JP6797401B2 - Zoom lens - Google Patents

Description

The present invention relates to a zoom lens used in a digital camera, a silver salt camera, a video camera, etc., and can secure a sufficient back focus while obtaining an ultra-wide angle of view exceeding 120 ° at a wide-angle end, and is 35 mm. It is related to a zoom lens that can handle a large image circle such as a format and can obtain good optical performance.

Conventionally, a zoom lens capable of obtaining an angle of view exceeding 120 ° at a wide-angle end is disclosed in, for example, the following patent document.

Patent Document 1 includes a first lens group G1 having a negative refractive force and a second lens group G2 having a positive refractive force in order from the object side, and the first lens group G1 is a first A lens having a negative refractive force. It is composed of a group G1A and a first B lens group G1B having a negative refractive force, and further, the first A lens group G1A is a first lens L1 of a negative meniscus lens in order from the object side, a negative meniscus having an aspherical surface on at least one surface. The first B lens group G1B is composed of the second lens L2 of the lens, has a negative meniscus lens L3 having an aspherical surface on at least one surface on the most object side, and at the time of focusing, the first B lens group G1B is placed on the object side. Disclosed is a zoom lens that employs an inner focus method that is compact and has high optical performance with little fluctuation in aberration due to focusing, while obtaining an ultra-wide lens angle exceeding 120 ° by a moving lens configuration.

Further, Patent Document 2 includes a first lens group G1 having a negative refractive force and a second lens group G2 having a positive refractive force in order from the object side, and the first lens group G1 has a negative refractive force. It is composed of a 1A lens group G1A and a first B lens group G1B having a negative refractive force. Further, the first A lens group G1A has an aspherical surface on at least one surface of the first lens L1 of the negative meniscus lens in order from the object side. It is composed of a second lens L2 of a negative meniscus lens, the first B lens group G1B has a negative meniscus lens L3 having an aspherical surface on at least one surface on the most object side, and the second lens group G2 is a second A lens group. It is composed of G2A, 2nd B lens group G2B, and 2nd C lens group G2C. When focusing, the 1st B lens group G1B is moved to the object side, and when zooming from the wide-angle end side to the telescopic end side, the 1st lens group A lens in which the distance between the G1 and the second A lens group G2A decreases, the distance between the second A lens group G2A and the second B lens group G2B decreases, and the distance between the second B lens group G2B and the second C lens group G2C increases. Depending on the configuration, it is possible to secure a sufficiently long back focus while obtaining an ultra-wide lens angle exceeding 120 °, and it is possible to support a large image circle such as the 35 mm format, and focusing. A zoom lens adopting an inner focus method having high optical performance with less fluctuation due to aberration is disclosed.

Japanese Unexamined Patent Publication No. 2011-227124 Japanese Unexamined Patent Publication No. 2013-15621

Further, although the zoom lens disclosed in Patent Document 1 can obtain an ultra-wide angle of view exceeding 120 °, it has high optical performance and compactness as a zoom lens compatible with the APS-C format. The purpose is to realize this, and when a zoom lens that can handle a large image circle such as the 35 mm format is used, it is sufficient to achieve a large wide angle of view, for example, with an angle of view exceeding 120 °. It is difficult to obtain high optical performance.

Further, the zoom lens disclosed in Patent Document 2 can obtain an ultra-wide angle of view exceeding 120 ° like the zoom lens disclosed in Patent Document 1, but four lenses are used for zooming. Since the lens configuration is such that the group moves and a part of the first lens group moves during focusing, the total number of moving lens groups of the zoom lens is as many as 5, and the fluctuation of aberration due to the eccentricity of each lens group is suppressed. It is difficult to ensure good optical performance in the finished product, and the correction of distortion is not sufficient.

The present invention is a zoom lens used in a digital camera, a silver salt camera, a video camera, etc., and it is possible to secure a sufficient back focus while obtaining an ultra-wide angle of view exceeding 120 ° at a wide-angle end. It is an object of the present invention to provide a zoom lens capable of supporting a large image circle such as a 35 mm format and capable of obtaining good optical performance.

In order to solve the above problems, the zoom lens according to the first invention of the present invention includes a first lens group having a negative refractive force and a second lens group having a positive refractive force in this order from the object side to the image side. It is composed of a third lens group having a positive refractive force, and when zooming from the wide-angle end to the telescopic end, the distance between the first lens group and the second lens group is reduced, and the second lens group and the first lens group are reduced. A zoom lens in which the distance between the three lens groups increases, and the first lens group is a first negative meniscus lens having a convex surface facing the object side and a first negative meniscus lens having a convex surface facing the object side in order from the object side to the image side. It has a 2 negative meniscus lens and a third negative meniscus lens with a convex surface facing the object side, and the lens surface on the object side of the first negative meniscus lens has an aspherical shape, and the object side of the third negative meniscus lens. The lens surface on the image side has an aspherical shape, and the second lens group has a positive refractive force of the second A lens group, an aperture aperture, and a negative refractive force of the second B lens in this order from the object side to the image side. It is composed of a group, and is characterized in that the second lens group moves from the object side to the image side along the optical axis when focusing from an infinity object to a short-range object.

Further, the zoom lens according to the second invention of the present invention is further characterized in that the following conditions are further satisfied in the first invention.
(1) L3Fasp_H <0.0
(2) 0.0 ≦ L3Fasp_L
(3) 0.0 <L3Rasp
L3Fasp_H: Aspherical sag amount (reference spherical surface) in the region where the main ray corresponding to the peripheral edge side passes through the relative image height ratio of 0.75 at the wide-angle end on the aspherical lens surface on the object side of the third negative meniscus lens. Difference in length on the optical axis from the reference spherical surface to the aspherical surface at each ray height based on the intersection of the optical axis and the optical axis)
L3Fasp_L: Aspherical sag amount (reference) in the region where the main ray corresponding to the optical axis side passes through the relative image height ratio of 0.5 at the wide-angle end on the aspherical lens surface on the object side of the third negative meniscus lens. Difference in length on the optical axis from the reference spherical surface to the aspherical surface at each ray height based on the intersection of the spherical surface and the optical axis)
L3Rasp: Aspherical sag amount on the aspherical lens surface on the image side of the third negative meniscus lens (length on the optical axis from the reference spherical surface to the aspherical surface at each ray height based on the intersection of the reference spherical surface and the optical axis) Difference)

Further, the zoom lens according to the third invention of the present invention is further characterized in that the following conditions are further satisfied in the first or second invention.
(4) 35 mm <1 / (| 1 / G2BR1 | + | 1 / G2BR2 |)
G2BR1: Radius of curvature (mm) of the lens surface on the object side of the second B lens group with negative refractive power
G2BR2: Radius of curvature (mm) of the lens surface on the image side of the second B lens group with negative refractive power

According to the present invention, it is a zoom lens used for a digital camera, a silver salt camera, a video camera, etc., and it is possible to secure a sufficient back focus while obtaining an ultra-wide angle of view exceeding 120 ° at a wide-angle end. Therefore, it is possible to provide a zoom lens capable of supporting a large image circle such as a 35 mm format and obtaining good optical performance.

