JP2002365548A - Zoom lens - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a compact zoom lens which can be applied to a comparatively large imaging element, whose angle of view at a wide-angle end exceeds 70 deg. and which maintains sufficient image-forming performance, even when its variable power ratio exceeds about 10. SOLUTION: This zoom lens is constituted of a 1st positive group G1, a 2nd negative group G2, a 3rd positive group G3, a 4th positive group G4 and a 5th group G5. In the case of varying power form the wide-angle end to a telephoto end, the respective lens groups from the 1st group G1 to the 5th group G5 are moved, so that the space between the 1st group and the 2nd group becomes larger and the space between the 2nd group and the 3rd group becomes smaller, and then the 5th group moves to return to the image side, while moving to the object side. The zoom lens satisfies conditional expression (1) for stipulating back focus and a conditional expression (2) for stipulating that it is an optical system with light being made incident on the image forming element at a small angle taken into account.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens, and more particularly to a large-diameter, wide-angle, high-magnification zoom lens which is optimal for a video camera or the like and has high performance.

[0002]

2. Description of the Related Art A high-magnification zoom lens for a camera has been developed for a commercial television camera or a cine camera for a relatively long time. Since the widespread use of video cameras, development has been active in business and home use. However, it is also known that when the angle of view on the wide angle side is 70 ° or more with a high magnification, a very advanced technology for optical design is required. In old times, the composition is, in order from the object side,
A type including a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power (or a negative refractive power), and a fourth lens group having a positive refractive power has become widespread. This is a type in which the magnification is changed by the second lens group and the image plane position is compensated by the third lens group. For example, there is Japanese Patent Publication No. 2-48087. This is a type that has many achievements, and is characterized in that the first lens unit and the fourth lens unit are fixed at the time of zooming. In addition, there is a method developed based on the idea of arranging a dedicated front converter for widening the angle in the first lens group in this type. For example, US Pat. No. 3,682,534. These were considered to be for business use, had a large number of lens components, and were large.

[0003] Further, in order from the object side, the first lens unit has a positive refractive power, the second lens unit has a negative refractive power, the third lens unit has a positive refractive power, and the fourth lens unit has a positive refractive power. There has been proposed a wide-angle high-magnification zoom lens of a type that is configured so that the second lens group to the fourth lens group are movable at the time of zooming and the fourth lens group focuses. For example, there is Japanese Patent Application Laid-Open No. 6-148520.

Further, the lens unit is composed of a first lens unit having a positive refracting power, a second lens unit having a negative refracting power, a third lens unit having a positive refracting power, and a fourth lens unit having a positive refracting power. There is a fifth-group zoom type of a fifth lens group composed of lenses, and a lens close to a wide-angle, high-magnification zoom lens considered in the present invention up to now is disclosed in US Pat. No. 5,973,854. This is designed with the intention of a conventional interchangeable lens for a silver halide film camera, and the final lens group is a single lens and can be a fixed group.

Further, in order from the object side, the first positive refractive power
U.S. Pat. No. 5,872, which comprises a lens group, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a negative refractive power. ,
No. 659 and US Pat. No. 4,861,145,
The fifth lens group has a single or doublet configuration, and the group behind the third lens group moves toward the object side during zooming from the wide-angle end to the telephoto end. A technique in which the fifth lens group is fixed at the time of zooming has already been disclosed.

US Pat. No. 5,299,064 is for a video camera, in which a first lens group, a third lens group, and a fifth lens group are fixed at the time of zooming, and a fourth lens group is moved. It can be said that this is a proposal for a zoom lens of a type that focuses on a relatively small imager size.

[0007] Further, the arrangement is such that, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power. Japanese Patent Application Laid-Open No. Hei 7-20381 discloses a type which is constituted and in which the first lens group and below are movable at the time of zooming.

[0008] These proposals have a simple lens configuration, but have a problem to cope with a future increase in the number of pixels of the imaging element. This type of zoom lens was rather developed in a camera using a conventional silver halide film. For example, a type in which the configuration includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power. U.S. Pat. No. 4,299,454 discloses a zoom system in which each lens group moves and a field angle at the wide-angle end exceeds 80 °.

Japanese Patent Publication No. 58-33531 has been proposed as having a zoom ratio of about 5 from about 74 ° to about 19 °. According to this proposal, the configuration is such that, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, and a positive refractive power. This is a type constituted by a fifth lens unit having a power, and has a feature in a focusing method in which the first lens unit and the second lens unit are integrated.

As a zoom lens covering an angle of view of about 74 ° to about 8.3 °, US Pat.
No. 6,950. This is because, in order from the object side, the first lens group having a positive refractive power, the second lens group having a negative refractive power, the third lens group having a positive refractive power, the fourth lens group having a negative refractive power, and the positive refractive power. Of the fifth lens group, wherein the fifth lens group is fixed during zooming.

From the object side, the first lens group has a positive refractive power, the second lens group has a negative refractive power, and the third to fifth lens groups have a positive refractive power. As a zoom lens having a large aperture ratio and a fixed group and an angle of view at the wide-angle end of about 74 °, there is one disclosed in Japanese Patent Application Laid-Open No. 6-281852.

Further, from the object side, the first lens group has a positive refractive power, the second lens group has a negative refractive power, and the third lens group has a fifth refractive power.
A zoom lens in which each lens group has a positive refractive power and each lens group moves during zooming is disclosed in
No. 161028.

[0013]

Although these prior arts have no problem in silver halide film applications, they are not suitable for digital camera applications. In a digital camera, a CCD is used as an image pickup device.
Has a problem of aperture ratio. However, since the aperture ratio is not taken into account in the prior art, the CCD cannot be used as it is without impairing the aperture ratio.
Also, considering the problem of color unevenness including chromatic aberration,
Although an optical design is required that takes the exit angle of the off-axis chief ray into consideration sufficiently and takes the image plane illuminance into consideration, this point is not considered in the prior art.

In a conventional video camera, there is a proposal as a wide-angle and high-magnification zoom lens, but it is assumed that the size of an image forming element is extremely small. Therefore, an optical design based on a conventional zoom lens for a video camera results in a zoom lens having a very large overall length and a large front lens diameter, and may not even be practical.

The present invention has been made in view of such problems of the prior art, and has an object to be applicable to a relatively large imaging element, a wide-angle end exceeding 70 °, and a zoom ratio of 1
An object of the present invention is to provide a small-sized zoom lens capable of maintaining a sufficient imaging performance even under severe specification conditions exceeding about 0 times.

[0016]

According to the present invention, there is provided a zoom lens having a first positive refractive power in order from the object side.
The zoom lens system includes a lens unit, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, a fourth lens unit having a positive refractive power, and a fifth lens unit. The respective lens groups from the first lens group to the fifth lens group move, so that the distance between the first lens group and the second lens group increases, and the distance between the second lens group and the third lens group decreases. Go to
The fifth lens unit moves to the object side, and satisfies the following conditional expression.

0.05 <f _BW / | f _W12 | <3.0 (1) 4 <| E _xpdW × Y | / f _W (2) where f _W is at the wide-angle end. The focal length of the entire system, f _BW is the distance from the last lens surface (not including filters) at the wide-angle end to the imaging plane, and | f _W12 | is the second to the second lens group at the wide-angle end.
The focal length to the lens group, _ExpdW is the distance on the optical axis from the image plane position (not including filters) at the wide angle end to the exit pupil,
Y is the actual maximum image height on the image plane.

In this case, it is desirable to satisfy the following conditional expression.

2.0 <f ₁ / f _W <12.0 (3) 0.3 <| f ₂ / f _W | <3.5 (4) 0.15 <f ₃ / f _W345 <3.0 (5) 2.0 <| f ₅ | / f _W345 <20 (6) where f ₁ is the focal length of the first lens unit, and f ₂ is the second lens. The focal length of the group, f _3, is the focal length of the third lens group, f
₅ is the focal length of the fifth lens group, and f _W345 is the focal length from the third lens group to the fifth lens group at the wide angle end.

It is preferable that the fourth lens group includes at least one set of cemented lenses.

Preferably, the fifth lens group includes at least one set of cemented lenses.

Focusing on a finite object is as follows.
It is desirable to perform this by moving the first lens group and the second lens group integrally or by moving only the second lens group.

Hereinafter, the reason for adopting the above configuration in the present invention and its operation will be described.

An object of the present invention is to provide a compact, high-performance, wide-angle, high-magnification zoom lens, which is intended for an optical system having a relatively short back focus. The conventional optical system includes, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a fourth lens group having a positive refractive power. Zoom lenses have become the mainstream of camera lenses, and in high-magnification zoom lenses, a system in which the first lens group and other lens groups are movable has become common. Further, the mutual movement of the third lens unit and the fourth lens unit is necessary to correct the fluctuation of the curvature of field at the time of zooming in addition to the zooming. It may even be considered one lens group.

However, in order to achieve a wider angle of view and a larger zoom ratio, one negative lens group is provided in addition to the positive lens group to move the zoom lens. This is also advantageous. In particular, as in the present invention, for example, when the zoom ratio is about 10 times or more, the superiority became clear. Generally, as the number of lens groups increases, it is considered that chromatic aberration correction is required for each lens group, and it is considered that the number of lens components increases. However, in the present invention, the aspherical surface is effectively used, the distortion is mainly corrected by the surface of the negative lens of the second lens unit, and the aspherical surface is sufficiently corrected by the rear lens unit so as to sufficiently correct coma and the like. Actively adopted and intended for miniaturization.

That is, in order from the object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power.
Consisting of a lens unit, a fourth lens unit having a positive refractive power, and a fifth lens unit, each of which moves from the first lens unit to the fifth lens unit during zooming from the wide-angle end to the telephoto end. And
The distance between the first lens group and the second lens group is increased,
The distance between the lens group and the third lens group moves so as to be narrow, and the fifth lens group moves toward the object side, and satisfies the following conditional expression.

0.05 <f _BW / | f _W12 | <3.0 (1) 4 <| E _xpdW × Y | / f _W (2) where f _W is at the wide angle end. The focal length of the entire system, f _BW is the distance from the last lens surface (not including filters) at the wide-angle end to the imaging plane, and | f _W12 | is the second to the second lens group at the wide-angle end.
The focal length to the lens group, _ExpdW is the distance on the optical axis from the image plane position (not including filters) at the wide angle end to the exit pupil,
Y is the actual maximum image height on the image plane.

The paraxial refractive power arrangement of the lens unit is regulated by the following conditional expression.

2.0 <f ₁ / f _W <12.0 (3) 0.3 <| f ₂ / f _W | <3.5 (4) 0.15 <f ₃ / f _W345 <3.0 (5) 2.0 <| f ₅ | / f _W345 <20 (6) where f ₁ is the focal length of the first lens unit, and f ₂ is the second lens. The focal length of the group, f _3, is the focal length of the third lens group, f
₅ is the focal length of the fifth lens group, and f _W345 is the focal length from the third lens group to the fifth lens group at the wide angle end.

It is a major object of the present invention to provide a zoom lens system which can sufficiently cope with an angle of view at the wide angle end of about 70 ° or more and has high image forming performance. For this,
As a zoom lens system, the first with positive refracting power from the object side
The lens system includes a lens group, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a negative refractive power, and a fifth lens group having a positive or negative refractive power. (1)-
This was realized by finding a power arrangement suitable for (6) and constructing and arranging an optimal lens for this.

Further, the present invention has solved the problems of large size and reduced performance, which are common in wide-angle and high-magnification zoom lenses.
The curvature of field in the peripheral portion of the wide-angle region can be solved by increasing the overall length to some extent or by using a symmetric lens configuration. However, this is a major problem due to development aimed at shortening the overall length. For this, the lens configuration and the use of the aspherical surface are important.

