JPH11174327A - Zoom lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a telephoto type zoom lens with a power variation ratio of about 10 while decreasing the number of lens elements and shortening the overall length by composing the zoom lens of lens groups having specified refractive index on the whole and specifying the refractive indicter of the respective lens groups and movement conditions for power variation. SOLUTION: The zoom lens consists of 1st positive and 2nd negative lens groups and a rear group which has more than one lens group and is positive on the whole. For power variation, lens groups are moved so that conditions represented as expressions are met, where D1W and D1T, and D2W and D2T are the intervals between the 1st and 2nd groups, and 2nd group and rear group at the wide-angle end and telephoto end. Further, conditions represented as expressions are met, where f2 is the focal length of the 2nd group, SKW, OTLW, and Ω are the back focus, overall optical length, and half field angle at the wide-angle end, o3W and o3T the distances from the most object side lens surface to the front side principal point position of the rear group at the wide-angle end and telephoto end, fW and fT the focal lengths of the whole system, and β2W and β2T the image forming powers of the 2nd group.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a telephoto zoom lens suitable for a film camera (photographic camera), a video camera, an electronic still camera, and the like, and more particularly to a telephoto zoom lens having a plurality of lens groups. The present invention relates to a zoom lens in which a lens unit is moved to perform zooming, and has a high zooming ratio of about 10 and high optical performance over the entire zooming range, while miniaturizing the entire lens system.

[0002]

2. Description of the Related Art Conventionally, a zoom lens having a high zoom ratio and high optical performance has been required for a photographic camera, a video camera and the like. Among these, various telephoto-type multi-unit zoom lenses in which three or more lens units are moved to perform zooming have been proposed.

For example, a three-unit zoom lens composed of three lens units having positive, negative, and positive refractive power in order from the object side;
Four lens groups of positive, negative, positive and positive refractive power, or four lens groups consisting of four lens groups of positive, negative, negative and positive refractive power, positive, negative, positive, negative and positive refraction In a five-unit zoom lens composed of five lens units of power or five lens units of positive, negative, positive, positive, and negative refractive power, a multi-unit zoom lens in which a plurality of lens units are moved to perform zooming is provided. Various proposals have been made.

In these three-group zoom lens, four-group zoom lens, and five-group zoom lens, a plurality of lens units are moved to perform zooming, thereby reducing the size of the entire lens system while maintaining a predetermined zooming ratio. Have gained.

The present applicant discloses in Japanese Patent Application Laid-Open No. 4-186212 a high zoom ratio of about 10 which is composed of six lens units having positive, negative, positive, negative, positive and negative refractive power in order from the object side. A six-unit zoom lens with a ratio is proposed.

Further, the present applicant discloses in Japanese Patent Application Laid-Open No. Hei 8-29686 a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a negative lens unit in that order from the object side. A telephoto zoom lens having a zoom ratio of about 4, which includes six lens units including a fourth unit having a refractive power, a fifth unit having a positive refractive power, and a sixth unit having a negative refractive power, is obtained.

[0007]

Generally, in a zoom lens, it is desired to increase the magnification (higher magnification) at the same time as making the entire lens system compact. To increase the magnification of a zoom lens, increase the number of lens groups that contribute to zooming,
In addition, there are a method of strengthening the zooming action by increasing the refractive power of each lens group, and a method of increasing the amount of movement of the lens group that contributes to zooming.

However, in the former case, it is necessary to increase the number of lens components in order to satisfactorily correct fluctuations of various aberrations caused by zooming, and it is difficult to make the entire lens system compact. Problems arise.

In the latter case, a large space must be secured for the movement of the lens unit due to zooming, and the overall length of the lens becomes long. There is a problem that it becomes difficult to support the group inside the lens barrel, and it becomes difficult to make the entire lens system compact.

According to the present invention, the zoom lens is composed of a plurality of lens units having a predetermined refractive power as a whole, and the refractive power of each lens unit and the moving conditions of each lens unit for performing zooming are appropriately set. By reducing the number of lenses and shortening the overall length of the lens, the wide-angle shooting angle of view of about 75 degrees with high optical performance over the entire zoom range,
It is an object of the present invention to provide a telephoto zoom lens having a zoom ratio of about 10.

[0011]

According to the present invention, there is provided a zoom lens system comprising: (1-1) a first lens unit having a positive refractive power in order from the object side;
The zoom lens has a second lens unit having a negative refractive power and a plurality of lens units. The lens unit includes a rear lens unit having a positive refractive power as a whole. The distances between the group and the second group at the wide-angle end and the telephoto end are D1W and D1 respectively.
T, the distance between the second group and the rear group at the wide-angle end and the telephoto end is D
2W, D2T, the distance from the lens surface closest to the object side of the rear group at the wide-angle end and the telephoto end to the front principal point position are respectively o3
W, o3T, back focus at wide angle end and total optical length,
The half angle of view is SKW, OTLW, ωW, the focal length of the second group is f2, the focal length of the entire system at the wide-angle end and the telephoto end is fW, fT, respectively, and the wide-angle end and the telephoto end of the second group are at the telephoto end. When the imaging magnifications are β2W and β2T, respectively, D1W <D1Tｏ (1) D2W> D2T ‥‥‥ (2) 0.2 <(o3W−o3T) / fW <1 ‥‥‥ (3) 4 < β2T / β2W ‥‥‥ (4) 0.2 <SKW / OTLW <0.4 ‥‥‥ (5) 0.03 <| f2 | / fT <0.07 ‥‥‥ (6) 0.3 <| f2 | / SKW <0.5 ‥‥‥ (7) 0.4 <OTLW / (fT · tan (ωW)) <0.85 ‥‥‥ (8)

[0012]

1 to 6 are lens sectional views of Numerical Examples 1 to 6 of the present invention. 7 to 18 are aberration diagrams of Numerical Examples 1 to 6 of the present invention.