Lens configuration diagram in the infinity in-focus state at the wide-angle end of the zoom lens of Example 1. Schematic diagram of longitudinal aberration in the infinity focusing state at the wide-angle end of the zoom lens of Example 1. Longitudinal aberration diagram at a shooting magnification of 1:40 at the wide-angle end of the zoom lens of Example 1. Schematic diagram of longitudinal aberration in the in-finity in-focus state at the intermediate focal length of the zoom lens of Example 1. Schematic diagram of longitudinal aberration at a shooting magnification of 1:40 at the intermediate focal length of the zoom lens of Example 1. Schematic diagram of longitudinal aberration in an infinity in-focus state at the telephoto end of the zoom lens of Example 1. Schematic diagram of longitudinal aberration at a shooting magnification of 1:40 at the telephoto end of the zoom lens of Example 1. Horizontal aberration diagram in the infinity in-focus state at the wide-angle end of the zoom lens of Example 1. Horizontal aberration diagram at a shooting magnification of 1:40 at the wide-angle end of the zoom lens of Example 1. FIG. 9 is a lateral aberration diagram in an infinity focusing state at an intermediate focal length of the zoom lens of Example 1. Horizontal aberration diagram at a shooting magnification of 1:40 at the intermediate focal length of the zoom lens of Example 1. Horizontal aberration diagram in the infinity in-focus state at the telephoto end of the zoom lens of Example 1. Horizontal aberration diagram at a shooting magnification of 1:40 at the telephoto end of the zoom lens of Example 1. Lens configuration diagram in the infinity focusing state at the wide-angle end of the zoom lens of the second embodiment Longitudinal aberration diagram in an infinity in-focus state at the wide-angle end of the zoom lens of Example 2. Longitudinal aberration diagram at a shooting magnification of 1:40 at the wide-angle end of the zoom lens of Example 2. Longitudinal aberration diagram in an infinity in-focus state at an intermediate focal length of the zoom lens of Example 2. Longitudinal aberration diagram at a shooting magnification of 1:40 at the intermediate focal length of the zoom lens of Example 2. Schematic diagram of longitudinal aberration in the infinity in-focus state at the telephoto end of the zoom lens of Example 2. Longitudinal aberration diagram at a shooting magnification of 1:40 at the telephoto end of the zoom lens of Example 2. Horizontal aberration diagram in the infinity in-focus state at the wide-angle end of the zoom lens of Example 2. Horizontal aberration diagram at a shooting magnification of 1:40 at the wide-angle end of the zoom lens of Example 2. Schematic diagram of lateral aberration in an infinity in-focus state at an intermediate focal length of the zoom lens of Example 2. Horizontal aberration diagram at a shooting magnification of 1:40 at the intermediate focal length of the zoom lens of Example 2. Horizontal aberration diagram in the infinity in-focus state at the telephoto end of the zoom lens of Example 2. Horizontal aberration diagram at a shooting magnification of 1:40 at the telephoto end of the zoom lens of Example 2. Lens configuration diagram in the infinity in-focus state at the wide-angle end of the zoom lens of Example 3. Schematic diagram of longitudinal aberration in an infinity in-focus state at the wide-angle end of the zoom lens of Example 3. Schematic diagram of longitudinal aberration at a shooting magnification of 1:40 at the wide-angle end of the zoom lens of Example 3. Schematic diagram of longitudinal aberration in an infinity in-focus state at an intermediate focal length of the zoom lens of Example 3. Schematic diagram of longitudinal aberration at a shooting magnification of 1:40 at the intermediate focal length of the zoom lens of Example 3. Schematic diagram of longitudinal aberration in the infinity in-focus state at the telephoto end of the zoom lens of Example 3. Schematic diagram of longitudinal aberration at a shooting magnification of 1:40 at the telephoto end of the zoom lens of Example 3. Horizontal aberration diagram in the infinity in-focus state at the wide-angle end of the zoom lens of Example 3. Horizontal aberration diagram at a shooting magnification of 1:40 at the wide-angle end of the zoom lens of Example 3. FIG. 9 is a lateral aberration diagram in an infinity focusing state at an intermediate focal length of the zoom lens of Example 3. Horizontal aberration diagram at a shooting magnification of 1:40 at the intermediate focal length of the zoom lens of Example 3. Horizontal aberration diagram in the infinity in-focus state at the telephoto end of the zoom lens of Example 3. Horizontal aberration diagram at a shooting magnification of 1:40 at the telephoto end of the zoom lens of Example 3. Lens configuration diagram in the infinity in-focus state at the wide-angle end of the zoom lens of Example 4. Schematic diagram of longitudinal aberration in the infinity in-focus state at the wide-angle end of the zoom lens of Example 4. Longitudinal aberration diagram at a shooting magnification of 1:40 at the wide-angle end of the zoom lens of Example 4. Schematic diagram of longitudinal aberration in an infinity in-focus state at an intermediate focal length of the zoom lens of Example 4. Longitudinal aberration diagram at a shooting magnification of 1:40 at the intermediate focal length of the zoom lens of Example 4. Schematic diagram of longitudinal aberration in an infinity in-focus state at the telephoto end of the zoom lens of Example 4. FIG. 6 is a longitudinal aberration diagram at a shooting magnification of 1:40 at the telephoto end of the zoom lens of Example 4. Horizontal aberration diagram in the infinity focusing state at the wide-angle end of the zoom lens of Example 4. Horizontal aberration diagram at a shooting magnification of 1:40 at the wide-angle end of the zoom lens of Example 4. FIG. 9 is a lateral aberration diagram in an infinity focusing state at an intermediate focal length of the zoom lens of Example 4. Horizontal aberration diagram at a shooting magnification of 1:40 at the intermediate focal length of the zoom lens of Example 4. FIG. 9 is a transverse aberration diagram in an infinity in-focus state at the telephoto end of the zoom lens of Example 4. Horizontal aberration diagram at a shooting magnification of 1:40 at the telephoto end of the zoom lens of Example 4.