Conditional expression (1) is a conditional expression that defines the back focus based on the lens closest to the image, which does not include the filters of the zoom lens system of the present invention. The optical system for conventional silver halide cameras assumes a single-lens reflex camera,
It has an optical design that assumes the space of a quick return mirror. When the value goes below the lower limit of 0.05 to condition (1), the insertion space for filters becomes insufficient. On the other hand, when the value exceeds the upper limit of 3.0, the back focus becomes too large for downsizing, which is one of the aims of the present invention, which is not preferable. This back focus is, for example, CC
In the case of a D imaging element, it is necessary to determine the number depending on the number of pixels, and it is necessary to optimize from a certain range in order to reduce the size.

It is more preferable that the conditional expression (1) falls within the following range.

0.1 <f _BW / | f _W12 | <1.0 (1 ′) In addition, the conditional expression (2) is different from the silver halide camera application, and in the case of a video camera or the like, It is necessary to consider the angle of incidence of the off-axis chief ray on the image plane. This conditional expression stipulates that the optical system takes into consideration that the light enters the imaging element at an angle as small as possible due to the aperture ratio and the like. If the lower limit of 4 to condition (2) is not satisfied, the aperture ratio is undesirably deteriorated. In particular, the conditional expression (2) means that the position of the exit pupil of the optical system is considered.

It is more preferable that the conditional expression (2) be in the following range.

30 <| E _xpdW × Y | / f _W (2 ′) Conditional expression (3) defines the power arrangement of the first lens unit. Since the first lens group moves at the time of zooming in the case of the zoom method as in the present invention, it is important to maintain the imaging performance while paying attention to the movement amount and the increase of the front lens diameter. is there. If the upper limit of 12.0 to condition (3) is exceeded, the amount of residual aberration of the first lens group decreases, which is advantageous for aberration correction. However, the amount of movement during zooming increases, and the entrance pupil distance also increases. As a result, the outer diameter of the lens increases, which tends to increase the overall size, which is not desirable. Also,
If the value is below the lower limit of 2.0, it is a direction of miniaturization,
Although the front lens diameter and the movement amount during zooming tend to decrease, this is not preferable from the viewpoint of aberration correction. In particular, it relates to correction of chromatic aberration in the telephoto range.

It is more preferable that the conditional expression (3) falls within the following range.

3.0 <f ₁ / f _W <10.0 (3 ′) Conditional expression (4) is a conditional expression that determines the power arrangement of the second lens unit having a negative refractive power. The second lens group is also concerned with determining the power of the first lens group. If the second lens group has a small power, the first lens group is also the same and tends to be large. In condition (4), when the value exceeds the upper limit of 3.5, the number of lens configurations may be small, but the power of the first lens unit other than the second lens unit also decreases, and
There are advantages in aberration correction, such as an increase in the diameter of the front lens of the first lens unit and an increase in the amount of movement during zooming. However, many other problems arise, which is undesirable. On the other hand, if the lower limit is less than 0.3, it is possible to reduce the size of the lens system, but it becomes difficult to correct aberrations.
Distortion and off-axis coma become noticeable. Further, even within this conditional expression, it is possible to obtain a compact lens system and high imaging performance only by using an appropriate lens configuration.

Conditional expression (5) is a conditional expression for determining the power of the third lens unit. In this zoom system, the image forming unit is constituted by the third lens unit to the fifth lens unit. From the viewpoint of the zoom system, it can be said that the image forming unit is constituted by three independent lens units. The zooming method differs from the zooming method in which the third lens group has a positive refractive power and the fourth lens group has a positive refractive power, which is a conventional zoom method. The third lens group has a role of converging a light beam from the second lens group having a strong diverging power and correcting spherical aberration and off-axis aberration. Further, it has a role of favorably correcting on-axis spherical aberration. Conditional expression (5)
If the upper limit of 3.0 is exceeded, the aberration correction surface of the third lens unit is very advantageous, but the amount of movement of the third lens unit during zooming increases, which is not preferable. When the value is below the lower limit of 0.15, the amount of movement at the time of zooming is reduced, which is desirable for miniaturization. However, from the viewpoint of aberration correction, not only spherical aberration correction becomes difficult, but also off-axis Correction of aberrations becomes difficult, which is undesirable.

Conditional expression (6) is a conditional expression for determining the power of the fifth lens unit. This lens group plays an important role in controlling the principal ray of the off-axis light beam. In particular, in the specifications of the CCD image pickup device and the like, it plays a significant role in that the off-axis principal ray has a role of giving a certain degree of telecentricity. If the upper limit of the conditional expression (20) is exceeded, aberration correction of the fifth lens group is facilitated, but the amount of movement during zooming increases, which is not preferable. On the other hand, when the value is below the lower limit of 2.0, it becomes difficult to correct off-axis aberrations, and it becomes difficult to correct aberrations unless the lens configuration is increased. Further, in this lens group, an increase in the lens configuration leads to an increase in the size of the entire lens system, so that a desired result is not often obtained. The fifth lens group may be a positive lens group or a negative lens group depending on the refractive power of the fourth lens group and the type of zooming movement. Further, it is shown in Examples described later that the range of refracting power that can be taken by the fifth lens group is considerably wide.

Further, in the present invention, it is intended to cover a wide angle end of about 70 ° or more while having a high magnification, and to propose an advanced optical system having a simple configuration. That is, in terms of focal length, the zoom lens is characterized in that the focal length at the wide-angle end is shorter than the effective diagonal length of the imaging surface of the optical system or the element. Further, as seen in the embodiment of the present invention, including the case where the CCD is considered as the imaging element, in consideration of the problem of the aperture ratio on the imaging surface, despite the fact that the effective diagonal length is larger than before, An optical system that can maintain a certain degree of telecentricity has been proposed.

After the paraxial configuration is determined by the above conditional expression, the thick lens configuration of the present invention is determined. That is, the first lens group includes at least one negative lens and a positive lens. In the present invention, a pair of cemented lenses or an air separation type doublet is used as a basic configuration. It consists of a lens. When the telephoto end is in the telephoto range as a high-magnification zoom lens, it is desirable to use anomalous dispersive glass, and it is easy to cope with an imaging element with a high pixel count.

The second lens group includes at least two negative lenses and one positive lens. In the present invention, as shown in conditional expression (4), miniaturization is intended by configuring with a large power, and includes a negative meniscus lens, a biconcave negative lens, a positive lens, and a negative lens from the object side. It is desirable to do. By making the object side surface of the first negative meniscus lens an aspherical surface, it is possible to perform correction on this surface where a large amount of distortion occurs. If an aspherical surface can be used for the subsequent negative lens, it is effective in correcting the curvature of field in a wide-angle range, and is important when aggressively increasing the angle of view. Also, it is well known that a doublet that is a cemented doublet of a negative lens and a positive lens or a doublet sandwiching an air lens is effective in correcting the Petzval sum for the lens closest to the image.

It is desirable that the third lens group includes at least two positive lenses and one negative lens. By using an aspheric surface for the positive lens, it is possible to reduce the on-axis spherical aberration, The effect is also great in correcting off-axis chromatic aberration. When the aperture stop is disposed adjacent to the object side of the third lens group, the aperture stop is more significant for correcting the axial aberration than the off-axis aberration.
That is, since the spherical aberration tends to be insufficiently corrected by the positive lens, the positive use of the aspherical surface for correcting the spherical aberration is very effective. This is a lens group that tends to have a high refractive power. In the case of increasing the aperture, the effect is higher if the aspherical surface has a plurality of surfaces. Normally, there is a fact that the action changes depending on the balance of aberration correction, rather than defining the aspherical shape. In this case, if the correction of on-axis spherical aberration is emphasized, the aspherical surface is configured such that the power of the lens becomes gentler toward the periphery of the lens. Further, an inflection point may occur on the aspheric surface due to the balance with off-axis aberration. This lens group may be composed of three positive lenses and one negative lens.

The fourth lens group is a positive lens group composed of a set of doublets. This lens group plays a large role in correcting off-axis aberrations, particularly correcting off-axis aberrations rather than zooming. The fourth lens group can be composed of one negative lens and a positive lens having a small power. However, by using an aspherical surface for the lens surface closest to the image, it is easier to correct off-axis aberrations. For example, in the case of a doublet with a negative lens and a positive lens, it is desirable to use an aspheric surface on the image side surface of the doublet.

The fifth lens group is composed of a cemented lens of at least one positive lens and one negative lens, or an air separation type doublet. When the refracting power of the fifth lens group is increased, it is desirable that the doublet be composed of two sets of doublets, with one doublet correcting chromatic aberration and the other doublet correcting Petzval sum. When at least one aspherical surface is used for the fifth lens group, it is possible to realize an optical system that maintains a certain degree of telecentricity and maintains a peripheral light amount.

In the present invention, the first lens unit and the third lens unit may move substantially linearly in some cases.
With respect to the other lens groups, the magnification relationship at the time of zooming, except for the relationship of the fourth lens group, generally indicates the absolute value of the magnification in the direction from the wide-angle end to the telephoto end except for the direction of magnification. To maintain. This enables efficient zooming.

In the zoom lens of the present invention, there are two basic zooming methods for the movement locus of the fourth lens group. This is as shown in the later-described embodiment. On the other hand, when the fourth lens group moves from the wide-angle end to the telephoto end as in the first to third embodiments, the fourth lens group moves to the object side while moving to the telephoto end. This is the case where the lens returns in the area and approaches the fifth lens group. The other case is, as shown in Examples 4 and 5, etc., where the zoom lens moves to the object side during zooming from the wide-angle end to the telephoto end, and approaches the third lens group in the telephoto range. This zooming movement changes depending on the refractive power arrangement of each lens group.

As a case where a great difference appears particularly,
There is a sign and the refractive power of the lens group. In Examples 1, 2, and 3, -0.0032, -0.00997, and-
0.0079. On the other hand, in Examples 4 and 5, they are 0.0104 and 0.00995, respectively. Thus, when the fifth lens group has a negative refractive power, the fourth lens group exhibits a non-linear movement with a return, while when the fifth lens group has a positive refractive power, a wide angle The embodiment shows a feature of moving to the object side during zooming from the end to the telephoto end.

In the present invention, particularly, the fifth lens group has a positive refracting power, the back focus at the wide-angle end is generally short, and the off-axis principal ray incident on the image plane has a certain degree of telecentricity. A major feature is that it is a close optical system.

Further, regarding the focusing, in the wide-angle and high-magnification zoom lens as in the present invention, the method by moving the first lens group used in the past zoom lens is as follows.
It is not practical because of enlargement and fluctuation of aberration, and it is better to move the first lens group and the second lens group integrally. Also,
From the viewpoint of aberration variation, if it is used for close-up photography,
Movement of the second lens group can be used.

According to the present invention, a simple high-magnification zoom lens can of course be a high-magnification zoom lens having a wide angle exceeding an angle of view of about 70 °. For this purpose, a proper zoom method, power arrangement, proper lens configuration, and
An effective method of using an aspheric surface was realized.

Embodiments 8 and 9 show the focusing method.
In the wide-angle range, as shown in FIG.
A method for reducing the amount of focus movement is required.

The following Tables 1, 2, 3, and 4 show Example 8 respectively.
Are shown. Table 1 shows the sum of aberration coefficients of each lens group at infinity at the wide-angle end. Table 2 shows aberration coefficients at 1 m at the wide-angle end when the second lens group is a focus lens group. Table 3 shows the total aberration coefficient at infinity at the telephoto end, and Table 4 shows the aberration coefficient at 1 m. Here, SA3 is a spherical aberration coefficient, CM3 is a coma aberration coefficient, and A
S3 is an astigmatism coefficient, DT3 is a distortion aberration coefficient, and PZ3 is an aberration coefficient of field curvature. (Table 1) group SA3 CM3 AS3 DT3 PZ3 G1 -0.00007 0.00139 -0.15849 4.24199 -0.09669 G2 0.04657 0.23763 0.09107 -5.75862 0.63836 G3 -0.80015 -2.11485 -0.59220 -0.09106 -0.26885 G4 0.29549 1.30197 0.46447 0.45241 -0.156132 -0.06706 -0.13348 Σ -0.47377 -0.69602 -0.10302 -1.22233 -0.02498.