In the drawing, L1 is a first lens unit having a positive refractive power, L2 is a second lens unit having a negative refractive power, L3 is a third lens unit having a positive refractive power, and L4 is a positive lens.
Is a fourth group having a negative refractive power, L5 is a fifth group having a positive refractive power, L
6 is a sixth group having a negative refractive power, S is a flare-cut aperture, S
P is an aperture. Arrows indicate the movement trajectories of the respective lens units when zooming from the wide-angle end to the telephoto end.

In this embodiment, the third to sixth groups are
The rear group as a whole has a positive refractive power. In the numerical examples 1 to 6 shown in FIGS. 1 to 6, a plurality of lens units are moved so as to satisfy the conditional expressions (1) and (2) at the time of zooming from the wide-angle end to the telephoto end. .

That is, the plurality of lens units are moved so that the distance between the first and second units increases and the distance between the second and third units decreases. In the numerical examples 1 to 4 shown in FIGS. 1 to 4, the distance between the third and fourth groups increases, the distance between the fourth and fifth groups decreases, and the distance between the fifth and sixth groups increases. All the lens units of the first to sixth groups are moved to the object side so that is reduced.

In the numerical examples 5 and 6 shown in FIGS. 5 and 6, the distance between the third lens unit and the fourth lens unit increases, the distance between the fourth lens unit and the fifth lens unit decreases, and the distance between the fifth lens unit and the sixth lens unit increases. In Numerical Embodiment 5, the second lens unit is fixed, and the first, third to sixth lens units are set to the object side, and in Numerical Embodiment 6, the second lens unit is shifted to the image plane side so that the distance between the groups increases. 1,
The third to sixth lens units are moved to the object side.

In Numerical Examples 1 to 6, the flare aperture S is
During zooming from the wide-angle end to the telephoto end, the lens is moved to the object side. As a result, off-axis flare caused by zooming is favorably cut.

In the zoom lens of the present invention, the sixth lens unit is moved to the image plane side when adjusting the focus from an object at infinity to an object at a short distance. This effectively secures the amount of light at the peripheral portion of the screen in the close object.

In the zoom lens of the present invention, the first lens unit and the second lens unit are arranged close to each other at the wide-angle end so that the combined refractive power becomes negative. The third, fourth, fifth and sixth groups (rear group) are arranged close to each other. Then, the refractive power of the combined lens group of the rear group from the third group is made positive.
As a result, the entire lens system becomes a retrofocus type.

At the telephoto end, the distance between the first lens unit and the second lens unit is increased. Further, the second and subsequent lens units are arranged close to each other so that the combined refractive power becomes negative. A stop is arranged near the third lens unit. Thus, the entire lens system is of a telephoto type (telephoto type).

In the present invention, by adopting such a lens configuration, while the refractive power arrangement is of a substantially retrofocus type at the wide-angle end, the sixth lens unit disposed closest to the image plane is formed as a negative lens unit, thereby achieving coma aberration. , Etc., is well corrected. At the same time, at the telephoto end, various aberrations such as spherical aberration are satisfactorily corrected while using a telephoto-type refractive power arrangement as a compact lens configuration.

Next, the technical meaning of the conditional expressions (3) to (8) will be described. Conditional expression (3) defines the change during zooming of the front principal point position of the rear lens unit, ie, the combined lens system of the third to sixth lens units, at the telephoto end with respect to the wide-angle end. The point position has moved to the object side. As a result, the movement of the principal point position is made larger than the actual movement of the rear unit, thereby achieving a compact lens system. If the change in the principal point position is smaller than the lower limit, the amount of movement of the rear group needs to be increased, and the lens system becomes larger.If the change in the principal point position exceeds the upper limit, the change in the principal point position becomes larger. This means that the refractive power of the lens group becomes strong, which is not preferable in terms of aberration correction.

Conditional expression (4) defines the zoom ratio of the sub-system by the second lens unit at the time of zooming from the wide angle end to the telephoto end. When is smaller, it is necessary to increase the magnification change allotment of the rear unit. Therefore, it is necessary to increase the moving amount of the rear unit or to increase the refractive power of each lens unit in the rear unit, which is preferable in terms of compactness or aberration correction. Absent. An increase in the zoom ratio of the second lens group beyond the upper limit means that the refractive power of the second lens group is increased or that the distance between the first lens group and the second lens group becomes longer at the telephoto end. In addition, it is difficult to correct various aberrations generated in the second lens group in a well-balanced manner by other lens groups.

