JPH09138348A - Variable power optical system - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make it possible to attain the compatibility of a wider angle with a higher variable power and smaller size. SOLUTION: This variable power optical system has, successively from an object side, a first lens group G1 having positive refracting power, a second lens group G2 having negative refracting power, a third lens group G3 having positive refracting power, a fourth lens group G4 having positive refracting power and a fifth lens group G5 having negative refracting power. At least the fifth lens group G5 is moved to the object side in such a manner that a first variable air spacing increases, a second variable air spacing decreases, a third variable air spacing increases and fourth variable air spacing decreases at the time of the varying the power from a wide angle end to a telephoto end. Further, the second lens group G2 has a negative partial lens group G21 arranged on the extreme object side and a partial lens group G22 arranged adjacently to the image side and satisfies the prescribed condition equations.

Description

Detailed Description of the Invention

[0001]

The present invention relates to a variable power optical system,
In particular, the present invention relates to a compact variable power optical system capable of achieving both high zooming and wide angle.

[0002]

2. Description of the Related Art In recent years, as a lens shutter type camera, a camera equipped with a zoom lens is becoming popular. In particular, a camera equipped with a so-called high-zoom zoom lens having a zoom ratio of more than 3 is becoming mainstream.

In these high-magnification zoom lenses, a so-called multi-group zoom lens having three or more movable lens groups at the time of magnification change is mainly used, and a zoom lens having an angle of view of about 60 ° at the wide-angle end is mainly used. Various proposals have been made. Further, a lens shutter type camera is required to be downsized, and various proposals have been made regarding a zoom lens suitable for downsizing the camera.

[0004]

However, in the conventional high variable power zoom lens, as the variable power ratio becomes higher,
The focal length at the telephoto end becomes longer. As a result, the total lens length increases and the aperture diameter increases,
There is an inconvenience that the camera becomes large and the portability deteriorates.

On the contrary, when a high zoom ratio is achieved by shortening the focal length at the wide-angle end without increasing the focal length at the telephoto end, the shortage of light amount at the peripheral portion of the screen becomes remarkable at the wide-angle end due to the cos 4 power law. So vignetting should be reduced so that the lack of light is not noticeable. However, in the conventional high-zoom zoom lens, when the angle of view becomes large due to the high zoom ratio, the off-axis light flux passing through the lens group away from the diaphragm separates from the optical axis, which causes an increase in the lens diameter. There was an inconvenience that it would end up.

The present invention has been made in view of the above-mentioned problems, and an object of the present invention is to provide a variable power optical system capable of achieving both wide angle, high variable power and small size.

[0007]

In order to solve the above-mentioned problems, in the first invention of the present invention, the first lens group G1 having a positive refractive power and the negative refractive power are arranged in this order from the object side. A second lens group G2, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power,
In a variable power optical system including a fifth lens group G5 having a negative refracting power, the first variable lens group G1 and the second lens group G2 are changed at the time of zooming from a wide-angle end to a telephoto end. The air gap increases, and the second lens group G2 and the third lens group G2
The second variable air gap with the lens group G3 is reduced,
At least the third variable air distance between the lens group G3 and the fourth lens group G4 is increased, and the fourth variable air distance between the fourth lens group G4 and the fifth lens group G5 is decreased. The fifth lens group G5 moves to the object side, and
The lens group G2 has at least a negative partial lens group G21 having a negative refractive power arranged closest to the object side and a partial lens group G22 arranged adjacent to the image side of the negative partial lens group G21. The use magnification at the wide-angle end of the second lens group G2 is β2w, the use magnification at the telephoto end of the second lens group G2 is β2t, and the negative partial lens group G21 and the partial lens group in the second lens group G2. The axial air distance from G22 is D2, and the focal length of the entire optical system at the wide-angle end is f
Provided is a variable power optical system which satisfies the following condition: 0.3 <β2t · β2w <1.0 0.08 <D2 / fw <0.16.

According to a preferred aspect of the first invention, the partial lens group G22 in the second lens group G2 has a positive refractive power, the focal length of the negative partial lens group G21 is f21, and the positive portion is The focal length of the lens group G22 is f22, and the second
When the focal length of the lens group G2 is f2, the condition of 1.5 <(| f21 | + f22) / | f2 | <2.5 is satisfied.

In order to solve the above problems, the second aspect of the present invention
According to the invention, in order from the object side, the first lens group G1 having a positive refractive power, the second lens group G2 having a negative refractive power, the plurality of lens groups, and the negative lens arranged closest to the image side. In the variable power optical system including the final lens group GR having a refractive power, the first variable air gap between the first lens group G1 and the second lens group G2 during zooming from the wide-angle end to the telephoto end is At least the first lens group G1 and the final lens group GR move toward the object side so that the plurality of lens groups have a positive refracting power as a whole, and the second lens group G2 has the most object. Provided on the side is a variable power optical system characterized in that a lens component having a convex surface facing the object side is provided.

According to a preferred aspect of the second invention, the second lens group G2 comprises, in order from the object side, a negative meniscus lens component having a convex surface facing the object side and a negative lens component having a concave surface facing the object side. , And a positive partial lens group having a positive refractive power.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION First, a general description will be given of a zoom lens suitable for a lens-shutter type camera and capable of high zooming. In order to realize a compact and highly portable camera with a zoom lens having a high zoom ratio, it is necessary to shorten the total lens length and the lens diameter. As a zoom type suitable for shortening the total lens length and reducing the lens diameter, for example, positive / negative type, positive / negative / negative type, etc. are known.

Unlike a single-lens reflex camera, the lens shutter type camera is characterized in that there is no restriction on the back focus of the taking lens system. Therefore, in order to reduce the lens diameter and the total lens length, in many zoom lenses, the negative lens group is arranged closest to the image side, and the back focus is shortened at the wide-angle end. Then, the off-axis light flux passing through the negative lens group is moved away from the optical axis as the angle of view changes, thereby correcting the on-axis aberration and the off-axis aberration independently. Also, by increasing the back focus during zooming from the wide-angle end to the telephoto end, the height of the off-axis light flux that passes through the negative lens group is changed by zooming, and fluctuations in off-axis aberrations due to zooming are suppressed. It is designed to obtain good imaging performance.

Further, the positive lens group is arranged on the most object side,
At the wide-angle end, the distance between the positive lens group and the lens group arranged adjacent to the image side of the positive lens group is shortened, and the total lens length is shortened, so that the height of the off-axis light flux passing through the positive lens group becomes the optical axis. We are approaching this to reduce the lens diameter. On the other hand, at the telephoto end, the distance between the positive lens group and the lens group adjacent to the image side is widened, and the positive lens group is moved to the object side, thereby making the refractive power arrangement a telephoto type and shortening the total lens length. It is trying to make it. The diaphragm is positioned between the positive lens group and the negative lens group near the center of the lens system.

In order to shorten the total lens length at the telephoto end, it is desirable that the refracting power of the first lens group be positively increased to enhance the converging action. However, since the refractive power of the first lens group is positively strong, the off-axis light flux passing through the first lens group is separated from the optical axis. As a result, the lens diameter is increased in order to obtain a predetermined amount of peripheral light. Therefore, in the conventional positive / negative type and positive / negative / negative type, the negative lens group is arranged closest to the object side to reduce the lens diameter. However, the total length of the lens at the telephoto end is increased, and as a result, the angle of view at the wide-angle end can only be widened to about 60 °.