(Table 2) Group SA3 CM3 AS3 DT3 PZ3 G1 -0.00009 -0.00230 -0.13835 4.18323 -0.09650 G2 0.04559 0.23633 0.06898 -5.76039 0.63705 G3 -0.79523 -2.10618 -0.59098 -0.09106 -0.26829 G4 0.29367 1.29661 -0.46359824 0.01551 -0.12166 0.09194 -0.06706 -0.13320 Σ -0.47157 -0.69717 -0.10490 -1.28287 -0.02493.

(Table 3) Group SA3 CM3 AS3 DT3 PZ3 G1 -0.32939 0.97038 -0.43820 0.74656 -0.07498 G2 1.13360 0.69728 0.58691 -0.54450 0.49499 G3 -6.13781 -5.87884 -0.49620 -0.01815 -0.20847 G4 2.63067 2.28139 -0.25762 0.1 -0.12387 -0.00379 -0.44429 -0.10350 Σ -2.74315 -1.66366 -0.09365 -0.14109 -0.01937

(Table 4) Group SA3 CM3 AS3 DT3 PZ3 G1 -0.05697 0.23458 -0.20323 0.86484 -0.07170 G2 0.71583 1.00826 0.33890 -0.77037 0.47333 G3 -5.36686 -5.37563 -0.47449 -0.01815 -0.19935 G4 2.30024 2.44273 0.246350.1195 -0.14 -0.11327 -0.00363 -0.44429 -0.09897 Σ -2.44293 -1.80333 -0.09609 -0.24868 -0.01852.

By comparing Tables 1 and 2, it can be seen that the aberration variation at the wide-angle end is very small if the focusing method is performed by the second lens group. Tables 3 and 4
Accordingly, at the telephoto end, aberration fluctuation due to focusing becomes conspicuous, but it can be said that the change is at a practical level.

Tables 5, 6, 7, and 8 show 3 in Example 9.
The following shows the aberration coefficient. Table 5 shows the sum of aberration coefficients of each lens group at infinity at the wide-angle end. Table 6 shows the aberration coefficient at 1 m at the wide-angle end when the first lens group and the second lens group are used as focus lens groups. Table 7 shows the sum of aberration coefficients at infinity at the telephoto end, and Table 8 shows aberration coefficients at 1 m. (Table 5) Group SA3 CM3 AS3 DT3 PZ3 G1 -0.00007 0.00158 -0.16139 4.28990 -0.09748 G2 0.05308 0.24186 0.08488 -5.85091 0.63487 G3 -0.37710 -1.48901 -0.48080 -0.03899 -0.26785 G4 0.32290 1.35146 0.46131 0.41841 -0.01979 -0.00822 -0.13550 Σ -0.02039 -0.02579 0.00266 -1.18980 -0.02575.

(Table 6) Group SA3 CM3 AS3 DT3 PZ3 G1 -0.00009 -0.00217 -0.14113 4.25856 -0.09747 G2 0.05225 0.24105 0.06288 -5.84861 0.63478 G3 -0.37694 -1.48859 -0.48073 -0.03899 -0.26781 G4 0.32276 1.35108 0.46125 0.4841 0.01918 -0.13165 0.09864 -0.00822 -0.13548 Σ -0.02120 -0.03028 0.00091 -1.21885 -0.02575.

(Table 7) group SA3 CM3 AS3 DT3 PZ3 G1 -0.35641 1.05024 -0.46784 0.78060 -0.07666 G2 1.28033 0.75120 0.62527 -0.57830 0.49928 G3 -3.59931 -4.33083 -0.39167 0.00254 -0.21064 G4 2.66621 2.56597 0.22760 0.105 0.11162 0.02437 -0.35010 -0.10656 Σ -0.05683 -0.07504 0.01773 -0.04206 -0.02025.

(Table 8) Group SA3 CM3 AS3 DT3 PZ3 G1 -0.11285 0.43331 -0.28860 0.90321 -0.07613 G2 0.94222 1.11440 0.41437 -0.78370 0.49580 G3 -3.52451 -4.27062 -0.38894 0.00254 -0.20918 G4 2.61080 2.53030 0.22601 0.1035 -0.12 0.11007 0.02420 -0.35010 -0.10582 Σ -0.13099 -0.30267 -0.01296 -0.12485 -0.02011.

By comparing Table 5 and Table 6 and comparing the respective aberration coefficient values, the focusing method by moving the first lens group and the second lens group toward the object side shows the aberration variation when viewed at the wide-angle end. Is very small. Further, at the telephoto end, it becomes clear by comparing Tables 7 and 8, but it can be seen that when focusing from infinity to a close distance, the aberration variation becomes conspicuous to some extent in the region of the third-order aberration coefficient. As can be seen from the aberration diagram, although it depends on the setting of the close distance, it is not an aberration fluctuation which is a serious problem in practical use, but a very stable method.

According to the focus method proposed here,
Even at a specific object distance, it is clear that the focusing movement amount changes as the focal length changes,
Aberration fluctuation in a wide-angle region where the focus movement amount is small is advantageous. More preferably, apart from focusing by moving the first and second lens groups together, the distance between the first and second lens groups is changed to correct aberration fluctuations during focusing. It is also possible to make it. In addition, for example, when the variation in aberration in the telephoto range becomes large, and when the magnification becomes high, there is a method of switching to another focus method.

[0065]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments 1 to 9 of the zoom lens according to the present invention will be described below. FIG. 1 is a sectional view of a lens at a wide angle end (a), an intermediate state (b), and a telephoto end (c) when focusing at infinity in Examples 1 to 7.
As shown in FIG. FIGS. 8 to 9 are sectional views of a lens at the wide-angle end (a) and the telephoto end (b) of Examples 8 and 9, respectively.
As shown in FIG. The numerical data of each embodiment will be described later.

(Embodiment 1) The embodiment 1 has a focal length of 14.1.
36mm to 143.57mm, F-number 2.9
9 to 4.02 high-magnification zoom lens,
The angle of view is assumed to be about 74 °. All lenses at the wide-angle end
The length is 114.1mm and the effective diameter of the front lens is also φ60mm
It is as follows. Wide angle end backfoil without filters
Ocus f _BWIs as short as about 6 mm.

At the time of zooming from the wide-angle end to the telephoto end, as shown in FIG. 1, the first lens group G1 and the third lens group G3
Moves greatly toward the object side, and the fourth lens group G4 and the fifth lens group G5 move while drawing a locus having a shape facing the convex side toward the object side while moving toward the object side.

The first lens group G1 comprises a cemented lens of a negative meniscus lens convex to the object side and a biconvex positive lens, and a positive meniscus lens convex to the object side.

The second lens group G2 includes a negative meniscus lens convex on the object side, a biconcave negative lens, a biconvex positive lens, and a negative meniscus lens convex on the image side.

The third lens group G3 comprises an aperture stop, a biconvex positive lens, a cemented lens of a negative meniscus lens convex on the object side and a negative meniscus lens convex on the object side, and a biconvex positive lens. ing.

The fourth lens group G4 comprises a cemented lens of a biconvex positive lens and a negative meniscus lens convex on the image side.

The fifth lens group G5 includes a positive meniscus lens convex on the image side, a biconcave negative lens, and a positive meniscus lens convex on the object side.

The aspherical surface is used on the object side surface of the negative meniscus lens of the second lens group G2 and on the object side surface of the biconcave negative lens located on the image side of this lens, thereby providing distortion and wide angle range. Peripheral performance has been improved. If this aspherical surface is not used, the distortion or coma at the wide-angle end deteriorates, and the field curvature increases. The object side surface of the biconvex positive lens on the object side of the third lens group G3;
An aspheric surface is also used on the object side surface of the doublet on the image side. Further, the image side surface of the positive meniscus lens on the object side of the fifth lens group G5 and the image side surface of the positive meniscus lens located closest to the image side are aspherical.

The first lens group G1 is intended to correct chromatic aberration by using glass having anomalous dispersion in one positive lens. The aperture stop is arranged on the object side of the third lens group G3, and moves together with the third lens group G3 during zooming. Also, the aperture stop changes its aperture diameter during zooming. The power of the second lens group G2 is large, so that the diameter of the first lens group G1 is kept small. In order to correct spherical aberration and off-axis chromatic aberration in the telephoto range, the third lens group G3 having a large power is composed of a doublet composed of two positive lenses, a lens having a small power, and a negative lens. Further, chromatic aberration is corrected using anomalous dispersion glass. Further, the fifth lens group G5 is formed of a triplet, and an aspheric surface having a large asphericity is employed for the image side surface of the first positive lens and the image side surface of the second positive lens located closest to the image side. . Thereby, stable imaging performance in the variable power range is obtained. Further, the emission angle of the off-axis principal ray is 5 ° or less, and it is possible to obtain stable performance.

The focal length of the first lens group G1 is 84.1 m
m, the focal length of the second lens group G2 is -9.43 mm, the focal length of the third lens group G3 is 20.54 mm, the focal length of the fourth lens group G4 is 119.09 mm, and the focal point of the fifth lens group G5 The distance is -313.61 mm.

FIG. 10 is an aberration diagram when focusing is performed at infinity according to the first embodiment. In this figure, (a) shows the aberration at the wide-angle end, (b) shows the aberration at the telephoto end, "SA" is spherical aberration, "AS" is astigmatism, "D"
“T” indicates distortion, “CC” indicates chromatic aberration of magnification.
In each aberration diagram, “FIY” indicates an image height. The same applies to the following aberration diagrams. In this embodiment, the distortion at the wide-angle end aims at a maximum value of -5% or less.

(Embodiment 2) In Embodiment 2, the focal length is 1
This is a zoom lens having an F number of 2.86 to 3.94 mm from 4.36 mm to 143.67 mm.

At the time of zooming from the wide-angle end to the telephoto end, as shown in FIG. 2, the first lens group G1 and the third lens group G3
Moves greatly toward the object side, and the fourth lens group G4 and the fifth lens group G5 move while drawing a locus having a shape facing the convex side toward the object side while moving toward the object side.

The first lens group G1 comprises a cemented lens of a negative meniscus lens convex to the object side and a biconvex positive lens, and a positive meniscus lens convex to the object side.

The second lens group G2 comprises a negative meniscus lens convex on the object side, a biconcave negative lens, a biconvex positive lens, and a negative meniscus lens convex on the image side.

The third lens group G3 comprises an aperture stop, a biconvex positive lens, a cemented lens of a biconvex positive lens and a biconcave negative lens, and a biconvex positive lens.

The fourth lens group G4 comprises a cemented lens of a biconvex positive lens and a negative meniscus lens convex on the image side.

The fifth lens group G5 comprises a negative meniscus lens convex on the object side, a cemented lens of a biconvex positive lens and a negative meniscus lens convex on the image side, and a biconvex positive lens.

The aspherical surfaces are used on the object side surface of the negative meniscus lens of the second lens group G2 and the object side surface of the biconcave negative lens located on the image side of this lens. Aspheric surfaces are used for the object side surface of the biconvex positive lens on the object side and the object side surface of the doublet on the image side.
Further, the fourth lens group G4 is formed of a cemented doublet, and is used on the image-side surface thereof. An aspherical surface is also used for the most image side surface of the fifth lens group G4. FIG. 11 is an aberration diagram when focusing is performed at infinity according to the second embodiment. The distortion is aimed at a maximum of -5% or less at the wide-angle end.

(Embodiment 3) In Embodiment 3, the focal length is 1
4.36mm to 139.5mm with F-number 2.
It is a zoom lens of 85 to 3.67.

At the time of zooming from the wide-angle end to the telephoto end, as shown in FIG. 3, the first lens group G1 and the third lens group G3
Moves largely toward the object side, the fourth lens group G4 moves while drawing a locus shaped so as to turn a convex surface toward the object side while moving toward the object side, and the fifth lens group G5 moves toward the object side. I do.

The first lens group G1 includes a cemented lens of a negative meniscus lens convex to the object side and a biconvex positive lens, and a positive meniscus lens convex to the object side.

The second lens group G2 includes a negative meniscus lens convex to the object side, a biconcave negative lens, a biconvex positive lens, and a biconcave negative lens.