Conditional expression (5) defines the ratio of the back focus at the wide-angle end to the total optical length at the wide-angle end.
This is for achieving the compactness of the lens system while securing the space for disposing the mirror box and the like on the image plane side of the lens system, while satisfying the desired specifications by setting so as to satisfy the conditional expressions. It achieves both compactness and high performance at the same time.

The conditional expressions (6), (7) and (8) are conditional expressions for achieving a compact and high zoom ratio. Conditional expression (6) 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, and conditional expression (7) defines the range of the focal length of the second group with respect to the back focus at the wide-angle end. And
Conditional expression (8) defines the total optical length at the wide-angle end with respect to the product of the maximum image height and the zoom ratio. Since the second lens group is a main variable power lens, it greatly affects downsizing of the lens system. In any formula, exceeding the lower limit value is advantageous for downsizing, but occurs in the second lens group. Various aberrations increase, which makes it difficult to correct them with other lens groups. If the aberration exceeds the upper limit, the overall length of the lens becomes undesirably long.

In the present invention, at least one of the following conditions should be satisfied in order to further reduce aberration variation over the entire zoom range and obtain high optical performance over the entire screen.

(A1) The rear group has at least one aspherical surface.

(A2) The rear unit is a third unit having a positive refractive power.
The zoom lens has four lens units, a fourth unit having a negative refractive power, a fifth unit having a positive refractive power, and a sixth unit having a negative refractive power. When zooming from the wide-angle end to the telephoto end, the i-th lens unit is used. Assuming that the air spacing at the wide-angle end and the telephoto end of the first lens unit and the (i + 1) -th lens unit are DiW and DiT, respectively, the following condition is satisfied: D3W <D3T ‥‥‥ (9) D4W> D4T ‥‥‥ (10) .

(A3) When the focal length of the i-th lens unit is fi, 0.2 <f1 / fT <0.5 {(11) 0.06 <f3 / fT <0.2} ( 12) 1 <| f4 | / f3 <1.5 (13) 0.5 <f5 / f3 <1.5 (14) 1 <| f6 | / f3 <3.5 (15) The following condition must be satisfied.

Conditional expression (11) defines the range of the focal length of the first lens group with respect to the focal length of the entire system at the telephoto end. The total lens length is shortened, and the light flux incident on the second lens group at the telephoto end. This is for reducing the diameter and reducing the lens diameter of the rear group. If the refractive power of the first lens unit is increased beyond the lower limit of conditional expression (11), aberrations generated in the first lens unit, particularly spherical aberrations, increase, and this is corrected by the second and subsequent lens units. Becomes difficult. On the other hand, if the refractive power of the first lens unit is weakened beyond the upper limit, compactness cannot be achieved.

Conditional expression (12) defines the range of the focal length of the third lens unit with respect to the focal length of the entire system at the telephoto end. When the refractive power of the third lens unit is increased beyond the lower limit of conditional expression (12), it becomes difficult to correct aberration.
When the refracting power of the group is weak, the back focus becomes long, which is against the compactness.

Conditional expressions (13) to (15) define the focal lengths of the fourth, fifth and sixth lens groups with respect to the focal length of the third lens group, respectively, and are mainly for achieving compactness and high performance. When the refractive power of the fourth lens unit is increased beyond the lower limit of conditional expression (13), the off-axis light flux incident on the fifth lens unit at the wide-angle end is separated from the optical axis. Becomes large. On the other hand, if the refractive power of the fourth unit is weakened beyond the upper limit, the overall length of the lens will be long.

When the refractive power of the fifth lens unit is increased beyond the lower limit value of the conditional expression (14), aberrations generated in this lens unit, particularly curvature of field and astigmatism, become large and correction becomes difficult. On the other hand, if the refractive power of the fifth lens unit is weakened beyond the upper limit, the overall length of the lens is undesirably long.

If the refractive power of the sixth lens unit is increased beyond the lower limit of conditional expression (15), the refractive power of the fifth lens unit must be increased accordingly, which is not preferable in terms of aberration correction. If the refractive power of the sixth lens unit becomes weaker than the upper limit, the amount of movement for focusing in the sixth lens unit increases, and the total length of the lens increases to secure this space.

(A4) The first group is composed of one negative lens and 2
The second group has at least two negative lenses and one positive lens; the third group has one negative lens and at least one positive lens;
The group has one negative lens and one positive lens.

As a result, aberrations are corrected with a small number of lenses as much as possible to achieve a compact and high-performance zoom lens.

(A5) The fifth lens unit includes at least one positive lens, a negative lens having a strong concave surface facing the object side, and an aspherical surface having a shape in which the positive refractive power becomes weaker from the center of the lens toward the periphery of the lens. It is to have.

As a result, aberrations are corrected with a minimum number of lenses as well as a balance, and a compact and high-performance zoom lens is achieved.

