JP4227223B2 - Zoom lens - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a zoom lens, and more particularly to a zoom lens suitable for a still camera such as a single-lens reflex camera or a video camera that uses a so-called rear focus and floating focus and has an anti-vibration function.
[0002]
[Prior art]
Conventionally, single-focus lenses for single-lens reflex cameras, particularly wide-angle lenses and macro lenses, have a so-called floating focus that moves two lens groups independently during focusing in order to prevent deterioration of optical performance in close-up shooting. The so-called focus method is used.
[0003]
Conventionally, as a zoom lens focusing method in a video camera, a still camera, or the like, a so-called front lens focusing method in which focusing is performed in the first group is common. This method has an advantage that the lens barrel structure can be simplified because the amount of extension of the focus lens with respect to the same object distance is constant regardless of the zoom position. However, when used in a high-magnification zoom lens, it is necessary to increase the lens outer diameter of the front lens in order to secure the amount of peripheral light during close-up shooting, which may hinder downsizing of the lens system or a telephoto zoom lens In particular, the auto focus cameras that are currently popular have the disadvantages that a high torque motor is required and the AF (auto focus) speed is slow to drive the first lens group, which has a heavy lens weight, with focus. there were.
[0004]
As other focus methods, various methods such as a rear focus method and an inner focus method have been proposed.
[0005]
This method has the advantage that the focusing lens group that composes the zoom lens can be made relatively small and light, so that it can be used for autofocus cameras, enabling quick focusing, etc., and downsizing the entire lens system There is an advantage of being able to
[0006]
Conventionally, rear focus type zoom lenses have been proposed in, for example, Japanese Patent Laid-Open Nos. 3-225307, 3-225308, and 3-225309. These utilize a rear focus or a floating focus in a telephoto zoom lens having a five-group configuration.
[0007]
Conventionally, as zoom lenses having a six-group configuration of positive, negative, positive, negative, positive, and negative refractive powers, there are JP-A-4-186212 and JP-A-8-29686. Japanese Patent Laid-Open No. 4-186212 is a high-magnification zoom lens including a wide angle region, and Japanese Patent Laid-Open No. 8-29686 is a telephoto zoom lens having a zoom ratio of about 4 times.
[0008]
Conventionally, a zoom lens having a so-called image stabilization function for correcting camera shake at the time of shooting is disclosed in Japanese Patent Laid-Open No. 8-136863.
[0009]
[Problems to be solved by the invention]
As a method for correcting blurring of a photographed image, there is a problem that an electrical method cannot be applied to a silver halide photographic camera. In addition, the prism that can change the prism apex angle on the object side of the optical system, the prism apex angle is changed in accordance with the blur, and the correction is made by mounting the prism on the object side of the optical system. For a large-diameter optical system, the correction optical system and the driving device are increased in size. Also, in terms of optical performance, there is a problem in that it becomes difficult to obtain a high-quality image because chromatic aberration due to the prism action occurs during correction.
[0010]
In addition, the method of shifting the image position by decentering a part of the moving lens group of the optical system and correcting the blurring makes the apparatus compact by appropriately selecting and arranging the moving lens group. be able to.
[0011]
However, in this method, the moving lens group is small and light, and it is necessary to perform the displacement action of a large image position with a small amount of movement while correcting decentration aberrations and preventing deterioration of image quality as much as possible. There was a problem that it was very difficult to meet.
[0012]
On the other hand, the inner focus type lens group for focusing is small and lightweight, so it is easy to operate and high-speed operation is possible, and the center of gravity of the entire lens system when focusing on an object at infinity and a close object is possible. There are advantages such as little change and easy holding.
[0013]
On the other hand, when the inner focus type is adopted in a lens having a bright F number, the aberration fluctuation at the time of focusing becomes large, and it is difficult to correct the aberration fluctuation at this time satisfactorily, which causes a decrease in optical performance. .