The third lens group G3 comprises an aperture stop, a biconvex positive lens, a cemented lens of a positive meniscus lens convex on the object side and a negative meniscus lens convex on the object side, and a biconvex positive lens. ing.

The fourth lens group G4 comprises a cemented lens of a biconvex positive lens and a negative meniscus lens convex on the image side.

The fifth lens group G5 includes a cemented lens of a negative meniscus lens convex on the image side and a positive meniscus lens convex on the image side, and a biconvex positive lens.

The aspherical surface is used for the object side surface of the negative meniscus lens of the second lens group G2, but is not used for the biconcave negative lens located on the image side of this lens. The object side surface of the biconvex positive lens on the object side of the third lens group G3;
An aspheric surface is also used on the object side surface of the doublet on the image side. Further, the fourth lens group G4 is formed of a cemented doublet, and is used on the image-side surface thereof. Further, the fifth lens group G4 is composed of a cemented doublet of a negative lens having a strong concave surface facing the object side and a positive lens having a low power and a biconvex positive lens having a strong convex surface facing the object side. An aspherical surface is also used for the most image side surface. FIG. 12 is an aberration diagram when focusing is performed at infinity according to the third embodiment. It can be seen that the corrected state of the distortion at the wide angle end and in the intermediate state is inferior to those in Examples 1 and 2.

(Embodiment 4) In Embodiment 4, the focal length is 1
The zoom lens has a size of 4.35 mm to 143.07 mm and an F number of 2.69 to 3.48. In this embodiment, the first lens group G1 is constituted by a doublet having a slight air gap, the second lens group G2 uses the same two aspheric surfaces as in the first embodiment, and the third lens group G3 is It is composed of two biconvex positive lenses and a biconcave negative lens having a strong concave surface on the object side, and uses an aspheric surface on the object side surface of the biconvex positive lens. This realizes correction of axial chromatic aberration and chromatic aberration including g-line in the telephoto range. The fifth lens group G5
Has two sets of bonded doublets, the chromatic aberration is corrected by the doublet on the object side, and the Petzval sum is corrected by the doublet on the image side.

At the time of zooming from the wide-angle end to the telephoto end, as shown in FIG. 4, the first lens unit G1 to the fifth lens unit G5 move to the object side. The four-lens group G4 moves particularly large toward the object side.

The first lens group G1 comprises a negative meniscus lens convex on the object side, a biconvex positive lens, and a positive meniscus lens convex on the object side.

The second lens group G2 includes a negative meniscus lens convex to the object side, a biconcave negative lens, a biconvex positive lens, and a biconcave negative lens.

The third lens group G3 includes an aperture stop, a biconvex positive lens, a biconvex positive lens, and a biconcave negative lens.

The fourth lens group G4 comprises a cemented lens of a negative meniscus lens convex on the object side and a positive meniscus lens convex on the object side.

The fifth lens group G5 includes a cemented lens of a negative meniscus lens convex to the object side and a biconvex positive lens, and a cemented lens of a positive meniscus lens convex to the image side and a negative meniscus lens convex to the image side. It is configured.

The aspheric surface is used on the object side surface of the negative meniscus lens of the second lens group G2 and the object side surface of the biconcave negative lens located on the image side of this lens. It is used for the object side surface of the two biconvex positive lenses and the image side surface of the biconcave negative lens. The fourth lens group G4
Used on the image-side surface of the bonded doublet. An aspherical surface is also used for the most image side surface of the fifth lens group G4. FIG. 13 is an aberrational diagram when focusing on infinity according to the fourth embodiment.

(Embodiment 5) In Embodiment 5, the focal length is determined as follows.
36mm to 143.07mm, F-number 2.7
5 to 3.41 zoom lens. The lens configuration and the movement of each lens unit during zooming are the same as in the fourth embodiment.
However, the power of the fourth lens group G4 is increased. This example has clarified that the fourth lens group G4 has an appropriate power arrangement.

At the time of zooming from the wide-angle end to the telephoto end, as shown in FIG. 5, the first to fourth lens units G1 to G4 move to the object side. The four-lens group G4 moves particularly large toward the object side. Also,
The fifth lens group moves back to the image side at the telephoto side while moving to the object side.

The first lens group G1 includes a negative meniscus lens convex on the object side, a positive meniscus lens convex on the object side,
It consists of a positive meniscus lens convex on the object side.

The second lens group G2 includes a negative meniscus lens convex to the object side, a biconcave negative lens, a biconvex positive lens, and a biconcave negative lens.

The third lens group G3 includes an aperture stop, a biconvex positive lens, a biconvex positive lens, and a biconcave negative lens.

The fourth lens group G4 comprises a cemented lens of a negative meniscus lens convex to the object side and a biconvex positive lens.

The fifth lens group G5 includes a cemented lens of a negative meniscus lens convex to the object side and a biconvex positive lens, and a cemented lens of a positive meniscus lens convex to the image side and a negative meniscus lens convex to the image side. It is configured.

The aspheric surfaces are used on the object side surface of the negative meniscus lens of the second lens group G2 and the object side surface of the biconcave negative lens located on the image side of this lens. It is used on the object side of two biconvex positive lenses. It is used on the image side surface of the doublet of the fourth lens group G4. It is used on the image-side surface of the doublet on the object side of the fifth lens group G4. FIG. 14 is an aberrational diagram when focusing on infinity according to the fifth embodiment.
Shown in

(Embodiment 6) Embodiment 6 has a focal length of 14.1.
It is a zoom lens having an F number of 2.77 to 3.63 with a diameter of 36 mm to 139.5 mm. In this embodiment, as in the third embodiment, the second lens group G2 has only one aspheric surface, and the movement during zooming is substantially the same as that in the third embodiment. In this embodiment, the fourth lens group G and the fifth lens group G5
Is implemented by two characteristic lens configurations.

At the time of zooming from the wide-angle end to the telephoto end, as shown in FIG. 6, the first lens group G1 and the third lens group G3
Greatly moves to the object side, and the fourth lens group G4 and the fifth lens group G5 move back to the image side at the telephoto side while moving to the object side.

The first lens group G1 includes a cemented lens of a negative meniscus lens convex to the object side and a biconvex positive lens, and a positive meniscus lens convex to the object side.

The second lens group G2 includes a negative meniscus lens convex to the object side, a biconcave negative lens, a biconvex positive lens, and a biconcave negative lens.

The third lens group G3 comprises an aperture stop, a biconvex positive lens, a cemented lens of a biconvex positive lens and a biconcave negative lens, and a biconvex positive lens.

The fourth lens group G4 comprises a positive meniscus lens convex on the image side and a positive meniscus lens convex on the image side.

The fifth lens group G5 includes a negative meniscus lens convex on the image side and a biconvex positive lens.

The aspherical surface is used for the object side surface of the negative meniscus lens of the second lens group G2, but is not used for the biconcave negative lens located on the image side of this lens. The object side surface of the biconvex positive lens on the object side of the third lens group G3;
An aspheric surface is also used on the object side surface of the doublet on the image side. Further, an aspherical surface is employed for the most image side surface of the fourth lens group G4 and the most image side surface of the fifth lens group G4. FIG. 15 shows an aberration diagram of the sixth embodiment when focusing is performed at infinity.

(Embodiment 7) The embodiment 7 has a focal length of 14.1.
36mm to 143.07mm, F-number is 3.5
2 to 4.85 zoom lenses. The movement during zooming is substantially the same as in the sixth embodiment. The lens diameter has been reduced due to the small aperture ratio, but in view of performance,
Two aspheric surfaces are used for the third lens group G3. Further, filters are inserted between the fifth lens group G5 and the image plane.

At the time of zooming from the wide-angle end to the telephoto end, as shown in FIG. 7, the first lens group G1 and the third lens group G3
Greatly moves to the object side, and the fourth lens group G4 and the fifth lens group G5 move back to the image side at the telephoto side while moving to the object side.

The first lens group G1 comprises a negative meniscus lens convex on the object side, a biconvex positive lens, and a positive meniscus lens convex on the object side.

The second lens group G2 comprises a negative meniscus lens convex on the object side, a biconcave negative lens, a biconvex positive lens, and a negative meniscus lens convex on the image side.

The third lens group G3 comprises an aperture stop, a biconvex positive lens, a biconvex positive lens, and a negative meniscus lens convex on the image side.

The fourth lens group G4 comprises a cemented lens of a positive meniscus lens convex on the image side and a negative meniscus lens convex on the image side.

The fifth lens group G5 is composed of a cemented lens of a biconcave negative lens and a biconvex positive lens, and a biconvex positive lens.

Although the aspherical surface is used on the object side surface of the negative meniscus lens of the second lens group G2, it is not used for the biconcave negative lens located on the image side of this lens. Further, aspherical surfaces are used for the object side surface of the biconvex positive lens on the image side of the third lens group G3 and the image side surface of the negative meniscus lens. The most image-side surface of the fourth lens group G4, the fifth lens group G
4 has an aspherical surface on the most image side surface. FIG. 16 is an aberrational diagram when focusing on infinity according to the seventh embodiment.
Shown in

Embodiments 8 and 9 below relate to a proposal of a focusing method of the present invention. The details of focusing are as described above.

(Eighth Embodiment) In the eighth embodiment, the focal length is 1
The zoom lens has a F number of 2.81 to 3.62 and a size of 4.36 mm to 143.07 mm. The structure of the lens and the aspherical surface to be used are close to those of the fourth embodiment.

At the time of zooming from the wide-angle end to the telephoto end, as shown in FIG. 8, all of the first lens unit G1 to the fifth lens unit G5 move to the object side. The fourth lens group G4 moves particularly large to the object side.

The first lens group G1 includes a negative meniscus lens convex on the object side, a biconvex positive lens, and a positive meniscus lens convex on the object side.

The second lens group G2 includes a negative meniscus lens convex to the object side, a biconcave negative lens, a biconvex positive lens, and a biconcave negative lens.

The third lens group G3 includes an aperture stop, a biconvex positive lens, a biconvex positive lens, and a biconcave negative lens.

The fourth lens group G4 is composed of a cemented lens composed of a negative meniscus lens convex on the object side and a positive meniscus lens convex on the object side.

The fifth lens group G5 comprises a cemented lens of a negative meniscus lens convex to the object side and a biconvex positive lens, a positive meniscus lens convex to the image side, and a negative meniscus lens convex to the image side. ing.

The aspheric surfaces are used on the object side surface of the negative meniscus lens of the second lens group G2 and the object side surface of the biconcave negative lens located on the image side of this lens. It is used for the object side surface of the two biconvex positive lenses and the image side surface of the biconcave negative lens. The fourth lens group G4
Used on the image-side surface of the doublet. An aspherical surface is also used for the most image side surface of the fifth lens group G4.

FIG. 17 is an aberration diagram for Example 8 when focusing on infinity, and FIG. 18 is an aberration diagram for focusing on an object distance of 2 m by moving the second lens group G2. It can be seen from these aberration diagrams that the aberration variation is small.

(Embodiment 9) In Embodiment 9, the focal length is 1
This is a zoom lens having a F number of 2.81 to 3.59 from 4.36 mm to 143.07 mm. The structure of the lens is close to that of the fourth embodiment.

At the time of zooming from the wide-angle end to the telephoto end, as shown in FIG. 9, all of the first to fifth lens units G1 to G5 move toward the object side. The fourth lens group G4 moves particularly largely to the object side.

The first lens group G1 comprises a negative meniscus lens convex on the object side, a biconvex positive lens, and a positive meniscus lens convex on the object side.

The second lens group G2 includes a negative meniscus lens convex to the object side, a biconcave negative lens, a biconvex positive lens, and a biconcave negative lens.

The third lens group G3 includes an aperture stop, a biconvex positive lens, a biconvex positive lens, and a biconcave negative lens.

The fourth lens group G4 comprises a cemented lens of a negative meniscus lens convex on the object side and a positive meniscus lens convex on the object side.