(A6) The sixth unit has a negative lens having a strong concave surface on the image surface side, and a positive lens having a convex surface facing the object side, and the radius of curvature of the lens surface on the image surface side of the negative lens. To R
N, where RP is the radius of curvature of the lens surface on the object side of the positive lens 0.3 <RN / | f6 | <0.8 {(16) 0.7 <RN / RP <1.2} Satisfies the following condition:

The conditional expressions (16) and (17) define the shape of the lens of the sixth unit. By satisfying this conditional expression, various aberrations are corrected in a well-balanced manner, and the focus is adjusted by the sixth unit. Even when it is performed, good optical performance is achieved from an infinite object distance to a close distance.

Next, numerical examples of the present invention will be described. In the numerical examples, 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 νi are the i-th lens surfaces in order from the object side. The refractive index and Abbe number of glass. In the aspherical shape, the radius of curvature at the center of the lens surface is R, the optical axis direction (the traveling direction of light) is the X axis, the direction perpendicular to the optical axis is the Y axis, and B, C, and D are asymmetrical. Assuming spherical coefficients,

[0042]

(Equation 1) This is represented by “E−X” means “× 10 ^−X ”. Table 1 shows the relationship between the above-described conditional expressions and various numerical values in the numerical examples. Numerical example 1 f = 29.3 to 293.3 FNo = 1: 3.4 to 28.3 2ω = 72.8 ° to 8.4 ° R 1 = 147.162 D 1 = 2.00 N 1 = 1.84666 ν 1 = 23.9 R 2 = 71.603 D 2 = 0.50 R 3 = 72.247 D 3 = 8.70 N 2 = 1.59240 ν 2 = 68.3 R 4 = -805.329 D 4 = 0.12 R 5 = 60.048 D 5 = 6.00 N 3 = 1.72916 ν 3 = 54.7 R 6 = 152.457 D 6 = Variable R 7 = 58.250 D 7 = 1.20 N 4 = 1.80400 ν 4 = 46.6 R 8 = 14.906 D 8 = 6.20 R 9 = -32.317 D 9 = 1.10 N 5 = 1.77250 ν 5 = 49.6 R10 = 65.022 D10 = 0.10 R11 = 30.303 D11 = 4.80 N 6 = 1.81786 ν 6 = 23.7 R12 = -28.937 D12 = 0.68 R13 = -23.786 D13 = 1.10 N 7 = 1.83481 ν 7 = 42.7 R14 = 97.594 D14 = Variable R15 = ∞ D15 = Variable R16 = (Aperture) D16 = 0.00 R17 = 32.673 D17 = 4.10 N 8 = 1.60311 ν 8 = 60.7 R18 = -39.395 D18 = 0.12 R19 = 30.683 D19 = 5.50 N 9 = 1.60311 ν 9 = 60.7 R20 = -20.132 D20 = 1.15 N10 = 1.85026 ν10 = 32.3 R21 =- 313.649 D21 = Variable R22 = -36.081 D22 = 3.10 N11 = 1.74077 ν11 = 27.8 R23 = -16.516 D23 = 1.10 N12 = 1.83481 ν12 = 42.7 R24 = 85.263 D24 = Variable R25 = 48.326 D25 = 3.30 N13 = 1.58313 ν13 = 59.4 R26 = -52.469 D26 = 0.15 R27 = 617.644 D27 = 5.30 N14 = 1.51633 ν14 = 64.2 R28 = -23.673 D28 = 0.15 R29 = 89.658 D29 = 6.20 N15 = 1.51633 ν15 = 64.2 R30 = -19.735 D30 = 1.20 N16 = 1.85026 ν16 = 32.3 R31 = -262.927 D31 = Variable R32 = -906.276 D32 = 1.70 N17 = 1.77250 ν17 = 49.6 R33 = 23.490 D33 = 1.20 R34 = 25.588 D34 = 2.60 N18 = 1.84666 ν18 = 23.9 R35 = 47.160 D35 = Variable R36 = ∞ Focal length 