JP2596817B2 - Zoom lens - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens for photographing, and more particularly to a zoom lens suitable for a photographing machine using an electronic image pickup tube or solid-state image pickup device as an image pickup device. .

[Related Art] Most of lens systems for photographing machines using an electronic image pickup tube and a solid-state image pickup device as image pickup devices are zoom lenses. These zoom lenses have an aperture ratio of F / 2.8 or more,
In most cases, the zoom ratio is three times or more.

These zoom lenses have a large aperture ratio and a high zoom ratio, but have a large number of components of 13 to 15 and are costly.

Recently, there have been proposed zoom lenses of this type having 12 to 18 components as disclosed in JP-A-60-123817 and JP-A-62-247318. Among them, the zoom lens described in Japanese Patent Application Laid-Open No. 62-247318 has a first lens unit whose basic configuration has a positive refractive power in order from the object side and is fixed at the time of zooming and movable at the time of focusing. A second lens group having a refractive power and movable for zooming, and a second lens group having a positive refractive power and moving along a locus having a convex shape on the image side to correct an image plane which fluctuates during zooming. It is composed of three groups and a fourth group which has an image forming function and is always fixed. In this conventional example, the first group is composed of three lenses, the second group is composed of three lenses, the third group is composed of one lens, and the fourth group is composed of four lenses. Among them, it is a zoom lens with a small number of lenses.

[Problem to be Solved by the Invention] The above-described conventional zoom lens has an angle of view of 45.5 ° to 16.2.
The zoom ratio is 3 and F / 1.4 at 、, but the first lens group has a large diameter and thickness and lacks compactness among zoom lenses of this type, and it is electrically focused, especially like auto focus However, there is a disadvantage that the power consumption is large and the focusing speed is not high.

The present invention has been made to solve the above-mentioned drawbacks, and has a small number of components, a small diameter of the first lens unit, an angle of view at the wide-angle end of about 48 °, a zoom ratio of 3 to 6, and an aperture ratio. Is F / 1.4-F / 2.8
It is an object of the present invention to provide a compact zoom lens having good imaging performance.

[Means for Solving the Problems] In order to achieve the above object, a zoom lens according to the present invention includes, in order from the object side, a first lens unit having a positive refractive power and a movable first lens unit along the optical axis during zooming. Second with negative refractive power
A second group having a positive refractive power that moves along the optical axis with a slightly different movement from the second group during zooming, and a fourth group that is always fixed and has a positive refractive power. And either the second group includes one positive lens or the third group includes one negative lens.

Further, the zoom lens of the present invention is characterized by satisfying the following conditions (1) to (4).

(1) 0.2 <| β _2S | <0.7 (2) 1.0 <| f _{II III} | / f _W <2.2 (3) ν _3P <63 (4) −0.06 <(D _2W −D _2T ) / f _S < 0.16 However, β _2S has a focal length of the whole system (F _W , f _T are the focal lengths of the entire system at the wide-angle end and the telephoto end, respectively), f _{II III} is the combined focal length of the second and third units at the telephoto end, ν _3P Is the Abbe number of the positive lens in the third group, and D _2W and D _2T are the distances between the second and third groups at the wide-angle end and the telephoto end, respectively.

A lens system such as the one disclosed in Japanese Patent Application Laid-Open No. 62-247318 requires a large amount of movable space as a whole because the movable space of the second group and the movable space of the third group are not shared. It is more advantageous for the mechanical structure that the movable group is on the same side of the aperture stop position as a boundary, so that the aperture stop is the third stop.
It is located on the image side of the group. Therefore, the entrance pupil position tends to be far from the first surface (the surface closest to the object). For this reason, the height at which the off-axis ray cuts the first lens unit increases, and the light amount becomes insufficient unless the diameter of the first lens unit is increased. When the diameter of the lens is increased, in the case of a convex lens, the thickness of the lens is increased in order to secure the rim. This causes a vicious cycle in which the position of the entrance pupil is further away from the first surface, and eventually the diameter of the front lens becomes large.

In the zoom lens of the present invention, the movable space of the second group and the movable space of the third group are arranged so as to share as much as possible without mechanical interference between them, and the overall space is reduced to reduce the entrance pupil. It is made to be close to one side. Specifically, the movement of the third unit with respect to the second unit is related, but it is preferable that the third unit be as close to the image side as possible at the telephoto end where the second unit is closest to the image side. The condition (1) is provided to make such a movement. That is, by setting the magnification β _2S of the second lens group at the intermediate focal length f _S within the range of the condition (1), the movement of the third lens group can satisfy the above requirements, and the front lens diameter becomes large. Can be prevented.

When the value of | β _2S | exceeds the upper limit (0.7) of the condition (1), the movable space of the second and third units cannot be shared as in the above-described conventional example, and the diameter of the front lens becomes large. Conversely, the lower limit (0.
Beyond 2), the second and third units mechanically interfere at the wide-angle end, and if designed to prevent this, the distance between the second and third units will increase at the telephoto end. As a result, wasted space is created and the diameter of the front lens becomes large.

In order to satisfy the above requirements, the condition (1) alone is not enough. Since the movement of the third lens group such as the zoom lens of the present invention is in a direction to cancel the zooming action of the second lens group,
The movement amount of the second lens unit is larger than in the conventional example. Therefore, a large amount of movable space is required, and it is difficult to reduce the diameter of the front lens. Condition (2) is provided in order to solve this and make the amount of movement of the second lens unit comparable to that of the conventional example.

In this condition (2), if the upper limit of 2.2 is exceeded, the second
The amount of movement of the group becomes large, and therefore the diameter of the front lens becomes large. Conversely, if the value exceeds the upper limit of 1.0, the fluctuation of spherical aberration and coma during zooming tends to increase, and the zoom ratio cannot be increased.