[0014]
According to the present invention, the zoom lens is composed of six lens groups having a predetermined refractive power as a whole, and by appropriately setting the refractive power of each lens group, the moving condition of each lens group for zooming, and the like. An object of the present invention is to provide a zoom lens having high optical performance over the entire zooming range while reducing the number of lenses and shortening the total lens length.
[0015]
A further object of the present invention is to appropriately dispose each lens element when correcting a displacement (blur) of a captured image by driving a part of a lens group of an optical system eccentrically in a direction perpendicular to the optical axis. Accordingly, it is an object of the present invention to provide a zoom lens that can reduce the size of the entire apparatus by satisfactorily correcting various decentering aberrations and realizing sufficiently large displacement correction (blur correction) with a sufficiently small amount of decentering drive.
[0016]
A further object of the present invention is to provide a zoom lens that satisfactorily corrects aberration fluctuations during focusing over a wide range of object distances from an infinite object to a close object while adopting an inner focus type and a floating type. is there.
[0017]
[Means for Solving the Problems]
The zoom lens according to the present invention includes, in order from the object side, a first group having a positive refractive power, a second group having a negative refractive power, a third group having a positive refractive power, a fourth group having a negative refractive power, and a positive refraction. the fifth group of force, is composed of six lens groups in the sixth unit having a negative refractive power, wherein at the zoom lens to perform zooming by changing the distances between the lens groups, the third group of the object side more positive lens, meniscus-shaped negative lens having a concave surface on the object side is constituted of a positive lens having a strong convex surface facing the object side, the fifth group was its strong concave surface from the object side positive lens, the image side The sixth group is composed of a negative lens, a positive lens, and a negative lens from the object side, and the distance between the i-th group and the i + 1th group at the wide-angle end is DiW, i-th The distance between the telephoto end of the first lens group and the (i + 1) th lens group is DiT, and the moving amount of the first lens group when zooming from the wide angle end to the telephoto end is m , First, second, third, a focal length of the fifth group in order f1, f2, f3, f5, the focal length at the telephoto end of the entire system was fT,
D1W <D1T
D2W> D2T
D3W <D3T
D4W> D4T
D5W> D5T
−0.23 <m1 / fT <−0.19
0.44 <f1 / fT <0.52
0.11 <| f2 | / fT <0.15
0.16 <f3 / fT <0.25
0.12 <f5 / fT <0.16
It satisfies the following conditional expression.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a lens cross-sectional view at a wide angle end according to Numerical Example 1 of the present invention, and FIGS. 2 to 5 are an object at wide angle end, an object at a wide angle end close to (4 m), and a telephoto end at infinity according to Numerical Example 1 according to the present invention. FIG. 7 is an aberration diagram for an object and an object close to the telephoto end (4 m).
[0019]
6 is a lens cross-sectional view at the wide-angle end according to Numerical Example 2 of the present invention, and FIGS. 7 to 10 are an object at wide-angle end infinity, an object close to the wide-angle end (4 m), and a telephoto end at infinity according to Numerical Example 2 according to the present invention. FIG. 7 is an aberration diagram for an object and an object close to the telephoto end (4 m).
[0020]
FIG. 11 is a lens cross-sectional view at the wide angle end according to Numerical Example 3 of the present invention, and FIGS. 12 to 15 are a wide angle end infinite object, a wide angle end closest object (4 m), and a telephoto end at infinity according to Numerical Example 3 of the present invention. FIG. 7 is an aberration diagram for an object and an object close to the telephoto end (4 m).
[0022]
However, the closest object 4m is when the unit of the numerical example described later is expressed in mm.
[0023]
In the figure, L1 is a first group having positive refractive power, L2 is a second group having negative refractive power, L3 is a third group having positive refractive power, L4 is a fourth group having negative refractive power, and L5 is positive. 5 is a fifth group of refractive power, L6 is a sixth group of negative refractive power, and SP is a stop. The arrows indicate the movement trajectory of each lens unit upon zooming from the wide-angle end to the telephoto end.
[0024]
In this embodiment, when zooming from the wide-angle end to the telephoto end, the first, third to sixth are moved so as to satisfy the conditional expressions (1) to (5) described above.