The fifth lens group G5 comprises a cemented lens of a negative meniscus lens convex to the object side and a biconvex positive lens, a biconvex positive lens, and a negative meniscus lens convex to the image side.

The aspheric surfaces are used on the object side surface of the negative meniscus lens of the second lens group G2 and the object side surface of the biconcave negative lens located on the image side of this lens. It is used on the object side of two biconvex positive lenses. It is used on the image side surface of the doublet of the fourth lens group G4. An aspherical surface is also used for the most image side surface of the fifth lens group G4.

FIG. 19 is an aberration diagram for Example 9 when focusing on infinity and FIG. 19 is an aberration diagram for focusing at a shooting distance of 2 m by moving the first lens group G1 and the second lens group G2 together. Are shown in FIG.

The numerical data of each of the above embodiments is shown below, where the symbols are the same as above, f is the focal length of the entire system, 2ω is the angle of view,
F _NO is the F-number, FB designates the back focal, WE wide-angle end, ST intermediate state, TE is the telephoto end, r _1, r ₂ ... curvature radius of each lens surface, d _1, d ₂ ... each lens surface , N _d1 , n _d2 ... are the d-line refractive indices of each lens, ν _d1 ,
ν _d2 ... is the Abbe number of each lens. The aspherical shape is represented by the following equation, where x is an optical axis where the traveling direction of light is positive, and y is a direction orthogonal to the optical axis.

X = (y ² / r) / [1+ ｛1- (K +
^{1) (y / r) 2} } 1/2] + A 4 y 4 + A 6 y 6 + A 8 y 8 +
A ₁₀ y ¹⁰ where r is the paraxial radius of curvature, K is the conic coefficient, A ₄ , A ₆ ,
A ₈ and A ₁₀ are fourth-order, sixth-order, eighth-order, and tenth-order aspherical coefficients, respectively.

[0146] (Example _{1) r 1 = 127.177 d 1} = 1.850 n d1 = 1.80518 ν d1 = 25.42 r 2 = 62.562 d 2 = 10.150 n d2 = 1.49700 ν d2 = 81.54 r 3 = -403.196 d 3 = 0.110 r _{4 = 54.338 d 4 = 6.500 n} d3 = 1.69680 ν d3 = 55.53 r 5 = 191.229 d 5 = D1 r 6 = 44.299 ( _{aspherical) d 6 = 1.200 n d4 =} 1.80610 ν d4 = 40.74 r 7 = 12.268 d 7 = 9.781 r ₈ = -23.021 (aspherical surface) d ₈ = 1.000 n _d5 = 1.74330 ν _d5 = 49.33 r ₉ = 29.480 d ₉ = 0.100 r ₁₀ = 31.054 d ₁₀ = 3.950 nd ₆ = 1.84666 ν _d6 = 23.78 r ₁₁ =- _{22.497 d 11 = 1.277 r 12 =} -14.550 d 12 = 0.850 n d7 = 1.77250 ν d7 = 49.60 r 13 = -115.826 d 13 = D2 r 14 = ∞ ( _{stop) d 14 = 0.700 r 15 =} 17.171 ( aspherical surface) d ₁₅ = 6.750 n _d8 = 1.49700 v _d8 = 81.54 r ₁₆ = -29.115 d ₁₆ = 0.100 r ₁₇ = 31.332 (aspherical surface) d ₁₇ = 2.800 n _d9 = 1.58913 v _d9 = 61.25 r ₁₈ = 30.660 d ₁₈ = 1.250 n _d10 = 1.80518 ν _d10 = 25.42 r ₁₉ = 16.689 d ₁₉ = 1.166 r ₂₀ = 23.864 d _{2 0 = 4.600 n d11 = 1.49700 ν} d11 = 81.54 r 21 = -74.360 d 21 = D3 r 22 = 203.717 d 22 = 9.537 n d12 = 1.49700 ν d12 = 81.54 r 23 = -24.212 d 23 = 1.450 n d13 = 1.77250 ν _{d13 = 49.60 r 24 = -44.642 d} 24 = D4 r 25 = -77.192 d 25 = 4.400 n d14 = 1.78472 ν d14 = 25.68 r 26 = -15.055 ( _{aspherical) d 26 = 0.100 r 27 =} -31.208 d 27 = _{1.350 n d15 = 1.80518 ν d15 =} 25.42 r 28 = 25.954 d 28 = 9.700 r 29 = 34.835 d 29 = 6.150 n d16 = 1.49700 ν d16 = 81.54 r 30 = 108.656 ( aspherical) r ₃₁ = ∞ (image plane) non Spherical coefficient 6th surface K = 0.0000 A ₄ = 2.5626 × 10 ^-7 A ₆ = -1.9814 × 10 ^-8 A ₈ = -1.6732 × 10 ^-10 A ₁₀ = 1.9550 × 10 ^-13 8th surface K = 0.0000 A ₄ = 4.1211 × 10 ^-5 A ₆ = 3.1399 × 10 ^-7 A ₈ = -1.1506 × 10 ^-9 A ₁₀ = 2.0248 × 10 ^-11 Surface 15 K = 0.0000 A ₄ = -3.3289 × 10 ^-5 A ₆ =- 1.4555 × 10 ^-7 A ₈ = 3.4900 × 10 ^-10 A ₁₀ = -2.1863 × 10 ^-12 Surface 17 K = 0.0000 A ₄ = -2.7626 × 10 ^-5 A ₆ = 5.4995 × 10 ^-8 A ₈ = -1.1813 × ₁₀ ^-10 A 10 = 2.9304 10 ^-12 26 surface _{K = 0.0000 A 4 = 1.0974 ×} 10 -4 A 6 = -2.1063 × 10 -7 A 8 = 1.3911 × 10 -9 A 10 = -1.2267 × 10 -12 30th surface K = 0.0000 A ₄ = -9.5702 × 10 ^-5 A ₆ = 2.4966 × 10 ^-7 A ₈ = -5.9688 × 10 ^-10 A ₁₀ = 9.2903 × 10 ^-13 Zoom data (∞) WEST TE f (mm) 14.359 44.498 143.568 F _NO 2.807 3.342 3.522 2ω (°) 79.3 29.2 9.0 FB (mm) 6.030 14.493 14.210 D1 0.975 20.617 47.046 D2 16.178 4.721 1.110 D3 2.559 1.000 33.000 D4 1.500 17.399 3.569.

[0147] (Example _{2) r 1 = 117.873 d 1} = 1.975 n d1 = 1.80518 ν d1 = 25.42 r 2 = 61.522 d 2 = 10.275 n d2 = 1.49700 ν d2 = 81.54 r 3 = -594.968 d 3 = 0.100 r _{4 = 57.108 d 4 = 6.375 n} d3 = 1.69680 ν d3 = 55.53 r 5 = 221.211 d 5 = D1 r 6 = 27.053 ( _{aspherical) d 6 = 1.200 n d4 =} 1.80610 ν d4 = 40.74 r 7 = 10.533 d 7 = 5.995 r ₈ = -17.383 (aspheric _{surface) d 8 = 1.000 n d5 =} 1.69680 ν d5 = 55.53 r 9 = 27.430 d 9 = 0.100 r 10 = 26.047 d 10 = 4.300 n d6 = 1.84666 ν d6 = 23.78 r 11 = - _{26.880 d 11 = 1.277 r 12 =} -13.880 d 12 = 0.850 n d7 = 1.74100 ν d7 = 52.64 r 13 = -79.961 d 13 = D2 r 14 = ∞ ( _{stop) d 14 = 0.700 r 15 =} 19.072 ( aspherical surface) _{d 15 = 5.958 n d8 = 1.49700} ν d8 = 81.54 r 16 = -29.005 d 16 = 2.046 r 17 = 18.647 ( _{aspherical) d 17 = 5.400 n d9 =} 1.56384 ν d9 = 60.67 r 18 = -90.621 d 18 = 1.100 _{n d10 = 1.80100 ν d10 = 34.97} r 19 = 16.667 d 19 = 4.704 r 20 = 29.735 d 2 _{0 = 4.950 n d11 = 1.49700 ν} d11 = 81.54 r 21 = -40.612 d 21 = D3 r 22 = 63.695 d 22 = 7.000 n d12 = 1.48749 ν d12 = 70.23 r 23 = -16.161 d 23 = 0.920 n d13 = 1.74330 ν _d13 = 49.33 r ₂₄ = -37.923 _{(aspherical) d 24 = D4 r 25 =} 30.239 d 25 = 0.880 n d14 = 1.88300 ν d14 = 40.76 r 26 = 15.354 d 26 = 2.104 r 27 = 35.463 d 27 = 10.100 n d15 _{= 1.59551 ν d15 = 39.24 r 28} = -12.469 d 28 = 1.350 n d16 = 1.81600 ν d16 = 46.62 r 29 = -375.825 d 29 = 0.100 r 30 = 38.916 d 30 = 5.443 n d17 = 1.49700 ν d17 = 81.54 r 31 = -218.085 (aspherical surface) r ₃₂ = ∞ (image surface) Aspherical surface coefficient 6th surface K = 0.0000 A ₄ = 7.1059 × 10 ^-6 A ₆ = 9.8999 × 10 ^-8 A ₈ = -1.3409 × 10 ^-9 A ₁₀ = 7.3223 × 10 ^-12 Surface 8 K = 0.0000 A ₄ = 2.9792 × 10 ^-5 A ₆ = 1.8988 × 10 ^-7 A ₈ = -3.9505 × 10 ^-10 A ₁₀ = 8.3972 × 10 ^-12 Surface 15 K = 0.0000 A ₄ = -1.3127 × 10 ^-5 A ₆ = -2.3534 × 10 ^-7 A ₈ = 1.0629 × 10 ^-9 A ₁₀ = -2.7306 × 10 ^-12 Surface 17 K = 0.0000 A ₄ = -3.9845 × 10 ^{_{-5 A 6 = 4.0878 × 10 -8}} A 8 = 3.0626 × 10 -11 A 10 = -2.4746 × 10 -13 24th surface _{K = 0.0000 A 4 = -3.6480 ×} 10 -6 A 6 = -3.2025 × 10 - ⁸ A ₈ = 1.1015 × 10 ^-10 A ₁₀ = -3.7919 × 10 ^-13 Surface 31 K = 0.0000 A ₄ = -6.4247 × 10 ^-5 A ₆ = -1.4763 × 10 ^-8 A ₈ = 2.1835 × 10 ^-10 A ₁₀ = -1.5886 × 10 ^-13 Zoom data (∞) WEST TE f (mm) 14.359 44.600 143.670 F _NO 2.864 3.470 3.940 2ω (°) 78.3 29.0 8.9 FB (mm) 6.038 14.085 14.113 D1 0.975 20.777 48.770 D2 16.178 4.416 1.110 D3 2.000 7.118 32.334 D4 1.500 13.725 3.250.