Regarding chromatic aberration, even if it occurs in each of the second group and the third group, the amount of change in the distance between the two groups is small, so that the chromatic aberration of each group can be offset at all focal lengths, and the chromatic aberration can be reduced. It can be corrected well. When the condition (2) is satisfied, the chromatic aberration cannot be canceled if a material having a large Abbe number is used for the positive lens of the third group as in the conventional example. Therefore, in the present invention, as shown in the condition (3), ν _3P <
63 media are used. When the value exceeds the upper limit of the condition (3), the chromatic aberration at the time of zooming is likely to fluctuate greatly.

It is preferable that the change in the chromatic aberration is such that the change in the relative distance between the second group and the third group is small. Therefore, in the present invention, the condition (4)
Was provided.

In the condition (4), when the value exceeds the upper limit of 0.16, the variation of chromatic aberration at the time of zooming tends to increase, and the lower limit of -0.06.
If the value exceeds 06, the distance between the second and third lens units at the telephoto end becomes large, and wasteful space is likely to occur, which is inconvenient in reducing the diameter of the front lens. (D _2W −D _2T ) / f _S = 0 is most desirable.

This condition (4) is also desirable for satisfying the condition (1) at high zooming.

In the lens system of the present invention, if the overall power of the third unit is too strong, it is difficult to control the movement of the focal position during zooming within a certain range in terms of manufacturing accuracy. Therefore, it is desirable that the focal length f _III of the third lens unit be within the range of the following condition (5).

If the lower limit of the condition is exceeded, it becomes difficult to keep the zooming movement amount of the focal position within an allowable range due to manufacturing accuracy. If the upper limit is exceeded, the amount of relative movement of the third lens group with respect to the second lens group becomes too large, which is not preferable because the movement space tends to be wasted.

In the present invention, the fourth unit is 3 in the lens system of the F / 2.8 class.
4 to 4, F / 2.0 class lens system 4 to 5, F
The /1.4 class lens system consists of 4 to 6 lenses.
From the viewpoint of reducing the number of components and the viewpoint that the fourth unit is an imaging system, it is preferable to use a triplet lens as the fourth unit. From the viewpoint of aberration correction,
It is preferable that a part or all of the first positive lens unit, the negative lens unit, and the second positive lens unit of the triplet system be constituted by a plurality of lenses, or that an aspheric surface be used.

When the number of components of the fixed group is reduced to the limit, coma aberration is particularly likely to deteriorate. That is, the off-axis upper light beam is strongly converged at the periphery of the fixed group (fourth group), and its longitudinal aberration has a large negative value. Also, as the F-number becomes smaller and brighter, correction of spherical aberration and coma becomes difficult.

From the above, in the F / 2.8 class, it is preferable that the fourth unit be a triplet type and that an aspherical surface be used as a part of the second positive lens unit of the triplet, or that the second positive lens unit be divided into two. The use of an aspheric surface in the second positive lens group or the division of this into two positive lenses is because the second positive lens has the least overlap of light fluxes at each image height, and reduces spherical aberration and coma. This is because correction can be easily performed separately.

For F / 2.0, F / 1.4 class, one or two first positive lens groups
, One to two negative lens groups, two to the second positive lens group
By using three lenses, spherical aberration and coma can be corrected well. In order to further improve the aberration, an aspheric surface is used for a part of the positive lens group, particularly a part of the second positive lens group, or a strong concave surface is directed to the image side of the second positive lens group for the purpose of aberration correction. It is desirable to add a negative lens, which can improve the imaging performance.

In the case of using an aspherical surface, it is not preferable to use a method of correcting aberrations that occur remarkably in one lens with another lens, because the effect of eccentricity becomes remarkable. Therefore, it is preferable to use a lens that significantly generates aberration so that the aberration is reduced. Therefore, if an aspherical surface whose refractive power becomes weaker than when a spherical surface having a curvature near the optical axis is used toward the periphery of the second positive lens unit which significantly generates coma aberration is used, the negative of the upper light beam becomes negative. Large longitudinal aberration is reduced. When the f-number becomes small and becomes bright, it becomes necessary to correct spherical aberration. This is because the first positive lens unit has a similar aspheric surface, that is, a spherical surface having the same curvature as the curvature near the optical axis toward the periphery. It is sufficient to use an aspherical surface whose refractive power is weaker than when a is used.

The aspheric surface used in the zoom lens of the present invention is represented by the following equation.

In the above equation, the x-axis is taken in the direction of the optical axis and the y-axis is taken in the direction perpendicular to the optical axis, r is the radius of curvature on the optical axis, and A _2i is the aspheric coefficient.

EXAMPLES Next, examples of the zoom lens of the present invention will be described.

