JP2011170086A - Large aperture zoom lens with anti-vibration function - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a large aperture zoom lens that ensures back focus optimum for a digital single lens reflex camera, has a zoom ratio of approximately three times, can fix an F value when zooming, is small in size, and has an anti-vibration function. <P>SOLUTION: An optical system includes a first positive lens group L1, a second negative lens group L2, a third positive lens group L3, and a fourth positive lens group L4. In zooming from a wide angle end to the telephoto end, the optical system moves these lens groups so that the interval between the first and second lens groups L1 and L2 increases, the interval between the second and third lens groups L2 and L3 and the interval between the third and fourth lens groups L3 and L4 decrease. The third lens group L3 includes a 3a-th positive lens component L3a, 3b-th negative lens component L3b, and a 3c-th positive lens component L3c, the 3b-th lens component L3b serves as an anti-vibration lens group. When zooming from the wide angle end to the telephoto end, the diameter of an aperture increases to fix the F value, and predetermined conditional expressions are satisfied. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

The present invention relates to a large-aperture zoom lens having an anti-vibration function particularly used in digital cameras, silver halide cameras, video cameras, and the like.

As a large-aperture zoom lens having a zoom ratio of about 3 times, an F value fixed during zooming, and having an anti-vibration function, for example, the following patent documents can be cited.

US Pat. No. 5,774,267

US Pat. No. 5,847,875

JP 2007-108398 A

Japanese Patent Laid-Open No. 2006-234892

The optical systems described in Patent Document 1 and Patent Document 2 are so-called negative group leading zoom lenses, and perform vibration isolation using the second lens group having a relatively large axial beam in the optical system. It was difficult to reduce the diameter and weight of the vibration lens group.

Moreover, as what employ | adopts what is called a positive group advance type | mold zoom lens, there exists an optical system described in patent document 3 and patent document 4, for example. Since the optical systems described in Patent Document 3 and Patent Document 4 perform image stabilization using the fourth lens group having a relatively small axial light beam in the optical system, the diameter and weight of the image stabilization lens group are reduced. Although it is advantageous and the F value is 2.8, which is a large aperture, it has a 5-group configuration, and the overall length is not sufficiently compact.

In order to solve the above problems, a large-aperture zoom lens having an image stabilization function according to an embodiment of the present invention includes a first lens unit L1 having a positive refractive power and negative refraction in order from the object side to the image side. The second lens unit L2 having a power, the third lens unit L3 having a positive refractive power, and the fourth lens unit L4 having a positive refractive power, and when zooming from the wide angle side to the telephoto side, The distance between the first lens group L1 and the second lens group L2 is large, the distance between the second lens group L2 and the third lens group L3 is small, and the distance between the third lens group L3 and the fourth lens group L4 is small. The first lens group L1, the second lens group L2, the third lens group L3, and the fourth lens group L4 are moved along the optical axis so that the third lens group L3 is sequentially positive from the object side to the image side. A third lens component L3a having a refractive power of 3b and a third lens component L3a having a negative refractive power. The image component can be moved by moving the third b lens component L3b in a direction substantially perpendicular to the optical axis, and a wide angle. When zooming from the end to the telephoto end, the F value is fixed regardless of zooming by increasing the aperture diameter.
A large-aperture zoom lens having an anti-vibration function characterized by satisfying the following conditional expression:
(1) 0.29 <ft / (f3 × Fnot) <0.69
(2) 1.35 <| f3b | / f3a <4.33
(3) 0.07 <f3c / | f3bc | <1.04
However,
ft is the focal length of the entire lens system at the telephoto end when focusing on infinity,
f3 is a focal length of the third lens unit L3,
Fnot is the F value of the entire lens system at the telephoto end,
f3a is the focal length of the 3a lens component L3a,
f3b is a focal length of the third b lens component L3b,
f3c is a focal length of the third c lens component L3c,
f3bc is a focal length of a synthesis system of the third b lens component L3b and the third c lens component L3c.

In addition, it is preferable that the first lens unit L1 satisfies the following conditional expression.
(4) 1.13 <f1 / ft <2.93
However,
f1 is a focal length of the first lens unit L1,
ft is the focal length when the entire lens system at the telephoto end is in focus at infinity.