(Example 3) r ₁ = 108.596 d ₁ = 2.000 n _d1 = 1.805518 v _d1 = 25.42 r ₂ = 56.173 d ₂ = 10.770 n _d2 = 1.49700 v _d2 = 81.54 r ₃ = -1089.662 d ₃ = 0.110 r _{4 = 49.852 d 4 = 6.870 n} d3 = 1.69680 ν d3 = 55.53 r 5 = 178.420 d 5 = D1 r 6 = 53.480 ( _{aspherical) d 6 = 1.200 n d4 =} 1.77250 ν d4 = 49.60 r 7 = 12.436 d 7 = _{6.993 r 8 = -24.755 d 8 =} 1.000 n d5 = 1.72916 ν d5 = 54.68 r 9 = 52.928 d 9 = 0.100 r 10 = 32.653 d 10 = 3.950 n d6 = 1.84666 ν d6 = 23.78 r 11 = -26.919 d 11 = _{1.277 r 12 = -18.206 d 12 =} 0.850 n d7 = 1.77250 ν d7 = 49.60 r 13 = 67.699 d 13 = D2 r 14 = ∞ ( _{stop) d 14 = 0.650 r 15 =} 17.672 ( aspherical) d ₁₅ = 5.100 n _{d8 = 1.49700 ν d8 = 81.54 r} 16 = -46.331 d 16 = 3.892 r 17 = 18.021 ( _{aspherical) d 17 = 3.250 n d9 =} 1.48749 ν d9 = 70.23 r 18 = 37.895 d 18 = 1.250 n d10 = 1.84666 ν d10 _{= 23.78 r 19 = 18.490 d 19} = 6.965 r 20 = 27.722 d 20 = 4.300 n d11 _{= 1.49700 ν d11 = 81.54 r 21} = -78.441 d 21 = D3 r 22 = 47.676 d 22 = 6.000 n d12 = 1.49700 ν d12 = 81.54 r 23 = -18.735 d 23 = 1.000 n d13 = 1.77250 ν d13 = 49.60 r 24 = -52.084 _{(aspherical) d 24 = D4 r 25 =} -17.260 d 25 = 0.850 n d14 = 1.60300 ν d14 = 65.44 r 26 = -146.577 d 26 = 1.850 n d15 = 1.84666 ν d15 = 23.78 r 27 = -126.664 d ₂₇ = 0.100 r ₂₈ = 33.977 d ₂₈ = _5.750 n _d16 = 1.49700 ν _d16 = 81.54 r ₂₉ = -89.821 (aspherical surface) r ₃₀ = ∞ (image surface) Aspherical surface coefficient 6th surface K = 0.0000 A ₄ = 7.5297 × 10 ^-6 A ₆ = -2.8649 × 10 ^-9 A ₈ = 2.8238 × 10 ^-11 A ₁₀ = 0 15th page K = 0.0000 A ₄ = -1.7097 × 10 ^-5 A ₆ = -1.2911 × 10 ^-7 A ₈ = 5.8459 × 10 ^-10 A ₁₀ = -1.8618 × 10 ^-12 Surface 17 K = 0.0000 A ₄ = -3.8679 × 10 ^-5 A ₆ = -2.5757 × 10 ^-8 A ₈ = -3.2358 × 10 ^-10 A ₁₀ = -1.8898 × 10 ^-12 24th page K = 0.0000 A ₄ = 5.4761 × 10 ^-6 A ₆ = -2.7865 × 10 ^-8 A ₈ = -2.2305 × 10 ^-11 A ₁₀ = -4.5417 × 10 ^-14 29 sides K = 0.0000 A ₄ = -3.4965 × 10 ^-5 A ₆ = 6.7077 × 10 ^-8 A ₈ = -9.0744 × 10 ^-11 A ₁₀ = 2.6864 × 10 ^-13 Zoom data (∞) WEST TE f (mm) 14.360 40.000 139.500 F _NO 2.851 3.306 3.673 FB (mm) 6.096 13.740 16.149 D1 0.970 19.777 45.000 D2 16.178 5.603 1.210 D3 2.000 7.756 33.000 D4 9.085 16.451 3.450.

[0149] (Example _{4) r 1 = 111.613 d 1} = 2.500 n d1 = 1.80518 ν d1 = 25.42 r 2 = 59.896 d 2 = 0.100 r 3 = 58.886 d 3 = 11.900 n d2 = 1.49700 ν d2 = 81.54 r 4 _{= -634.952 d 4 = 0.100 r 5} = 61.583 d 5 = 7.000 n d3 = 1.71300 ν d3 = 53.87 r 6 = 203.484 d 6 = D1 r 7 = 70.912 ( _{aspherical) d 7 = 1.300 n d4 =} 1.74330 ν d4 = _{49.33 r 8 = 13.281 d 8 =} 5.822 r 9 = -27.322 ( aspheric _{surface) d 9 = 1.100 n d5 =} 1.58913 ν d5 = 61.28 r 10 = 21.798 d 10 = 0.150 r 11 = 21.948 d 11 = 3.950 n d6 = 1.84666 _{ν d6 = 23.78 r 12 = -62.544} d 12 = 1.078 r 13 = -26.090 d 13 = 1.050 n d7 = 1.74100 ν d7 = 52.64 r 14 = 62.070 d 14 = D2 r 15 = ∞ ( stop) d ₁₅ = 1.150 r ₁₆ = 20.648 _{(aspherical) d 16 = 6.200 n d8 =} 1.49700 ν d8 = 81.54 r 17 = -41.205 d 17 = 0.100 r 18 = 38.393 ( _{aspherical) d 18 = 5.100 n d9 =} 1.58913 ν d9 = 61.28 r 19 _{= -38.151 d 19 = 1.134 r 20} = -23.073 d 20 = 1.450 n d10 = 1.80610 ν d ₁₀ = 40.92 r ₂₁ = 80.177 _{(aspherical) d 21 = D3 r 22 =} 17.196 d 22 = 2.000 n d11 = 1.80349 ν d11 = 30.40 r 23 = 12.886 d 23 = 13.182 n d12 = 1.53996 ν d12 = 59.46 r 24 = 254.214 _{(aspherical) d 24 = D4 r 25 =} 24.007 d 25 = 1.300 n d13 = 1.80518 ν d13 = 25.42 r 26 = 14.490 d 26 = 8.650 n d14 = 1.49700 ν d14 = 81.54 r 27 = -375.936 d 27 = 1.670 r ₂₈ = -105.865 d ₂₈ = 8.350 n _d15 = 1.76182 ν _d15 = 26.52 r ₂₉ = -15.700 d ₂₉ = 1.600 _nd16 = 1.80610 ν _d16 = 40.74 r ₃₀ = -131.463 (aspherical surface) r ₃₁ = ∞ (image surface) ) Aspheric surface 7th surface K = 0.0000 A ₄ = 5.9482 × 10 ^-6 A ₆ = -4.3050 × 10 ^-8 A ₈ = 1.2290 × 10 ^-10 A ₁₀ = -6.8542 × 10 ^-13 9th surface K = 0.0000 A ₄ = 8.2323 × 10 ^-6 A ₆ = 1.4081 × 10 ^-7 A ₈ = -9.9300 × 10 ^-10 A ₁₀ = 9.5347 × 10 ^-12 Surface 16 K = 0.0000 A ₄ = 1.7978 × 10 ^-5 A ₆ = -8.0132 × 10 ^-8 A ₈ = -2.3002 × 10 ^-10 A ₁₀ = 1.3472 × 10 ^-12 Surface 18 K = 0.0000 A ₄ = -3.5758 × 10 ^-5 A ₆ = 2.7967 × 10 ^-8 A ₈ = 5.8324 × 10 ^{- 10} A ₁₀ = 3.7519 × 10 ^-12 21st plane K = 0.0000 A ₄ = -1.7543 × 10 ^-5 A ₆ = 7.8636 × 10 ^-8 A ₈ = 3.5554 × 10 ^-10 A ₁₀ = 2.8448 × 10 ^-12 24th Surface K = 0.0000 A ₄ = 5.8971 × 10 ^-5 A ₆ = 1.3408 × 10 ^-7 A ₈ = -7.7682 × 10 ^-11 A ₁₀ = 2.4568 × 10 ^-12 Surface 30 K = 0.0000 A ₄ = -6.0896 × 10 ^-6 A ₆ = -3.0249 × 10 ^-8 A ₈ = 2.0113 × 10 ^-11 A ₁₀ = -3.4201 × 10 ^-13 Zoom data (∞) WEST TE f (mm) 14.350 45.150 143.069 F _NO 2.688 3.039 3.482 2ω ( °) 79.4 27.7 9.1 FB (mm) 9.187 21.736 24.073 D1 1.550 26.551 50.872 D2 15.870 5.821 1.350 D3 13.466 5.531 1.270 D4 1.500 16.610 31.777.

[0150] (Example _{5) r 1 = 92.462 d 1} = 2.300 n d1 = 1.80518 ν d1 = 25.42 r 2 = 52.274 d 2 = 0.100 r 3 = 51.548 d 3 = 10.550 n d2 = 1.49700 ν d2 = 81.54 r 4 _{= 2128.505 d 4 = 0.100 r 5} = 60.461 d 5 = 7.000 n d3 = 1.71300 ν d3 = 53.87 r 6 = 241.046 d 6 = D1 r 7 = 140.533 ( _{aspherical) d 7 = 1.300 n d4 =} 1.74330 ν d4 = 49.33 _{r 8 = 13.625 d 8 = 5.399} r 9 = -37.223 ( aspheric _{surface) d 9 = 1.100 n d5 =} 1.58913 ν d5 = 61.28 r 10 = 17.206 d 10 = 0.150 r 11 = 17.673 d 11 = 3.950 n d6 = 1.84666 ν _{d6 = 23.78 r 12 = -54.835 d} 12 = 1.078 r 13 = -24.618 d 13 = 1.050 n d7 = 1.74100 ν d7 = 52.64 r 14 = 51.486 d 14 = D2 r 15 = ∞ ( stop) d ₁₅ = 1.150 r ₁₆ = 19.811 _{(aspherical) d 16 = 5.000 n d8 =} 1.49700 ν d8 = 81.54 r 17 = -477.814 d 17 = 2.098 r 18 = 20.334 ( _{aspherical) d 18 = 6.900 n d9 =} 1.49700 ν d9 = 81.54 r 19 = _{-19.775 d 19 = 0.208 r 20 =} -20.811 d 20 = 1.200 n d10 = 1.80100 ν _{d10 = 34.97 r 21 = 49.225 d} 21 = D3 r 22 = 30.552 d 22 = 1.800 n d11 = 1.78800 ν d11 = 47.37 r 23 = 17.932 d 23 = 6.600 n d12 = 1.55292 ν d12 = 51.14 r 24 = -47.765 ( non _{spherical) d 24 = D4 r 25 =} 21.866 d 25 = 1.300 n d13 = 1.80100 ν d13 = 34.97 r 26 = 16.328 d 26 = 8.850 n d14 = 1.49700 ν d14 = 81.54 r 27 = -181.530 ( aspherical) d ₂₇ = _{1.800 r 28 = -49.404 d 28 =} 8.500 n d15 = 1.63444 ν d15 = 43.45 r 29 = -14.925 d 29 = 1.600 n d16 = 1.72916 ν d16 = 54.68 r 30 = -133.171 r 31 = ∞ ( image plane) aspherical Coefficient 7th surface K = 0.0000 A ₄ = 1.4696 × 10 ^-5 A ₆ = -5.0394 × 10 ^-8 A ₈ = 2.5159 × 10 ^-10 A ₁₀ = -6.0791 × 10 ^-13 9th surface K = 0.0000 A ₄ = 1.3583 × 10 ^-7 A ₆ = 2.0644 × 10 ^-7 A ₈ = -3.2998 × 10 ^-9 A ₁₀ = 1.8852 × 10 ^-11 Surface 16 K = 0.0000 A ₄ = 1.6337 × 10 ^-5 A ₆ = -1.3391 × 10 ^-7 A ₈ = 1.1289 × 10 ^-9 A ₁₀ = -4.1480 × 10 ^-12 Surface 18 K = 0.0000 A ₄ = -4.6928 × 10 ^-5 A ₆ = -1.6549 × 10 ^-8 A ₈ = -3.4585 × 10 ^-10 A ₁₀ = -4.0346 × 10 ^-12 Surface 24 K = 0.0000 A ₄ = 9.6586 × 10 ^-6 A ₆ = 7.2807 × 10 ^-9 A ₈ = -1.0460 × 10 ^-10 A ₁₀ = 9.1618 × 10 ^-14 Surface 27 K = 0.0000 A ₄ = 3.1895 × 10 ^-6 A ₆ = -3.7152 × 10 ^-8 A ₈ = 1.0981 × 10 ^-10 A ₁₀ = -8.8276 × 10 ^-13 Zoom data (∞) WEST TE f (mm) 14.360 45.150 143.071 F _NO 2.753 2.967 3.411 2ω (°) 78.7 27.6 8.9 FB (mm) 12.894 21.720 20.394 D1 1.550 27.083 49.525 D2 16.178 5.956 1.350 D3 13.573 7.311 1.270 D4 1.500 23.160 40.729.