Example 1 f = 9 to 27 mm, F / 2.8, 2ω = 48.7 ゜ to 18.2 ゜ r ₁ = 20.5698 d ₁ = 1.5000 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 15.2436 d ₂ = 0.3800 r ₃ = 16.2889 d ₃ = 5.5000 n ₂ = 1.69680 v ₃ = 55.52 r ₄ = 1264.2130 d ₄ = D ₁ (variable) r ₅ = 52.6236 d ₅ = 0.9000 n ₃ = 1.83400 v ₃ = 37.16 r ₆ = 8.9934 d ₆ = 2.3000 r ₇ = − 17.5175 d ₇ = 0.9000 n ₄ = 1.69680 v ₄ = 55.52 r ₈ = 13.0000 d ₈ = 1.6000 n ₅ = 1.69895 v ₅ = 30.12 r ₉ = 25.3099 d ₉ = D ₂ (variable) r ₁₀ = 22.5861 d ₁₀ = 1.9000 n ₆ = 1.84666 ν ₆ = 23.78 r ₁₁ = -89.7285 d ₁₁ = D ₃ (variable) r ₁₂ = ∞ (aperture) d ₁₂ = 1.5000 r ₁₃ = 10.0989 d ₁₃ = 5.8658 n ₇ = 1.72342 ν ₇ = 38.03 r ₁₄ = _{-38.4266 d 14 = 0.5000 r 15 =} -12.5379 d 15 = 1.0000 n 8 = 1.84666 ν 8 = 23.78 r 16 = 12.3959 d 16 = 1.8688 r 17 = 53.9661 d 17 = 3.2000 n 9 = 1.69680 ν 9 = 55.52 r 18 = −12.8206 d ₁₈ = 0.1500 r ₁₉ = 25.9278 d ₁₉ = 2.3000 n ₁₀ = 1.69680 ν ₁₀ = 55.52 r _{20 = -41.7135 d 20 = 4.0000 r 21} = ∞ d 21 = 10.1000 n 11 = 1.51633 ν 11 = 64.15 r 22 = ∞ d 22 = 5.1000 n 12 = 1.54771 ν 12 = 62.83 r 23 = ∞ d 23 = 1.2100 r 24 = ∞ d ₂₄ = 0.6000 n ₁₃ = 1.48749 ν ₁₃ = 70.20 r ₂₅ = ｆ f 9.27 15.58 26.19 D ₁ 0.600 7.282 12.749 D ₂ 0.800 1.466 0.800 D ₃ 13.449 6.102 1.300 β _2S = −0.407, | f _{II III} | / f _W = 1.207 ν _3P = 23.78, (D _2W −D _2T ) / f _S = 0.0 Example 2 f = 9 to 27 mm, F / 2.0, 2ω = 48.7 ゜ to 18.2 ゜ r ₁ = 21.9333 d ₁ = 1.5000 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 16.5730 d ₂ = 0.7000 r ₃ = 18.0721 d ₃ = 6.5000 n ₂ = 1.69680 v ₂ = 55.52 r ₄ = −2286.1934 d ₄ = D ₁ (variable) r ₅ = 70.3935 d ₅ = 0.9000 n ₃ = 1.83400 v ₃ = 37.16 r ₆ = 9.2358 d ₆ = 2.9000 r ₇ = _{-16.7332 d 7 = 0.9000 n 4 =} 1.69680 ν 4 = 55.52 r 8 = 15.0000 d 8 = 1.6000 n 5 = 1.69895 ν 5 = 30.12 r 9 = 39.5957 d 9 = D 2 ( _{variable) r 10 = 27.6482 d 10 =} 2.1000 n ₆ = 1.84666 v ₆ = 23.78 r ₁₁ = −62.4928 d ₁₁ = D ₃ (variable) r ₁₂ = ∞ (aperture) d ₁₂ = 1.5000 r ₁₃ = 14.5675 d ₁₃ = 6.4043 n ₇ = 1.80610 v ₇ = 40.95 r _{14 = -50.1841 d 14 = 0.7500 r 15} = -15.0522 d 15 = 2.6651 n 8 = 1.84666 ν 8 = 23.78 r 16 = 17.2822 d 16 = 1.3423 r 17 = 56.1518 d 17 = 3.6000 n 9 = 1.69680 ν 9 = 55.52 r 18 = -14.5156 d ₁₈ = 0.1500 r ₁₉ = 24.7980 d ₁₉ = 2.9000 n ₁₀ = 1.69680 ν ₁₀ = 55.52 r ₂₀ = -46.2758 d ₂₀ = 4.1000 r ₂₁ = ∞ d ₂₁ = 10.1000 n ₁₁ = 1.51633 ν ₁₁ = 64.15 r ₂₂ = ∞ d ₂₂ = 5.1000 n ₁₂ = 1.54771 ν ₁₂ = 62.83 r ₂₃ = ∞ d ₂₃ = 1.2100 r ₂₄ = ∞ d ₂₄ = 0.6000 n ₁₃ = 1.48749 ν ₁₃ = 70.20 r ₂₅ = ∞ f 9.27 15.58 26.19 D ₁ 0.600 7.625 13.509 D ₂ 0.800 1.481 0.800 D ₃ 14.209 6.503 1.300 β _2S = −0.399, | f _{II III} | / f _W = 1.282 ν _3P = 23.78, (D _2W −D _2T ) / f _S = 0.0 Example 3 f = 9 to 54 mm, F / 2.8, 2ω = 48.7 ゜ to 9.2 ゜ r ₁ = 126.1022 d ₁ = 1.5000 n ₁ = 1.80518 ν ₁ = 25.43 r ₂ = 48.5060 d ₂ = 4.5000 n ₂ = 1.60311 ν ₂ = 60.70 r ₃ = -310.3639 d ₃ = 0.1500 r ₄ = 36.2200 d ₄ = 3.8000 n ₃ = 1.69680 ν ₃ = 55.52 r ₅ = 137.5296 d ₅ = D ₁ (variable) r ₆ = 80.2290 d ₆ = 0.9000 n ₄ = 1.83400 v ₄ = 37.16 r ₇ = 13.9236 d ₇ = 2.8000 r ₈ = −23.8032 d ₈ = 0.9000 n ₅ = 1.69680 v ₅ = 55.52 r ₉ = 15.0000 d ₉ = 2.3000 n ₆ = 1.69895 v ₆ = 30.12 r ₁₀ = 61.3240 d ₁₀ = D _{2 (variable) r 11 = 55.7543 d 11 =} 1.7000 n 7 = 1.84666 ν 7 = 23.78 r 12 = -155.1359 d 12 = D 3 ( variable) r ₁₃ = ∞ (stop) d ₁₃ = 1.5000 ₁₄ = _{11.8785 d 14 = 10.0865 n 8 =} 1.80610 ν 8 = 40.95 r 15 = -70.5443 d 15 = 0.5000 r 16 = -14.9376 d 16 = 1.0000 n 9 = 1.84666 ν 9 = 23.78 r 17 = 13.0264 d 17 = 0.7000 r 18 = 57.8903 d ₁₈ = 3.2000 n ₁₀ = 1.69680 ν ₁₀ = 55.52 r ₁₉ = -16.5053 d ₁₉ = 0.1500 r _{20 = 19.5419 d 20 = 2.3000 n} 11 = 1.72342 ν 11 = 38.03 r 21 = -1097.4735 d 21 = 4.0000 r 22 = ∞ d 22 = 10.1000 n 12 = 1.51633 ν 12 = 64.15 r 23 = ∞ d 23 = 5.1000 n 13 = 1.54771 ν ₁₃ = 62.83 r ₂₄ = ∞ d ₂₄ = 1.2100 r ₂₅ = ∞ d ₂₅ = 0.6000 n ₁₄ = 1.48749 ν ₁₄ = 70.20 r ₂₆ = ∞ f 9.27 22.04 52.38 D ₁ 0.600 17.883 29.244 D ₂ 0.800 5.594 0.800 D ₃ 29.944 7.867 1.300 β _2S = −0.500, | f _{II III} | / f _W = 1.579 ν _3P = 23.78, (D _2W −D _2T ) / f _S = 0.0 Example 4 f = 9 to 27 mm, F / 1.4, 2ω = 48.7 ゜ to 18.2 ゜ r ₁ = 24.4460 d ₁ = 2.0000 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 18.5611 d ₂ = 0.6700 r ₃ = 19.6562 d ₃ = 8.0000 n ₂ = 