The third b lens component L3b preferably includes at least one aspheric surface.

In addition, it is preferable that the fourth lens unit L4 includes at least one aspheric surface and satisfies the following conditional expression.
(5) 0.877 <f4 / f34w <2.145
However,
f4 is a focal length of the fourth lens unit L4,
f34w is a focal length of the combined system of the third lens unit L3 and the fourth lens unit L4 at the wide angle end.

According to the present invention, it is possible to secure an optimal back focus for a digital single lens reflex camera, a zoom ratio is about 3 times, an F value can be fixed during zooming, an optical system can be kept small, and A large-diameter zoom lens having a vibration function can be provided.

It is a lens block diagram in the wide angle end of Example 1 of this invention. It is a longitudinal aberration figure at the time of infinity focusing in the wide angle end of Example 1 of the present invention. It is a longitudinal aberration figure at the time of infinity focusing in the telephoto end of Example 1 of the present invention. It is a transverse aberration figure at the normal time at the time of infinity focusing in the wide angle end of Example 1 of the present invention. In order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing on infinity at the wide-angle end in Embodiment 1 of the present invention, the image stabilizing lens group is moved by +0.139 mm in the direction perpendicular to the optical axis. FIG. 6 is a lateral aberration diagram during vibration isolation. In order to perform image blur correction corresponding to an incident angle of −0.2 ° when focusing on infinity at the wide-angle end in Embodiment 1 of the present invention, the anti-vibration lens group is set to −0. It is a lateral aberration diagram at the time of vibration isolation moved by 139 mm. It is a lateral aberration diagram at the normal time when focusing on infinity at the telephoto end according to the first embodiment of the present invention. In order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing on infinity at the telephoto end according to the first embodiment of the present invention, the anti-vibration lens group is moved by +0.295 mm in the direction perpendicular to the optical axis. FIG. 6 is a lateral aberration diagram during vibration isolation. In order to perform image blur correction corresponding to an incident angle of −0.2 ° at the infinite focus at the telephoto end according to the first exemplary embodiment of the present invention, the image stabilizing lens group is set to −0. It is a lateral aberration diagram at the time of vibration isolation moved by 295 mm. It is a lens block diagram in the wide angle end of Example 2 of this invention. It is a longitudinal aberration figure at the time of infinity focusing in the wide-angle end of Example 2 of the present invention. It is a longitudinal aberration figure at the time of infinity focusing in the telephoto end of Example 2 of the present invention. It is a transverse aberration figure at the normal time at the time of infinity focusing in the wide angle end of Example 2 of the present invention. In order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing on infinity at the wide-angle end in Example 2 of the present invention, the image stabilizing lens unit is moved by +0.123 mm in the direction perpendicular to the optical axis. FIG. 6 is a lateral aberration diagram during vibration isolation. In order to perform image blur correction corresponding to an incident angle of −0.2 ° when focusing on infinity at the wide angle end in Example 2 of the present invention, the image stabilizing lens group is set to −0. It is a lateral aberration figure at the time of vibration proof which moved 123 mm. It is a transverse aberration figure at the normal time at the time of infinity focusing in the telephoto end of Example 2 of the present invention. In order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing on infinity at the telephoto end according to the second embodiment of the present invention, the image stabilizing lens unit is moved by +0.255 mm in the direction perpendicular to the optical axis. FIG. 6 is a lateral aberration diagram during vibration isolation. In order to perform image blur correction corresponding to an incident angle of −0.2 ° at the infinite focus at the telephoto end according to the second exemplary embodiment of the present invention, the image stabilizing lens unit is set to −0. It is a lateral aberration diagram at the time of vibration isolation moved by 255 mm. It is a lens block diagram in the wide angle end of Example 3 of this invention. It is a longitudinal aberration figure at the time of infinity focusing in the wide-angle end of Example 3 of the present invention. It is a longitudinal aberration figure at the time of infinity focusing in the telephoto end of Example 3 of the present invention. It is a transverse aberration figure at the normal time at the time of infinity focusing in the wide angle end of Example 3 of the present invention. In order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing at infinity