JPH05241073A - Zoom lens - Google Patents

Abstract

PURPOSE:To obtain the zoom lens which has a wide view angle and a high power variation ratio by providing four lens groups on the whole and properly setting the refracting powers of the respective lens groups and the movement conditions of the respective lens groups accompanying power variation. CONSTITUTION:The zoom lens has the four lens groups which are a 1st group L1, a 2nd group L2, a 3rd group L3, and a 4th group L4 having a negative, a positive, a negative, and a positive refracting power in order from an object side; when the power is varied from the wide-angle end to the telephoto end, at least the 1st group L1, 2nd group L2, and 4th group L4 are moved so that the air interval between the 1st group L1 and 2nd group L3 decreases, the air interval between the 2nd group L2 and 3rd group L3 increases, and the air interval between the 3rd group Ls and 4th group L4 decreases. The lens constitution of each lens group and an aspherical surface shape when the aspherical surface is used are properly set.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens suitable for a single-lens reflex camera, a video camera, etc., and more particularly, a so-called negative lead type lens group preceded by a lens group having a negative refractive power. The present invention relates to a large-angle zoom lens having a wide angle of view and a high zoom ratio.

[0002]

2. Description of the Related Art Negative lead type zoom lenses, which are preceded by a lens unit having a negative refracting power, are characterized in that a wide angle of view is relatively easy and a close-up shooting distance is shortened. However, it has drawbacks such as an increased aperture diameter and difficulty in achieving a high zoom ratio.

A zoom lens which has been improved in view of these drawbacks, and which is downsized and has a high zoom ratio, is disclosed in, for example, Japanese Patent Publication No. 49-23912, Japanese Patent Publication No. 53-34539, and Japanese Patent Publication No. 57-. 163213, JP-A-58-4
113, JP-A-63-241511, and JP-A-2-201310.

In each of these publications, a zoom lens is composed of four lens groups as a whole of a lens group having negative, positive, negative, and positive refractive powers in order from the object side, and a predetermined lens group among them is appropriately moved. I am changing the magnification.

[0005]

In recent years, a standard zoom lens used in a single-lens reflex camera, a video camera or the like is required to have a wide field angle and a high zoom ratio. For example, in a single-lens reflex camera for 35 mm film, the focal length is 35 mm to 70 mm and the focal length is 28 mm to 7 mm.
A wide-angle zoom lens of about 0 mm is used as a standard zoom lens.

More recently, the focal length is 28 mm to 80 m.
There is a demand for a standard zoom lens having a large aperture ratio, in which the zooming range is widened to the telephoto side having a focal length of 28 mm to 85 mm to achieve high zooming.

However, in general, at such a shooting angle of view and a high zoom ratio, the total lens length becomes long, and complicated zoom movement is required for zooming. As a result, the lens barrel has a multiple structure, and the lens The problem arises that the lens barrel becomes large and complicated.

According to the present invention, the zoom lens is composed of four lens groups as a whole, and by appropriately setting the refracting power of each lens group and the moving condition of each lens group due to zooming,
An object of the present invention is to provide a zoom lens which has a relatively wide angle of view and which has a high optical performance over the entire zoom range of a high zoom ratio, which shortens the entire lens length and prevents the lens barrel from becoming large and complicated. ..

In particular, the present invention has a large aperture ratio of F number 2.8, a wide field angle of 80 degrees or more at the wide angle end, and a high zoom ratio of about 3 and a total zoom ratio of about 3. An object of the present invention is to provide a zoom lens having high optical performance over a range.

[0010]

A zoom lens according to the present invention comprises, in order from the object side, a first group having a negative refractive power, a second group having a positive refractive power, a third group having a negative refractive power, and a positive group. The fourth of power
The zoom lens has four lens groups, and the air distance between the first and second groups decreases and the air distance between the second and third groups increases when zooming from the wide-angle end to the telephoto end. However, at least the first, second and fourth groups are arranged so that the air gap between the third group and the fourth group is reduced.
When the lens groups are moved and the lens configuration or aspherical surface of each lens group is used, the aspherical surface shape is set appropriately. Besides, the features of the present invention are disclosed in the embodiments.

[0011]

1 to 9 are numerical examples 1 to 9 of the present invention.
3 is a lens cross-sectional view of FIG. In the lens cross-sectional view, L1 is the first group of negative refractive power, L2 is the second group of positive refractive power, L3 is the third group of negative refractive power, L4 is the fourth group of positive refractive power, SP
Is the aperture.

In the present invention, zooming is performed by moving a predetermined lens group so that the air space between the lens groups changes.

In particular, when changing the magnification from the wide-angle end to the telephoto end, the air gap between the first and second groups decreases, the air gap between the second and third groups increases, and the third and fourth groups change. At least the first, second, and fourth groups are moved so that the air space between the groups is reduced. Specifically, the zooming from the wide-angle end to the telephoto end is performed by moving the first group to the image side, the second group to the object side, and the fourth group to the object side.

At this time, the second lens unit and the fourth lens unit may be independently moved to the object side, or may be moved integrally to simplify the lens barrel. Focusing is performed by moving the entire first group, or by dividing the first group into two lens groups, an 11th group and a 12th group, from the object side, and moving the 12th group. ..

Next, the features of each numerical example shown in FIGS. 1 to 9 will be described in order.

(1-1) In Numerical Embodiments 1, 2, and 3 shown in FIGS. 1, 2, and 3, the zooming from the wide-angle end to the telephoto end is performed by changing the air distance between the first group and the second group. At least the first, second, and fourth groups are moved so that the air spacing between the second group and the third group increases and the air spacing between the third group and the fourth group decreases. The third group has independent or cemented lenses of a positive lens and a negative lens, and the fourth group has independent or cemented lenses of a negative lens and a positive lens. As a result, while shortening the total lens length, a wide angle of view and high optical performance with little aberration variation over the entire zoom range are obtained.

The second lens group has three lenses, in order from the object side, a meniscus-shaped negative lens having a strong negative refracting surface facing the image side, a positive lens, and a positive lens having a convex surface facing the object side. I am configuring. As a result, good aberration correction is performed while the second lens group has a relatively strong positive refractive power. Especially on the telephoto side, the diameter of the light beam emitted from the second lens unit is reduced, the aperture diameter is shortened, and the lens barrel diameter is reduced.