Japanese Patent Application Laid-Open No. 7-279
In the positive / negative positive / negative type zoom lens disclosed in Japanese Patent Publication No. 79, the second lens group is composed of a negative lens arranged on the object side and a positive lens arranged on the image side. With this configuration, the positive lens group can be arranged on the most object side of the lens system, and the total lens length is shortened. However, the axial air gap between the negative lens and the positive lens forming the second lens group is narrow, and when attempting to realize high zooming, the ratio of zooming of the second lens group becomes large. As a result, performance deterioration due to mutual decentering of the negative lens and the positive lens becomes significant.

Next, the function of each lens unit constituting the variable power optical system according to the present invention will be described. In the variable power optical system of the present invention, the negative lens group is arranged closest to the image side in the variable power optical system of the present invention, as in the zoom lens of the multi-group configuration according to the prior art. Then, in the shortest focal length state (wide-angle end), by shortening the back focus, the height of the off-axis light flux passing through the negative lens group is changed depending on the angle of view, and the on-axis aberration and the off-axis aberration are independently obtained. I am trying to correct it.

However, if the back focus at the wide-angle end is made too short, the off-axis light flux passing through the negative lens group will be too far from the optical axis, so that the lens diameter cannot be reduced. Also, dust tends to adhere to the lens surface closest to the image side, but if the back focus becomes too short,
The dust attached to the lens surface is reflected in the photo. Therefore, it is important to set the back focus at the wide-angle end to an appropriate value.

On the contrary, in the longest focal length state (telephoto end), the back focus is increased. That is,
When the focal length of the lens system changes from the shortest focal length state to the longest focal length state, by moving the negative lens group to the object side, the negative lens group is passed in the longest focal length state rather than the shortest focal length state. By making the height of the off-axis light beam close to the optical axis, fluctuations of off-axis aberration that occur when the focal length of the lens system changes are suppressed as much as possible.

In the present invention, in order to achieve a wide angle and at the same time to shorten the total lens length at the telephoto end, the first lens group having a positive refractive power and the second lens group having a negative refractive power are sequentially arranged from the object side. , A positive partial system which is composed of a plurality of lens groups and whose air distance changes when the focal length of the lens system changes, and a negative lens group which is arranged closest to the image side. Then, each lens group is made to function so as to satisfy the following five conditions.

The negative partial lens group arranged on the object side and the positive partial lens group arranged on the image side constitute a second lens group, and the two partial lens groups are arranged with an appropriate air gap. . An aperture stop is arranged near the positive subsystem to reduce the distance between the second lens group and the aperture stop during zooming from the wide-angle end to the telephoto end. The negative lens group is arranged closest to the image side, and when the focal length of the lens system changes from the wide-angle end to the telephoto end, the negative lens group is moved to the object side so that the use magnification of the negative lens group positively increases. .

When the focal length of the lens system changes from the wide-angle end to the telephoto end, the composite refractive power of the positive subsystem is weakened positively. At least the first lens group is moved toward the object side so that the air gap between the first lens group and the second lens group increases when the focal length of the lens system changes from the wide-angle end to the telephoto end.

In the present invention, the second lens group is composed of the negative partial lens group arranged on the object side and the positive partial lens group arranged on the image side, and the aperture stop is arranged on the image side of the second lens group. doing. In particular, at the wide-angle end, the air gap between the first lens group and the second lens group is narrowed to bring the off-axis light flux passing through the first lens group closer to the optical axis. Further, by arranging the second lens group with a negative and positive refractive power, the off-axis light flux passing through the first lens group can be brought closer to the optical axis, and the lens diameter can be reduced.

Further, by forming the second lens group by the negative partial lens group arranged on the object side and the positive partial lens group arranged on the image side, the principal point position of the second lens group is set to the lens position. You can lean toward the object. As a result, it is possible to correct the occurrence of positive distortion and obtain an appropriate back focus. Furthermore, when the focal length changes from the wide-angle end to the telephoto end,
By widening the distance to the lens group, the refractive power arrangement of the entire lens system is shifted to the telephoto type, leading to a reduction in the total lens length.

At the telephoto end, since the refracting power arrangement is a telephoto type, the off-axis light flux passing through the first lens group is separated from the optical axis. Therefore, by bringing the stop closer to the second lens group that diverges the off-axis light flux, the off-axis light flux passing through the first lens group is brought closer to the optical axis, and the lens diameter is reduced.

In addition, if the axial air gap between the negative lens group and the positive lens group is narrowed, it is advantageous for shortening the overall lens length, but as described above, the performance deterioration due to mutual decentering becomes significant. Therefore, in the present invention, the axial air gap between the negative lens group and the positive lens group is widened, and the focal length of the second lens group is set appropriately. From the above, the conditions of and are required.

Conventionally, in a lens system such as a lens shutter type in which the back focus is not restricted, when the focal length changes from the wide-angle end to the telephoto end, the negative lens group and the negative lens group arranged closest to the image side. The negative lens group is moved to the object side so as to narrow the distance from the principal point position of the entire lens group arranged on the object side. Thus, by using the negative lens group for multiplication, not only the fluctuation of the off-axis aberration due to the above-described zooming is satisfactorily suppressed, but also the zooming effect is effectively performed. Therefore, in the present invention as well, the negative lens group is arranged closest to the image side, and the condition of is necessary.

The telephoto ratio is known as one measure for shortening the total lens length. This telephoto ratio is a value obtained by dividing the total lens length by the focal length of the entire lens system. In order to reduce the telephoto ratio, the refractive power of the positive lens unit arranged on the object side, the refractive power of the negative lens unit arranged on the image side, and the distance between the principal points of these two lens units should be set appropriately. is important.

In the present invention, at the telephoto end rather than at the wide-angle end, the converging action, that is, the combined refracting power, of the positive subsystem including the plurality of positive lens units arranged on the image side of the second lens unit is weakened. Then, by making the composite refractive power from the second lens group to the negative lens group arranged closest to the image side negative,
The refractive power arrangement is a telephoto type, and the telephoto ratio is 1 or less.

At the wide-angle end, refraction takes place by the negative partial system including the first lens group and the second lens group, the positive partial system including a plurality of positive lens groups, and the negative lens group arranged closest to the image side. The force configuration is configured. As a result, at the wide-angle end, a given focal length cannot be obtained unless the positive subsystem has a strong positive refractive power. Therefore, in the present invention, the refractive power of the positive subsystem is made stronger at the wide-angle end than at the telephoto end. From the above, the condition of is important.

In the present invention, a negative / negative (symmetrical) refractive power arrangement is provided at the wide-angle end, and a positive / negative (telescopic type) refractive power arrangement is provided at the telephoto end. At the wide-angle end, the total lens length is shortened to bring the off-axis light flux passing through the first lens group closer to the optical axis, thereby reducing the lens diameter. Further, at the telephoto end, in order to effectively use the converging action of the first lens group for shortening the overall lens length, the distance between the first lens group and the second lens group during zooming from the wide-angle end to the telephoto end is It is desirable that the first lens group spreads and moves toward the object side. Therefore, in the present invention, the condition of is required.

The conditional expressions of the present invention will be described below. In the first aspect of the present invention, the following conditional expression (1)
And (2) are satisfied. 0.3 <β2t ・ β2w <1.0 (1) 0.08 <D2 / fw <0.16 (2)

Here, β2w: Use magnification at the wide-angle end of the second lens group G2 β2t: Use magnification at the telephoto end of the second lens group G2 D2: Negative partial lens group G21 and partial lens group in the second lens group G2 On-axis air gap with G22 fw: Focal length of entire optical system at wide-angle end

Conditional expression (1) is a conditional expression which defines the use magnification of the second lens group G2 over the entire zoom range from the wide-angle end to the telephoto end. When the upper limit of conditional expression (1) is exceeded, the first lens group G1 and the second lens group G1 at the wide-angle end.
The combined refracting power of 2 becomes weaker negatively, and it becomes impossible to obtain a sufficient back focus. On the contrary, if the lower limit value of the conditional expression (1) is exceeded, the combined refractive power of the first lens group G1 and the second lens group G2 becomes negative at the telephoto end, and the total lens length can be shortened. It's gone.

