. , It becomes possible to realize a zoom lens having a high resolution.

If it falls below the lower limit in the conditional expression (5), the refractive power of the fourth lens group with respect to the first lens group becomes too strong, the correction of curvature of field becomes excessive, and a zoom lens having high resolution is realized. Becomes difficult. On the other hand, if the upper limit is exceeded in the conditional expression (5), the refractive power of the fourth lens group with respect to the first lens group becomes too weak, the overall length of the optical system is extended, and it becomes difficult to realize a small zoom lens. ..

The lower limit of the conditional expression (5) is preferably set to be 2.00 or more, more preferably 2.10 or more. Further, the upper limit of the conditional expression (5) is preferably set to be 4.00 or less, more preferably 3.90 or less.

Further, in the zoom lens according to the present invention, it is preferable to move the first lens group so as to draw a convex locus on the image side at the time of scaling. By doing so, it becomes easy to obtain an image magnification at the telephoto end, and it becomes easy to realize a zoom lens having a high variable magnification ratio.

As described above, by providing the zoom lens according to the present invention with the above configuration, it is possible to achieve miniaturization, weight reduction, and high resolution while ensuring a high magnification ratio, and it is suitable for moving images. Can also be suitably applied. In particular, by satisfying the conditional expression (1), chromatic aberration can be satisfactorily corrected. By satisfying the conditional expression (2), the weight of the optical system can be further reduced. By satisfying the conditional equation (3), the overall length of the optical system can be further shortened while maintaining good resolution performance (particularly, good correction of spherical aberration is possible). By satisfying the conditional equation (4), while maintaining good resolution performance (particularly, good correction of spherical aberration becomes possible), the amount of movement of the third lens group during focusing is suppressed. The total length of the optical system can be further shortened. By satisfying the conditional expression (5), the overall length of the optical system can be further shortened while maintaining good resolution performance (particularly, good correction of curvature of field becomes possible).

Further, in the present invention, by providing a zoom lens having the above configuration and an image pickup element that converts an optical image formed by the zoom lens into an electrical signal, the zoom is compact, lightweight, and has high resolution. An image pickup device equipped with a lens can be realized.

Hereinafter, examples of the zoom lens according to the present invention will be described in detail with reference to the drawings. The present invention is not limited to the following examples.

FIG. 1 is a cross-sectional view taken along an optical axis showing the configuration of the zoom lens according to the first embodiment. This zoom lens has a first lens group G ₁ having a negative refractive power, a second lens group G ₂ having a positive refractive power, and a third lens group having a negative refractive power in order from the object side (not shown). G ₃ and a fourth lens group G ₄ having a positive refractive power are arranged and configured. A cover glass CG is arranged between the fourth lens group G ₄ and the image plane IMG. The cover glass CG is arranged as needed.

The first lens group G ₁ includes a negative meniscus lens L ₁₁ having a convex surface facing the object side, a negative meniscus lens L ₁₂ having a convex surface facing the object side, and both concave negative lenses L ₁₃ in order from the object side. The convex lens L ₁₄ and the convex lens L 14 are arranged and configured. Aspherical surfaces are formed on both sides of the negative meniscus lens L ₁₂ . The biconcave negative lens L ₁₃ and the biconvex positive lens L ₁₄ are joined to each other.

The second lens group G ₂ includes a negative meniscus lens L ₂₁ having a convex surface facing the object side, a positive meniscus lens L ₂₂ having a convex surface facing the object side, and an aperture stop STP defining a predetermined diameter, in order from the object side. , A biconvex positive lens L ₂₃ , a biconcave negative lens L ₂₄ , and a biconvex positive lens L ₂₅ are arranged and configured. The negative meniscus lens L ₂₁ and the positive meniscus lens L ₂₂ are joined. The biconvex positive lens L ₂₃ and the biconcave negative lens L ₂₄ are joined to each other. Aspherical surfaces are formed on both sides of the biconvex positive lens L ₂₅ .

The third lens group G ₃ is configured by arranging both concave and negative lenses L ₃₁ and a positive meniscus lens L ₃₂ with a convex surface facing the object side in order from the object side.

The fourth lens group G ₄ is configured by arranging a biconvex positive lens L ₄₁ and a biconcave negative lens L ₄₂ in order from the object side. Aspherical surfaces are formed on both sides of both concave and negative lenses L ₄₂ .

In this zoom lens, the second lens group G ₂ and the third lens group are gradually narrowed so that the distance between the first lens group G ₁ and the second lens group G ₂ is gradually narrowed when scaling from the wide-angle end to the telephoto end. The distance between the 4th lens group G ₄ and the cover glass CG gradually increases so that the distance between the _{3rd lens group G 3 and} the 4th lens group G ₄ gradually increases. Each lens group moves so as to spread to.

Specifically, each lens group moves as follows when scaling from the wide-angle end to the telephoto end. The first lens group G ₁ moves along the optical axis so as to draw a convex locus toward the image plane IMG side. That is, once it moves to the image plane IMG side, it moves to the object side. The second lens group G ₂ monotonically moves from the image plane IMG side to the object side along the optical axis. The third lens group G ₃ monotonically moves from the image plane IMG side to the object side along the optical axis. The fourth lens group G ₄ monotonically moves from the image plane IMG side to the object side along the optical axis.

Further, in this zoom lens, focusing is performed by moving the third lens group G ₃ from the object side to the image plane IMG side along the optical axis.

Hereinafter, various numerical data relating to the zoom lens according to the first embodiment will be shown.