The first lens group has, in order from the object side, a meniscus negative lens having a concave surface facing the image side, a negative lens, and a meniscus positive lens having a convex surface facing the object side. Generally, if the positive lens is arranged closest to the object side, the distortion aberration on the wide angle side can be corrected well, but the outer diameter of the lens increases.

Therefore, in the present invention, as described above, the first lens unit is constructed so that the negative lens is located closest to the object side, the distortion aberration is corrected by the other lens unit, the lens outer diameter is reduced, and the close-up distance is set. Is being shortened.

The third lens group is designed to be fixed during zooming to simplify the lens barrel structure. Further, the zooming from the wide-angle end to the telephoto end may be performed by moving the second and fourth groups integrally to the object side, which simplifies the lens barrel structure as described above. You can

The focal lengths of the second and third lens units are F2 and F, respectively.
When set to 3, F2 <| F3 | ... (1-a).

By giving the second lens unit a strong positive refracting power, the aperture diameter is made small and the lens barrel diameter is made small in the same manner as described above. Further, the third lens group is made to have a relatively weaker refractive power than the second lens group, and even if the third lens group is composed of two lenses, good aberration correction can be performed.

When the focal length of the fourth lens unit is F4 and the focal length of the entire system at the telephoto end is FT, 0.5 <F4 / FT <2 ... (1-b). As a result, good aberration correction is performed while the overall size of the lens system is reduced.

If the lower limit of conditional expression (1-b) is exceeded and the refracting power of the fourth lens unit becomes too strong, the fourth lens unit will be corrected for aberrations favorably with two lenses, a negative lens and a positive lens. Becomes difficult. If the upper limit is exceeded and the refractive power of the fourth lens unit becomes too weak, the amount of movement of each lens unit during zooming increases,
It is not good because the total lens length becomes longer.

(1-2) In Numerical Embodiments 4 and 5 shown in FIGS. 4 and 5, zooming is performed by changing the air spacing of each lens unit, and the second unit is a meniscus whose convex surface faces the object side. A cemented lens in which a negative negative 21st lens and a positive 22nd lens whose both lens surfaces are convex surfaces are cemented together, and a positive 23rd lens with a strong positive refractive surface facing the object side, The second
The radius of curvature of the cemented lens surface of the cemented lens in which the object side surface of the first lens or the 23rd lens is an aspherical surface is R2, 2, the aspherical surface coefficient of the aspherical surface is B, C, and the 23rd
The lens outer diameter is DE, and the focal length of the second lens group is F2.
0.6 <R2,2 / F2 <1.0 ... (2-a) B <0 ... (2-b) B + Cx (DE / 2) ² <0 ... (2 -C) The following condition is satisfied. As a result, while shortening the total lens length, various aberrations associated with zooming are corrected well, and high optical performance is obtained over the entire zoom range.

In this embodiment, a divergent light beam enters the second lens unit from the first lens unit having a negative refractive power. For this reason, when the F-number is made bright, a light beam is incident on the optical axis of the second lens unit at a high position, and as a result, a remarkably large aberration occurs in the peripheral portion of the second lens unit, deteriorating the optical performance.

On the other hand, there are methods of increasing the number of lenses in the second lens group and weakening the refractive power of the second lens group. However, these methods are not preferable because the total lens length becomes long and the lens outer diameter of the first group increases.

Therefore, in the present embodiment, various aberrations frequently generated in the second lens group, particularly spherical aberration and coma aberration, are corrected by the conditional expression (2-
The three lenses satisfying the requirements a), (2-b) and (2-c) and the aspherical surface satisfactorily correct the light to obtain high optical performance.

Conditional expression (2-a) is mainly for correcting coma aberration. If the lower limit of conditional expression (2-a) is exceeded, coma will be overcorrected, and if the upper limit is exceeded, the remaining coma will be corrected by another lens surface, and it will be good with spherical aberration and astigmatism. It becomes difficult to correct it. Furthermore, it becomes difficult to correct various aberrations of the entire system in a well-balanced manner.

The conditional expressions (2-b) and (2-c) are for properly setting the aspherical shape, and particularly for favorably correcting spherical aberration and coma. Of these, conditional expression (2-b) is 3
It represents the secondary aberration component, which has a negative effect, that is, a function of weakening the positive refracting power in the peripheral portion, so that spherical aberration and coma are overcorrected, and combined with conditional expression (2-a), Corrects aberrations and coma.

Conditional expression (2-c) appropriately defines the aspherical surface shape including the fifth-order aberration component, and in particular, the aspherical surface amount at the position of the lens outer diameter DE tends to weaken the refractive power at the peripheral portion. I have to. As a result, the occurrence of various aberrations is reduced while the second lens group has a relatively strong positive refractive power. In addition, this makes it possible to give the first lens unit a strong negative refracting power to shorten the total lens length.

In addition to the above, in the fifth embodiment 5, the first group has at least two negative lenses and positive lenses. As a result, mainly astigmatism and distortion are satisfactorily corrected.

The first group consists of the eleventh group and the twelfth group in order from the object side.
It has two lens groups, and the 12th group is moved on the optical axis for focusing. As a result, the total lens length is kept constant even if focusing is performed, the lens does not project to the outside, and the relatively lightweight and small twelfth lens group is moved, for example, when performing automatic focusing. Drive control is easy.

(1-3) In Numerical Examples 6 and 7 shown in FIGS. 6 and 7, zooming is performed by changing the air spacing of each lens group, and the second group is a meniscus whose convex surface faces the object side. A cemented lens in which a negative negative 21st lens and a positive 22nd lens whose both lens surfaces are convex surfaces are cemented together, and a positive 23rd lens with a strong positive refractive surface facing the object side, The second
The image side surface of the second lens or the 23rd lens is an aspherical surface, and the radius of curvature of the cemented lens surface of the cemented lens is R
2, 2, the aspherical surface coefficients of the aspherical surface are B and C, the lens outer diameter of the 23rd lens is DE, and the focal length of the second group is F2. 0.6 <R2,2 / F2 <1. 0 ... (3-a) B> 0 ... (3-b) B + C × (DE / 2) ² > 0 ... (3-c). As a result, similar to Numerical Examples 3 and 4, the overall lens length is shortened, various aberrations associated with zooming are satisfactorily corrected, and high optical performance is obtained over the entire zooming range.