Conditional expression (2) defines the axial air distance between the negative partial lens group G21 arranged closest to the object side in the second lens group and the partial lens group G22 arranged closer to the image side. It is an expression. If the upper limit of conditional expression (2) is exceeded, the total lens length at the telephoto end becomes too large. On the other hand, when the value goes below the lower limit of conditional expression (2), the off-axis light flux passing through the first lens group G1 is separated from the optical axis at the wide-angle end, and the lens diameter is increased. Further, a large off-axis aberration is generated in the first lens group G1, so that a larger number of lenses is required to obtain a predetermined optical performance.

In general, a lens system including a wide-angle range has a large angle of view. Therefore, if not only the optical performance in the central portion of the screen but also the optical performance in the peripheral portion of the screen is not sufficiently high, good optical performance over the entire screen is obtained. Can't get In particular, in order to obtain good optical performance over the entire screen, it is necessary to suppress the variation of coma aberration due to the angle of view.

In the present invention, the partial lens group G22 in the second lens group G2 has a positive refracting power in order to suppress the variation of the coma aberration at the wide angle end due to the angle of view and to reduce the lens diameter. It is desirable that the following conditional expression (3) is satisfied. 1.5 <(| f21 | + f22) / | f2 | <2.5 (3)

Here, f21: focal length of negative partial lens group G21 f22: focal length of positive partial lens group G22 f2: focal length of second lens group G2

Conditional expression (3) is a conditional expression which defines the sum of the size of the focal length of the negative partial lens group G21 and the size of the positive partial lens group G22 constituting the second lens group G2. The second lens group G2 is one of the lens groups responsible for zooming during zooming from the wide-angle end to the telephoto end, and has a relatively strong refractive power for obtaining a sufficient back focus at the wide-angle end. .

In the present invention, the refracting power of the partial lens group G21 disposed closest to the object side of the second lens group G2 is set to the second power.
The refractive power of the lens group G2 is made negative and stronger, and the refractive power of the partial lens group G22 arranged on the image side of the partial lens G21 is made positive. Thus, not only the axial aberration is satisfactorily corrected, but also the principal point position of the second lens group G2 is positioned closer to the object of the lens system to obtain a sufficient back focus at the wide-angle end, and the refractive power arrangement is symmetrical. To suppress positive distortion.

If the upper limit of conditional expression (3) is exceeded, the off-axis light flux passing through the second lens group G2 at the wide-angle end is separated from the optical axis, so that a large lens diameter is required to secure a predetermined amount of peripheral light. Will be changed. On the contrary, when the lower limit value of the conditional expression (3) is not reached, the second lens group G2 at the wide angle end.
Since the off-axis light flux passing through the optical axis approaches the optical axis, the lens diameter can be reduced. However, the difference in height between the off-axis light beam passing through the second lens group G2 and the on-axis light beam becomes small, and it becomes impossible to suppress the variation of coma aberration due to the angle of view.

In the present invention, the following conditional expression (4) should be satisfied in order to obtain a sufficient back focus for reducing the lens diameter at the wide-angle end and to shorten the total lens length at the telephoto end. desirable. 1 <| f12 | / fw <2 (4) Here, f12: Composite focal length of the first lens group G1 and the second lens group G2 at the wide-angle end.

Conditional expression (4) is a conditional expression that regulates the combined refractive power of the first lens group G1 and the second lens group G2 at the wide-angle end. If the value exceeds the upper limit of conditional expression (4),
Sufficient back focus cannot be obtained at the wide-angle end, and the off-axis light flux passing through the fifth lens group G5 is separated from the optical axis, resulting in an increase in the lens diameter. Further, dust on the photosensitive agent is reflected by the lens surface closest to the image plane and is reflected on the photosensitive agent. On the other hand, if the lower limit of conditional expression (4) is not reached, the overall lens length at the telephoto end will become large.

According to the second aspect of the present invention, a plurality of lens groups are arranged between the second lens group G2 and the final lens group GR arranged closest to the image side. The composite focal length of these multiple lens groups is always positive during zooming, and increases when the focal length of the entire lens system changes from the shortest focal length state (wide-angle end) to the longest focal length state (telephoto end). Is set. A lens component having a convex surface facing the object side is disposed on the most object side of the second lens group G2.

In the structure of the second aspect of the present invention, it is desirable to satisfy the following conditional expression (5) in order to simultaneously achieve widening of the angle and high zooming. 0.5 <| f2 | / fw <0.9 (5) The first lens group G1 has a positive refractive power. Therefore, at the wide-angle end where the incident angle of the off-axis light beam is large, the off-axis light beam exits the first lens group G1 at a larger angle and
It is incident on the lens group G2. Therefore, since the lens component arranged closest to the object side in the second lens group G2 has a convex surface directed toward the object side, it is possible to suppress the occurrence of off-axis aberrations and enable a wide angle.

Conditional expression (5) is a conditional expression which defines the focal length of the second lens group G2. If the upper limit of conditional expression (5) is exceeded, the diverging action of the second lens group G2 weakens, and sufficient back focus cannot be obtained at the wide-angle end, increasing the lens diameter of the fifth lens group G5. I will invite you.

On the contrary, when the value goes below the lower limit of the conditional expression (5), the off-axis light flux passing through the second lens group G2 approaches the optical axis at the wide-angle end. As a result, the height difference between the on-axis light flux and the off-axis light flux passing through the second lens group G2 becomes too small, and the on-axis aberration and the off-axis aberration cannot be corrected independently, which is sufficient. Optical performance cannot be obtained. In order to further improve performance, set the lower limit of conditional expression (5) to 0.5.
It is desirable to set it to 8.

The second lens group G2 has, in order from the object side, a negative meniscus lens having a convex surface facing the object side, a negative lens having a concave surface facing the object side, and a positive partial lens group having a positive refractive power. Is desirable. As described above, the lens disposed closest to the object side in the second lens group G2 has a convex surface directed toward the object side, and has a weak refractive power for obtaining a sufficient back focus at the wide-angle end. Therefore, by arranging a negative lens with a concave surface facing the object side on the image side,
I try to get enough back focus. Further, in order to satisfactorily correct the axial aberration generated by the second lens group G2 independently, a positive partial lens group having a positive refractive power is arranged on the image side of the two negative lenses. It goes without saying that high performance can be achieved by configuring the two negative lenses arranged in the second lens group G2 with a larger number of lenses.

In the present invention, as described above, the fifth lens group G5 (or the final lens group GR) has a large proportion of zooming. Therefore, in order to improve the performance, it is necessary for the fifth lens group G5 to independently perform better aberration correction. Further, in order to suppress the occurrence of spherical aberration, the fifth lens group G5 includes at least one positive lens and one negative lens.
It is desirable to constitute. Further, in order to reduce the lens diameter on the most image side, it is desirable to arrange a positive lens on the most object side of the fifth lens group G5 and a negative lens on the most image side of the fifth lens group G5. Further, by introducing an aspherical surface into the fifth lens group G5, high performance can be achieved. Further, by constructing the positive lens in the fifth lens group G5 with an aspherical lens made of a plastic material, not only high performance but also weight saving and cost reduction can be achieved at the same time.