1.69680 v ₂ = 55.52 r ₄ = 176.9296 d ₄ = D ₁ (variable) r ₅ = 28.5775 d ₅ = 0.9000 n ₃ = 1.83400 v ₃ = 37.16 r ₆ = 9.4317 d ₆ = 4.3000 r ₇ =- _{19.1379 d 7 = 0.9000 n 4 =} 1.69680 ν 4 = 55.52 r 8 = 21.0000 d 8 = 1.6000 n 5 = 1.69895 ν 5 = 30.12 r 9 = 38.5204 d 9 = D 2 ( _{variable) r 10 = 30.6746 d 10 =} 2.4000 n ₆ = 1.84666 ν ₆ = 23.78 r ₁₁ = -82.4297 d ₁₁ = D ₃ (variable) r ₁₂ = ∞ (aperture) d ₁₂ = 2.000 r ₁₃ = 20.3769 d ₁₃ = 5.0385 n ₇ = 1.80610 ν ₇ = 40.95 r ₁₄ = _{-33.2123 d 14 = 0.4400 r 15 =} -20.3574 d 15 = 1.0000 n 8 = 1.84666 ν 8 = 23.78 r 16 = -105.5308 d 16 = 5.4215 r 17 = -219.3635 d 17 = 1.5000 n 9 = 1.80518 ν 9 = 25.43 r ₁₈ = 17.9140 d ₁₈ = 0.4800 r ₁₉ = 25.7928 d ₁₉ = 3.8000 n ₁₀ = 1.69680 ν ₁₀ = 55.52 r ₂₀ = -20.9625 d ₂₀ = 0.1500 r ₂₁ = 15.4959 d ₂₁ = 3.5000 n ₁₁ = 1.69680 ν ₁₁ = 55.52 r ₂₂ = 166.0511 d ₂₂ = 4.1000 r ₂₃ = ∞ d ₂₃ = 5.5000 n ₁₂ = 1.51633 ν ₁₂ = 64.15 r ₂₄ = ∞ d ₂₄ = 1.2100 r ₂₅ = ∞ d ₂₅ = 0.6000 n ₁₃ = 1.48749 ν ₁₃ = 70.20 r ₂₆ = ∞ f 9.27 15.58 26.19 D ₁ 0.600 9.176 16.020 D ₂ 0.800 1.609 0.800 D ₃ 16.720 7.335 1.300 β _2S = −0.402 , | f _{II III} | / f _W = 1.532 ν _3P = 23.78, (D _2W −D _2T ) / f _S = 0.0 Example 5 f = 9 to 54 mm, F / 1.4, 2ω = 48.7 ゜ to 9.2 ゜ r ₁ = 122.3468 d ₁ = 1.5000 n ₁ = 1.80518 ν ₁ = 25.43 r ₂ = 52.8269 d ₂ = 6.1000 n ₂ = 1.60311 ν ₂ = 60.70 r ₃ = -309.5818 d ₃ = 0.1500 r ₄ = 42.2763 d ₄ = 4.8000 n ₃ = 1.69680 ν ₃ = 55.52 r ₅ = 148.9164 d ₅ = D ₁ (variable) r ₆ = 421.8362 d ₆ = 0.9000 n ₄ = _{1.83400 ν 4 = 37.16 r 7 =} 14.6941 d 7 = 3.7000 r 8 = -26.7472 d 8 = 0.9000 n 5 = 1.69680 ν 5 = 55.52 r 9 = 16.0263 d 9 = 3.0000 n 6 = 1.84666 ν 6 = 23.78 r 10 = 79.8436 d ₁₀ = D _{2 (variable) r 11 = 79.0512 d 11 =} 1.9000 n 7 = 1.76200 ν 7 = 40.10 r 12 = -88.8672 d 12 = D 3 ( variable) r ₁₃ = ∞ (stop) d ₁₃ = 2.0000 r _{14 = 24.0479 d 14 = 4.2000 n 8} = 1.77250 ν 8 = 49.66 r 15 = -61.6587 d 15 = 0.8500 r 16 = -28.4314 d 16 = 1.0000 n 9 = 1.84666 ν 9 = 23.78 r 17 = -61.5608 d 17 = 12.8426 r ₁₈ = 180.3724 d ₁₈ = 1.0000 n ₁₀ = 1.84666 ν ₁₀ = 23.78 r ₁₉ = 21.3949 d ₁₉ = 1.500 0 r ₂₀ = 64.0009 d ₂₀ = 3.7000 n ₁₁ = 1.69680 ν ₁₁ = 55.52 r ₂₁ = −30.7674 d ₂₁ = 0.1500 r ₂₂ = 16.6824 d ₂₂ = 4.2000 n ₁₂ = 1.69680 ν ₁₂ = 55.52 r ₂₃ = 99.8035 d ₂₃ = 4.0000 r ₂₄ = ∞ d ₂₄ = 10.1000 n ₁₃ = 1.51633 ν ₁₃ = 64.15 r ₂₅ = ∞ d ₂₅ = 5.1000 n ₁₄ = 1.54771 ν ₁₄ = 62.83 r ₂₆ = ∞ d ₂₆ = 1.2100 r ₂₇ = ∞ d ₂₇ = 0.6000 n ₁₅ = 1.48749 ν ₁₅ = 70.20 r ₂₈ = ∞ f 9.27 22.03 52.37 D ₁ 1.000 20.294 32.565 D ₂ 0.800 6.048 0.800 D ₃ 32.865 8.324 1.300 β _2S = −0.503, | f _{II III} | / f _W = 1.741 ν _3P = 40.10, (D _2W -D _2T ) / f _S = 0.0 Example 6 f = 9 to 27 mm, F / 2.0, 2ω = 48.7 ゜ to 18.2 ゜ r ₁ = 22.6371 d ₁ = 1.5000 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 16.8471 d ₂ = 0.6100 r ₃ = 18.3095 d ₃ = 6.5000 n ₂ = 1.69680 v ₂ = 55.52 r ₄ = −780.5033 d ₄ = D ₁ (variable) r ₅ = 84.9168 d ₅ = 0.9000 n ₃ = 1.83400 v ₃ = 37.16 r ₆ = 9.4135 d ₆ = 2.8000 r ₇ = _{-18.3476 d 7 = 0.9000 n 4 =} 1.69680 ν 4 = 55.52 r 8 = 15.0000 d 8 = 1.6000 n 5 = 1.69895 ν 5 = 30.12 r 9 = 33.4221 d 9 = D 2 ( _{variable) r 10 = 24.0076 d 10 =} 2.0000 n ₆ = 1.84666 v ₆ = 23.78 r ₁₁ = -78.6562 d ₁₁ = D ₃ (variable) r ₁₂ = ∞ (aperture) d ₁₂ = 1.7000 r ₁₃ = 21.9904 d ₁₃ = 3.3771 n ₇ = 1.80610 v ₇ = 40.95 r _{14 = -28.3595 d 14 = 0.3700 r 15} = -16.9163 d 15 = 1.0000 n 8 = 1.84666 ν 8 = 23.78 r 16 = 1554.4198 d 16 = 7.7963 r 17 = 60.9381 d 17 = 3.6000 n 9 = 1.69680 ν 9 = 55.52 r 18 = -18.9727 d ₁₈ = 0.1500 r ₁₉ = 22.8935 d ₁₉ = 3.2000 n ₁₀ = 1.69680 ν ₁₀ = 55.52 r ₂₀ = -46.9645 d ₂₀ = 0.7500 r ₂₁ = -19.7470 d ₂₁ = 1.5000 n ₁₁ = 1.84666 ν ₁₁ = 23.78 r ₂₂ = -122.5983 d ₂₂ = 2.000 r ₂₃ = ∞ d ₂₃ = 10.1000 n ₁₂ = 1.51633 ν ₁₂ = 64.15 r ₂₄ = ∞ d ₂₄ = 5.1000 n ₁₃ = 1.54771 v ₁₃ = 62.83 r ₂₅ = ∞ d ₂₅ = 1.2100 r ₂₆ = d ₂₆ = 0.6000 n ₁₄ = 1.48749 ν ₁₄ = 70.20 r ₂₇ = ∞ f 9.27 15.58 26.19 D ₁ 0.600 7.777 13.792 D ₂ 0.800 1.445 0.800 D ₃ 14.492 6.670 1.300 β _2S = −0.387, | f _{II III} | / f _W = 1.311 ν _3P = 23.78, (D _2W −D _2T ) / f _S = 0.0 Example 7 f = 9 to 27 mm, F / 2.8, 2ω = 48.7 ゜ to 18.2 ゜ r ₁ = 20.6095 d ₁ = 1.5000 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 15.2707 d ₂ = 0.3800 r ₃ = 16.2427 d ₃ = 5.5000 n ₂ = 1.69680 v ₂ = 55.52 r ₄ = 724.6233 d ₄ = D ₁ (variable) r ₅ = 53.2280 d ₅ = 0.9000 n ₃ = 1.83400 v ₃ = 37.16 r ₆ = 8.9415 d ₆ = 2.3000 r ₇ = − _{17.1990 d 7 = 0.9000 n 4 =} 1.69680 ν 4 = 55.52 r 8 = 26.1266 d 8 = D 2 ( _{variable) r 9 = 22.1635 d 9 =} 2.5000 n 5 = 1.84666 ν 5 = 23.78 r 10 = -24.0000 d 10 = 1.0000 n ₆ = 1.69680 v ₆ = 55.52 r ₁₁ = −155.8588 d ₁₁ = D ₃ (variable) r ₁₂ = ∞ (aperture) d ₁₂ = 1.5000 r ₁₃ = 10.0584 d ₁₃ = 5.8930 n ₇ = 1.70154 v ₇ = 41.21 r _{14 = -35.7295 d 14 = 0.5000 r 15} = -12.5150 d 15 = 1.0000 n 8 = 1.84666 ν 8 = 23.78 r 16 = 12.4372 d 16 = 1.7958 r 17 = 50.5874 d 17 = 3.2000 n 9 = 1.69350 ν 9 = 53.23 r 18 = -12.7714 d ₁₈ = 0.1500 r ₁₉ = 25.2199 d ₁₉ = 2.3000 n ₁₀ = 1.69350 ν ₁₀ = 53.23 r ₂₀ = -40.8570 d ₂₀ = 4.000 r ₂₁ = ∞ d ₂₁ = 10.1000 n ₁₁ = 1.51633 ν ₁₁ = 64.15 r ₂₂ = ∞ d ₂₂ = 5.1000 n ₁₂ = 1.54771 ν ₁₂ = 62.83 r ₂₃ = ∞ d ₂₃ = 1.2100 r ₂₄ = ∞ d ₂₄ = 0.6000 n ₁₃ = 1.48749 ν ₁₃ = 70.20 r ₂₅ = ∞ f 9.27 15.58 26.19 D ₁ 0.600 7.332 12.821 D ₂ 0.800 1.465 0.800 D ₃ 13.521 6.125 1.300 β _2S = −0.407, | f _{II III} | / f _W = 1.214 ν _3P = 23.78, (D _2W −D _2T ) / f _S = 0.0 Example 8 f = 9 to 27 mm, F / 2.8, 2ω = 48.7 ゜ to 18.2 ゜ r ₁ = 20.3585 d ₁ = 1.5000 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 15.4113 d ₂ = 0.3200 r ₃ = 16.3678 d ₃ = 5.2000 n ₂ = 1.69680 v ₂ = 55.52 r ₄ = 289.7401 d ₄ = D ₁ (variable) r ₅ = 53.8105 d ₅ = 0.9000 n ₃ = 1.83400 v ₃ = 37.16 r ₆ = 8.8546 d ₆ = 2.3000 r ₇ = − _{18.1138 d 7 = 0.9000 n 4 =} 1.69680 ν 4 = 55.52 r 8 = 36.9531 d 8 = D 2 ( _{variable) r 9 = 22.7181 d 9 =} 2.2000 n 5 = 1.84666 ν 5 = 25.78 r 10 = -24.0000 d 10 = 1.0000 n ₆ = 1.69680 v ₆ = 55.52 r ₁₁ = 44346.8880 d ₁₁ = D ₃ (variable) r ₁₂ = ∞ (aperture) d ₁₂ = 1.5000 r ₁₃ = 10.7102 d ₁₃ = 6.2055 n ₇ = 1.70154 v ₇ = 41.21 r ₁₄ = _{-23.6782 d 14 = 0.2000 r 15 =} -14.1954 d 15 = 1.0000 n 8 = 1.84666 ν 8 = 23.78 r 16 = 13.9290 d 16 = 2.8026 r 17 = 17.4080 ( _{aspherical) d 17 = 5.0000 n 9 =} 1.69680 ν 9 = 55.52 r ₁₈ = -11.4365 d ₁₈ = 4.0000 r ₁₉ = ∞ d ₁₉ = 10.1000 n ₁₀ = 1.51633 ν _{10 = 64.15 r 20 = ∞ d 20} = 5.1000 n 11 = 1.54771 ν 11 = 62.83 r 21 = ∞ d 21 = 1.2100 r 22 = ∞ d 22 = 0.6000 n 12 = 1.48749 ν 12 = 70.20 r 23 = ∞ aspherical coefficients A ₄ = -0.26854 x 10 ^-3 , A ₆ = 0.13179 x 10 ^-5 A ₈ = -0.28548 x 10 ^-7 f 9.27 15.58 26.19 D ₁ 0.600 7.630 13.116 D ₂ 0.800 1.582 0.800 D ₃ 13.816 6.004 1.300 β _2S = -0.434 , | f _{II III} | / f _W = 1.243 ν _3P = 23.78, (D _2W −D _2T ) / f _S = 0.0 Example 9 f = 9 to 54 mm, F / 1.4, 2ω = 48.7 ゜ to 9.2 ゜ r ₁ = 133.2040 d ₁ = 1.5000 n ₁ = 1.80518 ν ₁ = 25.43 r ₂ = 59.2562 d ₂ = 6.5000 n ₂ = 1.60311 ν ₂ = 60.70 r ₃ = −218.4745 d ₃ = 0.1500 r ₄ = 46.7875 d ₄ = 4.3000 n ₃ = 1.69680 ν ₃ = 55.52 r ₅ = 136.2198 d ₅ = D ₁ (variable) r ₆ = 74.8595 d ₆ = 0.9000 n ₄ = 1.83400 ν ₄ = 37.16 r ₇ = 16.5062 d ₇ = 4.3000 r ₈ = −22.9074 d ₈ = 0.9000 n ₅ = 1.69690 ν ₅ = 55.52 r ₉ = 161.7260 d ₉ = D ₂ (variable) r ₁₀ = 53.4934 d ₁₀ = 3.0000 n ₆ = 1.84666 ν ₆ = 23.78 r ₁₁ = −39.3515 d ₁₁ = 1.0000 n ₇ = 1.69680 ν ₇ = 55.52 r ₁₂ = 368.8143 d ₁₂ = D ₃ (variable) r ₁₃ = ∞ (aperture) d ₁₃ = 2.0000 r _{14 = 19.8034 d 14 = 4.5000 n 8} = 1.77250 ν 8 = 49.66 r 15 = -59.8241 d 15 = 0.7500 r 16 = -27.0622 d 16 = 1.0000 n 9 = 1.84666 ν 9 = 23.78 r 17 = 4023.1309 d 17 = 9.5718 r 18 = 70.2215 d ₁₈ = 4.5000 n ₁₀ = 1.69680 ν ₁₀ = 55.52 r ₁₉ = -27.0510 d ₁₉ = 0.15 00 r ₂₀ = 20.5147 d ₂₀ = 3.0000 n ₁₁ = 1.69680 v ₁₁ = 55.52 r ₂₁ = 204.7427 d ₂₁ = 1.6000 r ₂₂ = -22.7 450 d ₂₂ = 1.0000 n ₁₂ = 1.84666 v ₁₂ = 23.78 r ₂₃ = -134.7313 d ₂₃ = 4.0000 r ₂₄ = ∞ d ₂₄ = 8.0000 n ₁₃ = 1.51633 ν ₁₃ = 64.15 r ₂₅ = ∞ d ₂₅ = 5.1000 n ₁₄ = 1.54771 ν ₁₄ = 62.83 r ₂₆ = ∞ f 9.27 22.04 52.38 D ₁ 0.600 20.994 34.882 D ₂ 0.800 6.621 0.800 D ₃ 35.582 9.367 1.300 β _2S = −0.499, | f _{II III} | / f _W = 1.890 ν _3P = 23.78, (D _2W −D _2T ) / f _S = 0.0 Example 10 f = 8 to 24 mm, F / 2.8, 2ω = 54.0 ° to 20.5 ° r ₁ = 73.2004 d ₁ = 1.6000 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 38.6631 d ₂ = 4.1000 n ₂ = 1.60311 ν ₂ = 60.70 r ₃ = -296.7193 d ₃ = 0.1500 r ₄ = 25.2092 d ₄ = 3.6000 n ₃ = 1.71300 ν ₃ = 53.84 r ₅ = 96.0259 d ₅ = D ₁ (variable) r ₆ = 42.4751 