In this embodiment, a divergent light beam enters the second lens unit from the first lens unit having a negative refractive power. For this reason, when the F number is increased, a light beam is incident at a high position from the optical axis of the second lens unit, and as a result, a significantly large aberration occurs at the peripheral portion of the second lens unit, deteriorating the optical performance.

On the other hand, there are methods of increasing the number of lenses in the second lens group and weakening the refractive power of the second lens group. However, these methods are not preferable because the total lens length becomes long and the lens outer diameter of the first group increases.

Therefore, in the present embodiment, various aberrations frequently generated in the second lens group, particularly spherical aberration and coma aberration, are corrected by the conditional expression (3-
The three lenses satisfying a), (3-b), and (3-c) and the aspherical surface satisfactorily correct the light to obtain high optical performance.

Conditional expression (3-a) is mainly for correcting coma aberration. If the lower limit of conditional expression (3-a) is exceeded, coma will be overcorrected, and if the upper limit is exceeded, the remaining coma will be corrected by another lens surface, and it will be good with spherical aberration and astigmatism. It becomes difficult to correct it. Furthermore, it becomes difficult to correct various aberrations of the entire system in a well-balanced manner.

Conditional expressions (3-b) and (3-c) are for properly setting the aspherical surface shape, and particularly for favorably correcting spherical aberration and coma. Of these, conditional expression (3-b) is 3
It represents a secondary aberration component, which has a negative effect, that is, a function of weakening the positive refracting power in the peripheral portion, to make the spherical aberration and the coma aberration overcorrected, and combine them with the conditional expression (3-a) to obtain a spherical surface. Corrects aberrations and coma.

Conditional expression (3-c) appropriately defines the aspherical surface shape including the fifth-order aberration component, and in particular, the aspherical surface amount at the position of the lens outer diameter DE is such that the refractive power is weakened in the peripheral portion. I have to. As a result, the occurrence of various aberrations is reduced while the second lens group has a relatively strong positive refractive power. In addition, this makes it possible to give the first lens unit a strong negative refracting power to shorten the total lens length.

In addition to this, in the seventh embodiment 7, the first group has at least two negative lenses and positive lenses as in the case of the numerical embodiments 4 and 5 described above. As a result, mainly astigmatism and distortion are satisfactorily corrected.

Further, the first group has two lens groups of the 11th group and the 12th group in order from the object side, and the 12th group is moved on the optical axis for focusing. This keeps the total lens length constant even after focusing, prevents the lens from protruding to the outside, and is relatively lightweight and compact.
By moving the two lens groups, drive control is facilitated when, for example, automatic focusing is performed.

(1-4) In Numerical Embodiments 8 and 9 shown in FIGS. 8 and 9, the zooming from the wide-angle end to the telephoto end is performed by reducing the air gap between the first group and the second group. The air gap between the second group and the third group is increased, and the air gap between the third group and the fourth group is decreased, and the fourth group includes at least one negative lens and at least one positive lens. The lens has at least one aspherical surface, the refractive power of the aspherical surface is φ4a, the radius of curvature formed by the intersection of the optical axis and the aspherical surface and the maximum diameter position of the aspherical surface is Rmax, the optical axis and the aspherical surface. When the radius of curvature formed by the intersection point of and the aspherical surface at a height H from the optical axis is RH, (| Rmax |-| RH |) .phi.4a <0 ... (4-a) I am satisfied. As a result, high optical performance is ensured over the entire zoom range while achieving high zoom ratio and large aperture ratio.

In this embodiment, the first lens unit has a negative refracting power and has a lens structure advantageous for widening the angle of view, and in addition to the first lens unit and the second lens unit, the third lens unit and the fourth lens unit have variable magnifications. To facilitate high zooming.

In general, it is necessary to increase the refractive power of each lens group in order to reduce the size of the entire lens system while achieving a high zoom ratio and a large aperture ratio. As a result, aberrations are often generated, and it is necessary to correct the number of lenses by increasing the number of lenses.

Therefore, in the present embodiment, by appropriately setting the lens configuration of the fourth lens group as described above, and particularly by using an aspherical surface, various aberrations such as spherical aberration and astigmatism can be satisfactorily corrected with a small number of lenses. ing.

Conditional expression (4-a) is such that the aspherical shape used in the fourth lens unit becomes weaker as the positive refractive power moves away from the center of the optical axis. Corrected well. If conditional expression (4-a) is not satisfied, spherical aberration and astigmatism will increase, and in order to correct these, the number of lenses in the fourth group must be increased, and as a result, the total lens length becomes longer, which is all that is required. Absent.

In addition, in the present embodiment, the first group has at least two negative lenses and positive lenses.
This shortens the focal length on the wide-angle side, widens the angle of view, and reduces the lens outer diameter of the first group. Also, astigmatism and distortion are well corrected.

The second lens unit has a negative meniscus 21st lens element having a convex surface directed toward the object side, and a positive 22nd lens element having convex lens surfaces on both sides.
The cemented lens has a cemented lens and a positive 23rd lens having a strong positive refracting surface facing the object side. The radius of curvature of the cemented lens surface of the cemented lens is R.
2, 2 and the focal length of the second lens unit is F2, the condition of 0.6 <R2,2 / F2 <1.0 ... (4-b) is satisfied.

In this embodiment, since the first lens unit has a negative refractive power, the on-axis light beam incident on the second lens unit is incident on a position higher on the optical axis than the first lens unit. Therefore, various aberrations are likely to occur. Therefore, the second lens group is configured as described above to satisfactorily correct various aberrations.

Conditional expression (4-b) is mainly used to properly set the radius of curvature of the cemented lens surface of the cemented lens and correct the coma aberration favorably. When the radius of curvature R2,2 becomes smaller than the lower limit of the conditional expression (4-b), the coma aberration becomes overcorrected, and conversely, when the radius of curvature R2,2 becomes larger than the upper limit, the remaining coma aberration becomes other. It becomes difficult to correct on the lens surface.

Next, numerical examples of the present invention will be shown. 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 gap from the object side, and Ni and νi are the values of the i-th lens in order from the object side, respectively. The refractive index of glass and the Abbe number.