Hereinafter, examples of the zoom lens according to the present invention will be described.

1, FIG. 14, FIG. 27, and FIG. 40 show lens configuration diagrams of Examples 1 to 4 according to the present invention.

The zoom lens of this embodiment is composed of a first lens group having a negative refractive power, a second lens group having a positive refractive power, and a third lens group having a positive refractive power in order from the object side to the image side. Will be done.

In addition, when zooming from the wide-angle end to the telephoto end, all the lens groups move along the optical axis, which reduces the distance between the first lens group and the second lens group, and the second lens group and the third lens. The spacing between groups increases.

The zoom lens of this embodiment is basically a retrofocus type in which a lens group having a negative refractive power is arranged on the object side and a lens group having a positive refractive power is arranged on the image side. As a result, it is possible to realize an angle of view exceeding 120 ° at the wide-angle end, and it is possible to support a single-lens reflex camera that secures sufficient back focus and has a reflex mirror on the optical path. Conventionally, the retrofocus type optical system has been put into practical use as an effective lens type for ensuring sufficient back focus.

Further, in the zoom lens of the present embodiment, the first lens group consists of a first negative meniscus lens having a convex surface facing the object side and a second negative meniscus lens having a convex surface facing the object side in order from the object side to the image side. And has a third negative meniscus lens with a convex surface facing the object side.

In a zoom lens having an ultra-wide angle of view at the wide-angle end as in this embodiment, it is important to refract the light beam of the peripheral angle of view where the incident angle is large with respect to the optical axis in consideration of aberration correction. .. In order to realize a wide angle of view at the wide-angle end and to prevent deterioration of coma and astigmatism that occur in the negative lens included in the first lens group, the first lens group is sequentially arranged from the object side to the image side. First, three negative meniscus lenses are arranged in succession to loosen the angle between the main ray at the peripheral edge and the optical axis.

Further, in the zoom lens of the present embodiment, the lens surface of the first negative meniscus lens on the object side of the first lens group has an aspherical shape, and the lens surfaces of the third negative meniscus lens on the object side and the image side are non-spherical. It has a spherical shape.

In a zoom lens based on the retrofocus type as in this embodiment, since the refractive power arrangement is asymmetric, distortion and astigmatism are likely to occur, and these are appropriately used in order to obtain good optical performance. Need to be corrected. In particular, in a zoom lens such as this embodiment in which the angle of view at the wide-angle end is an ultra-wide angle of view, the entrance pupil diameter for a constant F number becomes smaller as the focal length becomes shorter. Further, the height from the optical axis through which the luminous flux of each angle of view passes through the first lens group arranged on the object side most in the optical system varies greatly depending on each angle of view. That is, the luminous flux passing through the first lens group passes through a local region depending on each angle of view. Therefore, by adopting an aspherical shape for the lens surface of the lenses constituting the first lens group, it is possible to perform appropriate aberration correction for each angle of view, and to realize good optical performance of the entire optical system. It becomes possible.

In the zoom lens of this embodiment, the lens surface of the first negative meniscus lens on the object side and the lens surfaces of the third negative meniscus lens on the object side and the image side have an aspherical shape.

In a lens configuration in which a lens group having a negative refractive power is arranged on the object side of the aperture as in the zoom lens of this embodiment, strong negative distortion occurs, but in order to correct this, the first lens group It is preferable that the lens surface of the first negative meniscus lens arranged on the object side is aspherical. However, since the occurrence of distortion is strongly related to the occurrence of astigmatism and it is necessary to correct the distortion that occurs at a lower image height, the distortion and astigmatism in the first lens group can be freely corrected. For the purpose of improving the degree, in addition to the lens surface on the object side of the first negative meniscus lens, the lens surfaces on the object side and the image side of the third negative meniscus lens are formed to have an astigmatic shape.

Distortion can be corrected even when the aspherical shape of the lens surface of the first negative meniscus lens on the object side is formed on the image side of the first negative meniscus lens, for example, but the light beam through which the light beam passes. Distortion can be corrected most effectively by forming an aspherical shape on the lens surface of the first negative meniscus lens placed on the object side, which has a height that varies greatly depending on the angle of view. It becomes.

Further, in the zoom lens of the present embodiment, the second lens group is composed of a second A lens group having a positive refractive power, an aperture aperture, and a second B lens group having a negative refractive power in this order from the object side to the image side.

The aperture diaphragm is arranged in the optical system for the purpose of adjusting the amount of light, but a drive mechanism for that purpose is required in order to change the aperture of the aperture diaphragm quickly and appropriately. Therefore, when arranging the aperture diaphragm in the optical system, it is necessary to consider not only the space of the aperture diaphragm but also the size of the aperture diaphragm unit including the drive mechanism for driving the aperture diaphragm unit. A certain space is required for the arrangement.

Since the zoom lens of this embodiment has a lens configuration in which the distance between the first lens group and the second lens group is reduced when zooming from the wide-angle end to the telephoto end, the aperture aperture of the first lens group and the second lens group is set. When arranging between them, the distance between the lens groups must be increased in consideration of the space of the aperture diaphragm unit at the telephoto end.

On the other hand, since the axial luminous flux emitted from the first lens group having a negative refractive power is diverged, if the distance between the first lens group and the second lens group is increased in order to arrange the aperture diaphragm, the second lens group There arises a problem that the diameter of the axial luminous flux incident on the lens becomes large. When the diameter of the axial light beam incident on the second lens group becomes large, the spherical aberration generated on the lens surfaces of the second lens group and the third lens group increases, and it becomes difficult to correct this, and the optical system The imaging performance may deteriorate. In addition, spherical aberration, axial coma, and axial astigmatism due to manufacturing errors also increase, so the manufacturing cost for appropriately controlling these during manufacturing to ensure good imaging performance increases. There is a risk that it will end up.

In this embodiment, by arranging the aperture diaphragm inside the second lens group, the diameter of the axial luminous flux incident on the second lens group without increasing the distance between the first lens group and the second lens group. It is possible to obtain good imaging performance by suppressing the increase in the image quality.