d ₆ = 0.9000 n ₄ = _{1.83400 ν 4 = 37.16 r 7 =} 8.9245 d 7 = 3.2000 r 8 = -14.4872 d 8 = 0.9000 n 5 = 1.69680 ν 5 = 55.52 r 9 = 13.1736 d 9 = 2.1000 n 6 = 1.84666 ν 6 = 23.78 r 10 = 99.3340 d ₁₀ = D _{2 (variable) r 11 = 38.3565 d 11 =} 1.6000 n 7 = 1.84666 ν 7 = 23.78 r 12 = -147.1026 d 12 = D 3 ( variable) r ₁₃ = ∞ (stop) d ₁₃ = 1.5000 r _{14 = 12.2431 d 14 = 6.0144 n 8} = 1.76200 ν 8 = 40.10 r 15 = -28.0696 d 15 = 0.2700 r 16 = -12.3996 d 16 = 1.4455 n 9 = 1.84666 ν 9 = 23.78 r 17 = 12.7019 d 17 = 2.8178 r 18 = 52.4534 d ₁₈ = 3.5000 n ₁₀ = 1.69680 ν ₁₀ = 55.52 r ₁₉ = -12.2285 d ₁₉ = 0.1500 r _{2 0 = 30.2496 d 20 = 2.5000 n} 11 = 1.69680 ν 11 = 55.52 r 21 = -43.4650 d 21 = 4.5000 r 22 = ∞ d 22 = 7.9000 n 12 = 1.51633 ν 12 = 64.15 r 23 = ∞ d 23 = 1.2000 n 13 = 1.51633 ν ₁₃ = 64.15 r ₂₄ = ∞ d ₂₄ = 5.1000 n ₁₄ = 1.54771 ν ₁₄ = 62.83 r ₂₅ = ∞ d ₂₅ = 0.9000 r ₂₆ = ∞ d ₂₆ = 0.7000 n ₁₅ = 1.51633 ν ₁₅ = 64.15 r ₂₇ = ∞ d ₂₇ = 0.3100 r ₂₈ = ∞ d ₂₈ = 0.6000 n ₁₆ = 1.48749 ν ₁₆ = 70.20 r ₂₉ = ｆ f 8.24 13.85 23.28 D ₁ 0.600 7.689 13.162 D ₂ 0.930 2.138 0.800 D ₃ 13.732 5.436 1.300 β _2S = -0.524, | f _{II III} | / f _W = 1.416 ν _3P = 23.78, (D _2W −D _2T ) / f _S = 0.094 Example 11 f = 9 to 27 mm, F / 2.8, 2ω = 48.7 ゜ to 18.2 ゜ r ₁ = 20.9352 d ₁ = 1.6000 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 15.6111 d ₂ = 0.4000 r ₃ = 16.5677 d ₃ = 5.9000 n ₂ = 1.69680 v ₂ = 55.52 r ₄ = 396.9886 d ₄ = D ₁ (variable) r ₅ = 42.8369 d ₅ = 0.9000 n ₃ = 1.80610 v ₃ = 40.95 r ₆ = 8.8637 d ₆ = 2.8000 r ₇ = − 16.5604 d ₇ = 0.9000 n ₄ = 1.69680 ν ₄ = 55.52 r ₈ = 15.4214 d ₈ = 1.7000 n ₅ = 1.84666 ν ₅ = 23.78 r ₉ = 55.2065 d ₉ = D ₂ (variable) r ₁₀ = 42.2632 d ₁₀ = 1.6000 n ₆ = 1.84666 ν ₆ = 23.78 r ₁₁ = -96.0817 d ₁₁ = D ₃ (variable) r ₁₂ = ∞ (aperture) d ₁₂ = 1.5000 r ₁₃ = 11.2213 d ₁₃ = 4.9431 n ₇ = 1.74950 ν ₇ = 35.27 r ₁₄ = _{-16.9103 d 14 = 0.2700 r 15 =} -11.2281 d 15 = 1.0000 n 8 = 1.84666 ν 8 = 23.78 r 16 = 12.0808 d 16 = 2.4357 r 17 = 43.8514 d 17 = 3.4000 n 9 = 1.69680 ν 9 = 55.52 r 18 = _{-12.2893 d 18 = 0.1500 r 19 =} 40.3001 d 19 = 2.0000 n 10 = 1.69680 ν 10 = 55.52 r 20 _{-52.7041 d 20 = 4.5000 r 21 =} ∞ d 21 = 7.9000 n 11 = 1.51633 ν 11 = 64.15 r 22 = ∞ d 22 = 1.2000 n 12 = 1.51633 ν 12 = 64.15 r 23 = ∞ d 23 = 5.1000 n 13 = 1.54771 ν ₁₃ = 62.83 r ₂₄ = ∞ d ₂₄ = 0.9000 r ₂₅ = ∞ d ₂₅ = 0.7000 n ₁₄ = 1.51633 ν ₁₄ = 64.15 r ₂₆ = ∞ d ₂₆ = 0.3100 r ₂₇ = ∞ d ₂₇ = 0.6000 n ₁₅ = 1.48749 ν ₁₅ = 70.20 r ₂₈ = ∞ f 9.27 15.58 26.19 D ₁ 0.600 7.569 13.030 D ₂ 0.930 2.122 0.800 D ₃ 13.600 5.439 1.300 β _2S = −0.522, | f _{II III} | / f _W = 1.246 ν _3P = 23.78, (D _2W − D _2T ) / f _S = 0.0083 Example 12 f = 9 to 27 mm, F / 2.8, 2ω = 48.7 ゜ to 18.2 ゜ r ₁ = 21.0708 d ₁ = 1.6000 n ₁ = 1.84666 ν ₁ = 23.78 r ₂ = 15.4497 d ₂ = 0.3000 r ₃ = 16.3292 d ₃ = 5.7000 n ₂ = 1.69680 v ₂ = 55.52 r ₄ = 709.5292 d ₄ = D ₁ (variable) r ₅ = 55.3981 d ₅ = 0.9000 n ₃ = 1.69580 v ₃ = 55.52 r ₆ = 8.3563 d ₆ = 2.4000 r ₇ = − _{17.9562 d 7 = 0.9000 n 4 =} 1.69680 ν 4 = 55.52 r 8 = 11.8475 d 8 = 1.9000 n 5 = 1.84666 ν 5 = 23.78 r 9 = 45.7885 d 9 = D 2 ( _{variable) r 10 = 33.3223 d 10 =} 1.5000 n ₆ = 1.69680 ν ₆ = 55.52 r ₁₁ = -174.6557 d ₁₁ = D ₃ (variable) r ₁₂ = ∞ (aperture) d ₁₂ = 1.5000 r ₁₃ = 10.8481 d ₁₃ = 5.2096 n ₇ = 1.74950 ν ₇ = 35.27 r ₁₄ = _{-17.7465 d 14 = 0.2100 r 15 =} -11.3031 d 15 = 0.9440 n 8 = 1.84666 ν 8 = 23.78 r 16 = 11.3031 d 16 = 2.9153 r 17 = 47.7945 d 17 = 3.5000 n 9 = 1.69680 ν 9 = 55.52 r 18 = _{-12.0729 d 18 = 0.1500 r 19 =} 40.1164 d 19 = 2.0000 n 10 = 1.69680 ν 10 = 55.52 r 20 _{-50.1483 d 20 = 4.9500 r 21 =} ∞ d 21 = 9.8000 n 11 = 1.51633 ν 11 = 64.15 r 22 = ∞ d 22 = 5.1000 n 12 = 1.54771 ν 12 = 62.83 r 23 = ∞ d 23 = 1.2100 r 24 = ∞ d ₂₄ = 0.6000 n ₁₃ = 1.48749 ν ₁₃ = 70.20 r ₂₅ = ｆ f 9.27 15.58 26.19 D ₁ 0.600 7.416 12.830 D ₂ 0.930 2.414 0.800 D ₃ 13.400 5.100 1.300 β _2S = -0.562, | f _{II III} | / f _W = 1.224 ν _3P = 55.52, (D _2W −D _2T ) / f _S = 0.0083 However r _1, r _2, ... are radii of curvature of each lens surface, d _1, d _2, ... is the thickness and lens distance of each lens, n _1, n _2, ... is the refractive index of each lens, [nu _1, ν ₂ ,... are Abbe numbers of the respective lenses.