(Surface data)
r ₁ = 36.1445
d ₁ = 1.2000 nd ₁ = 1.59561 ν d ₁ = 67.00
r ₂ = 11.9369
d ₂ = 4.1786
r ₃ = 20.0000 (aspherical surface)
d ₃ = 1.5000 nd ₂ = 1.6979 ν d ₂ = 55.46
r ₄ = 9.7567 (aspherical surface)
d ₄ = 6.4499
r ₅ = -29.9941
d ₅ = 0.6500 nd ₃ = 1.44845 ν d ₃ = 81.61
r ₆ = 15.5345
d ₆ = 3.7013 nd ₄ = 1.80831 νd ₄ = 46.50
r ₇ = -295.9645
d ₇ = D (7) (variable)
r ₈ = 18.8800
d ₈ = 0.6000 nd ₅ = 1.83945 ν d ₅ = 42.72
r ₉ = 8.8369
d ₉ = 2.8000 nd ₆ = 1.61669 ν d ₆ = 44.27
r ₁₀ = 47.3804
d ₁₀ = 1.5000
r ₁₁ = ∞ (opening aperture)
d ₁₁ = 3.4702
r ₁₂ = 14.7421
d ₁₂ = 2.7578 nd ₇ = 1.44845 ν d ₇ = 81.61
r ₁₃ = -48.4383
d ₁₃ = 0.6000 nd ₈ = 1.80633 ν d ₈ = 29.84
r ₁₄ = 28.0242
d ₁₄ = 0.9637
r ₁₅ = 40.3028 (aspherical surface)
d ₁₅ = 2.7732 nd ₉ = 1.44856 ν d ₉ = 81.56
r ₁₆ = -16.1149 (aspherical surface)
d ₁₆ = D (16) (variable)
r ₁₇ = -62.3217
d ₁₇ = 0.6500 nd ₁₀ = 1.91695 ν d ₁₀ = 35.25
r ₁₈ = 21.7156
d ₁₈ = 0.7068
r ₁₉ = 25.2705
d ₁₉ = 2.0216 nd ₁₁ = 1.93323 ν d ₁₁ = 20.88
r ₂₀ = 111.3000
d ₂₀ = D (20) (variable)
r ₂₁ = 27.0257
d ₂₁ = 4.7390 nd ₁₂ = 1.44845 ν d ₁₂ = 81.61
r ₂₂ = -23.2392
d ₂₂ = 0.1500
r ₂₃ = -42.3506 (aspherical surface)
d ₂₃ = 1.2000 nd ₁₃ = 1.85639 ν d ₁₃ = 40.10
r ₂₄ = 600.0000 (aspherical surface)
d ₂₄ = D (24) (variable)
r ₂₅ = ∞
d ₂₅ = 3.5600 nd ₁₄ = 1.51872 ν d ₁₄ = 64.20
r ₂₆ = ∞
d ₂₆ = 3.6260
r ₂₇ = ∞ (image plane)

(Cone coefficient (κ) and aspherical coefficient (A ₄ , A ₆ , A ₈ , A ₁₀ ))
(Third side)
κ = 1.00000,
A ₄ = 4.38991 x 10 ^-5 , A ₆ = -3.54 159 x 10 ^-7 ,
A ₈ = 9.26420 × 10 ^-10 , A ₁₀ = -3.293 14 × 10 ^-12
(4th page)
κ ＝ -7.69271 × 10 ^-1 ,
A ₄ = 1.07041 × 10 ^-4 , A ₆ = -1.221 38 × 10 ^-7 ,
A ₈ = 6.63998 × 10 ^-11 , A ₁₀ = -1.610 17 × 10 ^-11
(15th page)
κ = 0,
A ₄ = -1.5520 6 x 10 ^-4 , A ₆ = 1.892 45 x 10 ^-7 ,
A ₈ = -2.4314 18 x 10 ^-8 , A ₁₀ = 8.84 116 x 10 ^-10
(Surface 16)
κ = 0,
A ₄ = -1.336697 x 10 ^-5 , A ₆ = 1.67 240 x 10 ^-7 ,
A ₈ = -1.65197 x 10 ^-8 , A ₁₀ = 6.86393 x 10 ^-10
(Surface 23)
κ = 0,
A ₄ = 1.64689 × 10 ^-4 , A ₆ = -1.22862 × 10 ^-6 ,
A ₈ = 6.914 95 × 10 ^-9 , A ₁₀ = -2.3231 17 × 10 ^-11
(Surface 24)
κ = 0,
A ₄ = 1.96588 × 10 ^-4 , A ₆ = -1.01713 × 10 ^-6 ,
A ₈ = 5.95149 × 10 ^-9 , A ₁₀ = -1.72677 × 10 ^-11

(Various data)
Wide-angle end intermediate focal length Telephoto end focal length 12.1603 16.6984 22.9174
F number 3.2996 3.7671 4.3804
Half angle of view (ω) 52.3781 40.9985 31.0120
D (7) 15.3971 7.2134 0.9000
D (16) 1.6387 4.0656 7.9199
D (20) 3.9091 5.3491 5.5896
D (24) 13.7332 15.5738 18.0227

(Zoom lens group data)
Focal length 1 1 -15.96 (f1)
2 8 18.75 (f2)
3 17 -36.40 (f3)
4 21 54.35 (f4)

(Numerical value related to conditional expression (1))
νd1n ave = 68.0
(Νd1n ave: average value of Abbe numbers of all negative lenses included in the first lens group G ₁ )

(Numerical value related to conditional expression (2))
nd1n max = 1.70
(Nd1n max: maximum value of the refractive index of the negative lens included in the first lens group G ₁ )

(Numerical value related to conditional expression (3))
f2 / | f1 | = 1.18

(Numerical value related to conditional expression (4))
f3 / f1 = 2.28

(Numerical value related to conditional expression (5))
f4 / | f1 | = 3.41

FIG. 2 is an aberration diagram of the zoom lens according to the first embodiment. In the spherical aberration diagram, the vertical axis represents the F number (indicated by FNO in the figure), the solid line is the d line (587.56 nm), the long broken line is the F line (486.13 nm), and the short broken line is the C line (656. It shows the characteristics of the wavelength corresponding to 28 nm). In the astigmatism diagram, the vertical axis represents the image height (indicated by Y in the figure), the solid line represents the characteristics of the sagittal plane (indicated by S in the figure), and the broken line represents the characteristics of the meridional plane (indicated by M in the figure). Shows. In the distortion diagram, the vertical axis represents the image height (indicated by Y in the figure).