[0025]
That is, the distance between the first group and the second group is increased, the distance between the second group and the third group is decreased, the distance between the third group and the fourth group is increased, and the distance between the fourth group and the fifth group is increased. The predetermined lens group is moved so that the distance between the fifth group and the sixth group decreases.
[0026]
In this embodiment, by changing the distance between the lens groups so as to satisfy the conditional expressions (1) to (5) and changing the magnification, each lens group is assigned a change in magnification, and from the wide-angle end to the telephoto end. Aberration correction is performed in a well-balanced manner and compactness is achieved.
[0027]
In Numerical Examples 1 to 3 , when zooming from the wide-angle end to the telephoto end, the first group, the third group, the fourth group, the fifth group, and the sixth group move to the object side, and the second group is fixed. is there. Focusing from an infinite object to a close object is performed by moving the sixth group to the image side and moving the fourth group to the object side. The movement for focusing to the same object distance is constant in the fourth group, and the sixth group increases as the focal length increases. In addition, so-called image stabilization for correcting camera shake or the like is possible, and image stabilization is performed by moving the second group in a direction perpendicular to the optical axis.
[0028]
In the present embodiment, the third lens unit is composed of a positive lens, a meniscus negative lens having a concave surface facing the object side, and a positive lens having a strong convex surface facing the object side, thereby enabling good aberration correction. The sixth group is composed of a negative lens, a positive lens, and a negative lens from the object side to reduce aberration fluctuations during focusing. In Numerical Examples 2 to 4, the sixth group is a single cemented lens unit. This reduces surface reflection ghosts and simplifies installation into the lens barrel. Further, each lens group is configured to satisfy the conditional expressions (6) to (10), and good optical performance is obtained.
[0029]
Next, the meaning of conditional expressions (6) to (10) will be described.
[0030]
Conditional expression (6) defines the amount of movement of the first group at the time of zooming from the wide-angle end to the telephoto end with respect to the focal length of the entire system at the telephoto end. In particular, in the present invention, the second group In order to perform vibration isolation, it is desired to reduce the weight and size of the second group, and to achieve this. A mirror for realizing this movement is a good direction for shortening the total lens length at the wide-angle end and reducing the lens outer diameter of the second group when the movement amount of the first group increases beyond the lower limit. The cylinder structure becomes complicated. If the amount of movement of the first lens unit becomes small beyond the upper limit, it becomes difficult to reduce both the total lens length at the wide-angle end and aberration correction at the telephoto end.
[0031]
Conditional expression (7) defines the range of the focal length of the first group relative to the focal length of the entire system at the telephoto end, and in the same way as the above conditional expression, while achieving the weight reduction and compactness of the second group in particular. This is to satisfy good performance. When the positive refractive power of the first group becomes stronger beyond the lower limit, it is a good direction for shortening the overall lens length and reducing the outer diameter of the lens. However, aberrations generated in the first group, particularly spherical aberration, increase, It becomes difficult to correct with the lens group. If the positive refractive power of the first lens group is weakened beyond the upper limit, it is a good direction for correcting aberrations, but it is against compactness.
[0032]
Conditional expression (8) defines the range of the focal length of the second group with respect to the focal length of the entire system at the telephoto end. In general, as means for reducing the size of the zoom lens, it is conceivable to increase the refractive power of each lens group, particularly to increase the refractive power of the second group. However, in the telephoto zoom lens, as the refractive power of the second group is increased, the refractive power arrangement of the lens system becomes a retrofocus type, and the back focus becomes longer than necessary. It is necessary to prevent an increase in back focus by making the lens an extreme telephoto type.
[0033]
Therefore, in the present invention, as a compacting method, compacting is achieved not by the above-described method but by multi-grouping. At this time, the focal length of the second group is defined so as to satisfy the conditional expression (8). If the refractive power of the second group becomes stronger beyond the lower limit, the amount of movement of each lens group for zooming can be reduced, but the back focus becomes longer and various aberrations generated in the second group become undesirably large. If the refractive power of the second group becomes weaker than the upper limit value, it is necessary to increase the amount of movement of each lens group for zooming, which is not preferable because the lens system increases.