According to another aspect, in the present invention, in order to prevent a photographing failure due to an image blur caused by a camera shake or the like which is likely to occur in a high zoom lens, a blur detection for detecting a blur of an optical system. The system and the driving means can be combined in a lens system. An image caused by the blur of the optical system detected by the blur detection system is shifted by decentering one or all of the lens groups constituting the optical system as a shift lens group. By correcting the blur (change in image position), the variable power optical system of the present invention can be used as a so-called anti-vibration optical system.

Further, in the present invention, it is possible to carry out focusing by a part of the lens groups constituting the lens system. In particular, it is preferable to perform focusing by using a lens group that is arranged on the object side of the shift lens group and on the image side of the first lens group. Further, it goes without saying that the variable power optical system according to the present invention can be applied not only to the zoom lens but also to a varifocal zoom lens in which the focal length state does not continuously exist.

[0051]

Embodiments of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is a diagram showing the distribution of refractive power of a variable power optical system according to each example of the present invention, and the movement of each lens group during zooming from the wide-angle end (W) to the telephoto end (T). . As shown in FIG. 1, the variable power optical system according to each example of the present invention has, in order from the object side, a first lens group G1 having a positive refractive power and a second lens group G2 having a negative refractive power. A third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power. When zooming from the wide-angle end to the telephoto end, the first lens group G1 and the second lens unit
The air gap with the lens group G2 increases, and the second lens group G2
The air gap between the third lens group G3 and the fourth lens group G4 increases, and the air gap between the third lens group G3 and the fourth lens group G4 increases.
Each lens group moves toward the object side so that the air gap between the lens group G4 and the fifth lens group G5 decreases.

In each embodiment, the aspherical surface has a height y in a direction perpendicular to the optical axis, a displacement amount (sag amount) in the optical axis direction at the height y is S (y), and a reference radius of curvature is R. , The conic coefficient is κ, and the aspherical coefficient of the nth order is Cn, it is expressed by the following mathematical expression (a).

[Number 1] ^{S (y) = (y 2} / R) / ^{[1+ (1-κ · y 2} / R 2) 1/2 ] ^{_{+ C 4 · y 4 + C}} 6 · y 6 + C 8 · y 8 + C 10 · Y ¹⁰ + ... (a) In each embodiment, an aspherical surface is marked with an asterisk on the right side of the surface number.

[Embodiment 1] FIG. 2 is a view showing the lens arrangement of a variable power optical system according to the first embodiment of the present invention. FIG.
Is a cemented positive lens L in which, in order from the object side, a biconvex lens and a negative meniscus lens having a concave surface facing the object side are cemented in order.
A first lens group G1 composed of 1; a biconcave lens L21; a second lens group G2 composed of a cemented positive lens L22 of a biconvex lens and a biconcave lens; a third lens group G3 composed of a biconvex lens L3; A fourth lens group G4 including a cemented negative lens L41 composed of a positive meniscus lens having a concave surface and a negative meniscus lens having a concave surface facing the object side, and a biconvex lens L42, and a positive meniscus lens L51 having a concave surface facing the object side. It is composed of a biconcave lens L52 and a fifth lens group G5 composed of a negative meniscus lens L53 having a concave surface facing the object side. In this way, the second lens group G2 includes the biconcave lens L21 as the negative partial lens group G21 having negative refractive power,
A cemented positive lens L22 as a positive partial lens group G22 having a positive refractive power.
Having.

The aperture stop S is arranged between the third lens group G3 and the fourth lens group G4, and moves integrally with the third lens group G3 during zooming from the wide-angle end to the telephoto end. FIG. 2 shows the positional relationship between the lens groups at the wide-angle end, and when the magnification is changed to the telephoto end, the lens units move on the optical axis along the zoom orbit shown by the arrow in FIG. Further, focusing is performed by moving the fourth lens group G4 along the optical axis.

The following table (1) lists the values of specifications of the first embodiment of the present invention. In Table (1), f is the focal length, F
NO is the F number, ω is the half angle of view, Bf is the back focus, and D0 is the object distance (the distance along the optical axis between the lens surface closest to the object and the object). Further, the surface number indicates the order of the lens surface from the object side along the direction in which the light beam travels, and the refractive index and Abbe number indicate values for the d-line (λ = 587.6 nm).

[0056]

[Table 1] f = 30.90 to 60.59 to 109.06 to 147.83 FNO = 4.28 to 6.63 to 9.27 to 11.00 ω = 36.25 to 19.09 to 10.93 to 8.15 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 41.5078 5.4529 1.48749 70.45 2 -55.2266 1.3329 1.84666 23.83 3 -113.7644 (d3 = variable) 4 -74.5157 0.9694 1.80420 46.51 5 14.7591 3.4674 6 19.1638 4.2412 1.71736 29.50 7 -21.9421 0.9694 1.83500 42.97 8 96.1461 (d8 = variable) 9 139.1311 1.8176 1.62280 56.93 10 11-25.756 (1.2 11 11 -25.756) d11 = variable) (aperture stop S) 12 -13.4641 2.4235 1.48749 70.45 13 -11.1444 0.9694 1.84666 23.83 14 -25.4463 0.1212 15 * 50.7008 3.0294 1.51680 64.20 16 * -12.5596 (d16 = variable) 17 -79.9123 3.1162 1.80518 25.46 18 -23.2642 0.1212 19 -53.8623 1.2118 1.77250 49.61 20 186.7832 5.2044 21 -14.3495 1.4541 1.83500 42.97 22 -63.8978 (Bf) ( aspherical data) (15 _{surface) κ = 0.3958 C 4 = +} 4.73140 × 10 -6 C 6 = -3.61077 × 10 - ⁷ C ₈ = -5.45939 × 10 ^-9 C ₁₀ = +2.94834 × 10 ^-10 (16 faces) κ = 0.7183 C ₄ = +5.14723 × 10 ^-5 C ₆ = + 1.96845 × 10 ^-7 C ₈ = -1.73463 × 10 ^-8 C ₁₀ = + 3.96586 × 10 ^-10 (Variable spacing during zooming) f 30.8998 60.5880 109.0585 147.8331 d3 1.3329 11.7434 22.1481 27.2882 d8 7.2489 3.9698 2.0599 1.8177 d11 3.4992 4.1256 4.9212 5.2106 d16 18.1965 10.4219 4.7835 1.8177 Bf 7.5734 27.0734 51.7002 69.7402 (focusing movement amount of the fourth lens group G4 at a photographing magnification of -1/30) Focal length f 30.8998 60.5880 109.0585 147.8331 D0 915.7731 1794.0639 3228.4984 4376.5357 0.4987 movement amount 0.6959 0.5663 0.4 However, the sign of the amount of movement is positive when moving from the image side to the object side (conditional corresponding value) β2t = -1.1841 β2w = -0.5497 f21 = -15.2446 f22 = +40.2661 f12 = -43.5818 f2 = -26.6313 (1 ) Β2t · β2w = 0.651 (2) D2 / fw = 0.112 (3) (| f21 | + f22) /|f2|=2.084 (4) | f12 | / fw = 1.410 (5) | F2 | / fw = .862

3 to 10 show d line (λ =
587.6 nm). FIG. 3 is a diagram of various aberrations at the wide-angle end (shortest focal length state) in the infinity focused state, and FIG. 4 is a diagram of various aberrations in the first intermediate focal length state in the infinity focused state, and FIG. FIG. 4 is a diagram of various aberrations in the second intermediate focal length state in the infinity in-focus state,
FIG. 6 is a diagram of various aberrations at the telephoto end (longest focal length state) in the infinity in-focus state. Further, FIG. 7 shows a photographing magnification -1 /
FIG. 9 is a diagram of various aberrations at the wide-angle end at 30 times, FIG. 8 is a diagram of various aberrations at a first intermediate focal length state at a shooting magnification of −1/30, and FIG. 9 is a shooting magnification of −1/30. 11 is a diagram of various aberrations in the second intermediate focal length state at the time of FIG.
[Fig. 3] is an aberration diagram at the telephoto end at a photographing magnification of -1/30.