FIG. 3 is a cross-sectional view taken along an optical axis showing the configuration of the zoom lens according to the second embodiment. The optical configuration of the zoom lens according to the present embodiment, the movement of each lens group at the time of magnification change, and the like are the same as those of the zoom lens shown in the first embodiment. Therefore, in this embodiment, the same members as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

Hereinafter, various numerical data relating to the zoom lens according to the second embodiment will be shown.

(Surface data)
r ₁ = 30.9464
d ₁ = 1.2000 nd ₁ = 1.59561 ν d ₁ = 67.00
r ₂ = 11.6715
d ₂ = 5.3972
r ₃ = 22.7838 (aspherical surface)
d ₃ = 1.5000 nd ₂ = 1.59412 ν d ₂ = 67.02
r ₄ = 9.6000 (aspherical surface)
d ₄ = 6.2598
r ₅ = -31.1490
d ₅ = 0.6500 nd ₃ = 1.44845 ν d ₃ = 81.61
r ₆ = 15.6938
d ₆ = 3.4248 nd ₄ = 1.80831 ν d ₄ = 46.50
r ₇ = -2108.2925
d ₇ = D (7) (variable)
r ₈ = 12.9644
d ₈ = 0.6000 nd ₅ = 1.88622 ν d ₅ = 40.14
r ₉ = 8.5916
d ₉ = 2.8000 nd ₆ = 1.62408 ν d ₆ = 36.30
r ₁₀ = 34.8241
d ₁₀ = 1.5000
r ₁₁ = ∞ (opening aperture)
d ₁₁ = 1.4911
r ₁₂ = 14.5432
d ₁₂ = 2.7666 nd ₇ = 1.44845 ν d ₇ = 81.61
r ₁₃ = -26.1893
d ₁₃ = 0.6000 nd ₈ = 1.80633 ν d ₈ = 29.84
r ₁₄ = 29.3688
d ₁₄ = 1.7308
r ₁₅ = 34.5599 (aspherical surface)
d ₁₅ = 2.6320 nd ₉ = 1.44856 ν d ₉ = 81.56
r ₁₆ = -14.9473 (aspherical surface)
d ₁₆ = D (16) (variable)
r ₁₇ = -44.6362
d ₁₇ = 0.6500 nd ₁₀ = 1.91695 ν d ₁₀ = 35.25
r ₁₈ = 22.7837
d ₁₈ = 0.3427
r ₁₉ = 24.5498
d ₁₉ = 2.0669 nd ₁₁ = 1.93323 ν d ₁₁ = 20.88
r ₂₀ = 96.2460
d ₂₀ = D (20) (variable)
r ₂₁ = 36.4942
d ₂₁ = 4.1829 nd ₁₂ = 1.44845 ν d ₁₂ = 81.61
r ₂₂ = -22.3562
d ₂₂ = 1.4093
r ₂₃ = -320.2790 (aspherical surface)
d ₂₃ = 1.2000 nd ₁₃ = 1.85639 ν d ₁₃ = 40.10
r ₂₄ = 89.5878 (aspherical surface)
d ₂₄ = D (24) (variable)
r ₂₅ = ∞
d ₂₅ = 3.5600 nd ₁₄ = 1.51872 ν d ₁₄ = 64.20
r ₂₆ = ∞
d ₂₆ = 3.6260
r ₂₇ = ∞ (image plane)

(Cone coefficient (κ) and aspherical coefficient (A ₄ , A ₆ , A ₈ , A ₁₀ ))
(Third side)
κ = 1.00000,
A ₄ = 2.892 12 × 10 ^-5 , A ₆ = 5.65789 × 10 ^-8 ,
A ₈ = -1.53 115 x 10 ^-9 , A ₁₀ = 8.68 297 x 10 ^-12
(4th page)
κ ＝ -8.58887 × 10 ^-1 ,
A ₄ = 8.66238 × 10 ^-5 , A ₆ = 2.95590 × 10 ^-7 ,
A ₈ = -1.34983 x 10 ^-9 , A ₁₀ = -1.8503 0 x 10 ^-11
(15th page)
κ = 0,
A ₄ = -1.6875 5 x 10 ^-4 , A ₆ = 1.20015 x 10 ^-7 ,
A ₈ = -4.1556 52 x 10 ^-8 , A ₁₀ = 9.29682 x 10 ^-10
(Surface 16)
κ = 0,
A ₄ = -1.947 10 x 10 ^-5 , A ₆ = 8.105 68 x 10 ^-8 ,
A ₈ = -3.31981 × 10 ^-8 , A ₁₀ = 7.1 2003 × 10 ^-10
(Surface 23)
κ = 0,
A ₄ = -1.00793 x 10 ^-4 , A ₆ = 1.7333 3 x 10 ^-6 ,
A ₈ = -9.72346 x 10 ^-9 , A ₁₀ = 2.16596 x 10 ^-11
(Surface 24)
κ = 0,
A ₄ = -7.04945 x 10 ^-5 , A ₆ = 1.76173 x 10 ^-6 ,
A ₈ = -9.46483 x 10 ^-9 , A ₁₀ = 2.41 106 x 10 ^-11

(Various data)
Wide-angle end intermediate focal length Telephoto end focal length 12.1595 16.6985 22.9197
F number 3.2677 3.7396 4.3658
Half angle of view (ω) 52.3678 41.1105 31.0052
D (7) 14.4779 6.7237 0.9000
D (16) 2.8706 6.1328 10.6621
D (20) 2.6987 3.7214 4.0198
D (24) 13.6268 14.8321 16.8281