[0034]
Conditional expression (9) defines the range of the focal length of the third group with respect to the focal length of the entire system at the telephoto end. If out of the range of the conditional expression, it becomes difficult to correct various aberrations in a balanced manner from the wide-angle end to the telephoto end.
[0035]
Conditional expression (10) defines the range of the focal length of the fifth group with respect to the focal length of the entire system at the telephoto end. When the refractive power of the fifth group becomes stronger beyond the lower limit, it is a good direction for reducing the size of the lens system, but various aberrations occurring in the fifth group, particularly spherical aberration at the wide-angle end, become unfavorable. If the upper limit is exceeded and the refractive power of the fifth group becomes weak, the total lens length becomes long, which is not preferable.
[0036]
In the present invention, it is preferable that at least one of the following conditions is satisfied in order to obtain a high optical performance over the entire screen with less aberration fluctuation over the entire zoom range.
[0037]
(A-1) Focusing from an infinite object to a close object is performed by moving the 4th group to the object side, moving the 6th group to the image side, and moving the 4th group to the object side, with the concave surface facing the 4th group to the object side. When the focal length of the fourth lens unit is f4, the lateral angle of the sixth lens unit at infinity and the horizontal magnification of the telephoto end are β6W and β6T, respectively,
0.28 <| f4 | / fT <0.4 (11)
2.0 <β6W <2.4 (12)
2.6 <β6T <3 (13)
The following conditional expression is satisfied.
[0038]
Conditional expression (11) defines the range of the fourth group focal length with respect to the focal length of the entire system at the telephoto end. When the refractive power of the fourth group becomes stronger beyond the lower limit, it is necessary to increase the refractive power of the sixth group accordingly, and in particular, many off-axis aberrations occur, and the refractive power of the fourth group exceeds the upper limit. As the lens becomes weaker, it becomes difficult to change the spherical aberration due to zooming corrected in this group.
[0039]
Conditional expressions (12) and (13) are the magnification at the wide-angle end of the sixth group and the magnification at the telephoto end of the sixth group for an infinitely distant object, respectively, in order to perform focusing in the sixth group satisfactorily It is. As a condition for focusing in the sixth group, it is necessary to appropriately set the sensitivity of the sixth group (the amount of movement of the image plane relative to the amount of movement of the sixth group).
In this embodiment, the sensitivity S6 of the sixth group is S6 = (1−β6 ² ).
It is represented by It is not preferable that the absolute value of the sensitivity S6 becomes extremely large or extremely small. If the sensitivity S6 becomes zero during zooming, it is impossible to perform focusing with this lens group. If the lateral magnification β6W decreases beyond the lower limit of conditional expression (12), the sensitivity of the sixth group at the wide-angle end decreases, and if the lateral magnification β6W increases beyond the upper limit, the sixth at the wide-angle end. Increases group sensitivity. When the lateral magnification β6T decreases beyond the lower limit of conditional expression (13), the sensitivity of the sixth lens group at the telephoto end decreases, and when the lateral magnification β6T increases beyond the upper limit, the sixth at the telephoto end. Increases group sensitivity. Therefore, it is necessary to make the refractive power arrangement appropriate so as to satisfy the conditional expression.
[0040]
In addition, the fourth lens unit is a meniscus negative lens having a concave surface on the object side, thereby suppressing the variation of spherical aberration due to zooming.
[0041]
(A-2) The amount of movement for focusing of the fourth group from an object at infinity to an object at an arbitrary finite distance is made substantially constant regardless of the focal length.