at the wide-angle end in Example 3 of the present invention, the image stabilizing lens unit is moved by +0.127 mm in the direction perpendicular to the optical axis. FIG. 6 is a lateral aberration diagram during vibration isolation. In order to perform image blur correction corresponding to an incident angle of −0.2 ° when focusing on infinity at the wide-angle end in Example 3 of the present invention, the image stabilizing lens unit is set to −0. It is a lateral aberration figure at the time of vibration proof which was moved 127 mm. It is a transverse aberration figure at the normal time at the time of infinity focusing in the telephoto end of Example 3 of the present invention. In order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing on infinity at the telephoto end according to the third embodiment of the present invention, the image stabilizing lens unit is moved by +0.261 mm in the direction perpendicular to the optical axis. FIG. 6 is a lateral aberration diagram during vibration isolation. In order to perform image blur correction corresponding to an incident angle of −0.2 ° at the infinite focus at the telephoto end according to the third exemplary embodiment of the present invention, the image stabilizing lens unit is set to −0. It is a lateral aberration diagram at the time of vibration isolation moved by 261 mm. It is a lens block diagram in the wide angle end of Example 4 of this invention. It is a longitudinal aberration figure at the time of infinity focusing in the wide-angle end of Example 4 of the present invention. It is a longitudinal aberration figure at the time of infinity focusing in the telephoto end of Example 4 of the present invention. It is a transverse aberration figure at the time of normal time at the time of infinity focusing in the wide angle end of Example 4 of the present invention. In order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing on infinity at the wide-angle end in Example 4 of the present invention, the image stabilizing lens unit is moved by +0.121 mm in the direction perpendicular to the optical axis. FIG. 6 is a lateral aberration diagram during vibration isolation. In order to perform image blur correction corresponding to an incident angle of −0.2 ° when focusing on infinity at the wide-angle end in Example 4 of the present invention, the image stabilizing lens group is set to −0. It is a lateral aberration figure at the time of vibration proof which moved 121 mm. It is a transverse aberration figure at the normal time at the time of infinity focusing in the telephoto end of Example 4 of the present invention. In order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing on infinity at the telephoto end in Example 4 of the present invention, the image stabilizing lens unit is moved by +0.262 mm in the direction perpendicular to the optical axis. FIG. 6 is a lateral aberration diagram during vibration isolation. In order to perform image blur correction corresponding to an incident angle of −0.2 ° at the infinite focus at the telephoto end according to the fourth exemplary embodiment of the present invention, the image stabilizing lens unit is set to −0. It is a transverse aberration figure at the time of vibration proof which moved 262 mm. It is a lens block diagram in the wide angle end of Example 5 of this invention. It is a longitudinal aberration figure at the time of infinity focusing in the wide angle end of Example 5 of this invention. It is a longitudinal aberration figure at the time of infinity focusing in the telephoto end of Example 5 of the present invention. It is a transverse aberration figure at the normal time at the time of infinity focusing in the wide angle end of Example 5 of the present invention. In order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing on infinity at the wide angle end in Example 5 of the present invention, the image stabilizing lens unit is moved by +0.121 mm in the direction perpendicular to the optical axis. FIG. 6 is a lateral aberration diagram during vibration isolation. In order to perform image blur correction corresponding to an incident angle of −0.2 ° when focusing on infinity at the wide-angle end in Example 5 of the present invention, the image stabilizing lens group is set to −0. It is a lateral aberration figure at the time of vibration proof which moved 121 mm. It is a transverse aberration figure at the normal time at the time of infinity focusing in the telephoto end of Example 5 of the present invention. In order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing on infinity at the telephoto end according to the fifth embodiment of the present invention, the image stabilizing lens unit is moved by +0.262 mm in the direction perpendicular to the optical axis. FIG. 6 is a lateral aberration diagram during vibration isolation. In order to perform image blur correction corresponding to an incident angle of −0.2 ° at the infinite focus at the telephoto end according to the fifth exemplary embodiment of the present invention, the image stabilizing lens unit is set to −0. It is a transverse aberration figure at the time of vibration proof which moved 262 mm.