Examples 1 to 12 have the lens configurations shown in FIGS. 1 to 12, respectively. The aberration conditions at the wide-angle end, the intermediate focal length, and the telephoto end in each embodiment are described in the first embodiment.
13, FIG. 14, FIG. 15, and Embodiment 2 correspond to FIG. 16, FIG.
FIG. 18, FIG. 18, and Embodiment 3 show FIGS. 19, 20, and 21, respectively.
Embodiment 4, FIG. 22, FIG. 23, and FIG. 24, respectively, FIG. 25, FIG. 26, and FIG.
29, FIG. 30, and Embodiment 7 correspond to FIGS. 31, 32, 33, respectively.
FIG. 34, FIG. 35, FIG. 36, and Embodiment 9 correspond to FIG.
Are respectively shown in FIGS. 37, 38 and 39, and the tenth embodiment is shown in FIG.
FIG. 41, FIG. 42, and FIG.
FIG. 45 and Embodiment 12 are as shown in FIGS. 46, 47 and 48, respectively.

[Effect of the Invention] The zoom lens according to the present invention has an angle of view of about 49 ° at the wide-angle end,
Despite having a zoom ratio of 3 to 6 and an F-number of 1.4 to 2.8 class, it was possible to construct with a very small number of lenses by adopting a new configuration or a new movement of the lens group during zooming. Things. Further, the zoom lens has a short overall length, a small front lens diameter, a small size and light weight, and excellent imaging characteristics.