In each aberration diagram, FNO is the F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in the present embodiment, various aberrations are satisfactorily corrected in each shooting distance state and each focal length state.

[Embodiment 2] FIG. 11 is a view showing the lens arrangement of a variable power optical system according to the second embodiment of the present invention. The variable power optical system of FIG. 11 includes, in order from the object side, a first lens group G1 including a cemented positive lens L1 including a biconvex lens and a negative meniscus lens having a concave surface facing the object side; a biconcave lens L21;
A second lens group G2 including a biconvex lens L22 and a biconcave lens L23, and a third lens group G including a biconvex lens L3.
3, a fourth lens group G4 including a negative lens L41 cemented with a positive meniscus lens having a concave surface facing the object side and a negative meniscus lens having a concave surface facing the object side, and a biconvex lens L42.
And a fifth lens group G5 including a positive meniscus lens L51 having a concave surface facing the object side, a biconcave lens L52, and a negative meniscus lens L53 having a concave surface facing the object side. As described above, the second lens group G2 includes the biconcave lens L21 as the negative partial lens group G21 having negative refractive power, and the biconvex lens L22 and the biconcave lens L23 as the positive partial lens group G22 having positive refractive power.

The aperture stop S is arranged between the third lens group G3 and the fourth lens group G4, and moves integrally with the third lens group G3 during zooming from the wide-angle end to the telephoto end. FIG. 11 shows the positional relationship between the lens groups at the wide-angle end, and when the magnification is changed to the telephoto end, the lens units move on the optical axis along the zoom orbit shown by the arrow in FIG. Further, focusing is performed by moving the fourth lens group G4 along the optical axis.

The following table (2) lists the values of specifications of the second embodiment of the present invention. In Table (2), f is the focal length, F
NO is the F number, ω is the half angle of view, Bf is the back focus, and D0 is the object distance (the distance along the optical axis between the lens surface closest to the object and the object). Further, the surface number indicates the order of the lens surface from the object side along the direction in which the light beam travels, and the refractive index and Abbe number indicate values for the d-line (λ = 587.6 nm).

[0062]

[Table 2] f = 30.91 to 60.56 to 108.75 to 147.79 FNO = 4.29 to 6.80 to 10.11 to 11.08 ω = 35.47 to 19.08 to 11.02 to 8.15 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 39.7793 5.4529 1.48749 70.45 2 -57.2345 1.3329 1.84666 23.83 3 -125.1163 (d3 = variable) 4 -195.9410 0.9694 1.80420 46.51 5 13.2476 4.2412 6 18.8668 3.8776 1.71736 29.50 7 -49.1158 1.2118 8 -37.2068 0.9694 1.83500 42.97 9 88.7773 (d9 = variable) 10 329.7999 1.8176 1.62041 1.2118 12 ∞ (d12 = variable) (aperture stop S) 13 -16.4460 3.0294 1.48749 70.45 14 -16.2558 0.9694 1.84666 23.83 15 -36.9396 0.1212 16 * 41.2706 2.4235 1.51680 64.20 17 * -15.1786 (d17 = variable) 18 -41.3062 3.0221 1.80518 25.46 19 -23.3882 1.2214 20 -101.1149 1.2118 1.80420 46.51 21 717.9226 5.4529 22 -15.5913 1.4541 1.83500 42.97 23 -100.8166 (Bf) (aspherical data) (16 surfaces) κ = 1.0000 C ₄ = -1.41981 × 10 ^-5 C ₆ = + 3.35 268 x 10 ^-7 C ₈ = -1.70549 x 10 ^-8 C ₁₀ = +1.57922 x 10 ^-10 (17 faces) κ = 1.0000 C ₄ = +4.25633 × 10 ^-5 C ₆ = +1.41730 × 10 ^-7 C ₈ = -2.16560 × 10 ^-9 C ₁₀ = -5.10870 × 10 ^-11 (Variable spacing during zooming) f 30.9085 60.5596 108.7492 147.7930 d3 0.6059 10.3280 18.3581 25.6688 d9 7.9183 4.9246 3.0855 1.8177 d12 3.5538 3.3180 3.2536 5.2106 d17 17.9040 9.9580 4.6131 1.8177 Bf 7.4454 27.8259 56.2960 68.4730 (Focusing distance f30.9085 60.5596 108.7492 147.7930 D0 916.1613) 1794.7822 3228.0551 4380.6388 Movement amount 0.7004 0.5475 0.4343 0.4646 However, the sign of the movement amount makes the movement from the image side to the object side positive (conditional value) β2t = -1.0807 β2w = -0.5252 f21 = -15.3980 f22 = +40.9782 f12 = -41.3730 f2 = -26.6313 (1) β2t · β2w = 0.568 (2) D2 / fw = 0.137 (3) (| f21 | + f22) /|f2|=2.117 (4) | f12 | /Fw=1.358

12 to 19 show d line (λ
= 587.6 nm). 12 is a diagram of various aberrations at the wide-angle end in the infinity focused state, FIG. 13 is a diagram of various aberrations in the first intermediate focal length state in the infinity focused state, and FIG. 14 is a state of the infinity focused state. FIG. 15 is a diagram of various types of aberration in the second intermediate focal length state, and FIG. 15 is a diagram of various types of aberration at the telephoto end in the infinity in-focus state. Also,
FIG. 16 is a diagram of various aberrations at the wide-angle end at a photographing magnification of −1/30, and FIG. 17 is a diagram of various aberrations at the first intermediate focal length state at a photographing magnification of −1/30. FIG. 19 is a diagram of various aberrations in the second intermediate focal length state at a photographing magnification of −1/30, and FIG. 19 is a diagram of various aberrations at the telephoto end at a photographing magnification of −1/30.

In each aberration diagram, FNO represents an F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in the present embodiment, various aberrations are satisfactorily corrected in each shooting distance state and each focal length state.

[Third Embodiment] FIG. 20 is a diagram showing a lens structure of a variable power optical system according to the third embodiment of the present invention. The variable power optical system of FIG. 20 includes, in order from the object side, a first lens group G1 including a cemented positive lens L1 including a biconvex lens and a negative meniscus lens having a concave surface facing the object side, a biconcave lens L21,
And a second lens group G2 composed of a cemented positive lens L22 composed of a biconvex lens and a biconcave lens, a third lens group G3 composed of a biconvex lens L3, a positive meniscus lens having a concave surface facing the object side and a concave surface facing the object side. A fourth lens element including a negative lens element L41 cemented with a negative meniscus lens element and a biconvex lens element L42.
It includes a lens group G4, a positive meniscus lens L51 having a concave surface facing the object side, and a fifth lens group G5 including a negative meniscus lens L52 having a concave surface facing the object side. As described above, the second lens group G2 has the biconcave lens L21 as the negative partial lens group G21 having negative refractive power and the cemented positive lens L22 as the positive partial lens group G22 having positive refractive power.

Further, the aperture stop S is arranged between the third lens group G3 and the fourth lens group G4, and moves integrally with the third lens group G3 during zooming from the wide-angle end to the telephoto end. FIG. 20 shows the positional relationship between the lens groups at the wide-angle end, and when the zoom lens moves to the telephoto end, it moves on the optical axis along the zoom orbit shown by the arrow in FIG. Further, focusing is performed by moving the fourth lens group G4 along the optical axis.