Hereinafter, a large-aperture zoom lens having an image stabilization function according to an embodiment of the present invention will be described.

A large-aperture zoom lens having an image stabilization function according to an embodiment of the present invention includes a first lens unit L1 having a positive refractive power and a second lens unit L2 having a negative refractive power in order from the object side to the image side. And a third lens unit L3 having a positive refractive power and a fourth lens unit L4 having a positive refractive power. When zooming from the wide angle side to the telephoto side, the first lens unit L1 and the second lens unit L4 The first lens unit L1 has a large interval with the lens unit L2, a small interval between the second lens unit L2 and the third lens unit L3, and a small interval between the third lens unit L3 and the fourth lens unit L4. The second lens unit L2, the third lens unit L3, and the fourth lens unit L4 are moved along the optical axis. The third lens unit L3 is a third lens component having a positive refractive power in order from the object side to the image side. L3a, the third-b lens component L3b having negative refractive power, and positive refraction The third c lens component L3c can move the image by moving the third b lens component L3b in a direction substantially perpendicular to the optical axis, and when zooming from the wide angle end to the telephoto end. By increasing the aperture diameter, the F value is fixed regardless of zooming,
A large-aperture zoom lens having an anti-vibration function that satisfies the following conditional expression
(1) 0.29 <ft / (f3 × Fnot) <0.69
(2) 1.35 <| f3b | / f3a <4.33
(3) 0.07 <f3c / | f3bc | <1.04
However,
ft is the focal length of the entire lens system at the telephoto end when focusing on infinity,
f3 is a focal length of the third lens unit L3,
Fnot is the F value of the entire lens system at the telephoto end,
f3a is the focal length of the 3a lens component L3a,
f3b is a focal length of the third b lens component L3b,
f3c is a focal length of the third c lens component L3c,
f3bc is a focal length of a synthesis system of the third b lens component L3b and the third c lens component L3c.

Conditional expression (1) defines the focal length of the third lens unit L3 and the F value of the entire lens system at the telephoto end in order to reduce the size and performance of the optical system and to alleviate performance deterioration due to manufacturing errors. is there.

If the upper limit of conditional expression (1) is exceeded and the focal length of the third lens unit L3 becomes short or the F value of the entire lens system at the telephoto end becomes bright, it is difficult to ensure a desired back focus at the wide angle end. In addition, the entrance pupil diameter at the telephoto end increases, and the apparent F value in the third lens unit L3 becomes brighter. For this reason, the axial luminous flux in the third lens unit L3 increases, which not only increases the diameter of the third lens unit L3 but also increases the spherical aberration. When trying to correct this, the third lens unit Since it is necessary to increase the number of components of L3, the overall length of the third lens unit L3 increases. In addition, due to manufacturing errors, there is a possibility that the performance is greatly deteriorated particularly when the third lens unit L3 is decentered.

If the lower limit of conditional expression (1) is exceeded and the F value of the entire lens system at the telephoto end becomes dark or the focal length of the third lens unit L3 increases, the entrance pupil diameter at the telephoto end decreases. Although it is advantageous for performance improvement and alleviation of performance deterioration due to manufacturing errors, not only the large aperture cannot be achieved, but also the positive refractive power of the third lens unit L3 becomes weak. Therefore, the axial light beam emitted from the third lens unit L3 becomes a divergent light beam and enters the fourth lens unit L4, the diameter of the fourth lens unit L4 increases, and the back at the wide angle end. The focus increases and the total length of the entire lens system increases.

Conditional expression (2) defines the focal length of the third-b lens component L3b which is the anti-vibration lens group.

If the upper limit of conditional expression (2) is exceeded and the focal length of the 3b lens component L3b is increased in absolute value, the negative refractive power will be weakened, so that the anti-vibration sensitivity will be low, and the 3b lens at the time of anti-vibration will be reduced. The amount of movement of the component L3b increases, and the parts for driving the image stabilizing lens group are enlarged.

Further, if the lower limit of conditional expression (2) is exceeded and the focal length of the 3b lens component L3b is shortened in absolute value, the negative refractive power becomes strong, so that it is difficult to correct decentration coma during image stabilization. Become.