[0042]
In the present invention, so-called floating is performed in which the fourth group is moved for aberration correction during focusing. Here, floating will be described. In the present invention, the main focus group is the sixth group, and the fourth group functions to correct aberration fluctuations due to focusing, particularly image plane fluctuations on the wide-angle side. Accordingly, the amount of extension of the fourth group can be changed relatively intentionally. In the present invention, the amount of extension of the fourth group with respect to the same object distance is made substantially constant regardless of the focal length. Thereby, the movement of the focus of the fourth group can be realized with a simple lens barrel structure as in the conventional front lens focus.
[0043]
(A-3) The first group includes a positive lens from the object side and a negative meniscus lens having a concave surface facing the image side, and a positive lens, and the second group includes two negative lenses and one positive lens. This is made up of lenses, and the second group is moved in a direction substantially perpendicular to the optical axis to correct the blur of the photographed image.
[0044]
As a result, the entire lens system is reduced in size while having high optical performance.
[0045]
(A-4) The six lenses in the sixth group are cemented.
[0046]
(A-5) In order to satisfactorily correct the variation in spherical aberration on the tele side and the variation in field curvature on the wide side due to focusing, and in order to achieve compactness, in this embodiment, the fifth lens unit is a positive lens from the object side. It consists of a negative lens, a positive lens, and a positive lens with a strong concave surface facing the image side.
[0047]
Next, numerical examples of the present invention will be shown. In the numerical example, ri is the radius of curvature of the i-th lens surface in order from the object side, di is the i-th lens thickness and air spacing from the object side, and ni and vi are respectively the i-th lens in order from the object side. Refractive index and Abbe number of glass.
[0048]
Table 1 shows the relationship between the above-described conditional expressions and numerical values in the numerical examples. Table 2 shows the amount of movement of the focus lens group (the fourth group and the sixth group).
[0049]
Numerical example 1
f = 103.0 to 389.3 FNo = 1: 4.6 to 5.8 2ω = 23.7 ° to 6.4 °
r 1 = 123.671 d 1 = 5.10 n 1 = 1.55963 v 1 = 61.2
r 2 = 455.856 d 2 = 0.15
r 3 = 112.146 d 3 = 3.50 n 2 = 1.74950 v 2 = 35.0
r 4 = 66.664 d 4 = 0.27
r 5 = 66.084 d 5 = 10.70 n 3 = 1.43387 v 3 = 95.1
r 6 = -45472.240 d 6 = variable
r 7 = ∞ d 7 = variable
r 8 = 2400.354 d 8 = 1.40 n 4 = 1.69680 v 4 = 55.5
r 9 = 63.095 d 9 = 3.30
r10 = -62.783 d10 = 1.40 n 5 = 1.62299 v 5 = 58.2
r11 = 70.270 d11 = 2.70 n 6 = 1.84666 v 6 = 23.8
r12 = 1061.104 d12 = variable