Table (3) below lists values of specifications of the third embodiment of the present invention. In Table (3), f is the focal length, F
NO is the F number, ω is the half angle of view, Bf is the back focus, and D0 is the object distance (the distance along the optical axis between the lens surface closest to the object and the object). Further, the surface number indicates the order of the lens surface from the object side along the direction in which the light beam travels, and the refractive index and Abbe number indicate values for the d-line (λ = 587.6 nm).

[0068]

[Table 3] f = 30.90 to 60.52 to 147.86 FNO = 4.24 to 6.54 to 11.00 ω = 35.75 to 18.99 to 8.14 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 39.8404 4.8483 1.48749 70.45 2 -63.1155 1.3333 1.84666 23.83 3 -137.3831 (d3 = variable) 4 -103.5869 0.9697 1.83500 42.97 5 14.5802 3.3938 6 18.4802 3.9999 1.71736 29.50 7 -24.6667 0.9697 1.83500 42.97 8 83.2334 (d8 = variable) 9 64.9550 1.8181 1.62280 56.93 10 -34.6927 1.2121 11 ∞ (d11 = variable) (aperture) Aperture S) 12 -13.4676 2.1817 1.54814 45.83 13 -11.9707 0.9697 1.84666 23.83 14 -24.7756 0.1212 15 76.3364 3.0302 1.56384 60.82 16 * -13.5260 (d16 = variable) 17 * -55.5207 2.9090 1.58518 30.24 18 -24.1618 4.4847 19 -13.7967 1.4545 1.77250 49. 20 -304.4820 (Bf) (Aspherical data) (16 surfaces) κ = 0.7210 C ₄ = +4.21055 × 10 ^-5 C ₆ = +8.40460 × 10 ^-8 C ₈ = +1.49447 × 10 ^-9 C ₁₀ = -1.65128 × 10 ^-11 (17 _{surface) κ = 1.0000 C 4 = +} 2.34570 × 10 -5 C 6 = + 1.00537 × 10 -7 C 8 = -9.75877 × 10 -10 C 10 = + 7.45322 × 10 -12 ( strange F 30.9000 60.5245 147.8616 d3 1.3333 11.8161 27.0135 d8 7.0880 3.7091 1.8181 d11 3.4753 4.1343 5.2120 d16 18.2872 10.5172 1.8181 Bf 8.3893 27.8860 72.2504 (focusing amount of fourth lens group G4 when shooting magnification-1 / 30) Focus distance f 30.9000 60.5245 147.8616 D0 917.1222 1794.0283 4380.8803 Movement amount 0.6727 0.5493 0.4324 However, the sign of the movement amount is the movement from the image side to the object side being positive (conditional corresponding value) β2t = -1.2170 β2w = -0.5647 f21 = -15.2500 f22 = + 39.2894 f12 = -44.6073 f2 = -27.0552 (1) β2t · β2w = 0.687 (2) D2 / fw = 0.110 (3) (| f21 | + f22) /|f2|=2.016 (4 ) | F12 | /fw=1.444

21 to 26 show d line (λ
= 587.6 nm). 21 is a diagram of various aberrations at the wide-angle end in the infinity focused state, FIG. 22 is a diagram of various aberrations in the intermediate focal length state in the infinity focused state, and FIG. 23 is a telephoto in the infinity focused state. FIG. 7 is a diagram of various aberrations at the edge. In addition, FIG. 24 shows a photographing magnification of -1/3.
FIG. 25 is a diagram of various aberrations at the wide-angle end at 0 ×, FIG. 25 is a diagram of various aberrations at an intermediate focal length state at a photographing magnification of −1/30, and FIG. 26 is a diagram at a photographing magnification of −1/30. FIG. 7 is a diagram of various types of aberration at the telephoto end.

In each aberration diagram, FNO is the F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in the present embodiment, various aberrations are satisfactorily corrected in each shooting distance state and each focal length state.

[Fourth Embodiment] FIG. 27 is a diagram showing a lens structure of a variable power optical system according to the fourth embodiment of the present invention. The variable power optical system of FIG. 27 includes, in order from the object side, a first lens group G1 including a cemented positive lens L1 including a biconvex lens and a negative meniscus lens having a concave surface facing the object side, and a negative lens having a convex surface facing the object side. A meniscus lens L21, a cemented negative lens L22 of a biconcave lens and a positive meniscus lens having a convex surface facing the object side,
And a second lens group G2 composed of a positive meniscus lens L23 having a convex surface facing the object side, a third lens group G3 composed of a positive meniscus lens L3 having a concave surface facing the object side, and a biconcave lens and a biconvex lens. A fifth lens group G4 including a fourth lens group G4 including a lens L41 and a biconvex lens L42, a positive meniscus lens L51 having a concave surface facing the object side, a biconcave lens L52, and a negative meniscus lens L53 having a concave surface facing the object side. It is composed of G5.

The aperture stop S is arranged between the third lens group G3 and the fourth lens group G4, and moves integrally with the third lens group G3 during zooming from the wide-angle end to the telephoto end. FIG. 27 shows the positional relationship between the lens groups at the wide-angle end, which moves on the optical axis along the zoom orbit shown by the arrow in FIG. 1 during zooming to the telephoto end. Further, focusing is performed by moving the fourth lens group G4 along the optical axis.

Table (4) below lists values of specifications of the fourth embodiment of the present invention. In Table (4), f is the focal length, F
NO is the F number, ω is the half angle of view, Bf is the back focus, and D0 is the object distance (the distance along the optical axis between the lens surface closest to the object and the object). Further, the surface number indicates the order of the lens surface from the object side along the direction in which the light beam travels, and the refractive index and Abbe number indicate values for the d-line (λ = 587.6 nm).

[0074]

[Table 4] f = 30.89 to 60.47 to 147.83 FNO = 4.25 to 6.84 to 11.08 ω = 35.78 to 19.08 to 8.12 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 44.5313 5.4529 1.48749 70.45 2 -48.9895 1.3329 1.84666 23.83 3 -94.5796 (d3 = variable) 4 * 25.0213 0.9694 1.69680 55.48 5 11.8160 3.7959 6 -50.3337 1.3329 1.83500 42.97 7 13.3518 2.7871 1.80518 25.46 8 82.1339 0.1212 9 22.7845 1.9388 1.60342 38.02 10 109.4243 (d10 = variable) 11 -114.0073 1.6965 1.83500 42.97 12-4 13 ∞ (d13 = variable) (aperture stop S) 14 -13.5390 0.9694 1.80610 33.27 15 19.3508 3.0294 1.51680 64.20 16 -15.8192 0.1212 17 44.1555 2.9082 1.60738 56.71 18 -16.9571 (d18 = variable) 19 -68.1265 3.2718 1.76182 26.55 20 -21.9370 0.4028 21 -77.4049 1.2118 1.83500 42.97 22 302.9330 5.1560 23 -14.5830 1.4541 1.83500 42.97 24 -134.7630 (Bf) ( aspherical surface data) (4 _{side) κ = 0.2448 C 4 = -3.58895} × 10 -5 C 6 = -1.58119 × 10 - ^{_{8 C 8 = -2.36594 × 10 -9}} C 10 = + 9.68023 × 10 -12 ( variable upon zooming F 30.8947 60.4706 147.8277 d3 0.6059 10.4855 26.1501 d10 6.9291 4.5354 1.8177 d13 3.5723 2.8976 5.2106 d18 18.4427 10.1370 1.8177 Bf 7.6737 28.6368 69.0640 (focusing amount of the fourth lens group G4 at a photographing magnification of 1/30) focal length f 30.8947 60.4706 147.8277 D0 912.9192 1787.5989 4369.9624 Movement amount 0.7688 0.5787 0.5065 However, the sign of the movement amount makes the movement from the image side to the object side positive (conditional corresponding value) β2t = -1.1794 β2w = -0.5542 f2 = -26.7037 (1) β2t ・ β2w = 0.654 (5) | f2 | /fw=0.864

28 to 33 show d line (λ
= 587.6 nm). 28 is a diagram of various aberrations at the wide-angle end in the infinity focused state, FIG. 29 is a diagram of various aberrations in the intermediate focal length state in the infinity focused state, and FIG. 30 is a telephoto state in the infinity focused state. FIG. 7 is a diagram of various aberrations at the edge. Further, FIG. 31 shows a photographing magnification of -1/3.
FIG. 32 is a diagram of various aberrations at the wide-angle end at 0 times, FIG. 32 is a diagram of various aberrations at an intermediate focal length state at a photographing magnification of −1/30, and FIG. 33 is a diagram at a photographing magnification of −1/30. FIG. 7 is a diagram of various types of aberration at the telephoto end.