Further, in this embodiment, in order to prevent the diameter of the axial luminous flux passing through the second lens group from becoming large, the second A lens group, which is the front group of the second lens group divided by the aperture diaphragm, is positively refracted. As a force, it was possible to obtain good imaging performance by reducing the diameter of the axial luminous flux passing through the second lens group.

Further, in the zoom lens of the present embodiment, the second lens group moves from the object side to the image side along the optical axis when focusing from an infinity object to a short-distance object.

As described above, the zoom lens in this embodiment adopts a retrofocus type lens configuration. In the retrofocus type optical system, the astigmatism fluctuates greatly with the change of the object distance.

In the zoom lens of the present embodiment, the distance between the second lens group and the third lens group is appropriate by adopting a lens configuration in which the second lens group moves from the object side to the image side along the optical axis during focusing. It is possible to cancel the fluctuation of astigmatism due to the change of the object distance by maintaining the state, and to avoid the complicated mechanism of the lens barrel by simplifying the moving lens group.

Further, the zoom lens of this embodiment satisfies the following conditions.
(1) L3Fasp_H <0.0
(2) 0.0 ≦ L3Fasp_L
(3) 0.0 <L3Rasp
L3Fasp_H: Aspherical sag amount (reference spherical surface) in the region where the main ray corresponding to the peripheral edge side passes through the relative image height ratio of 0.75 at the wide-angle end on the aspherical lens surface on the object side of the third negative meniscus lens. Difference in length on the optical axis from the reference spherical surface to the aspherical surface at each ray height based on the intersection of the optical axis and the optical axis)
L3Fasp_L: Aspherical sag amount (reference) in the region where the main ray corresponding to the optical axis side passes through the relative image height ratio of 0.5 at the wide-angle end on the aspherical lens surface on the object side of the third negative meniscus lens. Difference in length on the optical axis from the reference spherical surface to the aspherical surface at each ray height based on the intersection of the spherical surface and the optical axis)
L3Rasp: Aspherical sag amount on the aspherical lens surface on the image side of the third negative meniscus lens (length on the optical axis from the reference spherical surface to the aspherical surface at each ray height based on the intersection of the reference spherical surface and the optical axis) Difference)

The conditional equation (1) is an aspherical surface in the region where the main ray corresponding to the peripheral edge side of the lens surface of the third negative meniscus lens on the object side has a relative image height ratio of 0.75 at the wide-angle end. It defines an appropriate range of sag amount.

If the upper limit of the conditional expression (1) is exceeded, a negative refractive power will be applied to the reference spherical surface in the above region on the aspherical lens surface on the object side of the third negative meniscus lens, so the retrofocus type is used as the basis. It becomes difficult to correct the negative distortion in the peripheral portion of the image having a high image height generated by the zoom lens of the present embodiment.

Conditional expression (2) is a non-existence in the region where the main ray corresponding to the optical axis side of the aspherical lens surface on the object side of the third negative meniscus lens passes by the relative image height ratio of 0.5 at the wide-angle end. It defines an appropriate range of spherical sag amount.

When the lower limit of the conditional equation (2) is exceeded, a positive refractive power is obtained with respect to the reference spherical surface in the above region on the aspherical lens surface on the object side of the third negative meniscus lens. Therefore, the zoom lens of this embodiment It is difficult to correct the positive distortion in the region where the image height is low, and the astigmatism appears positively, which is not preferable.

The conditional expression (3) defines an appropriate range of the aspherical sag amount on the aspherical lens surface on the image side of the third negative meniscus lens.

When the lower limit of the conditional equation (3) is exceeded, a negative refractive power is applied to the reference spherical surface on the aspherical lens surface on the image side of the third negative meniscus lens, resulting in negative distortion and negative distortion in the entire image. It becomes difficult to suppress astigmatism.

Further, the zoom lens of this embodiment satisfies the following conditions.
(4) 35 mm <1 / (| 1 / G2BR1 | + | 1 / G2BR2 |)
G2BR1: Radius of curvature (mm) of the lens surface on the object side of the second B lens group with negative refractive power
G2BR2: Radius of curvature (mm) of the lens surface on the image side of the second B lens group with negative refractive power

The conditional expression (4) defines an appropriate range for the relationship between the radius of curvature of the lens surface at the air interface between the object side and the image side of the second B lens group.

In the zoom lens of this embodiment, since the aperture diaphragm is arranged inside the second lens group, the difference in height from the optical axis for the light beam of each angle of view passing through the second lens group and thereafter is small. Further, since the lens configuration is based on the retrofocus type, the diameter of the axial light beam passing through the second lens group and thereafter tends to be large, and the sensitivity of aperture aberration tends to be high. Furthermore, by arranging the aperture diaphragm inside the second lens group and preferentially using the variable distance between the first lens group and the second lens group for the scaling effect, the second lens group is based on the aperture diaphragm. It will be divided into a second A lens group (front group) and a second B lens group (rear group), and it may be difficult to suppress the occurrence of aberration due to relative eccentricity caused by manufacturing errors of these lens groups. There is. Therefore, in order to obtain good optical performance in the finished product, it is necessary to suppress the sensitivity of aberration generation due to the relative eccentricity between the second A lens group and the second B lens group constituting the second lens group.

If the lower limit of the conditional expression (4) is exceeded, the refractive power of the second B lens group becomes stronger, and it becomes difficult to suppress the deterioration of the optical performance due to the eccentricity of the second B lens group. Further, in order to maintain the refractive power arrangement in the retrofocus type lens configuration which is the basis of the zoom lens of this embodiment, the refractive power of the second A lens group is also increased, and the second A lens group and the second B lens group are further increased. It becomes difficult to suppress the deterioration of the optical performance due to the manufacturing error of the lens.

By setting the lower limit of the conditional expression (4) to 40, the effect of the present invention can be further ensured.

Next, the lens configuration of the embodiment according to the zoom lens of the present invention will be described. In the following description, the lens configuration will be described in order from the object side to the image side.

FIG. 1 is a lens configuration diagram of a zoom lens according to a first embodiment of the present invention.

The zoom lens of the first embodiment is composed of a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a positive refractive power in order from the object side. Further, the second lens group G2 is composed of a second A lens group G2A having a positive refractive power, an aperture diaphragm S, and a second B lens group G2B having a negative refractive power in order from the object side.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves from the object side to the image side, and the second lens group G2 and the third lens group G3 move from the image side to the object side.

When focusing from an infinity object to a short-distance object, the second lens group G2 moves from the object side to the image side.