r13 = -177.051 d13 = 4.80 n 7 = 1.43875 v 7 = 95.0
r14 = -35.917 d14 = 1.20
r15 = -39.113 d15 = 2.00 n 8 = 1.69680 v 8 = 55.5
r16 = -68.642 d16 = 0.20
r17 = 60.698 d17 = 3.00 n 9 = 1.62299 v 9 = 58.2
r18 = 477.360 d18 = 2.50
r19 = (Aperture) d19 = Variable
r20 = -40.615 d20 = 2.90 n10 = 1.60311 v10 = 60.6
r21 = -77.406 d21 = variable
r22 = 790.908 d22 = 3.30 n11 = 1.48749 v11 = 70.2
r23 = -59.012 d23 = 0.15
r24 = 305.494 d24 = 1.50 n12 = 1.80518 v12 = 25.4
r25 = 46.466 d25 = 1.30
r26 = 83.041 d26 = 3.30 n13 = 1.48749 v13 = 70.2
r27 = -146.852 d27 = 0.15
r28 = 41.620 d28 = 4.00 n14 = 1.66672 v14 = 48.3
r29 = 2851.209 d29 = variable
r30 = 381.304 d30 = 1.45 n15 = 1.80610 v15 = 40.9
r31 = 36.649 d31 = 0.33
r32 = 36.066 d32 = 4.30 n16 = 1.72825 v16 = 28.5
r33 = -220.633 d33 = 1.45 n17 = 1.77250 v17 = 49.6
r34 = 48.298

Focal length 102.99 164.43 389.28
Variable interval
d 6 7.03 40.76 91.36
d 7 2.00 2.00 2.00
d 12 22.21 15.73 6.42
d 19 11.72 16.09 22.24
d 21 26.74 18.89 7.51
d 29 23.08 19.08 1.73
skinf 73.85 87.81 119.69

f FNo 2w w
103.0 4.6 23.7 11.9
164.4 5.2 15.0 7.5
389.3 5.8 6.4 3.2

Numerical example 2
f = 102.7 to 389.2 FNo = 1: 4.6 to 5.8 2ω = 23.8 ° to 6.4 °
r 1 = 117.449 d 1 = 5.20 n 1 = 1.48749 v 1 = 70.2
r 2 = 506.654 d 2 = 0.15
r 3 = 108.121 d 3 = 3.50 n 2 = 1.74950 v 2 = 35.0
r 4 = 67.497 d 4 = 0.12
r 5 = 68.071 d 5 = 10.40 n 3 = 1.43387 v 3 = 95.1
r 6 = -7912.525 d 6 = variable
r 7 = ∞ d 7 = variable
r 8 = -371.134 d 8 = 1.40 n 4 = 1.71300 v 4 = 53.9
r 9 = 58.940 d 9 = 3.50
r10 = -57.436 d10 = 1.40 n 5 = 1.62299 v 5 = 58.2
r11 = 64.689 d11 = 2.60 n 6 = 1.84666 v 6 = 23.8
r12 = -28288.289 d12 = variable
r13 = 225.869 d13 = 5.90 n 7 = 1.43875 v 7 = 95.0
r14 = -36.078 d14 = 1.10
r15 = -37.529 d15 = 2.00 n 8 = 1.70154 v 8 = 41.2
r16 = -56.400 d16 = 0.20
r17 = 52.957 d17 = 2.40 n 9 = 1.62012 v 9 = 49.5
r18 = 110.626 d18 = 3.00
r19 = (Aperture) d19 = Variable
r20 = -41.960 d20 = 2.90 n10 = 1.60311 v10 = 60.6
r21 = -88.566 d21 = variable
r22 = 1463.246 d22 = 3.50 n11 = 1.48749 v11 = 70.2
r23 = -55.561 d23 = 0.15
r24 = 309.587 d24 = 1.60 n12 = 1.80518 v12 = 25.4
r25 = 46.432 d25 = 1.30
r26 = 83.246 d26 = 3.20 n13 = 1.51633 v13 = 64.1
r27 = -163.106 d27 = 0.15
r28 = 41.344 d28 = 4.00 n14 = 1.66672 v14 = 48.3
r29 = 598.945 d29 = variable
r30 = 431.689 d30 = 1.40 n15 = 1.83481 v15 = 42.7
r31 = 36.686 d31 = 3.90 n16 = 1.72825 v16 = 28.5
r32 = -272.789 d32 = 1.40 n17 = 1.77250 v17 = 49.6
r33 = 53.286

Focal length 102.68 161.53 389.19
Variable interval
d 6 7.74 41.09 91.13
d 7 2.00 2.00 2.00
d 12 20.89 15.49 6.44
d 19 11.91 14.86 20.25
d 21 26.80 19.97 10.38
d 29 22.57 18.94 1.94
skinf 74.01 86.92 117.18

f FNo 2w w
102.7 4.6 23.8 11.9
161.5 5.1 15.3 7.6
389.2 5.8 6.4 3.2

Numerical example 3
f = 102.9 to 389.2 FNo = 1: 4.6 to 5.8 2ω = 23.7 ° to 6.4 °
r 1 = 112.875 d 1 = 5.60 n 1 = 1.48749 v 1 = 70.2
r 2 = 666.390 d 2 = 0.15
r 3 = 107.690 d 3 = 3.50 n 2 = 1.74950 v 2 = 35.0