The aspherical shape is the X axis in the optical axis direction, the H axis in the direction perpendicular to the optical axis, the traveling direction of light is positive, and R is the paraxial radius of curvature,
When A, B, C, D, and E are aspherical coefficients, respectively

[0054]

[Equation 1] It is expressed by Numerical Example 1 F = 28.8 to 77.3 FNO = 1: 3.5 to 4.5 2ω = 73.8 ° to 31.3 ° R 1 = 57.039 D 1 = 1.80 N 1 = 1.77250 ν 1 = 49.6 R 2 = 23.561 D 2 = 6.90 R 3 = -13365.018 D 3 = 1.60 N 2 = 1.77250 ν 2 = 49.6 R 4 = 40.913 D 4 = 0.10 R 5 = 30.586 D 5 = 3.90 N 3 = 1.80518 ν 3 = 25.4 R 6 = 65.175 D 6 = variable R 7 = 61.327 D 7 = 1.50 N 4 = 1.84666 ν 4 = 23.9 R 8 = 25.956 D 8 = 0.07 R 9 = 27.135 D 9 = 4.00 N 5 = 1.69680 ν 5 = 55.5 R10 = -157.956 D10 = 0.10 R11 = 35.052 D11 = 3.15 N 6 = 1.69680 ν 6 = 55.5 R12 = -166.755 D12 = Variable R13 = (Aperture) D13 = 1.75 R14 = -51.650 D14 = 2.10 N 7 = 1.80518 ν 7 = 25.4 R15 = -25.090 D15 = 1.30 N 8 = 1.60311 ν 8 = 60.7 R16 = 46.084 D16 = Variable R17 = 122.517 D17 = 1.30 N 9 = 1.80518 ν 9 = 25.4 R18 = 31.966 D18 = 0.42 R19 = 35.150 D19 = 5.00 N10 = 1.58313 ν10 = 59.4 R20 = -37.015 Aspheric R21 = 0.0

[0055]

[Table 1] R20: Aspherical surface coefficient A = 0 B = 4.88834 × 10 ⁻⁶ C = −6.838115 × 10 ⁻⁹ D = 1.53483 × 10 ⁻¹⁰ E = −5.17930 × 10 ⁻¹³ Numerical example 2 F = 28.8 to 77.01 FNO = 1 : 3.5 to 4.5 2 ω = 73.8 ° to 31.4 ° R 1 = 69.290 D 1 = 1.80 N 1 = 1.77250 ν 1 = 49.6 R 2 = 26.715 D 2 = 6.90 R 3 = 3674.837 D 3 = 1.60 N 2 = 1.77250 ν 2 = 49.6 R 4 = 37.386 D 4 = 0.10 R 5 = 31.958 D 5 = 3.90 N 3 = 1.80518 ν 3 = 25.4 R 6 = 69.851 D 6 = variable R 7 = 62.034 D 7 = 1.50 N 4 = 1.84666 ν 4 = 23.9 R 8 = 25.952 D 8 = 0.07 R 9 = 26.641 D 9 = 4.00 N 5 = 1.69680 ν 5 = 55.5 R10 = -110.081 D10 = 0.10 R11 = 31.365 D11 = 3.15 N 6 = 1.69680 ν 6 = 55.5 R12 = -395.214 D12 = Variable R13 = (Aperture) D13 = 1.75 R14 = -55.195 D14 = 2.10 N 7 = 1.80518 ν 7 = 25.4 R15 = -25.214 D15 = 1.30 N 8 = 1.60311 ν 8 = 60.7 R16 = 38.462 D16 = Variable R17 = 78.946 D17 = 1.30 N 9 = 1.80518 ν 9 = 25.4 R18 = 26.654 D18 = 0.42 R19 = 29.350 D19 = 5.00 N10 = 1.58313 ν10 = 59.4 R20 = -44.797 Aspheric R21 = 0.0

[0056]

[Table 2] R20: Aspherical coefficient A = 0 B = 4.54988 × 10 ⁻⁶ C = 3.91367 × 10 ⁻⁹ D = 1.11697 × 10 ⁻¹⁰ E = −6.30557 × 10 ⁻¹³ Numerical example 3 F = 28.8 to 77.38 FNO = 1: 3.5 to 4.5 2ω = 73.8 ° to 31.2 ° R 1 = 67.090 D 1 = 1.80 N 1 = 1.77250 ν 1 = 49.6 R 2 = 27.602 D 2 = 6.80 R 3 = -912.555 D 3 = 1.60 N 2 = 1.77250 ν 2 = 49.6 R 4 = 36.134 D 4 = 0.10 R 5 = 31.918 D 5 = 3.90 N 3 = 1.80518 ν 3 = 25.4 R 6 = 73.004 D 6 = Variable R 7 = 48.711 D 7 = 1.50 N 4 = 1.84666 ν 4 = 23.9 R 8 = 22.792 D 8 = 4.00 N 5 = 1.69680 ν 5 = 55.5 R 9 = -89.964 D 9 = 0.10 R10 = 31.729 D10 = 3.10 N 6 = 1.69680 ν 6 = 55.5 R11 = 248.913 D11 = Variable R12 = (Aperture) D12 = 1.75 R13 = -51.342 D13 = 2.10 N 7 = 1.80518 ν 7 = 25.4 R14 = -23.117 D14 = 1.30 N 8 = 1.60311 ν 8 = 60.7 R15 = 38.796 D15 = Variable R16 = 76.641 D16 = 1.30 N 9 = 1.84666 ν 9 = 23.9 R17 = 29.240 D17 = 0.45 R18 = 32.398 D18 = 5.00 N10 = 1.58313 ν10 = 59.4 R19 = -45.125 Aspheric surface

[0057]