In each aberration diagram, FNO is the F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in the present embodiment, various aberrations are satisfactorily corrected in each shooting distance state and each focal length state.

[Embodiment 5] FIG. 34 is a diagram showing the lens structure of a variable power optical system according to the fifth embodiment of the present invention. The variable power optical system of FIG. 34 includes, in order from the object side, a first lens group G1 including a cemented positive lens L1 including a biconvex lens and a negative meniscus lens having a concave surface facing the object side, and a negative lens having a convex surface facing the object side. A second lens group G2 including a meniscus lens L21, a biconcave lens L22, and a cemented positive lens L23 including a biconvex lens and a biconcave lens; a third lens group G3 including a positive meniscus lens L3 having a concave surface facing the object side; A positive meniscus lens cemented with a positive meniscus lens having a concave surface facing the object side and a negative meniscus lens having a concave surface facing the object side, and a fourth lens group G4 including a biconvex lens L42, and a positive meniscus lens having a concave surface facing the object side. It is composed of L51, a biconcave lens L52, and a fifth lens group G5 including a negative meniscus lens L53 having a concave surface facing the object side.

The aperture stop S is arranged between the third lens group G3 and the fourth lens group G4, and moves integrally with the third lens group G3 during zooming from the wide-angle end to the telephoto end. FIG. 34 shows the positional relationship of each lens group at the wide-angle end, and moves on the optical axis along the zoom orbit shown by the arrow in FIG. 1 during zooming to the telephoto end. Further, focusing is performed by moving the fourth lens group G4 along the optical axis.

The following table (5) lists the values of specifications of the fifth embodiment of the present invention. In Table (5), f is the focal length, F
NO is the F number, ω is the half angle of view, Bf is the back focus, and D0 is the object distance (the distance along the optical axis between the lens surface closest to the object and the object). Further, the surface number indicates the order of the lens surface from the object side along the direction in which the light beam travels, and the refractive index and Abbe number indicate values for the d-line (λ = 587.6 nm).

[0080]

[Table 5] f = 30.92 to 60.12 to 147.79 FNO = 4.02 to 6.40 to 11.00 ω = 35.80 to 18.97 to 8.07 ° Surface number Curvature radius Surface spacing Refractive index Abbe number 1 51.0994 5.0894 1.48749 70.45 2 -44.1190 1.3329 1.84666 23.83 3 -76.0097 (d3 = variable) 4 * 27.3639 0.9694 1.69680 55.48 5 10.4370 3.6353 6 -68.4246 0.9694 1.83500 42.97 7 38.4023 0.3635 8 14.8954 3.8776 1.71736 29.50 9 -26.0186 0.9694 1.83500 42.97 10 65.3204 (d10 = variable) 11 -9337.4469 2.0600 1.51680 2.1812 13 ∞ (d13 = variable) (aperture stop S) 14 -17.1666 3.0294 1.48749 70.45 15 -8.0010 0.9694 1.84666 23.83 16 -12.7488 0.1212 17 80.0742 2.4235 1.48749 70.45 18 -21.8595 (d18 = variable) 19 -197.0321 2.9803 1.84666 23.83 20- 28.2805 1.7494 21 -42.5548 1.2118 1.83500 42.97 22 340.6548 4.3603 23 -16.2846 1.4541 1.80420 46.51 24 -297.6284 (Bf) (aspherical data) (4 surfaces) κ = 1.9548 C ₄ = -6.18887 × 10 ^-5 C ₆ = -1.54322 × 10 ^-7 C ₈ = -2.57961 × 10 ^-9 C ₁₀ = + 1.43098 × 10 ^-11 (Variable when changing magnification Interval) f 30.9169 60.1178 147.7946 d3 0.8482 10.3647 25.4903 d10 5.4134 3.6051 1.8177 d13 2.4631 4.2714 6.0588 d18 17.6574 9.7281 1.8177 Bf 7.1756 26.3770 68.0529 (focusing amount of the fourth lens group G4 at a photographing magnification of -1/30 times) focal length f 30.9169 60.1178 147.7946 D0 920.5109 1785.3567 4386.4065 Moving amount 0.6731 0.5133 0.3931 However, the sign of the moving amount is positive when moving from the image side to the object side (condition corresponding value) β2t = -0.8272 β2w = -0.4374 f2 = -22.8696 (1) β2t ・ β2w = 0.362 (5) | f2 | /fw=0.740

35 to 40 show d line (λ
= 587.6 nm). 35 is a diagram of various aberrations at the wide-angle end in the infinity focused state, FIG. 36 is a diagram of various aberrations in the infinity focused state at an intermediate focal length state, and FIG. 37 is a telephoto in the infinity focused state. FIG. 7 is a diagram of various aberrations at the edge. In addition, FIG. 38 shows a photographing magnification of -1/3.
FIG. 39 is a diagram of various aberrations at the wide-angle end at 0 ×, FIG. 39 is a diagram of various aberrations at an intermediate focal length state at a photographing magnification of −1/30, and FIG. 40 is a diagram at a photographing magnification of −1/30. FIG. 7 is a diagram of various types of aberration at the telephoto end.

In each aberration diagram, FNO is the F number,
NA indicates the numerical aperture, Y indicates the image height, A indicates the half angle of view for each image height, and H indicates the object height for each image height. In the aberration diagram showing astigmatism, a solid line indicates a sagittal image plane, and a broken line indicates a meridional image plane. Further, in the aberration diagram showing the spherical aberration, a broken line indicates a sine condition (sine condition). As is clear from the aberration diagrams, in the present embodiment, various aberrations are satisfactorily corrected in each shooting distance state and each focal length state.

[0083]

As described above, according to the present invention, 70 °
It is possible to realize a variable-magnification optical system capable of achieving a wide angle exceeding that and achieving both high zoom ratio and compact size.

[Brief description of the drawings]

FIG. 1 is a diagram showing the distribution of refractive power of a variable power optical system according to each example of the present invention, and how each lens unit moves during zooming from a wide-angle end (W) to a telephoto end (T). .

FIG. 2 is a diagram showing a lens configuration of a variable power optical system according to a first example of the present invention.

FIG. 3 is a diagram of various types of aberration at the wide-angle end in the in-focus state of Example 1 at infinity.

FIG. 4 is a diagram of various types of aberration in the first intermediate focal length state in the infinity in-focus state according to the first exemplary embodiment.

FIG. 5 is a diagram of various types of aberration in the second intermediate focal length state in the infinity in-focus state according to the first exemplary embodiment.

FIG. 6 is a diagram of various types of aberration at the telephoto end in the in-focus state of Example 1 at infinity.

FIG. 7 is a diagram of various types of aberration at the wide-angle end when the imaging magnification of the first embodiment is −1/30.