[0151] (Example _{6) r 1 = 112.227 d 1} = 2.000 n d1 = 1.80518 ν d1 = 25.42 r 2 = 57.264 d 2 = 11.100 n d2 = 1.49700 ν d2 = 81.54 r 3 = -490.436 d 3 = 0.100 r _{4 = 52.852 d 4 = 6.800 n} d3 = 1.69680 ν d3 = 55.53 r 5 = 209.300 d 5 = D1 r 6 = 65.339 ( _{aspherical) d 6 = 1.200 n d4 =} 1.77250 ν d4 = 49.60 r 7 = 12.576 d 7 = 6.355 r ₈ = -18.878 d ₈ = 1.000 n _d5 = 1.72916 ν _d5 = 54.68 r ₉ = 46.601 d ₉ = 0.100 r ₁₀ = 33.405 d ₁₀ = 3.950 nd ₆ = 1.84666 ν _d6 = 23.78 r ₁₁ = -22.269 d ₁₁ = _{1.277 r 12 = -16.441 d 12 =} 0.850 n d7 = 1.77250 ν d7 = 49.60 r 13 = 396.524 d 13 = D2 r 14 = ∞ ( _{stop) d 14 = 0.650 r 15 =} 16.400 ( aspherical) d ₁₅ = 6.150 n _{d8 = 1.49700 ν d8 = 81.54 r} 16 = -30.914 d 16 = 0.172 r 17 = 21.541 ( _{aspherical) d 17 = 3.400 n d9 =} 1.49700 ν d9 = 81.54 r 18 = -629.302 d 18 = 1.570 n d10 = 1.74950 ν _{d10 = 35.28 r 19 = 14.696 d} 19 = 0.341 r 20 = 16.525 d 20 = 5.150 n d _{11 = 1.49700 ν d11 = 81.54 r} 21 = -62.456 d 21 = D3 r 22 = -22.724 d 22 = 7.760 n d12 = 1.49700 ν d12 = 81.54 r 23 = -17.687 d 23 = 0.100 r 24 = -30.027 d 24 = _{1.770 n d13 = 1.77250 ν d13 =} 49.60 r 25 = -26.523 ( _{aspherical) d 25 = D4 r 26 =} -14.878 d 26 = 1.700 n d14 = 1.77250 ν d14 = 49.60 r 27 = -30.634 d 27 = 0.100 r 28 _{= 44.023 d 28 = 6.900 n d15} = 1.49700 ν d15 = 81.54 r 29 = -68.866 ( aspherical) r ₃₀ = ∞ (image plane) aspheric coefficients sixth surface _{K = 0.0000 A 4 = 1.1760 ×} 10 -5 A 6 _{^{= -7.2310 × 10 -9 A 8 =}} 8.4899 × 10 -11 A 10 = 0 fifteenth surface _{K = 0.0000 A 4 = -1.8417 ×} 10 -5 A 6 = -2.1774 × 10 -7 A 8 = 6.3157 × 10 - ¹⁰ A ₁₀ = -3.1753 × 10 ^-12 Surface 17 K = 0.0000 A ₄ = -4.8230 × 10 ^-5 A ₆ = 3.0756 × 10 ^-8 A ₈ = -8.0575 × 10 ^-10 A ₁₀ = 6.9722 × 10 ^-12 25th page K = 0.0000 A ₄ = 2.4672 × 10 ^-5 A ₆ = 1.7253 × 10 ^-8 A ₈ = 1.9870 × 10 ^-10 A ₁₀ = -2.1997 × 10 ^{-13 Page} 29 K = 0.0000 A ₄ = -6.0262 × 10 ^-5 A ₆ = 1.3333 × 10 ^-7 A ₈ = -1.986 4 × 10 ^-10 A ₁₀ = 3.0550 × 10 ^-13 Zoom data (∞) WEST TE f (mm) 14.360 40.000 139.500 F _NO 2.765 3.402 3.633 2ω (°) 80.0 32.9 9.1 FB (mm) 6.005 18.192 12.852 D1 1.042 19.777 45.000 D2 14.821 6.087 1.210 D3 2.000 13.335 30.537 D4 11.897 8.991 3.250.

[0152] (Example _{7) r 1 = 99.983 d 1} = 2.000 n d1 = 1.80518 ν d1 = 25.42 r 2 = 56.005 d 2 = 0.177 r 3 = 55.915 d 3 = 10.000 n d2 = 1.49700 ν d2 = 81.54 r 4 _{= -407.344 d 4 = 0.100 r 5} = 51.263 d 5 = 6.000 n d3 = 1.61800 ν d3 = 63.33 r 6 = 199.802 d 6 = D1 r 7 = 48.967 ( _{aspherical) d 7 = 1.270 n d4 =} 1.77250 ν d4 = _{49.60 r 8 = 10.448 d 8 =} 4.857 r 9 = -17.964 d 9 = 1.050 n d5 = 1.74100 ν d5 = 52.64 r 10 = 68.047 d 10 = 0.100 r 11 = 31.856 d 11 = 3.550 n d6 = 1.84666 ν d6 = 23.78 _{r 12 = -22.934 d 12 = 1.078} r 13 = -16.068 d 13 = 1.000 n d7 = 1.78800 ν d7 = 47.37 r 14 = -265.443 d 14 = D2 r 15 = ∞ ( _{stop) d 15 = 1.303 r 16 =} 13.345 _{d 16 = 4.060 n d8 = 1.49700} ν d8 = 81.54 r 17 = -74.617 d 17 = 3.141 r 18 = 25.624 ( _{aspherical) d 18 = 4.970 n d9 =} 1.49700 ν d9 = 81.54 r 19 = -14.090 d 19 = 0.100 _{r 20 = -13.543 d 20 = 1.090} n d10 = 1.80100 ν d10 = 34.97 r 21 = -47.007 ( _{Spherical) d 21 = D3 r 22 =} -46.474 d 22 = 6.372 n d11 = 1.48749 ν d11 = 70.23 r 23 = -12.712 d 23 = 6.318 n d12 = 1.80100 ν d12 = 34.97 r 24 = -16.977 ( aspherical) d _{24 = D4 r 25 = -16.977 d} 25 = 1.530 n d13 = 1.80440 ν d13 = 39.59 r 26 = 102.335 d 26 = 3.750 n d14 = 1.74077 ν d14 = 27.79 r 27 = -63.254 d 27 = 0.100 r 28 = 29.604 d _{28 = 6.463 n d15 = 1.49700 ν} d15 = 81.54 r 29 = -111.048 ( _{aspherical) d 29 = D5 r 30 =} ∞ d 30 = 2.460 n d16 = 1.54771 ν d16 = 62.84 r 31 = ∞ d 31 = 1.000 n d17 = 1.51633 ν _d17 = 64.14 r ₃₂ = ₃₂ d ₃₂ = 0.500 r ₃₃ = ｄ d ₃₃ = 0.700 _{nd 18} = 1.51633 ν _d18 = 64.14 r ₃₄ = ∞ r ₃₅ = ∞ (image plane) Aspheric coefficient Seventh surface K = 0.0000 A ₄ = 1.4223 × 10 ^-5 A ₆ = 2.9976 × 10 ^-9 A ₈ = -2.2239 × 10 ^-10 A ₁₀ = 1.4053 × 10 ^-12 Surface 18 K = 0.0000 A ₄ = -5.7699 × 10 ^-5 A ₆ = -9.6075 × 10 ^-9 A ₈ = -8.2047 × 10 ^-9 A ₁₀ = 8.1027 × 10 ^-11 Surface 21 K = 0.0000 A ₄ = 2.4996 × 10 ^-5 A ₆ = 2.6089 × 10 ^-7 A ₈ = -4.4687 × 10 ^-9 A ₁₀ = 1.0312 × 10 ^-10 Surface 24 K = 0.0000 A ₄ = 2.5134 × 10 ^-5 A ₆ = -1.2819 × 10 ^-8 A ₈ = 1.0852 × 10 ^-10 A ₁₀ = -7.9288 × ₁₀ ^-13 29th surface _{K = 0.0000 A 4 = -4.1397 ×} 10 -5 A 6 = 1.7634 × 10 -7 A 8 = -4.1085 × 10 -10 A 10 = 5.8985 × 10 - ¹³ zoom data (∞) WE ST TE f ( mm) 14.357 39.989 143.044 F NO 3.517 4.340 4.849 2ω (°) 78.8 32.2 8.8 FB (mm) 1.215 1.215 1.215 D1 1.595 19.377 45.338 D2 15.328 6.162 1.100 D3 1.000 11.175 26.846 D4 11.207 9.152 5.049 D5 1.000 14.667 10.881.

[0153] (Example _{8) r 1 = 101.370 d 1} = 2.300 n d1 = 1.80518 ν d1 = 25.42 r 2 = 53.848 d 2 = 0.100 r 3 = 54.052 d 3 = 11.000 n d2 = 1.49700 ν d2 = 81.54 r 4 _{= -1397.113 d 4 = 0.100 r 5} = 47.816 d 5 = 7.500 n d3 = 1.72916 ν d3 = 54.68 r 6 = 142.634 d 6 = D1 r 7 = 60.373 ( _{aspherical) d 7 = 1.250 n d4 =} 1.80610 ν d4 = _{40.74 r 8 = 12.304 d 8 =} 5.698 r 9 = -20.695 ( aspheric _{surface) d 9 = 1.050 n d5 =} 1.62952 ν d5 = 61.61 r 10 = 25.120 d 10 = 0.150 r 11 = 23.289 d 11 = 4.300 n d6 = 1.84666 _{ν d6 = 23.78 r 12 = -29.901} d 12 = 1.277 r 13 = -16.015 d 13 = 0.850 n d7 = 1.77250 ν d7 = 49.60 r 14 = 6876.227 d 14 = D2 r 15 = ∞ ( stop) d ₁₅ = 0.700 r ₁₆ = 26.890 _{(aspherical) d 16 = 5.814 n d8 =} 1.49700 ν d8 = 81.54 r 17 = -102.442 d 17 = 0.100 r 18 = 21.044 ( _{aspherical) d 18 = 7.548 n d9 =} 1.49700 ν d9 = 81.54 r 19 _{= -23.816 d 19 = 0.197 r 20} = -23.916 d 20 = 1.100 n d10 = 1.78590 _{ν d10 = 44.20 r 21 = 120.169} ( _{aspherical) d 21 = D3 r 22 =} 14.347 d 22 = 2.000 n d11 = 1.80100 ν d11 = 34.97 r 23 = 10.796 d 23 = 10.191 n d12 = 1.49700 ν d12 = 81.54 r 24 = 52.280 _{(aspherical) d 24 = D4 r 25 =} 44.639 d 25 = 1.300 n d13 = 1.78590 ν d13 = 44.20 r 26 = 22.376 d 26 = 8.900 n d14 = 1.49700 ν d14 = 81.54 r 27 = -63.482 d 27 = _{0.100 r 28 = -1889.877 d 28 =} 5.900 n d15 = 1.60946 ν d15 = 39.20 r 29 = -25.066 d 29 = 0.535 r 30 = -22.365 d 30 = 1.750 n d16 = 1.80610 ν d16 = 40.74 r 31 = -70.513 ( Aspheric surface) r ₃₂ = ∞ (image surface) aspheric surface coefficient seventh surface K = 0.0000 A ₄ = 1.0169 × 10 ^-5 A ₆ = -1.1539 × 10 ^-8 A ₈ = 1.5793 × 10 ^-10 A ₁₀ = -6.8542 × 10 ^-13 9th surface K = 0.0000 A ₄ = 1.2790 × 10 ^-5 A ₆ = 2.3129 × 10 ^-7 A ₈ = -3.7083 × 10 ^-9 A ₁₀ = 2.9822 × 10 ^-11 16th surface K = 0.0000 A ₄ = 4.2597 × 10 ^-5 A ₆ = -2.2521 × 10 ^-7 A ₈ = 1.5360 × 10 ^-9 A ₁₀ = -3.4809 × 10 ^-12 Surface 18 K = 0.0000 A ₄ = -4.9336 × 10 ^-5 A ₆ = 9 .0403 × 10 ^-8 A ₈ = -5.3345 × 10 ^-10 A ₁₀ = -2.4267 × 10 ^-12 Surface 21 K = 0.0000 A ₄ = -1.7543 × 10 ^-5 A ₆ = 7.8636 × 10 ^-8 A ₈ = 3.5554 × 10 ^-10 A ₁₀ = 2.8448 × 10 ^-12 Surface 24 K = 0.0000 A ₄ = 1.0347 × 10 ^-4 A ₆ = 3.2425 × 10 ^-7 A ₈ = -6.9709 × 10 ^-10 A ₁₀ = 1.3579 × 10 ^-11 31 surface _{K = 0.0000 A 4 = -1.3058 ×} 10 -5 A 6 = -2.0178 × 10 -8 A 8 = 9.4047 × 10 -12 A 10 = -2.4178 × 10 -14 zoom data (∞) WE ST TE f (mm) 14.360 45.000 143.070 F _NO 2.809 3.144 3.622 2ω (°) 79.9 28.7 9.4 FB (mm) 6.033 28.233 19.061 D1 0.970 22.777 43.394 D2 16.178 5.218 1.300 D3 8.991 2.940 1.270 D4 9.218 11.161 38.035.