[Table 3] R19: Aspherical surface coefficient A = 0 B = 4.7416 × 10 ⁻⁶ C = 3.16871 × 10 ⁻⁸ D = −1.19894 × 10 ⁻¹⁰ E = 2.29582 × 10 ⁻¹³ Numerical example 4 F = 28.8 to 77.49 FNO = 1: 2.8 2 ω = 73.8 ° ~ 31.2 ° R 1 = 90.266 D 1 = 2.00 N 1 = 1.77250 ν 1 = 49.6 R 2 = 38.296 D 2 = 9.00 R 3 = -461.888 D 3 = 4.50 N 2 = 1.69895 ν 2 = 30.1 R 4 = -96.235 D 4 = 0.12 R 5 = -179.098 D 5 = 1.80 N 3 = 1.77250 ν 3 = 49.6 R 6 = 59.711 D 6 = 1.70 R 7 = 39.696 D 7 = 2.90 N 4 = 1.84666 ν 4 = 23.9 R 8 = 48.254 D 8 = Variable R 9 = 61.886 D 9 = 1.50 N 5 = 1.84666 ν 5 = 23.8 R10 = 36.536 D10 = 7.00 N 6 = 1.71300 ν 6 = 53.8 R11 = -92.015 D11 = 0.10 R12 = 43.139 Aspheric D12 = 5.50 N 7 = 1.77250 ν 7 = 49.6 R13 = -469.393 D13 = 1.50 N 8 = 1.84666 ν 8 = 23.8 R14 = 129.333 D14 = Variable R15 = (Aperture) D15 = 1.00 R16 = 805.385 D16 = 4.10 N 9 = 1.84666 ν 9 = 23.8 R17 = -23.912 D17 = 1.10 N10 = 1.77250 ν10 = 49.6 R18 = 56.787 D18 = 2.80 R19 = -32.304 D19 = 1.10 N11 = 1.83481 ν11 = 42.7 R20 = -279.112 D20 = variable R21 = -61.974 D21 = 1.20 N12 = 1.84666 ν12 = 23.8 R22 = 82.543 D22 = 3.80 N13 = 1.7130 0 ν13 = 53.8 R23 = -34.909 D23 = 0.10 R24 = 49.546 D24 = 1.80 N14 = 1.76182 ν14 = 26.5 R25 = 39.572 D25 = 3.50 R26 = -706.308 D26 = 2.80 N15 = 1.69680 ν15 = 55.5 R27 = -64.519 D27 = 0.10 R28 = 77.104 D28 = 4.80 N16 = 1.71300 ν16 = 53.8 R29 = -104.361 D29 = 1.40 N17 = 1.84666 ν10 = 23.8 R30 = -193.661

[0058]

[Table 4] R12: Aspherical coefficient A = 0 B = -1.67796 × 10 ^-7 C = -1.68935 × 10 ^-9 D = -1.43301 × 10 ^-12 Numerical Example 5 F = 28.8 to 77.63 FNO = 1: 2.8 2ω = 73.8 ° ~ 31.1 ° R 1 = 107.701 Aspheric D 1 = 2.20 N 1 = 1.83481 ν 1 = 42.7 R 2 = 43.329 D 2 = 16.00 R 3 = -663.644 D 3 = 2.00 N 2 = 1.83481 ν 2 = 42.7 R 4 = 35.965 D 4 = 5.00 N 3 = 1.84666 ν 3 = 23.8 R 5 = 96.556 D 5 = 1.50 R 6 = 56.255 D 6 = 2.50 N 4 = 1.84666 ν 4 = 23.8 R 7 = 62.609 D 7 = Variable R 8 = 78.988 Aspheric surface D 8 = 1.50 N 5 = 1.84666 ν 5 = 23.8 R 9 = 39.104 D 9 = 7.50 N 6 = 1.71300 ν 6 = 53.8 R10 = -85.722 D10 = 0.10 R11 = 41.699 D11 = 7.00 N 7 = 1.77250 ν 7 = 49.6 R12 = -136.277 D12 = 1.50 N 8 = 1.84666 ν 8 = 23.8 R13 = 183.298 D13 = Variable R14 = (Aperture) D14 = 1.00 R15 = 413.138 D15 = 4.10 N 9 = 1.84666 ν 9 = 23.8 R16 = -27.684 D16 = 1.10 N10 = 1.77250 ν10 = 49.6 R17 = 53.170 D17 = 2.80 R18 = -32.983 D18 = 1.10 N11 = 1.83481 ν11 = 42.7 R19 = -4847.456 D19 = variable R20 = -80.792 D20 = 1.20 N12 = 1.84666 ν12 = 23.8 R21 = -461.613 D21 = 3.50 N13 = 1.71300 ν13 = 53.8 R22 = -36.396 D22 = 0.1 0 R23 = 45.586 D23 = 1.80 N14 = 1.76182 ν14 = 26.5 R24 = 37.053 D24 = 3.50 R25 = -159.162 D25 = 2.50 N15 = 1.69680 ν15 = 55.5 R26 = -56.467 D26 = 0.10 R27 = 95.167 D27 = 5.00 N16 = 1.71300 ν16 = 53.8 R28 = -47.606 D28 = 1.40 N17 = 1.84666 ν17 = 23.8 R29 = -121.554

[0059]

[Table 5] R1: Aspherical coefficient A = 0 B = 7.15543 × 10 ^-7 C = -2.45904 × 10 ^-10 D = -1.41751 × 10 ^-13 R8: Aspherical coefficient A = 0 B = 3.12771 × 10 ^-7 C = 9.559892 × 10 ^-11 Numerical Example 6 F = 28.8 to 77.43 FNO = 1: 2.8 2ω = 73.8 ° to 31.2 ° R 1 = 72.775 D 1 = 2.00 N 1 = 1.77250 ν 1 = 49.6 R 2 = 37.706 D 2 = 9.00 R 3 = -474.784 D 3 = 4.50 N 2 = 1.69895 ν 2 = 30.1 R 4 = -94.031 D 4 = 0.12 R 5 = -151.662 D 5 = 1.80 N 3 = 1.77250 ν 3 = 49.6 R 6 = 60.031 D 6 = 1.70 R 7 = 40.187 D 7 = 2.90 N 4 = 1.84666 ν 4 = 23.9 R 8 = 46.071 D 8 = Variable R 9 = 77.426 D 9 = 1.50 N 5 = 1.84666 ν 5 = 23.8 R10 = 35.026 D10 = 7.00 N 6 = 1.71300 ν 6 = 53.8 R11 = -89.434 Aspheric surface D11 = 0.10 R12 = 39.339 D12 = 5.50 N 7 = 1.77250 ν 7 = 49.6 R13 = 244.065 D13 = 1.50 N 8 = 1.84666 ν 8 = 23.8 R14 = 139.168 D14 = variable R15 = (aperture ) D15 = 1.00 R16 = 289.330 D16 = 4.10 N 9 = 1.84666 ν 9 = 23.8 R17 = -24.625 D17 = 1.10 N10 = 1.77250 ν10 = 49.6 R18 = 54.408 D18 = 2.80 R19 = -31.708 D19 = 1.10 N11 = 1.83481 ν11 = 42.7 R20 = -632.173 D20 = Variable R21 = -58.935 D21 = 1.20 N1 2 = 1.84666 ν12 = 23.8 R22 = 83.573 D22 = 3.80 N13 = 1.71300 ν13 = 53.8 R23 = -33.512 D23 = 0.10 R24 = 48.387 D24 = 1.80 N14 = 1.76182 ν14 = 26.5 R25 = 39.391 D25 = 3.50 R26 = 263.616 D26 = 2.80 N15 = 1.69680 ν15 = 55.5 R27 = -73.712 D27 = 0.10 R28 = 79.107 D28 = 4.80 N16 = 1.71300 ν16 = 53.8 R29 = -103.977 D29 = 1.40 N17 = 1.84666 ν17 = 23.8 R30 = -302.891