r 4 = 66.588 d 4 = 0.12
r 5 = 67.147 d 5 = 10.00 n 3 = 1.43387 v 3 = 95.1
r 6 = 1910.719 d 6 = variable
r 7 = ∞ d 7 = variable
r 8 = -570.514 d 8 = 1.40 n 4 = 1.71300 v 4 = 53.9
r 9 = 56.723 d 9 = 3.63
r10 = -54.676 d10 = 1.40 n 5 = 1.62299 v 5 = 58.2
r11 = 69.446 d11 = 2.60 n 6 = 1.84666 v 6 = 23.8
r12 = -998.563 d12 = variable
r13 = 190.902 d13 = 6.40 n 7 = 1.43875 v 7 = 95.0
r14 = -35.709 d14 = 1.10
r15 = -36.408 d15 = 2.00 n 8 = 1.64769 v 8 = 33.8
r16 = -57.661 d16 = 0.20
r17 = 52.613 d17 = 2.60 n 9 = 1.59551 v 9 = 39.2
r18 = 105.172 d18 = 3.50
r19 = (Aperture) d19 = Variable
r20 = -45.038 d20 = 2.90 n10 = 1.60311 v10 = 60.6
r21 = -97.329 d21 = variable
r22 = -520.130 d22 = 3.50 n11 = 1.48749 v11 = 70.2
r23 = -56.696 d23 = 0.15
r24 = 147.567 d24 = 1.60 n12 = 1.80518 v12 = 25.4
r25 = 44.814 d25 = 1.12
r26 = 79.107 d26 = 3.20 n13 = 1.51633 v13 = 64.1
r27 = -300.545 d27 = 0.15
r28 = 41.007 d28 = 4.00 n14 = 1.63854 v14 = 55.4
r29 = 1408.886 d29 = variable
r30 = 400.379 d30 = 1.40 n15 = 1.83481 v15 = 42.7
r31 = 36.824 d31 = 4.20 n16 = 1.72825 v16 = 28.5
r32 = -273.139 d32 = 1.40 n17 = 1.77250 v17 = 49.6
r33 = 51.619

Focal length 102.90 205.68 389.18
Variable interval
d 6 5.02 51.00 88.15
d 7 2.00 2.00 2.00
d 12 22.31 13.57 8.14
d 19 11.51 16.32 18.57
d 21 27.22 15.13 11.50
d 29 22.62 16.31 1.55
skinf 73.86 96.20 117.77

f FNo 2w w
102.9 4.6 23.7 11.9
205.7 5.5 12.0 6.0
389.2 5.8 6.4 3.2
[0050]
[Table 1]
[0051]
【The invention's effect】
According to the present invention,
(A-1) The zoom lens is composed of six lens groups having a predetermined refractive power as a whole, and the refractive power of each lens group and the movement conditions of each lens group for zooming are appropriately set. Thus, it is possible to achieve a zoom lens having high optical performance over the entire zooming range while reducing the number of lenses and shortening the total lens length.
[0052]
(A-2) When correcting the displacement (blur) of a captured image by driving a part of the lens group of the optical system in the direction perpendicular to the optical axis, various lens elements are arranged appropriately. It is possible to achieve a zoom lens that can reduce the size of the entire apparatus by correcting decentration aberrations well and realizing sufficiently large displacement correction (blur correction) with a sufficiently small amount of decentering drive.
[0053]
(A-3) A zoom lens that corrects aberration fluctuations at the time of focusing can be achieved over a wide range of object distances from infinity to short-distance objects while adopting an inner focus type and floating type. .
[0054]
(B-4) A zoom lens is composed of six lens groups, and focusing is possible by using the sixth group and the fourth group. A zoom ratio of 4 with good optical performance from an infinite object to a close object is possible. A telephoto zoom lens of about double magnification can be achieved.