(Zoom lens group data)
Focal length 1 1-15.42 (f1)
2 8 18.66 (f2)
3 17 -31.07 (f3)
4 21 41.42 (f4)

(Numerical value related to conditional expression (1))
νd1n ave = 71.9
(Νd1n ave: average value of Abbe numbers of all negative lenses included in the first lens group G ₁ )

(Numerical value related to conditional expression (2))
nd1n max = 1.60
(Nd1n max: maximum value of the refractive index of the negative lens included in the first lens group G ₁ )

(Numerical value related to conditional expression (3))
f2 / | f1 | = 1.21

(Numerical value related to conditional expression (4))
f3 / f1 = 2.01

(Numerical value related to conditional expression (5))
f4 / | f1 | = 2.69

FIG. 4 is an aberration diagram of the zoom lens according to the second embodiment. In the spherical aberration diagram, the vertical axis represents the F number (indicated by FNO in the figure), the solid line is the d line (587.56 nm), the long broken line is the F line (486.13 nm), and the short broken line is the C line (656. It shows the characteristics of the wavelength corresponding to 28 nm). In the astigmatism diagram, the vertical axis represents the image height (indicated by Y in the figure), the solid line represents the characteristics of the sagittal plane (indicated by S in the figure), and the broken line represents the characteristics of the meridional plane (indicated by M in the figure). Shows. In the distortion diagram, the vertical axis represents the image height (indicated by Y in the figure).

FIG. 5 is a cross-sectional view taken along an optical axis showing the configuration of the zoom lens according to the third embodiment. In the zoom lens according to the present embodiment, optics other than the fact that the positive meniscus lens L ₃₁₄ with the convex surface facing the object side is arranged in place of the biconvex positive lens L ₁₄ of the first lens group G ₁ in the first embodiment. The configuration and movement of each lens group at the time of scaling are the same as those of the zoom lens shown in Example 1. Therefore, in this embodiment, the same members as those in the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

Hereinafter, various numerical data relating to the zoom lens according to the third embodiment will be shown.

(Surface data)
r ₁ = 33.9498
d ₁ = 1.2000 nd ₁ = 1.59561 ν d ₁ = 67.00
r ₂ = 12.5148
d ₂ = 5.4644
r ₃ = 20.5583 (aspherical surface)
d ₃ = 1.5000 nd ₂ = 1.59412 ν d ₂ = 67.02
r ₄ = 9.6000 (aspherical surface)
d ₄ = 7.5127
r ₅ = -33.0572
d ₅ = 0.6500 nd ₃ = 1.43810 ν d ₃ = 95.10
r ₆ = 17.4533
d ₆ = 3.1978 nd ₄ = 1.80831 ν d ₄ = 46.50
r ₇ = 198.7410
d ₇ = D (7) (variable)
r ₈ = 12.1269
d ₈ = 0.6000 nd ₅ = 1.88622 ν d ₅ = 40.14
r ₉ = 8.7861
d ₉ = 2.8000 nd ₆ = 1.61669 ν d ₆ = 44.27
r ₁₀ = 29.1110
d ₁₀ = 2.2471
r ₁₁ = ∞ (opening aperture)
d ₁₁ = 2.7420
r ₁₂ = 10.5006
d ₁₂ = 2.7823 nd ₇ = 1.44845 ν d ₇ = 81.61
r ₁₃ = -128.4436
d ₁₃ = 0.6000 nd ₈ = 1.80633 ν d ₈ = 29.84
r ₁₄ = 19.4029
d ₁₄ = 0.3867
r ₁₅ = 30.7206 (aspherical surface)
d ₁₅ = 2.1368 nd ₉ = 1.44856 ν d ₉ = 81.56
r ₁₆ = -24.3421 (aspherical surface)
d ₁₆ = D (16) (variable)
r ₁₇ = -77.3626
d ₁₇ = 0.6500 nd ₁₀ = 1.91695 ν d ₁₀ = 35.25
r ₁₈ = 19.7771
d ₁₈ = 0.2119
r ₁₉ = 20.4747
d ₁₉ = 1.8487 nd ₁₁ = 1.93323 ν d ₁₁ = 20.88
r ₂₀ = 42.3042
d ₂₀ = D (20) (variable)
r ₂₁ = 30.9906
d ₂₁ = 5.5489 nd ₁₂ = 1.44845 ν d ₁₂ = 81.61
r ₂₂ = -23.6498
d ₂₂ = 0.1500
r ₂₃ = -320.2790 (aspherical surface)
d ₂₃ = 1.2000 nd ₁₃ = 1.58547 ν d ₁₃ = 59.46
r ₂₄ = 74.7284 (aspherical surface)
d ₂₄ = D (24) (variable)
r ₂₅ = ∞
d ₂₅ = 3.5600 nd ₁₄ = 1.51872 ν d ₁₄ = 64.20
r ₂₆ = ∞
d ₂₆ = 3.6260
r ₂₇ = ∞ (image plane)