Conditional expression (3) defines the focal length of the third c lens component L3c for miniaturization and high performance of the optical system.

In the present invention, Petzval sums generated in the third b lens component L3b and the third c lens component L3c are in a canceling relationship with each other. Therefore, when the upper limit value of the conditional expression (3) is exceeded and the focal length of the third c lens component L3c is shortened, the positive refractive power becomes strong, and the negative Petzval sum generated in the third c lens component L3c increases. Overcorrection of the positive Petzval sum generated in the 3b lens component L3b is difficult, so that it is difficult to correct the image plane of the entire lens system. In addition, since the axial light beam emitted from the third c lens component L3c becomes a convergent light beam and enters the fourth lens unit L4, it is difficult to ensure the back focus at the wide angle end.

When the lower limit of conditional expression (3) is exceeded and the focal length of the third c lens component L3c is increased, the positive refractive power becomes weaker, and the negative Petzval sum generated in the third c lens component L3c becomes smaller. Correction is insufficient for the positive Petzval sum generated in the third-b lens component L3b, making it difficult to correct the image plane of the entire lens system. Further, since the axial light beam emitted from the third c lens component L3c becomes a divergent light beam and enters the fourth lens unit L4, not only the diameter of the fourth lens unit L4 increases but also the back at the wide angle end. The focus increases and the total length of the entire lens system increases.

In addition, it is preferable that the first lens unit L1 in the large-aperture zoom lens according to the present invention satisfies the following conditional expression.
(4) 1.13 <f1 / ft <2.93
However,
f1 is a focal length of the first lens unit L1,
ft is the focal length when the entire lens system at the telephoto end is in focus at infinity.

Conditional expression (4) defines the focal length of the first lens unit L1 in order to achieve both miniaturization and high performance of the optical system.

When the upper limit of conditional expression (4) is exceeded, the focal length of the first lens unit L1 is increased, and the power of the first lens unit L1 is decreased, not only the diameter of the first lens unit L1 is increased, but also the first The magnification burden after the lens unit L1 is reduced, and the amount of movement of the lens after the first lens unit L1 must be increased, resulting in an increase in the overall length of the optical system.

Further, when the lower limit of conditional expression (4) is exceeded and the focal length of the first lens unit L1 is shortened, the positive refractive power becomes strong. Therefore, negative spherical aberration increases especially on the telephoto end side, making correction difficult. It becomes.

In addition, the third b lens component L3b has at least one aspherical surface, thereby suppressing the occurrence of decentration coma during the image stabilization and minimizing the deterioration of the imaging performance.

In the large-aperture zoom lens of the present invention, in the fourth lens unit L4, the light beam passes more through the periphery of the lens as the peripheral field angle is reached. Therefore, in order to effectively correct coma and astigmatism, in the fourth lens unit L4, the negative refractive power increases from the optical axis toward the lens periphery, or the positive refractive power decreases. It is preferable to provide at least one aspherical surface and satisfy the following conditional expression.
(5) 0.877 <f4 / f34w <2.145
However,
f4 is a focal length of the fourth lens unit L4,
f34w is the focal length of the combined system of the third lens unit L3 and the fourth lens unit L4 at the wide angle end.

Conditional expression (5) defines the focal length of the fourth lens unit L4 for reducing the size and performance of the optical system and alleviating performance degradation due to manufacturing errors.

If the upper limit of conditional expression (5) is exceeded and the focal length of the fourth lens unit L4 is increased, the positive refractive power is weakened, so that the back focus at the wide-angle end is increased, and the total length of the entire lens system is increased. End up.

Further, if the lower limit value of conditional expression (5) is exceeded and the focal length of the fourth lens unit L4 becomes shorter, the positive refractive power becomes stronger, and it becomes difficult to secure a desired back focus at the wide angle end. In addition, it is difficult to correct coma and astigmatism, particularly on the telephoto end side. In addition, due to manufacturing errors, deterioration of coma and astigmatism increases particularly when the fourth lens unit L4 is decentered.

The aperture stop in the large-aperture zoom lens of the present invention is disposed between the second lens unit L2 and the third lens unit L3, and is moved in the same manner as the third lens unit L3 during zooming. Since the lower ray coma flare can be satisfactorily cut while securing the peripheral light amount, performance at an intermediate angle of view can be ensured.