29.34 79.16 293.34 Variable interval D 6 1.20 29.86 58.53 D 14 10.93 5.51 0.08 D 15 7.20 3.24 1.03 D 21 1.78 3.43 5.09 D 24 9.49 4.88 0.99 D 31 1.48 8.87 1.42 D 35 0.00 6.29 24.95 Aspheric surface 18th surface BCD -4.398542e-06 -1.062085e-08 -4.509332e-11 26th surface BCD 1.787188e- 05 2.204995e-08 -3.845670e-11 Numerical example 2 f = 29.1 to 293.4 FNo = 1: 3.4 to 28.3 2ω = 73.3 ° to 8.4 ° R 1 = 161.035 D 1 = 2.00 N 1 = 1.84666 ν 1 = 23.9 R 2 = 73.711 D 2 = 0.50 R 3 = 75.268 D 3 = 8.13 N 2 = 1.59240 ν 2 = 68.3 R 4 = -622.915 D 4 = 0.12 R 5 = 60.379 D 5 = 5.66 N 3 = 1.72916 ν 3 = 54.7 R 6 = 175.454 D 6 = Variable R 7 = 68.597 D 7 = 1.20 N 4 = 1.80400 ν 4 = 46.6 R 8 = 17.807 D 8 = 8.05 R 9 = -40.483 D 9 = 1.10 N 5 = 1.77250 ν 5 = 49.6 R10 = 62.018 D10 = 0.10 R11 = 34.572 D11 = 5.20 N 6 = 1.81786 ν 6 = 23.7 R12 = -32.490 D12 = 0.68 R13 = -26.629 D13 = 1.10 N 7 = 1.83481 ν 7 = 42.7 R14 = 160.370 D14 = Variable R15 = ∞ D15 = Variable R16 = (Aperture) D16 = 0.00 R17 = 42.318 D17 = 4.30 N 8 = 1.60311 ν 8 = 60.7 R18 = -40.708 D18 = 0.12 R19 = 44.885 D19 = 5.50 N 9 = 1.60311 ν 9 = 60.7 R20 = -22.354 D20 = 1.15 N10 = 1.85026 ν10 = 32.3 R21 = 1085.160 D21 = Variable R22 = -39.776 D22 = 3.90 N11 = 1.74077 ν11 = 27.8 R23 = -17.858 D23 = 1.10 N12 = 1.83481 ν12 = 42.7 R24 = 952.872 D24 = Variable R25 = 72.008 D25 = 3.80 N13 = 1.58313 ν13 = 59.4 R26 = -59.547 D26 = 0.15 R27 = 194.065 D27 = 5.30 N14 = 1.51633 ν14 = 64.2 R28 = -29.392 D28 = 0.15 R29 = 66.043 D29 = 6.20 N15 = 1.51633 ν15 = 64.2 R30 = -28.210 D30 = 1.20 N16 = 1.85026 ν16 = 32.3 R31 = 1036.891 D31 = variable R32 = 558693.510 D32 = 1.70 N17 = 1.77250 ν17 = 49.6 R33 = 27.554 D33 = 1.20 R34 = 27.360 D34 = 3.50 N18 = 1.84666 ν18 = 23.9 R35 = 38.788 D35 = variable R36 = 焦点 Focal length 29.10 76.59 293.43 Variable spacing D 6 1.50 27.07 52.64 D 14 10.93 5.57 0.20 D 15 14.22 8.90 1.20 D 21 1 .78 9.12 15.09 D 24 14.56 7.21 1.24 D 31 4.19 5.62 1.45 D 35 0.00 11.18 30.35 Aspheric surface 18th surface BCD -2.753723e-06 -3.014994e-09 -1.340648e-11 26th surface BCD 9.640159e-06 7.779398 e-09 -3.959658e-12 Numerical example 3 f = 29.1 to 293.4 FNo = 1: 3.4 to 5.9 2ω = 73.2 ° to 8.4 ° R 1 = 159.429 D 1 = 2.00 N 1 = 1.84666 ν 1 = 23.9 R 2 = 74.844 D 2 = 0.50 R 3 = 75.353 D 3 = 9.00 N 2 = 1.59240 ν 2 = 68.3 R 4 = -642.596 D 4 = 0.12 R 5 = 62.980 D 5 = 5.80 N 3 = 1.72916 ν 3 = 54.7 R 6 = 180.083 D 6 = Variable R 7 = 103.387 D 7 = 1.20 N 4 = 1.80400 ν 4 = 46.6 R 8 = 19.542 D 8 = 9.27 R 9 = -41.774 D 9 = 1.10 N 5 = 1.77250 ν 5 = 49.6 R10 = 62.034 D10 = 0.10 R11 = 37.044 D11 = 5.20 N 6 = 1.81786 ν 6 = 23.7 R12 = -32.164 D12 = 0.68 R13 = -27.280 D13 = 1.10 N 7 = 1.83481 ν 7 = 42.7 R14 = 162.068 D14 = Variable R15 = ∞ D15 = Variable R16 = (Aperture) D16 = 0.00 R17 = 39.921 D17 = 4.30 N 8 = 1.60311 ν 8 = 60.7 R18 = -42.916 D18 = 0.12 R19 = 42.927 D19 = 5.50 N 9 = 1.60311 ν 9 = 60.7 R20 = -23.500 D20 = 1.15 N10 = 1.85026 ν10 = 32.3 R21 = 1193.550 D21 = Variable R22 = -39.465 D22 = 3.90 N11 = 1.74077 ν11 = 27.8 R23 = -19.636 D23 = 1.10 