The first lens group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface directed toward the object side having an aspherical lens surface on the object side, a negative meniscus lens L2 having a convex surface directed toward the object side, and an object. It is composed of a negative meniscus lens L3 whose convex surface is directed toward an object whose side and image side lens surfaces are aspherical, a biconcave lens, and a junction lens of a negative meniscus lens and a biconvex lens whose convex surface is directed toward the object side.

The second lens group G2 is composed of a biconvex lens, an aperture diaphragm S, a biconvex lens, a biconcave lens, and a positive meniscus lens having a convex surface directed toward the object side, in order from the object side.

The third lens group G3 is, in order from the object side, a junction lens of a biconvex lens and a biconcave lens, a biconvex lens, a negative meniscus lens with a convex surface facing the object side, and a junction lens of the biconvex lens, and the object side and the image side. It consists of a positive meniscus lens with a convex surface facing the image side, which has an aspherical lens surface.

FIG. 14 is a lens configuration diagram of the zoom lens of the second embodiment according to the present invention.

The zoom lens of the second embodiment is composed of a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a positive refractive power in order from the object side. Further, the second lens group G2 is composed of a second A lens group G2A having a positive refractive power, an aperture diaphragm S, and a second B lens group G2B having a negative refractive power in order from the object side.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves from the object side to the image side, and the second lens group G2 and the third lens group G3 move from the image side to the object side.

When focusing from an infinity object to a short-distance object, the second lens group G2 moves from the object side to the image side.

The first lens group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface directed toward the object side having an aspherical lens surface on the object side, a negative meniscus lens L2 having a convex surface directed toward the object side, and an object. Negative meniscus lens L3 with convex surface facing the object side where the lens surfaces on the side and image side are aspherical, biconcave lens, negative meniscus lens with the convex surface facing the object side, and positive meniscus with the convex surface facing the object side. Consists of a lens junction lens.

The second lens group G2 is composed of a biconvex lens, an aperture diaphragm S, a positive meniscus lens with a concave surface facing the object side, a biconcave lens, and a biconvex lens in order from the object side.

The third lens group G3 is, in order from the object side, a junction lens of a biconvex lens and a biconcave lens, a biconvex lens, a negative meniscus lens with a convex surface facing the object side, and a junction lens of the biconvex lens, and the object side and the image side. It consists of a positive meniscus lens with a convex surface facing the image side, which has an aspherical lens surface.

FIG. 27 is a lens configuration diagram of the zoom lens of the third embodiment according to the present invention.

The zoom lens of the third embodiment is composed of a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a positive refractive power in order from the object side. Further, the second lens group G2 is composed of a second A lens group G2A having a positive refractive power, an aperture diaphragm S, and a second B lens group G2B having a negative refractive power in order from the object side.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves from the object side to the image side, and the second lens group G2 and the third lens group G3 move from the image side to the object side.

When focusing from an infinity object to a short-distance object, the second lens group G2 moves from the object side to the image side.

The first lens group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface directed toward the object side having an aspherical lens surface on the object side, a negative meniscus lens L2 having a convex surface directed toward the object side, and an object. Negative meniscus lens L3 with convex surface facing the object side where the lens surfaces on the side and image side are aspherical, biconcave lens, negative meniscus lens with the convex surface facing the object side, and positive meniscus with the convex surface facing the object side. Consists of a lens junction lens.

The second lens group G2 is composed of a biconvex lens, an aperture diaphragm S, a biconvex lens, a biconcave lens, and a biconvex lens in order from the object side.

The third lens group G3 is, in order from the object side, a junction lens of a biconvex lens and a biconcave lens, a biconvex lens, a negative meniscus lens with a convex surface facing the object side, and a junction lens of the biconvex lens, and the object side and the image side. It consists of a positive meniscus lens with a convex surface facing the image side, which has an aspherical lens surface.

FIG. 40 is a lens configuration diagram of the zoom lens of the fourth embodiment according to the present invention.

The zoom lens of the fourth embodiment is composed of a first lens group G1 having a negative refractive power, a second lens group G2 having a positive refractive power, and a third lens group G3 having a positive refractive power in order from the object side. Further, the second lens group G2 is composed of a second A lens group G2A having a positive refractive power, an aperture diaphragm S, and a second B lens group G2B having a negative refractive power in order from the object side.

When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves from the object side to the image side, and the second lens group G2 and the third lens group G3 move from the image side to the object side.

When focusing from an infinity object to a short-distance object, the second lens group G2 moves from the object side to the image side.

The first lens group G1 includes, in order from the object side, a negative meniscus lens L1 having a convex surface directed toward the object side having an aspherical lens surface on the object side, a negative meniscus lens L2 having a convex surface directed toward the object side, and an object. Negative meniscus lens L3 with convex surface facing the object side where the lens surfaces on the side and image side are aspherical, biconcave lens, negative meniscus lens with the convex surface facing the object side, and positive meniscus with the convex surface facing the object side. Consists of a lens junction lens.

The second lens group G2 is composed of a biconvex lens, an aperture diaphragm S, a positive meniscus lens with a concave surface facing the object side, a biconcave lens, and a biconvex lens in order from the object side.

The third lens group G3 is, in order from the object side, a junction lens of a biconvex lens and a biconcave lens, a biconvex lens, a negative meniscus lens with a convex surface facing the object side, and a junction lens of the biconvex lens, and the object side and the image side. It consists of a positive meniscus lens with a convex surface facing the image side, which has an aspherical lens surface.

Next, numerical examples and conditional expression corresponding values of the examples of the zoom lens of the present invention will be described.

In [plane data], the surface number is the number of the lens surface or aperture stop counted from the object side, r is the radius of curvature of each lens surface, d is the distance between each lens surface, and nd is the d line (wavelength 587.56 nm). The refractive index and vd indicate the Abbe number with respect to the d line.

* (Asterisk) attached to the surface number indicates that the lens surface shape is aspherical. In addition, BF represents back focus.

The (aperture) attached to the surface number indicates that the aperture diaphragm is located at that position. ∞ (infinity) is entered for the radius of curvature for a plane or aperture stop.

In [Aspherical surface data], the value of each coefficient that gives the aspherical shape of the lens surface marked with * in [Surface data] is shown. The shape of the aspherical surface is represented by the following formula. In the following equation, the displacement from the optical axis in the direction orthogonal to the optical axis is y, the displacement (sag amount) from the intersection of the aspherical surface and the optical axis in the optical axis direction is z, and the radius of curvature of the reference sphere is r. The cornic coefficient is represented by K. Further, the aspherical coefficients of the third, fourth, fifth, sixth, seventh, eighth, ninth, tenth, eleventh and twelfth orders are represented by A3, A4, A5, A6, A7, A8, A9, A10, A11 and A12, respectively. There is.