(Example 9) r ₁ = 101.441 d ₁ = 2.300 n _d1 = 1.80518 v _d1 = 25.42 r ₂ = 53.262 d ₂ = 0.373 r ₃ = 53.611 d ₃ = 11.000 n _d2 = 1.49700 v _d2 = 81.54 r _{4 = -1213.504 d 4 = 0.100 r 5} = 47.555 d 5 = 7.500 n d3 = 1.72916 ν d3 = 54.68 r 6 = 145.723 d 6 = D1 r 7 = 76.046 ( _{aspherical) d 7 = 1.250 n d4 =} 1.80610 ν d4 = _{40.74 r 8 = 12.898 d 8 =} 5.918 r 9 = -21.407 ( aspheric _{surface) d 9 = 1.050 n d5 =} 1.62692 ν d5 = 61.85 r 10 = 24.000 d 10 = 0.150 r 11 = 22.786 d 11 = 4.300 n d6 = 1.84666 _{ν d6 = 23.78 r 12 = -30.266} d 12 = 1.277 r 13 = -16.631 d 13 = 0.850 n d7 = 1.77250 ν d7 = 49.60 r 14 = 314.002 d 14 = D2 r 15 = ∞ ( stop) d ₁₅ = 0.700 r ₁₆ = 26.521 _{(aspherical) d 16 = 5.752 n d8 =} 1.49700 ν d8 = 81.54 r 17 = -112.830 d 17 = 0.100 r 18 = 21.063 ( _{aspherical) d 18 = 7.520 n d9 =} 1.49700 ν d9 = 81.54 r 19 _{= -23.907 d 19 = 0.134 r 20} = -23.964 d 20 = 1.100 n d10 = 1.78590 _{d10 = 44.20 r 21 = 125.951 d} 21 = D3 r 22 = 14.342 d 22 = 2.000 n d11 = 1.80100 ν d11 = 34.97 r 23 = 10.832 d 23 = 9.615 n d12 = 1.49700 ν d12 = 81.54 r 24 = 49.327 ( aspherical _{) d 24 = D4 r 25 =} 42.656 d 25 = 1.300 n d13 = 1.78590 ν d13 = 44.20 r 26 = 20.093 d 26 = 8.900 n d14 = 1.49700 ν d14 = 81.54 r 27 = -56.838 d 27 = 0.100 r 28 = 304.190 _{d 28 = 5.900 n d15 = 1.61919} ν d15 = 37.84 r 29 = -26.853 d 29 = 0.610 r 30 = -23.569 d 30 = 1.750 n d16 = 1.80610 ν d16 = 40.74 r 31 = -100.907 ( aspherical) r ₃₂ = ∞ (image surface) Aspheric coefficient 7th surface K = 0.0000 A ₄ = 1.1483 × 10 ^-5 A ₆ = -8.3178 × 10 ^-9 A ₈ = 1.2646 × 10 ^-10 A ₁₀ = 0 9th surface K = 0.0000 A ₄ = 8.2042 × 10 ^-6 A ₆ = 1.7436 × 10 ^-7 A ₈ = -3.1666 × 10 ^-9 A ₁₀ = 2.5387 × 10 ^-11 Surface 16 K = 0.0000 A ₄ = 4.2966 × 10 ^-5 A ₆ =- 2.2200 × 10 ^-7 A ₈ = 1.5200 × 10 ^-9 A ₁₀ = -3.5262 × 10 ^-12 Surface 18 K = 0.0000 A ₄ = -4.8894 × 10 ^-5 A ₆ = 9.0031 × 10 ^-8 A ₈ = -5.7540 × 10 ^-10 A ₁₀ = -2.1527 × 10 ^-12 Surface 24 K = 0.0000 A ₄ = 1.0203 × 10 ^-4 A ₆ = 3.1862 × 10 ^-7 A ₈ = -9.2601 × 10 ^-10 A ₁₀ = 1.5124 × 10 ^-11 Surface 31 K = 0.0000 A ₄ = -1.3197 × 10 ^-5 A ₆ = -2.3802 × 10 ^-8 A ₈ = 1.2168 × 10 ^-11 A ₁₀ = -3.4583 × 10 ^-14 Zoom data (∞) WEST TE f (mm) 14.360 45.000 143.070 F _NO 2.821 3.125 3.588 2ω (°) 78.6 28.5 9.3 FB (mm) 6.045 29.605 20.002 D1 0.970 22.688 42.961 D2 16.178 5.172 1.300 D3 9.230 2.963 1.270 D4 10.130 9.259 37.684.

Hereinafter, the conditional expressions (1) of Examples 1 to 9 will be described.
This shows values related to (6).

F _BW / | f _W12 || E _xpdW × Y | / f _W Example 1 0.474 39.467 Example 2 0.484 39.084 Example 3 0.464 41.547 Example 4 0.657 110.825 Example 5 0.878 116.49 Example 6 0.460 40.647 Example Example 7 0.378 45.867 Example 8 0.465 81.317 Example 9 0.468 80.583.

[0157] _{f 1 / f W | f 2} / f W | f 3 / f W345 | f 5 | / f W345 Example 1 5.857 0.657 0.943 14.401 Example 2 5.944 0.654 1.006 4.740 Example 3 5.563 0.662 1.044 5.854 Example 4 6.288 0.716 1.202 3.483 Example 5 6.048 0.741 1.242 3.789 Example 6 5.494 0.665 0.885 8.615 Example 7 5.468 0.672 0.862 4.678 Example 8 5.417 0.648 1.161 3.088 Example 9 5.341 0.644 1.167 3.076

[0158]

According to the present invention, the present invention can be applied to a comparatively large image forming element, not only a high-magnification zoom lens but also a wide-angle end angle of view exceeding 70 ° and a zoom ratio exceeding about 10 times. In addition, it is possible to provide a small zoom lens that maintains sufficient imaging performance. Further, it is possible to provide a method of compensating for image movement due to optimal movement of the lens group in such a zoom lens.

[Brief description of the drawings]

FIG. 1 is a sectional view of a zoom lens according to a first embodiment of the present invention at a wide-angle end (a), in an intermediate state (b), and at a telephoto end (c).

FIG. 2 is a sectional view of a zoom lens according to a second embodiment of the present invention, similar to FIG.

FIG. 3 is a sectional view of a zoom lens according to a third embodiment of the present invention, similar to FIG.

FIG. 4 is a sectional view of a zoom lens according to a fourth embodiment of the present invention, similar to FIG.

FIG. 5 is a sectional view of a zoom lens according to a fifth embodiment of the present invention, similar to FIG.

FIG. 6 is a sectional view of a zoom lens according to a sixth embodiment of the present invention, similar to FIG.

FIG. 7 is a sectional view of a zoom lens according to a seventh embodiment of the present invention, similar to FIG.

FIG. 8 is a sectional view of a zoom lens according to an eighth embodiment of the present invention at the wide-angle end (a) and at the telephoto end (b).

9 is a sectional view of a zoom lens according to a ninth embodiment of the present invention, similar to FIG.

FIG. 10 is an aberration diagram at a wide-angle end (a), in an intermediate state (b), and at a telephoto end (c) when focusing is performed at infinity according to the first embodiment.

FIG. 11 is an aberration diagram similar to FIG. 8 of the second embodiment.

FIG. 12 is an aberration diagram similar to FIG. 8 of the third embodiment.

FIG. 13 is an aberration diagram similar to FIG. 8 of the fourth embodiment.

14 is an aberration diagram similar to FIG. 8 in Example 5. FIG.

FIG. 15 is an aberration diagram similar to FIG. 8 of the sixth embodiment.

FIG. 16 is an aberration diagram similar to FIG. 8 of the seventh embodiment.

FIG. 17 is an aberration diagram at a wide-angle end (a), in an intermediate state (b), and at a telephoto end (c) when focusing is performed at infinity according to the eighth embodiment.

FIG. 18 is an aberration diagram at a wide-angle end (a), in an intermediate state (b), and at a telephoto end (c) when focusing to 2 m in Example 8.

FIG. 19 is an aberration diagram at a wide-angle end (a), in an intermediate state (b), and at a telephoto end (c) when focusing on infinity according to the ninth embodiment.

FIG. 20 is an aberration diagram at a wide-angle end (a), in an intermediate state (b), and at a telephoto end (c) when focusing to 2 m in Example 8.

[Explanation of symbols]

 G1 first lens group G2 second lens group G3 third lens group G4 fourth lens group G5 fifth lens group

Continued on front page F-term (reference) 2H087 KA03 MA12 MA13 MA19 PA11 PA12 PA13 PA16 PA19 PB15 PB16 PB17 QA02 QA06 QA07 QA17 QA21 QA25 QA32 QA34 QA37 QA41 QA42 QA45 QA46 RA05 RA12 RA13 RA36 SA43 SA64 SA52 SA64 SA66 SA66 SB15 SB24 SB25 SB33 SB43 SB44 SB45

Claims (6)

[Claims] 1. A first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group, in that order from the object side. Each of the first to fifth lens units moves during zooming from the wide-angle end to the telephoto end, and the distance between the first and second lens units increases. Move so that the distance between the second lens group and the third lens group becomes smaller,
A zoom lens wherein the lens group moves to the object side and satisfies the following conditional expression. 0.05 <f _BW / | f _W12 | <3.0 (1) 4 <| E _xpdW × Y | / f _W (2) where f _W is the value of the entire system at the wide-angle end. Focal length, f _BW is the distance from the last lens surface (not including filters) at the wide-angle end to the imaging plane, and | f _W12 | is the second from the first lens group at the wide-angle end.
The focal length to the lens group, _ExpdW is the distance on the optical axis from the image plane position (not including filters) at the wide angle end to the exit pupil,
Y is the actual maximum image height on the image plane. 2. The zoom lens according to claim 1, wherein the following conditional expression is satisfied. 2.0 <f ₁ / f _W <12.0 (3) 0.3 <| f ₂ / f _W | <3.5 (4) 0.15 <f ₃ / f _W345 < 3.0 (5) 2.0 <| f ₅ | / f _W345 <20 (6) where f ₁ is the focal length of the first lens group, and f ₂ is the focal point of the second lens group. Distance, f ₃ is the focal length of the third lens group, f
₅ is the focal length of the fifth lens group, and f _W345 is the focal length from the third lens group to the fifth lens group at the wide angle end. 3. The zoom lens according to claim 1, wherein the fourth lens group includes at least one set of cemented lenses. 4. The zoom lens according to claim 1, wherein the fifth lens group includes at least one set of cemented lenses. 5. Focusing on a finite object is performed in the first step.
The zoom lens according to any one of claims 1 to 4, wherein the zooming is performed by moving the lens group and the second lens group integrally or by moving only the second lens group. 6. The zoom lens according to claim 1, wherein the fifth lens group moves to return to the image side while moving to the object side.