N12 = 1.83481 ν12 = 42.7 R24 = 624.286 D24 = Variable R25 = 43.718 D25 = 6.70 N13 = 1.58313 ν13 = 59.4 R26 = -26.475 D26 = 0.15 R27 = 41.063 D27 = 7.70 N14 = 1.48749 ν14 = 70.2 R28 = -23.701 D28 = 1.20 N15 = 1.87400 ν15 = 35.3 R29 = 985.069 D29 = Variable R30 = 367.002 D30 = 1.70 N16 = 1.77250 ν16 = 49.6 R31 = 26.090 D31 = 1.20 R32 = 28.774 D32 = 3.50 N17 = 1.84666 ν17 = 23.9 R33 = 41.780 D33 = Variable R34 = ∞ Focal length 29.11 73.45 293.44 Variable interval D 6 1.50 27.66 53.82 D 14 10.93 5.56 0.19 D 15 15.34 10.32 1.19 D 21 1.78 5.58 9.39 D 24 13.19 7.22 1.29 D 29 2.47 3.15 1.46 D 33 0.16 13.35 33.02 Aspheric surface 18th surface BCD -2.033999e-06 -3.668419e-09 -6.128422e-12 26th surface BCD 1.019878e-05 8.957166e-09 -2.083278e-11 Numerical example 4 f = 29.1 to 293.4 FNo = 1: 3.5 to 5.9 2ω = 73.2 ° to 8.4 ° R 1 = 166.814 D 1 = 2.00 N 1 = 1.84666 ν 1 = 23.9 R 2 = 76.531 D 2 = 0.50 R 3 = 77.217 D 3 = 9.16 N 2 = 1.59240 ν 2 = 68.3 R 4 = -510.331 D 4 = 0.12 R 5 = 62.609 D 5 = 5.85 N 3 = 1.72916 ν 3 = 54.7 R 6 = 1 76.276 D 6 = Variable R 7 = 116.709 D 7 = 1.20 N 4 = 1.80400 ν 4 = 46.6 R 8 = 19.257 D 8 = 8.28 R 9 = -42.983 D 9 = 1.10 N 5 = 1.77250 ν 5 = 49.6 R10 = 69.016 D10 = 0.10 R11 = 36.359 D11 = 5.20 N 6 = 1.81786 ν 6 = 23.7 R12 = -32.572 D12 = 0.68 R13 = -27.622 D13 = 1.10 N 7 = 1.83481 ν 7 = 42.7 R14 = 129.928 D14 = Variable R15 = ∞ D15 = Variable R16 = (aperture) D16 = 0.00 R17 = 36.258 D17 = 4.30 N 8 = 1.60311 ν 8 = 60.7 R18 = -40.026 D18 = 0.12 R19 = 42.476 D19 = 5.50 N 9 = 1.60311 ν 9 = 60.7 R20 = -21.079 D20 = 1.15 N10 = 1.85026 ν10 = 32.3 R21 = 385.651 D21 = Variable R22 = -45.725 D22 = 3.90 N11 = 1.74077 ν11 = 27.8 R23 = -17.148 D23 = 1.10 N12 = 1.83481 ν12 = 42.7 R24 = 262.403 D24 = Variable R25 = 72.819 D25 = 5.30 N13 = 1.58313 ν13 = 59.4 R26 = -37.006 D26 = 0.15 R27 = 73.092 D27 = 7.00 N14 = 1.48749 ν14 = 70.2 R28 = -26.888 D28 = 2.00 R29 = -30.346 D29 = 1.20 N15 = 1.84666 ν15 = 23.8 R30 = -68.383 D30 = Variable R31 = 430.508 D31 = 1.70 N16 = 1.77250 ν16 = 49.6 R32 = 28.425 D32 = 1.20 R33 = 29.781 D33 = 3.50 N17 = 1.84666 ν17 = 23.9 R34 = 39.405 D34 = Variable R35 = ∞ Focal length 29.11 7 3.70 293.43 Variable spacing D 6 1.50 27.68 53.86 D 14 10.93 5.53 0.13 D 15 14.55 9.69 1.13 D 21 1.78 5.18 8.58 D 24 14.73 7.96 1.22 D 30 3.21 3.74 1.45 D 34 0.00 14.42 35.34 Aspheric coefficient Surface 18 BCD -1.854221e- 06 -1.156923e-08 1.107726e-12 Surface 26 BCD 1.120399e-05 1.617871e-08 1.616471e-11 Numerical example 5 f = 29.2 to 293.4 FNo = 1: 3.4 to 5.9 2ω = 73.1 ° to 8.4 ° R 1 = 176.095 D 1 = 2.00 N 1 = 1.84666 ν 1 = 23.9 R 2 = 78.897 D 2 = 0.50 R 3 = 79.445 D 3 = 9.16 N 2 = 1.59240 ν 2 = 68.3 R 4 = -412.913 D 4 = 0.12 R 5 = 65.114 D 5 = 5.37 N 3 = 1.72916 ν 3 = 54.7 R 6 = 171.328 D 6 = Variable R 7 = 82.164 D 7 = 1.60 N 4 = 1.88300 ν 4 = 40.8 R 8 = 22.879 D 8 = 5.84 R 9 =- 146.218 D 9 = 1.20 N 5 = 1.77250 ν 5 = 49.6 R10 = 30.217 D10 = 4.20 N 6 = 1.76182 ν 6 = 26.5 R11 = -451.170 D11 = 2.10 R12 = -32.770 D12 = 1.00 N 7 = 1.77250 ν 7 = 49.6 R13 = 