[Brief description of the drawings]

1 to 12 show Embodiments 1 to 12 of the present invention, respectively.
13 to 48 are aberration curve diagrams of each embodiment.

Claims (3)

(57) [Claims] 1. A first lens having a positive refractive power in order from the object side.
A second group having a negative refractive power that is movable along the optical axis at the time of zooming, and a slightly different movement along the optical axis during zooming. A third lens unit having a positive refractive power, and a fourth lens unit having a fixed refractive power and a fixed refractive power. The second lens unit includes one positive lens, or the third lens unit includes one positive lens. A zoom lens comprising a negative lens according to the above, wherein the following conditions are satisfied. (1) 0.2 <| β _2S | <0.7 (2) 1.0 <| f _{II III} | / f _W <2.2 (3) ν _3P <63 (4) −0.06 <(D _2W −D _2T ) / f _S < 0.16 However, β _2S has a focal length of the whole system (F _W, f _T are each wide angle end, the focal length of the entire system at the telephoto end) the second group of magnification when, f _{II III} is the composite focal length of the second and third lens groups at the telephoto end, D _2W Is the distance between the second and third groups at the wide-angle end, _D2T is the distance between the second and third groups at the telephoto end, and _ν3P is the Abbe number of the positive lens of the third group. 2. The zoom lens according to claim 1, wherein the following condition (5) is satisfied. Where f _III is the focal length of the third lens unit. 3. The zoom lens according to claim 1, wherein the fourth group is a triplet type.