(Cone coefficient (κ) and aspherical coefficient (A ₄ , A ₆ , A ₈ , A ₁₀ ))
(Third side)
κ = 1.00000,
A ₄ = -7.18752 x 10 ^-6 , A ₆ = 1.73362 x 10 ^-8 ,
A ₈ = -4.11962 x 10 ^-10 , A ₁₀ = -2.58725 x 10 ^-13
(4th page)
κ ＝ -8.77947 × 10 ^-1 ,
A ₄ = 5.04440 × 10 ^-5 , A ₆ = 3.32103 × 10 ^-8 ,
A ₈ = 1.91678 × 10 ^-9 , A ₁₀ = -2.69349 × 10 ^-11
(15th page)
κ = 0,
A ₄ = -7.70822 x 10 ^-5 , A ₆ = 2.89943 x 10 ^-6 ,
A ₈ = 1.39540 × 10 ^-7 , A ₁₀ = 7.49915 × 10 ^-10
(Surface 16)
κ = 0,
A ₄ = 1.51955 × 10 ^-4 , A ₆ = 4.74831 × 10 ^-6 ,
A ₈ = 7.25441 × 10 ^-8 , A ₁₀ = 3.27423 × 10 ^-9
(Surface 23)
κ = 0,
A ₄ = -1.29885 x 10 ^-4 , A ₆ = 1.98555 x 10 ^-6 ,
A ₈ = -1.101 22 x 10 ^-8 , A ₁₀ = 2.259 63 x 10 ^-11
(Surface 24)
κ = 0,
A ₄ = -9.59295 x 10 ^-5 , A ₆ = 1.97820 x 10 ^-6 ,
A ₈ = -1.02422 x 10 ^-8 , A ₁₀ = 2.191 56 x 10 ^-11

(Various data)
Wide-angle end intermediate focal length Telephoto end focal length 12.1600 16.6991 22.9204
F number 3.1883 3.6745 4.3338
Half angle of view (ω) 52.3872 41.0321 31.0136
D (7) 15.1586 7.0723 0.9000
D (16) 1.6003 4.3537 7.9411
D (20) 4.4626 6.1158 7.1560
D (24) 11.6194 12.8430 15.3877

(Zoom lens group data)
Focal length 1 1 -16.57 (f1)
2 8 18.29 (f2)
3 17 -28.77 (f3)
4 21 36.94 (f4)

(Numerical value related to conditional expression (1))
νd1n ave = 76.4
(Νd1n ave: average value of Abbe numbers of all negative lenses included in the first lens group G ₁ )

(Numerical value related to conditional expression (2))
nd1n max = 1.60
(Nd1n max: maximum value of the refractive index of the negative lens included in the first lens group G ₁ )

(Numerical value related to conditional expression (3))
f2 / | f1 | = 1.10

(Numerical value related to conditional expression (4))
f3 / f1 = 1.74

(Numerical value related to conditional expression (5))
f4 / | f1 | = 2.23

FIG. 6 is an aberration diagram of the zoom lens according to the third embodiment. In the spherical aberration diagram, the vertical axis represents the F number (indicated by FNO in the figure), the solid line is the d line (587.56 nm), the long broken line is the F line (486.13 nm), and the short broken line is the C line (656. It shows the characteristics of the wavelength corresponding to 28 nm). In the astigmatism diagram, the vertical axis represents the image height (indicated by Y in the figure), the solid line represents the characteristics of the sagittal plane (indicated by S in the figure), and the broken line represents the characteristics of the meridional plane (indicated by M in the figure). Shows. In the distortion diagram, the vertical axis represents the image height (indicated by Y in the figure).

FIG. 7 is a cross-sectional view taken along an optical axis showing the configuration of the zoom lens according to the fourth embodiment. In the zoom lens according to the present embodiment, optics other than the fact that the biconvex positive lens L ₄₂₂ is arranged in place of the positive meniscus lens L ₂₂ whose convex surface is directed toward the object side of the second lens group G ₂ in the third embodiment. The configuration and movement of each lens group at the time of scaling are the same as those of the zoom lens shown in Example 3. Therefore, in this embodiment, the same members as those in the third embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

Hereinafter, various numerical data relating to the zoom lens according to the fourth embodiment will be shown.

(Surface data)
r ₁ = 30.2479
d ₁ = 1.2000 nd ₁ = 1.59561 ν d ₁ = 67.00
r ₂ = 11.2071
d ₂ = 4.8485
r ₃ = 20.1731 (aspherical surface)
d ₃ = 1.5000 nd ₂ = 1.6979 ν d ₂ = 55.46
r ₄ = 9.6000 (aspherical surface)
d ₄ = 5.8933
r ₅ = -34.8702
d ₅ = 0.6500 nd ₃ = 1.44845 ν d ₃ = 81.61
r ₆ = 14.1654
d ₆ = 3.3705 nd ₄ = 1.80831 ν d ₄ = 46.50
r ₇ = 186.7264
d ₇ = D (7) (variable)
r ₈ = 15.5490
d ₈ = 0.6000 nd ₅ = 1.83945 ν d ₅ = 42.72
r ₉ = 10.7089
d ₉ = 2.8000 nd ₆ = 1.61669 ν d ₆ = 44.27
r ₁₀ = -341.2266
d ₁₀ = 1.5000
r ₁₁ = ∞ (opening aperture)
d ₁₁ = 3.0722
r ₁₂ = 24.0280
d ₁₂ = 2.3343 nd ₇ = 1.44845 ν d ₇ = 81.61
r ₁₃ = -20.8607
d ₁₃ = 0.6000 nd ₈ = 1.80633 ν d ₈ = 29.84
r ₁₄ = 57.4121
d ₁₄ = 4.2744
r ₁₅ = 26.4365 (aspherical surface)
d ₁₅ = 2.9566 nd ₉ = 1.44856 ν d ₉ = 81.56
r ₁₆ = -21.3386 (aspherical surface)
d ₁₆ = D (16) (variable)
r ₁₇ = -49.9700
d ₁₇ = 0.6500 nd ₁₀ = 1.91695 ν d ₁₀ = 35.25
r ₁₈ = 21.7156
d ₁₈ = 0.2640
r ₁₉ = 23.7819
d ₁₉ = 2.2712 nd ₁₁ = 1.93323 ν d ₁₁ = 20.88
r ₂₀ = 111.3000
d ₂₀ = D (20) (variable)
r ₂₁ = 23.5605
d ₂₁ = 5.3175 nd ₁₂ = 1.44845 ν d ₁₂ = 81.61
r ₂₂ = -22.8051
d ₂₂ = 0.1500
r ₂₃ = -36.6347 (aspherical surface)
d ₂₃ = 1.2000 nd ₁₃ = 1.85639 ν d ₁₃ = 40.10
r ₂₄ = 600.0000 (aspherical surface)
d ₂₄ = D (24) (variable)
r ₂₅ = ∞
d ₂₅ = 3.5600 nd ₁₄ = 1.51872 ν d ₁₄ = 64.20
r ₂₆ = ∞
d ₂₆ = 3.6260
r ₂₇ = ∞ (image plane)