30.717 D13 = 3.50 N 8 = 1.84666 ν 8 = 23.9 R14 = -537.666 D14 = Variable R15 = ∞ D15 = Variable R16 = (Aperture) D16 = 0.00 R17 = 36.678 D17 = 4.30 N 9 = 1.60311 ν 9 = 60.7 R18 = -48.951 D18 = 0.12 R19 = 41.305 D19 = 5 .50 N10 = 1.60311 ν10 = 60.7 R20 = -24.016 D20 = 1.15 N11 = 1.85026 ν11 = 32.3 R21 = 3006.130 D21 = Variable R22 = -41.049 D22 = 3.90 N12 = 1.74077 ν12 = 27.8 R23 = -19.216 D23 = 1.10 N13 = 1.83481 ν13 = 42.7 R24 = 174.787 D24 = Variable R25 = 64.567 D25 = 3.80 N14 = 1.58313 ν14 = 59.4 R26 = -55.024 D26 = 0.15 R27 = 120.999 D27 = 5.30 N15 = 1.51633 ν15 = 64.2 R28 = -31.558 D28 = 0.15 R29 = 80.834 D29 = 6.20 N16 = 1.51633 ν16 = 64.2 R30 = -26.649 D30 = 1.20 N17 = 1.85026 ν17 = 32.3 R31 = -736.496 D31 = Variable R32 = 504.957 D32 = 1.70 N18 = 1.77250 ν18 = 49.6 R33 = 24.057 D33 = 1.20 R34 = 25.302 D34 = 3.50 N19 = 1.84666 ν19 = 23.9 R35 = 35.122 D35 = Variable R36 = ∞ Focal length 29.18 70.82 293.41 Variable interval D 6 1.07 28.32 55.57 D 14 11.18 5.59 0.00 D 15 14.54 10.33 1.00 D 21 1.78 4.08 6.38 D 24 14.49 8.59 1.13 D 31 2.95 3.62 3.91 D 35 0.00 12.72 32.50 Aspheric surface 18th surface BCD -2.192208e-06 -5.428259e-09 -1.605349e-11 26th surface BCD 9.913685e-06 6.922341e-09 -4.960535e-12 Numerical value Example 6 f = 29.2 to 293.4 FNo = 1: 3.2 to 5.9 2ω = 73.2 ° to 8.4 ° R 1 = 179.983 D 1 = 2.00 N 1 = 1.84666 ν 1 = 23.9 R 2 = 79.963 D 2 = 0.50 R 3 = 80.392 D 3 = 8.96 N 2 = 1.59240 ν 2 = 68.3 R 4 = -489.305 D 4 = 0.12 R 5 = 66.234 D 5 = 5.41 N 3 = 1.72916 ν 3 = 54.7 R 6 = 178.683 D 6 = Variable R 7 = 88.005 D 7 = 1.60 N 4 = 1.88300 ν 4 = 40.8 R 8 = 23.692 D 8 = 5.25 R 9 =- 149.406 D 9 = 1.20 N 5 = 1.77250 ν 5 = 49.6 R10 = 30.124 D10 = 4.20 N 6 = 1.76182 ν 6 = 26.5 R11 = -374.753 D11 = 2.10 R12 = -36.531 D12 = 1.00 N 7 = 1.77250 ν 7 = 49.6 R13 = 32.990 D13 = 3.50 N 8 = 1.84666 ν 8 = 23.9 R14 = -502.240 D14 = Variable R15 = ∞ D15 = Variable R16 = (Aperture) D16 = 0.00 R17 = 34.110 D17 = 4.30 N 9 = 1.60311 ν 9 = 60.7 R18 = -48.852 D18 = 0.12 R19 = 49.608 D19 = 5.50 N10 = 1.60311 ν10 = 60.7 R20 = -24.687 D20 = 1.15 N11 = 1.85026 ν11 = 32.3 R21 = 443.556 D21 = Variable R22 = -40.507 D22 = 3.90 N12 = 1.74077 ν12 = 27.8 R23 = -19.622 D23 = 1.10 N13 = 1.83481 ν13 = 42.7 R24 = 219.661 D24 = Variable R25 = 60.152 D25 = 3.80 N14 = 1.58313 ν14 = 59.4 R26 = -69.157 D26 = 0.15 R27 = 148.517 D27 = 5.30 N15 = 1.51633 ν15 = 64.2 R28 = -32.318 D28 = 0.15 R29 = 91.680 D29 = 6.20 N16 = 1.51633 ν16 = 64.2 R30 = -29.909 D30 = 1.20 N17 = 1.85026 ν17 = 32.3 R31 = -302.836 D31 = Variable R32 = 166.517 D32 = 1.70 N18 = 1.77250 ν18 = 49.6 R33 = 23.219 D33 = 1.20 R34 = 24.003 D34 = 3.50 N19 = 1.84666 ν19 = 23.9 R35 = 30.380 D35 = Variable R36 = ∞ Focal length 29.15 70.26 293.42 Variable distance D 6 1.07 28.70 56.32 D 14 11.18 5.63 0.09 D 15 18.81 12.81 1.09 D 21 1.78 3.67 5.56 D 24 16.18 9.80 1.20 D 31 3.55 4.43 5.98 D 35 0.00 12.65 32.56 Aspheric surface 18th surface BCD -1.097627e-06 -3.935952e-09 -9.163848e-12 26th surface BCD 1.012967e-05 6.024586e-09 -4.395509e-12