[Various data] shows values such as the focal length when focusing at infinity.

[Variable spacing data] shows the value of the variable spacing of the lens surface when the object distance is focused at each focal length.

[Lens group data] shows the lens surface number on the most object side constituting each lens group and the combined focal length of the entire lens group.

In all the following specification values, the units of the focal length f, the radius of curvature r, the lens surface spacing d, and other lengths described are mm (mm) unless otherwise specified, but optics. The system is not limited to this because the same optical performance can be obtained in both proportional expansion and proportional reduction.

Further, in the aberration diagram corresponding to each embodiment, d, g, and C represent the d-line, g-line, and C-line, respectively, and ΔS and ΔM represent the sagittal image plane and the meridional image plane, respectively. ..

Numerical Example 1
Unit: mm
[Surface data]
Face number rd nd vd
Paraboloid ∞ d0
1 * 135.5528 4.0000 1.69090 52.98
2 26.7393 11.6744
3 35.6623 1.3263 1.90043 37.37
4 21.4633 7.9774
5 * 38.4325 2.0000 1.59051 66.72
6 * 21.0195 12.0179
7 -96.3664 1.3789 1.43700 95.10
8 78.1980 2.0424
9 510.6072 1.1927 1.43700 95.10
10 33.1888 8.6806 1.88300 40.80
11 -9290.8481 d11
12 29.9799 5.3542 1.51823 58.96
13 -82.7997 1.9905
14 (Aperture) ∞ 2.0937
15 90.3724 3.2168 1.64769 33.84
16 -24.8054 0.8000 1.95375 32.32
17 39.5546 2.3987 1.92286 20.88
18 300.3209 d18
19 321.7525 2.8623 1.43700 95.10
20 -28.6685 0.8000 1.88300 40.80
21 113.6323 0.1500
22 25.3126 5.1691 1.43700 95.10
23 -39.5030 0.1500
24 27.3701 0.8500 1.88300 40.80
25 15.9424 7.0291 1.43700 95.10
26 -88.4908 1.0466
26 * -35.2987 2.0105 1.55232 71.54
26 * -34.3786 3.0000
29 ∞ 1.4500 1.52301 58.59
30 ∞ BF
Image plane ∞

[Aspherical data]
1 side 5 side 6 side 27 side 28 side
K 0.0000 0.0000 0.0000 0.0000 0.0000
A3 0.00000E + 00 -5.06363E-04 -5.16702E-04 0.00000E + 00 0.00000E + 00
A4 8.50106E-06 2.16537E-04 2.40168E-04 3.08647E-05 4.80767E-05
A5 0.00000E + 00 -4.37028E-05 -5.19226E-05 0.00000E + 00 0.00000E + 00
A6 -7.38137E-09 3.57798E-06 5.04244E-06 2.00116E-07 2.51071E-07
A7 0.00000E + 00 -5.19243E-08 -2.11789E-07 0.00000E + 00 0.00000E + 00
A8 5.75851E-12 -7.24855E-09 3.52902E-09 -2.36080E-09 -2.41699E-09
A9 0.00000E + 00 1.99694E-10 -3.30352E-11 0.00000E + 00 0.00000E + 00
A10 -2.51692E-15 1.52426E-11 -1.02396E-11 3.25141E-12 4.50605E-12
A11 0.00000E + 00 -8.51817E-13 1.08633E-12 0.00000E + 00 0.00000E + 00
A12 4.78883E-19 1.21790E-14 -2.78944E-14 0.00000E + 00 0.00000E + 00

[Various data]
Zoom ratio 1.86
Wide-angle medium telephoto focal length 12.40 16.48 23.05
F number 4.15 4.14 4.15
Full angle of view 2 ω 121.28 104.67 85.40
Image height Y 21.63 21.63 21.63
Total lens length 167.46 158.43 156.40

[Variable interval data]
(Object distance infinity)
Wide-angle intermediate telephoto
d0 ∞ ∞ ∞
d11 33.7543 16.7198 1.8391
d18 5.8527 6.1655 6.5197
BF 35.1909 42.8777 55.3811

(Shooting distance 40 times)
Wide-angle intermediate telephoto
d0 465.4085 639.2961 894.6208
d11 34.9353 17.4217 2.3301
d18 4.6717 5.4636 6.0288
BF 35.1909 42.8777 55.3811

[Lens group data]
Focal length
G1 1 -21.27
G2 12 60.35
G3 19 60.04
G2A 12 43.17
G2B 15 -113.27

Numerical Example 2
Unit: mm
[Surface data]
Face number rd nd vd
Paraboloid ∞ d0
1 * 133.5319 4.0000 1.69090 52.98
2 29.0193 9.0505
3 36.9009 1.5021 1.90043 37.37
4 21.9843 10.7139
5 * 42.2390 2.0000 1.59051 66.72
6 * 20.2270 11.6548
7 -86.0416 1.1437 1.43700 95.10
8 52.6015 2.2862
9 91.7008 1.2591 1.43700 95.10
10 32.9014 7.1882 1.88300 40.80
11 1862.5231 d11
12 29.8520 3.4522 1.51823 58.96
13 -71.3696 1.9863
14 (Aperture) ∞ 2.2734
15 -115.9957 6.0384 1.64769 33.84
16 -20.1455 0.8000 1.95375 32.32
17 63.0450 2.3712 1.92286 20.88
18 -94.8658 d18
19 61.6687 3.0762 1.43700 95.10
20 -32.4970 1.5798 1.88300 40.80
21 164.7325 0.2180
22 23.8093 4.6565 1.43700 95.10
23 -50.0635 0.1500
24 37.3944 0.8500 1.88300 40.80
25 15.9218 7.2421 1.43700 95.10
26 -118.2573 0.9554
27 * -43.5089 1.7137 1.55232 71.54
28 * -34.3648 36.7415
29 ∞ 1.4500 1.52301 58.59
30 ∞ BF
Image plane ∞