[Brief description of the drawings]
FIG. 1 is a lens cross-sectional view at the wide-angle end of Numerical Example 1 of the present invention. FIG. 2 is an aberration diagram of an object at infinity at the wide-angle end of Numerical Example 1 of the present invention. FIG. 4 is an aberration diagram of an object at infinity at the telephoto end according to Numerical Example 1 of the present invention. FIG. 5 is an aberration diagram at a telephoto end near object (4 m) according to Numerical Example 1 of the present invention. Aberration diagram [FIG. 6] Lens cross-sectional view at the wide-angle end of Numerical Example 2 of the present invention [FIG. 7] Aberration diagram of an object at infinity at the wide-angle end according to Numerical Example 2 of the present invention [FIG. FIG. 9 is an aberration diagram of an object at infinity at a telephoto end according to Numerical Example 2 of the present invention. FIG. 10 is an object at close to a telephoto end according to Numerical Example 2 according to the present invention (4 m). FIG. 11 is a lens cross-sectional view at the wide angle end according to Numerical Example 3 of the present invention. FIG. 12 is an object at infinity at the wide angle end according to Numerical Example 3 of the present invention. Aberration diagram [FIG. 13] Aberration diagram of a wide-angle end object (4 m) according to Numerical Example 3 of the present invention [FIG. 14] Aberration diagram of a telephoto end infinity object according to Numerical Example 3 of the present invention [FIG. 15] Aberration diagram of telephoto end closest object (4 m) in Numerical Example 3
L1 1st group L2 2nd group L3 3rd group L4 4th group L5 5th group L6 6th group SP Aperture ΔS Sagittal image plane ΔM Meridional image plane d d-line g g-line C sine condition

Claims (5)

In order from the object side, the first group of positive refractive power, the second group of negative refractive power, the third group of positive refractive power, the fourth group of negative refractive power, the fifth group of positive refractive power, the negative In the zoom lens which is composed of six lens groups of the sixth lens group having a refractive power and performs zooming by changing the interval between the lens groups, the third lens group is a positive lens from the object side, and an object side. It consists of a negative meniscus lens with a concave surface, a positive lens with a strong convex surface on the object side, and the fifth group is a positive lens on the object side, a negative lens with a strong concave surface on the image side, a positive lens, and a positive lens. is composed of a lens, the sixth negative lens from the object side group, a positive lens, a negative lens, the i-th group and DiW apart at the wide-angle end of the (i + 1) group, the i group and tele of the i + 1 group The distance at the end is DiT, the moving amount at the time of zooming from the wide-angle end to the telephoto end of the first group is m1, the first, second, third, The focal length of the group order f1, f2, f3, f5, the focal length at the telephoto end of the entire system was fT,
D1W <D1T
D2W> D2T
D3W <D3T
D4W> D4T
D5W> D5T
−0.23 <m1 / fT <−0.19
0.44 <f1 / fT <0.52
0.11 <| f2 | / fT <0.15
0.16 <f3 / fT <0.25
0.12 <f5 / fT <0.16
A zoom lens satisfying the following conditional expression: Focusing from infinity to a close object, along with moving the fourth group to the object side, carried out by moving the sixth group on the image side, a meniscus wherein the fourth group having a concave surface on the object side consists of Jo negative lens, the fourth focal length of the group f4, infinite lateral magnification at the wide angle end of the sixth group when focusing on distant object, Beta6W each lateral magnification at the telephoto end, and β6T When
0.28 <| f4 | / fT <0.4
2.0 <β6W <2.4
2.6 <β6T <3
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. 2. The zoom lens according to claim 1, wherein the amount of movement of the fourth group for focusing from an object at infinity to an object at an arbitrary finite distance is substantially constant regardless of the focal length . The first group is a positive lens from the object side, a meniscus-shaped negative lens having a concave surface facing the image side, is a positive lens, the second group is composed of two negative lenses and one positive lens, the zoom lens according to claim 1, characterized in that the second group for compensating for the shot image blurring is moved in the optical axis direction substantially perpendicular. The zoom lens according to claim 1 , wherein the six lenses of the sixth group are each cemented.