[0060]

[Table 6] R11: Aspherical surface coefficient A = 0 B = -3.75089 × 10 ⁻⁷ C = 2.89669 × 10 ⁻¹⁰ D = 6.62424 × 10 ⁻¹³ Numerical example 7 F = 28.8 to 77.4 FNO = 1: 2.8 2ω = 73.8 ° to 31.2 ° R 1 = 112.318 Aspheric D 1 = 2.20 N 1 = 1.83481 ν 1 = 42.7 R 2 = 43.560 D 2 = 16.00 R 3 = -1512.328 D 3 = 2.00 N 2 = 1.83481 ν 2 = 42.7 R 4 = 35.617 D 4 = 5.00 N 3 = 1.84666 ν 3 = 23.8 R 5 = 88.280 D 5 = 1.50 R 6 = 53.563 D 6 = 2.50 N 4 = 1.84666 ν 4 = 23.8 R 7 = 60.304 D 7 = Variable R 8 = 79.550 D 8 = 1.50 N 5 = 1.84666 ν 5 = 23.8 R 9 = 39.269 D 9 = 7.50 N 6 = 1.71300 ν 6 = 53.8 R10 = -88.346 D10 = 0.10 R11 = 41.335 D11 = 7.00 N 7 = 1.77250 ν 7 = 49.6 R12 = -147.232 D12 = 1.50 N 8 = 1.84666 ν 8 = 23.8 R13 = 188.635 Aspherical D13 = Variable R14 = (Aperture) D14 = 1.00 R15 = 662.981 D15 = 4.10 N 9 = 1.84666 ν 9 = 23.8 R16 = -26.757 D16 = 1.10 N10 = 1.77250 ν10 = 49.6 R17 = 55.441 D17 = 2.80 R18 = -33.069 D18 = 1.10 N11 = 1.83481 ν11 = 42.7 R19 = -7905.451 D19 = variable R20 = -83.147 D20 = 1.20 N12 = 1.84666 ν12 = 23.8 R21 = 833.745 D21 = 3.50 N13 = 1.71300 ν13 = 53.8 R22 = -36.241 D22 = 0.10 R23 = 45.804 D23 = 1.80 N14 = 1.76182 ν14 = 26.5 R24 = 37.229 D24 = 3.50 R25 = -182.280 D25 = 2.50 N15 = 1.69680 ν15 = 55.5 R26 = -57.812 D26 = 0.10 R27 = 87.431 D27 = 5.00 N16 = 1.71300 ν16 = 53.8 R28 = -56.322 D28 = 1.40 N17 = 1.84666 ν17 = 23.8 R29 = -149.333

[0061]

[Table 7] R1: Aspherical coefficient A = 0 B = 5.78991 × 10 ^-7 C = -4.62210 × 10 ^-11 D = 1.60066 × 10 ^-14 R13: Aspherical coefficient A = 0 B = 3.56175 × 10 ^-7 C = -1.61754 × 10 ^-11 D = 1.481666 × 10 ^-13 numerical example 8 F = 28.8 ~77.46 FNO = 1 : 2.8 2ω = 73.8 ° ~31.2 ° R 1 = 75.223 aspheric D 1 = 2.20 N 1 = 1.83481 ν 1 = 42.7 R 2 = 37.278 D 2 = 16.00 R 3 = -1600.958 D 3 = 2.00 N 2 = 1.83481 ν 2 = 42.7 R 4 = 32.493 D 4 = 5.50 N 3 = 1.84666 ν 3 = 23.8 R 5 = 71.677 D 5 = 1.50 R 6 = 50.112 D 6 = 3.00 N 4 = 1.84666 ν 4 = 23.8 R 7 = 61.032 D 7 = Variable R 8 = 74.083 D 8 = 1.50 N 5 = 1.84666 ν 5 = 23.8 R 9 = 32.486 D 9 = 7.50 N 6 = 1.71300 ν 6 = 53.8 R10 = -289.769 D10 = 0.10 R11 = 76.844 D11 = 5.50 N 7 = 1.77250 ν 7 = 49.6 R12 = -151.673 D12 = 1.40 N 8 = 1.84666 ν 8 = 23.8 R13 = 340.344 D13 = 0.10 R14 = 54.698 D14 = 4.50 N 9 = 1.77250 ν 9 = 49.6 R15 = 1076.398 D15 = Variable R16 = (Aperture) D16 = 1.00 R17 = 179.919 D17 = 4.10 N10 = 1.84666 ν10 = 23.8 R18 = -29.320 D18 = 1.10 N11 = 1.77250 ν11 = 49.6 R19 = 55.441 D19 = 2.90 R20 = -32.601 D20 = 1.10 N12 = 1.83481 ν12 = 42.7 R21 = 199.184 D21 = Variable R22 = -146.326 D22 = 1.40 N13 = 1.84666 ν13 = 23.8 R23 = -238.520 D23 = 3.80 N14 = 1.71300 ν14 = 53.8 R24 = -31.546 D24 = 0.10 R25 = -92.279 D25 = 2.80 N15 = 1.69680 ν15 = 55.5 R26 = -56.757 D26 = 0.10 R27 = 125.405 Aspherical D27 = 5.00 N16 = 1.71300 ν16 = 53.8 R28 = -38.566 D28 = 1.40 N17 = 1.84666 ν17 = 23.8 R29 = -373.726