[Aspherical data]
1 side 5 side 6 side 27 side 28 side
K 0.0000 0.0000 0.0000 0.0000 0.0000
A3 0.00000E + 00 -5.37715E-04 -5.18213E-04 0.00000E + 00 0.00000E + 00
A4 7.92621E-06 2.25403E-04 2.38912E-04 1.99936E-05 3.52523E-05
A5 0.00000E + 00 -4.41792E-05 -5.17564E-05 0.00000E + 00 0.00000E + 00
A6 -6.39306E-09 3.58069E-06 5.03353E-06 2.31740E-07 2.77610E-07
A7 0.00000E + 00 -5.23857E-08 -2.12648E-07 0.00000E + 00 0.00000E + 00
A8 4.45245E-12 -7.22809E-09 3.50675E-09 -2.33328E-09 -2.40330E-09
A9 0.00000E + 00 2.01591E-10 -3.11119E-11 0.00000E + 00 0.00000E + 00
A10 -1.79721E-15 1.51557E-11 -1.02846E-11 9.97910E-13 2.52463E-12
A11 0.00000E + 00 -8.53398E-13 1.08656E-12 0.00000E + 00 0.00000E + 00
A12 3.49541E-19 1.21655E-14 -2.80015E-14 0.00000E + 00 0.00000E + 00

[Various data]
Zoom ratio 1.86
Wide-angle medium telephoto focal length 12.39 16.64 23.08
F number 4.04 4.04 4.16
Full angle of view 2 ω 121.27 104.29 85.36
Image height Y 21.63 21.63 21.63
Total lens length 167.88 158.00 155.77

[Variable interval data]
(Object distance infinity)
Wide-angle intermediate telephoto
d0 ∞ ∞ ∞
d11 34.5864 16.4855 1.6422
d18 5.4321 5.8016 6.4075
BF 1.5104 9.3633 21.3709

(Shooting distance 40 times)
Wide-angle intermediate telephoto
d0 465.4085 639.2961 894.6208
d11 35.6759 17.1996 2.1665
d18 4.3427 5.0874 5.8832
BF 1.5103 9.3633 21.3709

[Lens group data]
Focal length
G1 1 -21.79
G2 12 67.76
G3 19 57.43
G2A 12 41.09
G2B 15 -88.33

Numerical Example 3
Unit: mm
[Surface data]
Face number rd nd vd
Paraboloid ∞ d0
1 * 142.3924 4.0000 1.69090 52.98
2 27.1497 11.2239
3 36.4307 1.2660 1.90043 37.37
4 21.9407 8.4667
5 * 38.9176 2.0000 1.59051 66.72
6 * 20.2959 12.0347
7 -101.1845 1.0000 1.43700 95.10
8 85.5727 1.8403
9 466.9892 1.0837 1.43700 95.10
10 32.4957 8.9541 1.88300 40.80
11 3509.3968 d11
12 28.9388 4.4785 1.51823 58.96
13 -74.4750 2.5793
14 (Aperture) ∞ 2.1146
15 262.9302 3.1822 1.64769 33.84
16 -22.0531 0.8000 1.95375 32.32
17 47.0741 2.4753 1.92286 20.88
18 -512.5043 d18
19 2056.5337 2.8774 1.43700 95.10
20 -27.2820 0.8000 1.88300 40.80
21 140.6569 0.1500
22 25.5757 5.3194 1.43700 95.10
23 -38.1548 0.1500
24 26.8408 0.8500 1.88300 40.80
25 15.9194 7.0266 1.43700 95.10
26 -90.9268 1.1147
27 * -35.1146 2.1120 1.55232 71.54
28 * -34.8587 3.0000
29 ∞ 1.4500 1.52301 58.59
30 ∞ BF
Image plane ∞

[Aspherical data]
1 side 5 side 6 side 27 side 28 side
K 0.0000 0.0000 0.0000 0.0000 0.0000
A3 0.00000E + 00 -4.86653E-04 -4.93023E-04 0.00000E + 00 0.00000E + 00
A4 8.47154E-06 2.21669E-04 2.42990E-04 2.98252E-05 4.80352E-05
A5 0.00000E + 00 -4.40889E-05 -5.21361E-05 0.00000E + 00 0.00000E + 00
A6 -7.45703E-09 3.56325E-06 5.01997E-06 1.94717E-07 2.46296E-07
A7 0.00000E + 00 -5.16370E-08 -2.11924E-07 0.00000E + 00 0.00000E + 00
A8 5.78701E-12 -7.21598E-09 3.52746E-09 -2.30569E-09 -2.36443E-09
A9 0.00000E + 00 2.00081E-10 -2.99069E-11 0.00000E + 00 0.00000E + 00
A10 -2.50858E-15 1.52610E-11 -1.00940E-11 3.01207E-12 4.35459E-12
A11 0.00000E + 00 -8.55171E-13 1.08298E-12 0.00000E + 00 0.00000E + 00
A12 4.76761E-19 1.21576E-14 -2.83764E-14 0.00000E + 00 0.00000E + 00

[Various data]
Zoom ratio 1.86
Wide-angle medium telephoto focal length 12.42 16.50 23.06
F number 4.16 4.14 4.18
Full angle of view 2 ω 121.16 104.60 85.40
Image height Y 21.63 21.63 21.63
Total lens length 167.09 158.09 156.01

[Variable interval data]
(Object distance infinity)
Wide-angle intermediate telephoto
d0 ∞ ∞ ∞
d11 33.7265 16.6953 1.8515
d18 5.8191 6.1370 6.4050
BF 35.1968 42.9053 55.4016

(Shooting distance 40 times)
Wide-angle intermediate telephoto
d0 465.4085 639.2961 894.6208
d11 34.8994 17.3956 2.3426
d18 4.6463 5.4366 5.9139
BF 35.1968 42.9053 55.4016

[Lens group data]
Focal length
G1 1 -21.26
G2 12 60.38
G3 19 59.68
G2A 12 40.82
G2B 15 -98.26