(Cone coefficient (κ) and aspherical coefficient (A ₄ , A ₆ , A ₈ , A ₁₀ ))
(Third side)
κ = 1.00000,
A ₄ = 8.45594 x 10 ^-5 , A ₆ = -6.91666 x 10 ^-7 ,
A ₈ = 1.64015 × 10 ^-9 , A ₁₀ = 1.14453 × 10 ^-12
(4th page)
κ ＝ -7.95393 × 10 ^-1 ,
A ₄ = 1.69360 × 10 ^-4 , A ₆ = -3.14226 × 10 ^-7 ,
A ₈ = -4.10529 x 10 ^-9 , A ₁₀ = 6.34 240 x 10 ^-12
(15th page)
κ = 0,
A ₄ = -4.70292 x 10 ^-5 , A ₆ = -8.706 26 x 10 ^-7 ,
A ₈ = 1.703 16 × 10 ^-8 , A ₁₀ = -4.548 18 × 10 ^-10
(Surface 16)
κ = 0,
A ₄ = 3.88403 × 10 ^-5 , A ₆ = -9.41698 × 10 ^-7 ,
A ₈ = 2.19223 x 10 ^-8 , A ₁₀ = -4.783 10 x 10 ^-10
(Surface 23)
κ = 0,
A ₄ = 9.25515 × 10 ^-5 , A ₆ = -3.58687 × 10 ^-7 ,
A ₈ = -6.60108 × 10 ^-10 , A ₁₀ = 9.65178 × 10 ^-12
(Surface 24)
κ = 0,
A ₄ = 1.27317 × 10 ^-4 , A ₆ = -1.46689 × 10 ^-7 ,
A ₈ = -1.87811 x 10 ^-9 , A ₁₀ = 1.71430 x 10 ^-11

(Various data)
Wide-angle end intermediate focal length Telephoto end focal length 12.1605 16.7002 22.9175
F number 3.3102 3.7520 4.3804
Half angle of view (ω) 52.3732 41.0349 31.0022
D (7) 14.2367 6.5795 0.9000
D (16) 1.5982 5.3054 10.4972
D (20) 2.2118 2.6212 2.6047
D (24) 12.7392 13.8556 15.5580

(Zoom lens group data)
Focal length 1 1 -14.18 (f1)
2 8 19.15 (f2)
3 17 -33.90 (f3)
4 21 53.76 (f4)

(Numerical value related to conditional expression (1))
νd1n ave = 68.0
(Νd1n ave: average value of Abbe numbers of all negative lenses included in the first lens group G ₁ )

(Numerical value related to conditional expression (2))
nd1n max = 1.70
(Nd1n max: maximum value of the refractive index of the negative lens included in the first lens group G ₁ )

(Numerical value related to conditional expression (3))
f2 / | f1 | = 1.35

(Numerical value related to conditional expression (4))
f3 / f1 = 2.39

(Numerical value related to conditional expression (5))
f4 / | f1 | = 3.79

FIG. 8 is an aberration diagram of the zoom lens according to the fourth embodiment. In the spherical aberration diagram, the vertical axis represents the F number (indicated by FNO in the figure), the solid line is the d line (587.56 nm), the long broken line is the F line (486.13 nm), and the short broken line is the C line (656. It shows the characteristics of the wavelength corresponding to 28 nm). In the astigmatism diagram, the vertical axis represents the image height (indicated by Y in the figure), the solid line represents the characteristics of the sagittal plane (indicated by S in the figure), and the broken line represents the characteristics of the meridional plane (indicated by M in the figure). Shows. In the distortion diagram, the vertical axis represents the image height (indicated by Y in the figure).

FIG. 9 is a cross-sectional view taken along an optical axis showing the configuration of the zoom lens according to the fifth embodiment. In the zoom lens according to the present embodiment, optics other than the fact that the negative meniscus lens L ₅₄₂ with the convex surface facing the object side is arranged in place of the biconcave negative lens L ₄₂ of the fourth lens group G ₄ in the third embodiment. The configuration and movement of each lens group at the time of scaling are the same as those of the zoom lens shown in Example 3. Aspherical surfaces are formed on both sides of the negative meniscus lens L ₅₄₂ . In this embodiment, the same members as those in the third embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

Hereinafter, various numerical data relating to the zoom lens according to the fifth embodiment will be shown.