[0062]

[Table 8] R1: Aspheric surface coefficient A = 0 B = 3.78122 × 10 ^-7 C = 2.31162 × 10 ^-10 D = -7.07093 × 10 ^-14 R27: Aspheric surface coefficient A = 0 B = -1.9333 × 10 ^-6 C = -4.86862 × 10 ^-9 D = 3.0832 × 10 ^-12 Numerical Example 9 F = 28.8 to 77.35 FNO = 1: 2.8 2ω = 73.8 ° to 31.2 ° R 1 = 82.212 Aspherical D 1 = 2.20 N 1 = 1.83481 ν 1 = 42.7 R 2 = 40.145 D 2 = 16.00 R 3 = -734.079 D 3 = 2.00 N 2 = 1.83481 ν 2 = 42.7 R 4 = 32.424 D 4 = 5.50 N 3 = 1.84666 ν 3 = 23.8 R 5 = 65.788 D 5 = 1.50 R 6 = 49.287 D 6 = 3.00 N 4 = 1.84666 ν 4 = 23.8 R 7 = 61.693 D 7 = Variable R 8 = 77.960 D 8 = 1.50 N 5 = 1.84666 ν 5 = 23.8 R 9 = 31.802 D 9 = 7.50 N 6 = 1.71300 ν 6 = 53.8 R10 = -198.781 D10 = 0.10 R11 = 77.219 D11 = 5.50 N 7 = 1.77250 ν 7 = 49.6 R12 = -168.989 D12 = 1.40 N 8 = 1.84666 ν 8 = 23.8 R13 = 357.536 D13 = 0.10 R14 = 50.032 D14 = 4.50 N 9 = 1.77250 ν 9 = 49.6 R15 = 1036.923 D15 = Variable R16 = (Aperture) D16 = 1.00 R17 = 159.183 D17 = 4.10 N10 = 1.84666 ν10 = 23.8 R18 = -28.287 D18 = 1.10 N11 = 1.77250 ν11 = 49.6 R19 = 53.088 D19 = 2.90 R20 = -34.394 D20 = 1.10 N1 2 = 1.83481 ν12 = 42.7 R21 = 122.601 D21 = Variable R22 = -152.863 D22 = 1.40 N13 = 1.84666 ν13 = 23.8 R23 = -275.361 D23 = 3.80 N14 = 1.71300 ν14 = 53.8 R24 = -31.874 D24 = 0.10 R25 = -92.992 D25 = 2.80 N15 = 1.69680 ν15 = 55.5 R26 = -57.447 D26 = 0.10 R27 = 126.107 D27 = 5.00 N16 = 1.71300 ν16 = 53.8 R28 = -38.422 D28 = 1.40 N17 = 1.84666 ν17 = 23.8 R29 = -550.494 Aspheric surface

[0063]

[Table 9] R1: Aspherical coefficient A = 0 B = 1.90348 × 10 ^-7 C = 2.99905 × 10 ^-10 D = -1.28883 × 10 ^-13 R29: Aspherical coefficient A = 0 B = 1.86774 × 10 ^-6 C = 6.79916 × 10 ^-9 D = -7.60901 x 10 ^-12

[0064]

As described above, according to the present invention, the total lens length can be shortened and the lens barrel structure can be realized by specifying the refracting powers of the four lens groups and the moving conditions of each lens group associated with zooming. It is possible to achieve a zoom lens having a relatively wide angle of view and a high optical performance over the entire zooming range with a high zooming ratio while being simple.

[Brief description of drawings]

FIG. 1 is a lens cross-sectional view of Numerical Example 1 of the present invention.

FIG. 2 is a lens cross-sectional view of Numerical Example 2 of the present invention.

FIG. 3 is a lens cross-sectional view of Numerical Example 3 of the present invention.

FIG. 4 is a lens cross-sectional view of Numerical Example 4 of the present invention.

FIG. 5 is a lens cross-sectional view of Numerical Example 5 of the present invention.

FIG. 6 is a lens cross-sectional view of Numerical Example 6 of the present invention.

FIG. 7 is a lens cross-sectional view of Numerical Example 7 of the present invention.

FIG. 8 is a lens cross-sectional view of Numerical Example 8 of the present invention.

FIG. 9 is a lens cross-sectional view of Numerical Example 9 of the present invention.

FIG. 10 is an aberration diagram at a zoom position at the wide-angle end according to Numerical Example 1 of the present invention.

FIG. 11 is an aberration diagram at a zoom position in the middle of Numerical Example 1 of the present invention.

FIG. 12 is an aberration diagram at a zoom position at a telephoto end according to Numerical Example 1 of the present invention.

FIG. 13 is an aberration diagram at a zoom position at the wide-angle end according to Numerical Example 2 of the present invention.

FIG. 14 is an aberration diagram at a zoom position in the middle of Numerical Example 2 of the present invention.

FIG. 15 is an aberration diagram at a zoom position at the telephoto end according to Numerical Example 2 of the present invention.

FIG. 16 is an aberration diagram at a zoom position at the wide-angle end according to Numerical Example 3 of the present invention.

FIG. 17 is an aberration diagram at a zoom position in the middle of Numerical Example 3 of the present invention.

FIG. 18 is an aberration diagram at a zoom position at a telephoto end according to Numerical Example 3 of the present invention.

FIG. 19 is an aberration diagram at a zoom position at the wide-angle end according to Numerical Example 4 of the present invention.

FIG. 20 is an aberration diagram at a zoom position in the middle of Numerical Example 4 of the present invention.

FIG. 21 is an aberration diagram at a zoom position at the telephoto end according to Numerical Example 4 of the present invention.

FIG. 22 is an aberration diagram at a zoom position at the wide-angle end according to Numerical Example 5 of the present invention.

FIG. 23 is an aberration diagram at a zoom position in the middle of Numerical Example 5 of the present invention.

FIG. 24 is an aberration diagram at a zoom position at a telephoto end according to Numerical Example 5 of the present invention.

FIG. 25 is an aberration diagram at a zoom position at the wide-angle end according to Numerical Example 6 of the present invention.