FIG. 8 is a diagram of various types of aberration in a first intermediate focal length state at a shooting magnification of −1/30 of the first example.

FIG. 9 is a diagram of various types of aberration in the second intermediate focal length state at the imaging magnification of −1 / 30 × of Example 1;

FIG. 10 is a diagram of various types of aberration at the telephoto end when Example 1 has a shooting magnification of −1/30.

FIG. 11 is a diagram showing a lens configuration of a variable power optical system according to Example 2 of the present invention.

FIG. 12 is a diagram of various types of aberration at the wide-angle end in the in-focus state of Example 2;

FIG. 13 is a diagram of various types of aberration in the first intermediate focal length state in the infinity in-focus state according to the second example.

FIG. 14 is a diagram of various types of aberration in a second intermediate focal length state in the infinity in-focus state according to the second example.

FIG. 15 is a diagram of various types of aberration at the telephoto end in the infinity in-focus state according to the second example.

FIG. 16 is a diagram of various types of aberration at the wide-angle end when the imaging magnification of the second embodiment is −1/30.

FIG. 17 is a diagram of various types of aberration in a first intermediate focal length state at a shooting magnification of −1/30 of Example 2.

FIG. 18 is a diagram of various types of aberration in the second intermediate focal length state at the imaging magnification of −1 / 30 × of Example 2;

FIG. 19 is a diagram of various types of aberration at the telephoto end at the imaging magnification of −1 / 30 × of Example 2;

FIG. 20 is a diagram illustrating a lens configuration of a zoom optical system according to Example 3 of the present invention.

FIG. 21 is a diagram of various types of aberration at the wide angle end in the in-focus state of Example 3;

FIG. 22 is a diagram of various types of aberration in the intermediate focal length state in the infinity in-focus state according to the third example.

FIG. 23 is a diagram of various types of aberration at the telephoto end in the infinity in-focus state according to the third example.

FIG. 24 is a diagram of various types of aberration at the wide-angle end when the imaging magnification of the third embodiment is −1/30.

FIG. 25 is a diagram of various types of aberration in the intermediate focal length state at the imaging magnification of −1/30 of Example 3.

FIG. 26 is a diagram of various types of aberration at the telephoto end when Example 3 has an imaging magnification of −1/30.

FIG. 27 is a diagram showing a lens configuration of a variable power optical system according to the fourth example of the present invention.

FIG. 28 is a diagram of various types of aberration at the wide angle end in the in-focus state of Example 4;

FIG. 29 is a diagram of various types of aberration in the intermediate focal length state in the infinity in-focus state according to the fourth example.

FIG. 30 is a diagram of various types of aberration at the telephoto end in the infinity in-focus state according to the fourth example.

FIG. 31 is a diagram of various types of aberration at the wide-angle end at the imaging magnification of −1/30 of Example 4.

FIG. 32 is a diagram of various types of aberration in the intermediate focal length state at the imaging magnification of −1 / 30 × of Example 4;

FIG. 33 is a diagram of various types of aberration at the telephoto end at the imaging magnification of −1 / 30 × of Example 4;

FIG. 34 is a diagram showing a lens configuration of a variable power optical system according to the fifth example of the present invention.

FIG. 35 is a diagram of various types of aberration at the wide angle end in the in-focus state of Example 5;

FIG. 36 is a diagram of various types of aberration in an intermediate focal length state in infinity focusing according to the example 5;

FIG. 37 is a diagram of various types of aberration at the telephoto end in the in-focus state of Example 5;

FIG. 38 is a diagram of various types of aberration at the wide-angle end when the imaging magnification of the fifth embodiment is −1/30.

FIG. 39 is a diagram of various types of aberration in the intermediate focal length state at the imaging magnification of −1/30 of Example 5.

FIG. 40 is a diagram of various types of aberration at the telephoto end when Example 5 has a shooting magnification of −1/30.

[Explanation of symbols]

 G1 first lens group G2 second lens group G3 third lens group G4 fourth lens group G5 fifth lens group Li each lens component S aperture stop

Claims (7)

[Claims] 1. A first lens group G1 having a positive refractive power and a second lens group G having a negative refractive power in order from the object side.
2, a third lens group G3 having a positive refractive power, a fourth lens group G4 having a positive refractive power, and a fifth lens group G5 having a negative refractive power, Upon zooming from the wide-angle end to the telephoto end, the first variable air space between the first lens group G1 and the second lens group G2 increases, and the second lens group G2 and the third lens group G3 The second variable air gap decreases, the third variable air gap between the third lens group G3 and the fourth lens group G4 increases,
The fourth of the fourth lens group G4 and the fifth lens group G5
At least the fifth lens group G5 moves toward the object side so that the variable air gap decreases, and the second lens group G2 includes the negative partial lens group G21 having the negative refracting power disposed closest to the object side. At least a partial lens group G22 disposed adjacent to the image side of the negative partial lens group G21 is provided, and the use magnification at the wide angle end of the second lens group G2 is β2w.
And the use magnification at the telephoto end of the second lens group G2 is β2t, and the axial air gap between the negative partial lens group G21 and the partial lens group G22 in the second lens group G2 is D
And the focal length of the entire optical system at the wide-angle end is fw, the condition of 0.3 <β2t · β2w <1.0 0.08 <D2 / fw <0.16 is satisfied. Variable magnification optical system. 2. The partial lens group G22 in the second lens group G2 has a positive refractive power, the focal length of the negative partial lens group G21 is f21, and the focal length of the positive partial lens group G22 is f22. 2. When the focal length of the second lens group G2 is f2, the condition of 1.5 <(| f21 | + f22) / | f2 | <2.5 is satisfied. Variable magnification optical system. 3. A combined focal length of the first lens group G1 and the second lens group G2 at the wide-angle end is f12,
3. The variable power optical system according to claim 1, wherein the condition of 1 <| f12 | / fw <2 is satisfied, where fw is the focal length of the entire optical system at the wide-angle end. 4. A first lens group G1 having a positive refractive power and a second lens group G having a negative refractive power in order from the object side.
In the variable power optical system including the second lens group 2, the plurality of lens groups, and the final lens group GR having the negative refracting power which is disposed closest to the image side, the first lens is used for zooming from the wide-angle end to the telephoto end. At least the first lens group G1 and the final lens group GR are moved toward the object side so that the first variable air space between the lens group G1 and the second lens group G2 is increased, and the plurality of lens groups are And a negative lens component having a convex surface facing the object side is provided on the most object side of the second lens group G2. 5. The second lens group G2 includes, in order from the object side, a negative meniscus lens component having a convex surface directed toward the object side,
The variable power optical system according to claim 4, further comprising a negative lens component having a concave surface directed toward the object side, and a positive partial lens unit having a positive refractive power. 6. A third lens group G having a positive refractive power between the second lens group G2 and the final lens group GR.
3 and a fourth lens group G4 having a positive refractive power, and a first variable air gap between the first lens group G1 and the second lens group G2 upon zooming from the wide-angle end to the telephoto end. Increases, the second variable air distance between the second lens group G2 and the third lens group G3 decreases, and the third variable air distance between the third lens group G3 and the fourth lens group G4 increases. Then
The fourth lens group G4 and the fourth lens group GR
When the focal length of the second lens group G2 is f2 and the focal length of the entire optical system at the wide-angle end is fw, the variable air gap is reduced to: 0.5 <| f2 | / fw <0.9 The variable power optical system according to claim 4 or 5, characterized in that 7. When the use magnification at the wide-angle end of the second lens group G2 is β2w and the use magnification at the telephoto end of the second lens group G2 is β2t, 0.3 <β2t · β2w <1.0 7. The variable power optical system according to claim 6, wherein the condition (4) is satisfied.