[0043]

[Table 1]

[0044]

According to the present invention, as described above, the zoom lens is constituted by a plurality of lens groups having a predetermined refractive power as a whole, and each lens group for performing the refractive power and zooming of each lens group. By appropriately setting the moving conditions of
To achieve a telephoto zoom lens with a high angle of view of about 75 degrees at the wide-angle end and a zoom ratio of about 10 with high optical performance over the entire zoom range while reducing the number of lenses and shortening the overall length of the lens. be able to.

[Brief description of the drawings]

FIG. 1 is a sectional view of a lens according to a numerical example 1 of the present invention.

FIG. 2 is a sectional view of a lens according to a numerical example 2 of the present invention.

FIG. 3 is a sectional view of a lens according to a numerical example 3 of the present invention.

FIG. 4 is a sectional view of a lens according to a numerical example 4 of the present invention.

FIG. 5 is a sectional view of a lens according to a numerical example 5 of the present invention.

FIG. 6 is a sectional view of a lens according to a sixth numerical example of the present invention;

FIG. 7 is an aberration diagram at a wide-angle end according to Numerical Embodiment 1 of the present invention.

FIG. 8 is an aberration diagram at a telephoto end in Numerical Example 1 of the present invention;

FIG. 9 is an aberration diagram at a wide-angle end according to Numerical Example 2 of the present invention.

FIG. 10 is an aberration diagram at a telephoto end in Numerical Example 2 of the present invention;

FIG. 11 is an aberration diagram at a wide angle end according to Numerical Example 3 of the present invention.

FIG. 12 is an aberration diagram at a telephoto end in Numerical Example 3 of the present invention.

FIG. 13 is an aberration diagram at a wide angle end according to Numerical Example 4 of the present invention.

FIG. 14 is an aberration diagram at a telephoto end in Numerical Example 4 of the present invention.

FIG. 15 is an aberration diagram at a wide angle end according to Numerical Example 5 of the present invention.

FIG. 16 is an aberration diagram at a telephoto end in Numerical Example 5 of the present invention.

FIG. 17 is an aberration diagram at a wide angle end according to Numerical Example 6 of the present invention.

FIG. 18 is an aberration diagram at a telephoto end in Numerical Example 6 of the present invention.

[Explanation of symbols]

 L1 First group L2 Second group L3 Third group L4 Fourth group L5 Fifth group L6 Sixth group S Flare stop SP stop IP image plane d d-line g g-line ΔS sagittal image plane ΔM meridional image plane

Claims (7)

[Claims] A first lens group having a positive refractive power, a second lens group having a negative refractive power, and a plurality of lens groups in order from the object side. At the time of zooming, a plurality of lens groups are moved.
The distance between the wide-angle end and the telephoto end of the second group and the second group is D1W and D1, respectively.
1T, the distances between the wide angle end and the telephoto end of the second group and the rear group are D2W and D2T, respectively, and the distance from the most object side lens surface of the rear group to the front principal point position at the wide angle end and the telephoto end are respectively o
3W, o3T, the back focus and the optical total length at the wide-angle end and the half angle of view are SKW, OTLW, and ωW, respectively, the focal length of the second lens unit is f2, and the focal length of the whole system at the wide-angle end and the telephoto end is fW. , FT, and when the imaging magnifications of the second group at the wide-angle end and the telephoto end are β2W and β2T, respectively, D1W <D1T D2W> D2T 0.2 <(o3W-o3T) / fW <14 <β2T / β2W 0 .2 <SKW / OTLW <0.4 0.03 <| f2 | / fT <0.07 0.3 <| f2 | / SKW <0.5 0.4 <OTLW / (fT · tan (ωW)) <0.8
5. A zoom lens characterized by satisfying the following condition: 2. The zoom lens according to claim 1, wherein the rear group has at least one aspheric surface. 3. The rear unit includes four lens units including a third unit having a positive refractive power, a fourth unit having a negative refractive power, a fifth unit having a positive refractive power, and a sixth unit having a negative refractive power. When zooming from the wide-angle end to the telephoto end, when the air spacing at the wide-angle end and the telephoto end of the i-th and (i + 1) -th groups is DiW and DiT, respectively, D3W <D3T D4W> D4T The zoom lens according to claim 1, wherein the following is satisfied. 4. When the focal length of the i-th lens unit is fi, 0.2 <f1 / fT <0.5 0.06 <f3 / fT <0.2 1 <| f4 | / f3 <1.5 4. The zoom lens according to claim 3, wherein the following condition is satisfied: 0.5 <f5 / f3 <1.5 1 <| f6 | / f3 <3.5. 5. The first group has one negative lens and two positive lenses, the second group has at least two negative lenses and one positive lens, and the third group has one A fourth lens unit having a negative lens and at least one positive lens;
The zoom lens according to claim 4, comprising one negative lens and one positive lens. 6. The fifth unit includes at least one positive lens, a negative lens having a strong concave surface facing the object side, and an aspheric surface having a shape in which positive refractive power becomes weaker from the center of the lens toward the periphery of the lens. The zoom lens according to claim 4, wherein the zoom lens has a zoom lens. 7. The sixth group includes a negative lens having a strong concave surface on the image surface side, and a positive lens having a convex surface facing the object side,
When the radius of curvature of the lens surface on the image surface side of the negative lens is RN and the radius of curvature of the lens surface on the object side of the positive lens is RP, 0.3 <RN / | f6 | <0.8 0.7 < The zoom lens according to claim 4, wherein the following condition is satisfied: RN / RP <1.2.