FIG. 26 is an aberration diagram at a zoom position in the middle of Numerical Example 6 of the present invention.

FIG. 27 is an aberration diagram at a zoom position at a telephoto end according to Numerical Example 6 of the present invention.

FIG. 28 is an aberration diagram at a zoom position at the wide-angle end according to Numerical Example 7 of the present invention.

FIG. 29 is an aberration diagram at a zoom position in the middle of Numerical Example 7 of the present invention.

FIG. 30 is an aberration diagram at a zoom position at the telephoto end according to Numerical Example 7 of the present invention.

FIG. 31 is an aberration diagram at a zoom position at the wide-angle end according to Numerical Example 8 of the present invention.

FIG. 32 is an aberration diagram at a zoom position in the middle of Numerical Example 8 of the present invention.

FIG. 33 is an aberration diagram at a zoom position at a telephoto end according to Numerical Example 8 of the present invention.

FIG. 34 is an aberration diagram at a zoom position at the wide-angle end according to Numerical Example 9 of the present invention.

FIG. 35 is an aberration diagram at a zoom position in the middle of Numerical Example 9 of the present invention.

FIG. 36 is an aberration diagram at a zoom position at the telephoto end according to Numerical Example 9 of the present invention.

[Explanation of symbols]

 L1 1st group L2 2nd group L3 3rd group L4 4th group SP Aperture d Fraunhofer spherical aberration at d line g Fraunhofer spherical aberration at g line S, C Satisfaction amount under sine condition S Sagittal section Image plane M Image plane at meridional section

Claims (14)

[Claims] 1. Four lens groups, in order from the object side, a first group having a negative refractive power, a second group having a positive refractive power, a third group having a negative refractive power, and a fourth group having a positive refractive power. And changing the magnification from the wide-angle end to the telephoto end by reducing the air space between the first group and the second group,
At least the first, so that the air gap between the second group and the third group increases and the air gap between the third group and the fourth group decreases.
The second and fourth groups are moved, the third group has an independent or cemented lens of a positive lens and a negative lens, and the fourth group has an independent or cemented lens of a negative lens and a positive lens. A zoom lens that is characterized by 2. The second group includes a meniscus-shaped negative lens having a strong negative refraction surface facing the image side in order from the object side, a positive lens, and a positive lens having a convex surface facing the object side. The zoom lens according to claim 1, wherein 3. The first lens group has, in order from the object side, a meniscus negative lens having a concave surface facing the image side, a negative lens, and a meniscus positive lens having a convex surface facing the object side. The zoom lens according to claim 1, wherein: 4. The zoom lens according to claim 1, wherein the third lens unit is fixed during zooming. 5. The zoom lens according to claim 1, wherein zooming from the wide-angle end to the telephoto end is performed by moving the second group and the fourth group integrally to the object side. 6. The four lens groups, in order from the object side, a first group having a negative refractive power, a second group having a positive refractive power, a third group having a negative refractive power, and a fourth group having a positive refractive power. The second lens unit has a negative meniscus lens 21 having a convex surface facing the object side, and a positive lens No. 22 having convex lens surfaces on both sides. A cemented lens with and
It has a positive 23rd lens having a strong positive refracting surface toward the object side, and the object side surface of the 21st lens or the 23rd lens is an aspherical surface, and the cemented lens surface of the cemented lens. The radius of curvature of R2, 2, the aspherical coefficient of the aspherical surface of B, C, the lens outer diameter of the 23rd lens of DE, the second
A zoom lens characterized by satisfying the condition of 0.6 <R2, 2 / F2 <1.0 B <0 B + C × (DE / 2) ² <0 when the focal length of the group is F2. 7. The zoom lens according to claim 6, wherein the first group includes at least two negative lenses and a positive lens. 8. The first lens group has two lens groups, an 11th lens group and a 12th lens group, in order from the object side, and the 12th lens group is moved on the optical axis for focusing. The zoom lens according to claim 6. 9. The four lens groups, in order from the object side, a first group having a negative refractive power, a second group having a positive refractive power, a third group having a negative refractive power, and a fourth group having a positive refractive power. The second lens unit has a negative meniscus lens 21 having a convex surface facing the object side, and a positive lens No. 22 having convex lens surfaces on both sides. A cemented lens with and
It has a positive 23rd lens having a strong positive refracting surface facing the object side, and the image side surface of the 22nd lens or the 23rd lens is an aspherical surface, and the cemented lens surface of the cemented lens. Is R2,2, the aspherical coefficient of the aspherical surface is B, C, the lens outer diameter of the 23rd lens is DE, and the focal length of the second group is F2. 0.6 <R2,2 / A zoom lens characterized by satisfying a condition of F2 <1.0 B> 0 B + C × (DE / 2) ² > 0. 10. The first lens group includes at least two negative lenses and a positive lens.
Zoom lens. 11. The first lens group has two lens groups, an 11th lens group and a 12th lens group, in order from the object side, and the 12th lens group is moved on the optical axis for focusing. The zoom lens according to claim 9. 12. A first group having a negative refractive power in order from the object side,
It has four lens groups, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power, and the zooming from the wide-angle end to the telephoto end is performed by the first lens group. The air gap between the second group and the second group, and the air gap between the second group and the third group is increased,
The fourth group has at least one negative lens, at least one positive lens, and at least one aspherical surface, and the refractive power of the aspherical surface is reduced. Is φ4a, the radius of curvature formed by the optical axis and the intersection of the aspherical surface and the maximum radial position of the aspherical surface is Rmax, and the radius of curvature is formed by the intersection of the optical axis and the aspherical surface and the aspherical surface position at a height H from the optical axis. A zoom lens characterized by satisfying a condition of (| Rmax | − | RH |) · φ4a <0 when the radius of curvature is RH. 13. The first lens group includes at least two negative lenses and one positive lens.
2 zoom lens. 14. The cemented lens in which the second lens unit is constructed by cementing a negative meniscus 21st lens having a convex surface directed toward the object side and a positive 22nd lens having convex lens surfaces on both sides, and is strong on the object side. And a positive 23rd lens having a positive refracting surface, and a radius of curvature of the cemented lens surface of the cemented lens is R2, 2 and a focal length of the second group is F2. 13. The zoom lens according to claim 12, wherein the condition <R2,2 / F2 <1.0 is satisfied.