(Surface data)
r ₁ = 34.3699
d ₁ = 1.2000 nd ₁ = 1.62032 ν d ₁ = 63.39
r ₂ = 12.8489
d ₂ = 5.4326
r ₃ = 20.1046 (aspherical surface)
d ₃ = 1.5000 nd ₂ = 1.59412 ν d ₂ = 67.02
r ₄ = 9.7698 (aspherical surface)
d ₄ = 7.1083
r ₅ = -37.0135
d ₅ = 0.6500 nd ₃ = 1.44845 ν d ₃ = 81.61
r ₆ = 16.4695
d ₆ = 3.9966 nd ₄ = 1.80831 ν d ₄ = 46.50
r ₇ = 20023.1523
d ₇ = D (7) (variable)
r ₈ = 12.6227
d ₈ = 0.6000 nd ₅ = 1.80633 ν d ₅ = 29.84
r ₉ = 9.710
d ₉ = 2.4915 nd ₆ = 1.62408 ν d ₆ = 36.30
r ₁₀ = 30.0925
d ₁₀ = 2.5572
r ₁₁ = ∞ (opening aperture)
d ₁₁ = 2.7742
r ₁₂ = 10.5901
d ₁₂ = 2.8267 nd ₇ = 1.44845 ν d ₇ = 81.61
r ₁₃ = -52.0180
d ₁₃ = 0.6000 nd ₈ = 1.80633 ν d ₈ = 29.84
r ₁₄ = 20.5123
d ₁₄ = 0.2592
r ₁₅ = 25.0330 (aspherical surface)
d ₁₅ = 2.0670 nd ₉ = 1.44856 ν d ₉ = 81.56
r ₁₆ = -29.3332 (aspherical surface)
d ₁₆ = D (16) (variable)
r ₁₇ = -45.0377
d ₁₇ = 0.6500 nd ₁₀ = 1.91695 ν d ₁₀ = 35.25
r ₁₈ = 28.2018
d ₁₈ = 2.9179
r ₁₉ = 40.1365
d ₁₉ = 2.0151 nd ₁₁ = 1.93323 ν d ₁₁ = 20.88
r ₂₀ = 383.0135
d ₂₀ = D (20) (variable)
r ₂₁ = 77.2896
d ₂₁ = 4.6070 nd ₁₂ = 1.44845 ν d ₁₂ = 81.61
r ₂₂ = -21.4598
d ₂₂ = 0.1500
r ₂₃ = 34.0442 (aspherical surface)
d ₂₃ = 1.2000 nd ₁₃ = 1.85639 ν d ₁₃ = 40.10
r ₂₄ = 24.7568 (aspherical surface)
d ₂₄ = D (24) (variable)
r ₂₅ = ∞
d ₂₅ = 3.5600 nd ₁₄ = 1.51872 ν d ₁₄ = 64.20
r ₂₆ = ∞
d ₂₆ = 3.6260
r ₂₇ = ∞ (image plane)

(Cone coefficient (κ) and aspherical coefficient (A ₄ , A ₆ , A ₈ , A ₁₀ ))
(Third side)
κ = 1.00000,
A ₄ = -2.61092 x 10 ^-5 , A ₆ = 3.18825 x 10 ^-8 ,
A ₈ = 2.1 2005 × 10 ^-10 , A ₁₀ = -4.15 154 × 10 ^-12
(4th page)
κ = -9.32 256 × 10 ^-1 ,
A ₄ = 3.57757 × 10 ^-5 , A ₆ = -2.02911 × 10 ^-8 ,
A ₈ = 3.92053 × 10 ^-9 , A ₁₀ = -3.0828 1 × 10 ^-11
(15th page)
κ = 0,
A ₄ = -2.59845 x 10 ^-5 , A ₆ = 4.46462 x 10 ^-6 ,
A ₈ = 1.00161 × 10 ^-7 , A ₁₀ = 1.00288 × 10 ^-9
(Surface 16)
κ = 0,
A ₄ = 2.21 120 × 10 ^-4 , A ₆ = 6.145 46 × 10 ^-6 ,
A ₈ = 6.05775 × 10 ^-8 , A ₁₀ = 3.18262 × 10 ^-9
(Surface 23)
κ = 0,
A ₄ = -1.732327 x 10 ^-4 , A ₆ = 7.98530 x 10 ^-7 ,
A ₈ = 9.71295 × 10 ^-11 , A ₁₀ =-9.24 158 × 10 ^-12
(Surface 24)
κ = 0,
A ₄ = -1.671 22 x 10 ^-4 , A ₆ = 9.58443 x 10 ^-7 ,
A ₈ = -7.731 26 x 10 ^-10 , A ₁₀ = -5.90203 x 10 ^-12

(Various data)
Wide-angle end intermediate focal length Telephoto end focal length 12.1593 16.6983 22.9197
F number 3.1215 3.5937 4.2742
Half angle of view (ω) 52.3842 41.1375 31.0037
D (7) 16.0593 7.4453 0.9000
D (16) 1.6042 3.2763 5.7054
D (20) 1.9278 4.2823 6.6782
D (24) 11.4118 13.2069 15.9272

(Zoom lens group data)
Focal length 1 1 -17.87 (f1)
2 8 17.87 (f2)
3 17 -34.51 (f3)
4 21 47.15 (f4)

(Numerical value related to conditional expression (1))
νd1n ave = 70.7
(Νd1n ave: average value of Abbe numbers of all negative lenses included in the first lens group G ₁ )

(Numerical value related to conditional expression (2))
nd1n max = 1.62
(Nd1n max: maximum value of the refractive index of the negative lens included in the first lens group G ₁ )

(Numerical value related to conditional expression (3))
f2 / | f1 | = 1.00

(Numerical value related to conditional expression (4))
f3 / f1 = 1.93

(Numerical value related to conditional expression (5))
f4 / | f1 | = 2.64

FIG. 10 is an aberration diagram of the zoom lens according to the fifth embodiment. In the spherical aberration diagram, the vertical axis represents the F number (indicated by FNO in the figure), the solid line is the d line (587.56 nm), the long broken line is the F line (486.13 nm), and the short broken line is the C line (656. It shows the characteristics of the wavelength corresponding to 28 nm). In the astigmatism diagram, the vertical axis represents the image height (indicated by Y in the figure), the solid line represents the characteristics of the sagittal plane (indicated by S in the figure), and the broken line represents the characteristics of the meridional plane (indicated by M in the figure). Shows. In the distortion diagram, the vertical axis represents the image height (indicated by Y in the figure).

The correspondence table of the conditional expression in each of the above Examples is shown below.