Numerical Example 4
Unit: mm
[Surface data]
Face number rd nd vd
Paraboloid ∞ d0
1 * 133.6942 4.0000 1.69090 52.98
2 28.1773 9.1045
3 34.8794 1.3124 1.90043 37.37
4 21.7866 9.9399
5 * 41.9726 2.0000 1.59051 66.72
6 * 20.4237 11.9844
7 -100.7895 1.0000 1.43700 95.10
8 67.8348 2.1062
9 213.4842 1.1912 1.43700 95.10
10 31.8225 7.6514 1.88300 40.80
11 1208.6604 d11
12 30.0062 3.9381 1.51823 58.96
13 -62.1241 1.3179
14 (Aperture) ∞ 2.3732
15 -81.7709 5.5446 1.64769 33.84
16 -19.6290 0.8000 1.95375 32.32
17 82.4301 2.5822 1.92286 20.88
18 -78.2877 d18
19 69.6958 3.0065 1.43700 95.10
20 -33.2675 2.7997 1.88300 40.80
21 163.2202 0.1500
22 25.2049 4.8679 1.43700 95.10
23 -44.7977 0.1500
24 35.0307 0.8500 1.88300 40.80
25 16.2033 6.2388 1.43700 95.10
26 -181.8537 1.2741
27 * -39.6274 1.6806 1.55232 71.54
28 * -33.1294 1.0000
29 ∞ 1.4500 1.52301 58.59
30 ∞ BF
Image plane ∞

[Aspherical data]
1 side 5 side 6 side 27 side 28 side
K 0.0000 0.0000 0.0000 0.0000 0.0000
A3 0.00000E + 00 -4.61958E-04 -4.53200E-04 0.00000E + 00 0.00000E + 00
A4 8.47759E-06 2.15575E-04 2.33695E-04 2.06045E-05 3.56656E-05
A5 0.00000E + 00 -4.39990E-05 -5.17906E-05 0.00000E + 00 0.00000E + 00
A6 -7.23616E-09 3.58795E-06 5.04097E-06 2.29893E-07 2.73620E-07
A7 0.00000E + 00 -5.24155E-08 -2.12243E-07 0.00000E + 00 0.00000E + 00
A8 5.42755E-12 -7.22183E-09 3.52306E-09 -2.31475E-09 -2.38976E-09
A9 0.00000E + 00 2.01363E-10 -3.05502E-11 0.00000E + 00 0.00000E + 00
A10 -2.35748E-15 1.51514E-11 -1.02750E-11 1.39220E-12 2.91203E-12
A11 0.00000E + 00 -8.54205E-13 1.08587E-12 0.00000E + 00 0.00000E + 00
A12 4.63233E-19 1.22255E-14 -2.81016E-14 0.00000E + 00 0.00000E + 00

[Various data]
Zoom ratio 1.86
Wide-angle medium telephoto focal length 12.38 16.62 23.08
F number 3.99 3.98 4.12
Full angle of view 2 ω 121.39 104.33 85.28
Image height Y 21.63 21.63 21.63
Total lens length 167.58 157.72 155.29

[Variable interval data]
(Object distance infinity)
Wide-angle intermediate telephoto
d0 ∞ ∞ ∞
d11 34.4489 16.5019 1.6666
d18 5.5444 5.921 6.4485
BF 37.2758 44.979 56.8615

(Shooting distance 40 times)
Wide-angle intermediate telephoto
d0 465.4085 639.2961 894.6208
d11 35.5647 17.2245 2.1933
d18 4.4286 5.1984 5.9218
BF 37.2758 44.979 56.8615

[Lens group data]
Focal length
G1 1 -21.89
G2 12 66.89
G3 19 57.72
G2A 12 39.62
G2B 15 -85.37

[Conditional expression correspondence value]
Conditional expression / Example Example 1 Example 2 Example 3 Example 4 Example 4
(4) 1 / (| 1 / G2BR1 | + | 1 / G2BR2 |) 69.47 52.19 173.78 40.00

In the zoom lens of the present embodiment, when focusing from an infinity object to a short-distance object, the second A lens group and the second B lens group arranged on the object side and the image side from the aperture diaphragm constituting the second lens group. It is also possible to suppress aberration fluctuations during focusing and further improve the optical performance by moving the lenses in the optical axis direction with different amounts of movement.

G1 1st lens group L1 1st negative meniscus lens L2 2nd negative meniscus lens L3 3rd negative meniscus lens G2 2nd lens group G2A 2A lens group G2B 2nd B lens group G3 3rd lens group S Aperture aperture I image plane

Claims (3)

From the object side to the image side, it is composed of a first lens group with a negative power, a second lens group with a positive power, and a third lens group with a positive power.
A zoom lens in which the distance between the first lens group and the second lens group decreases and the distance between the second lens group and the third lens group increases when zooming from the wide-angle end to the telephoto end.
The first lens group consists of a first negative meniscus lens having a convex surface facing the object side, a second negative meniscus lens having a convex surface facing the object side, and a second negative meniscus lens having a convex surface facing the object side, in order from the object side to the image side. Has 3 negative meniscus lenses,
The lens surface of the first negative meniscus lens on the object side has an aspherical shape.
The lens surfaces on the object side and the image side of the third negative meniscus lens have an aspherical shape.
The second lens group is composed of a second A lens group having a positive refractive power, an aperture diaphragm, and a second B lens group having a negative refractive power in order from the object side to the image side.
A zoom lens characterized in that the second lens group moves from the object side to the image side along the optical axis when focusing from an infinity object to a short-distance object. The zoom lens according to claim 1, wherein the zoom lens satisfies the following conditions.
(1) L3Fasp_H <0.0
(2) 0.0 ≦ L3Fasp_L
(3) 0.0 <L3Rasp
L3Fasp_H: Aspherical sag amount (reference spherical surface) in the region where the main ray corresponding to the peripheral edge side passes through the relative image height ratio of 0.75 at the wide-angle end on the aspherical lens surface on the object side of the third negative meniscus lens. Difference in length on the optical axis from the reference spherical surface to the aspherical surface at each ray height based on the intersection of the optical axis and the optical axis)
L3Fasp_L: Aspherical sag amount (reference) in the region where the main ray corresponding to the optical axis side passes through the relative image height ratio of 0.5 at the wide-angle end on the aspherical lens surface on the object side of the third negative meniscus lens. Difference in length on the optical axis from the reference spherical surface to the aspherical surface at each ray height based on the intersection of the spherical surface and the optical axis)
L3Rasp: Aspherical sag amount on the aspherical lens surface on the image side of the third negative meniscus lens (length on the optical axis from the reference spherical surface to the aspherical surface at each ray height based on the intersection of the reference spherical surface and the optical axis) Difference) The zoom lens according to claim 1 or 2, wherein the zoom lens satisfies the following conditions.
(4) 35 mm <1 / (| 1 / G2BR1 | + | 1 / G2BR2 |)
G2BR1: Radius of curvature (mm) of the lens surface on the object side of the second B lens group with negative refractive power
G2BR2: Radius of curvature (mm) of the lens surface on the image side of the second B lens group with negative refractive power

Images