In the numerical data in each of the above embodiments, r ₁ , r ₂ , ... Are the radius of curvature of the lens, aperture aperture surface, etc., and d ₁ , d ₂ , ... Are the lens, aperture aperture, etc. The wall thickness or their interplanar spacing, nd ₁ , nd ₂ , ... Is the refractive index for the d-line (587.56 nm) of the lens, etc., and νd ₁ , νd ₂ , ... For the d-line of the lens, etc. It shows the Abbe number. The unit of length is "mm", and the unit of angle is "°".

Further, in each of the above aspherical shapes, the height in the direction perpendicular to the optical axis is h, the amount of displacement in the optical axis direction at the height h when the lens surface top is the origin is Z, and the paraxial curvature radius is r. When the cone coefficient is κ, the _nth -order aspherical coefficient is An, and the image plane direction is positive, it is expressed by the following equation.

As described above, the zoom lens of each of the above embodiments can achieve miniaturization, weight reduction, and high resolution while ensuring a high magnification ratio by satisfying each of the above conditional expressions. , It is also suitable for movie shooting. In particular, by satisfying the conditional expression (1), chromatic aberration can be satisfactorily corrected. By satisfying the conditional expression (2), the weight of the optical system can be further reduced. By satisfying the conditional equation (3), the overall length of the optical system can be further shortened while maintaining good resolution performance (particularly, good correction of spherical aberration is possible). By satisfying the conditional equation (4), the movement amount of the third lens group G ₃ during focusing is suppressed while maintaining good resolution performance (particularly, good correction of spherical aberration is possible). Therefore, the total length of the optical system can be further shortened. By satisfying the conditional expression (5), the overall length of the optical system can be further shortened while maintaining good resolution performance (particularly, good correction of curvature of field becomes possible).

Further, in the zoom lens of each of the above embodiments, the aberration correction ability can be further improved by appropriately arranging a lens or a junction lens having an aspherical surface formed therein.

<Application example>
Hereinafter, an example in which the zoom lens shown in Examples 1 to 5 of the present invention is applied to an image pickup apparatus will be shown. FIG. 11 is a diagram showing an application example of an image pickup apparatus provided with a zoom lens according to the present invention. FIG. 11 shows a state in which the lens barrel 110 accommodating the zoom lens 100 is attached to the image pickup apparatus 200.

The zoom lens 100 is shown in Examples 1 to 5. The lens barrel 110 is attached to and detached from the image pickup apparatus 200 via the mount portion 111. As the mount portion 111, a mount such as a screw type or a bayonet type is used. This example uses a bayonet-type mount.

The image captured by the zoom lens 100 is imaged on the image pickup surface of the image pickup device 201 (CCD, CMOS, etc.) mounted on the image pickup device 200, and the output signal from the image pickup element 201 related to the image is a signal processing circuit (not shown). The image is displayed on the display unit 202.

FIG. 11 shows an example in which the zoom lens according to the present invention is used in a mirrorless interchangeable-lens camera. However, the zoom lens according to the present invention can be used not only for a mirrorless interchangeable-lens camera but also for other interchangeable lens cameras, digital still cameras, surveillance cameras, video cameras and the like.

As described above, the zoom lens according to the present invention is useful for a small image pickup device that requires a high magnification ratio and high resolution performance, and is a lens interchangeable type camera such as a mirrorless single-lens camera or a single-lens reflex camera. It is suitable for surveillance cameras, video cameras, digital still cameras and the like.

G ₁ 1st lens group G ₂ 2nd lens group G ₃ 3rd lens group G ₄ 4th lens group L ₁₁ , L ₁₂ , L ₂₁ , L ₃₂ , L ₅₄₂ Negative meniscus lens L ₁₃ , L ₂₄ , L ₃₁ , L ₄₂ Double Concave Negative Lens L _14, L ₂₃ , L ₂₅ , L ₄₁ , L ₄₂₂ Double Convex Positive Lens L ₂₂ , L ₃₂ , L ₃₁₄ Positive Menis Cass Lens STP Aperture Aperture CG Cover Glass IMG Image Surface 100 Zoom Lens 110 Lens Mirror Cylinder 111 Mount unit 200 Imaging device 201 Imaging element 202 Display unit

Claims (4)

The first lens group having a negative refractive power, the second lens group having a positive refractive power, the third lens group having a negative refractive power, and the third lens group having a positive refractive power arranged in order from the object side. It consists of the 4th lens group.
By changing the distance on the optical axis of each lens group, the magnification is changed from the wide-angle end to the telephoto end.
At the time of scaling, the first lens group is moved so as to draw a convex trajectory toward the image side.
Focusing is performed by moving the third lens group along the optical axis.
A zoom lens characterized by satisfying the conditional expression shown below.
(1) νd1n ave ≧ 67.5
(3) 0.75 ≤ f2 / | f1 | ≤ 1.70
(5) 2.10 ≤ f4 / | f1 | ≤ 4.20
However, νd1nave is the average value of the Abbe numbers of all the negative lenses included in the first lens group, f1 is the focal length of the first lens group, f2 is the focal length of the second lens group , and f4 is the first lens group. The focal lengths of the four lens groups are shown. The zoom lens according to claim 1, wherein the zoom lens satisfies the conditional expression shown below.
(2) nd1n max ≦ 1.80
However, nd1n max indicates the maximum value of the refractive index of the negative lens included in the first lens group. The zoom lens according to claim 1 or 2, wherein the zoom lens satisfies the conditional expression shown below.
(4) 1.50 ≦ f3 / f1 ≦ 2.70
However, f1 indicates the focal length of the first lens group, and f3 indicates the focal length of the third lens group. An image pickup apparatus comprising the zoom lens according to any one of claims 1 to 3 and an image pickup element that converts an optical image formed by the zoom lens into an electrical signal.

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