In addition, it is desirable that the large-aperture zoom lens of the present invention has a configuration in which the second lens unit L2 moves toward the object side when focusing from an infinite object distance to a close object.

Furthermore, by setting the Abbe number difference Δνd of the cemented lenses included in the fourth lens unit L4 to 66 or more, it is possible to reduce performance deterioration due to manufacturing errors while ensuring a desired refractive power.

Hereinafter, a large-aperture zoom lens having an image stabilization function according to a numerical example of the present invention will be described in detail with reference to the drawings.

FIG. 1 is a lens configuration diagram at the wide-angle end of a large-aperture zoom lens having an image stabilization function according to the first embodiment.

The third-b lens component L3b can perform image blur correction by moving an image on the image plane I in a direction substantially perpendicular to the optical axis by moving the lens component L3b in a direction substantially perpendicular to the optical axis. In order from a negative biconcave lens and a positive biconvex lens.

FIG. 2 is a longitudinal aberration diagram when focusing on infinity at the wide-angle end of the large-aperture zoom lens having an image stabilization function according to Example 1. FIG. 3 is a longitudinal aberration diagram when focusing on infinity at the telephoto end of the large-aperture zoom lens having an image stabilization function according to Example 1. FIG. 4 is a transverse aberration diagram at normal time when focusing on infinity at the wide-angle end of the large-aperture zoom lens having the image stabilization function according to Example 1. FIG. 5 shows an image stabilization lens group as an optical axis in order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing at infinity at the wide-angle end of the large-aperture zoom lens having the image stabilization function according to the first embodiment. On the other hand, a lateral aberration diagram at the time of anti-vibration is shown by moving +0.139 mm in the vertical direction. In Example 1, the anti-vibration lens group is the third-b lens component L3b. FIG. 6 illustrates the image stabilization lens group as an optical axis in order to perform image blur correction corresponding to an incident angle of −0.2 ° when focusing at infinity at the wide-angle end of the large-aperture zoom lens having the image stabilization function according to the first embodiment. The lateral aberration diagram at the time of anti-vibration moved by −0.139 mm in the vertical direction is shown. FIG. 7 is a lateral aberration diagram in a normal state when focusing on infinity at the telephoto end of the large-aperture zoom lens having the image stabilization function according to the first example. FIG. 8 shows the image stabilization lens group as the optical axis in order to perform image blur correction corresponding to an incident angle of 0.2 ° at the infinite focus at the telephoto end of the large-aperture zoom lens having the image stabilization function according to the first embodiment. On the other hand, a lateral aberration diagram at the time of anti-vibration is shown by moving +0.295 mm in the vertical direction. FIG. 9 illustrates the image stabilization lens group in order to perform image blur correction corresponding to an incident angle of −0.2 ° at the infinite focus at the telephoto end of the large-aperture zoom lens having the image stabilization function according to the first embodiment. The lateral aberration diagram at the time of image stabilization when moved by −0.295 mm in the direction perpendicular to the axis is shown.

Table 1 below shows specification values of the large-aperture zoom lens having the image stabilization function according to Example 1.

In (overall specifications), f represents a focal length, Fno represents an F value, and 2ω represents an angle of view (unit: °). In (lens specifications), the first column N is the order of the lens surfaces counted from the object side, the second column R is the radius of curvature of the lens surfaces, the third column D is the lens surface spacing, and the fourth column nd is the d line ( The refractive index at the wavelength λ = 587.6 nm), the fifth column νd represents the Abbe number at the d-line (wavelength λ = 587.6 nm). Further, r = 0.0000 represents a plane, Bf represents back focus, the diaphragm represents a diaphragm surface, * represents an aspheric surface, and the refractive index n = 1.0000 of air is omitted from the description. (Variable interval at infinity shooting) shows the relationship between the focal length f and the variable interval. In (conditional expression), the corresponding value of each conditional expression for the embodiment is shown. (Aspherical data) represents the aspherical coefficient and conic coefficient when the lens surface number N and the shape of the aspherical surface are expressed by the following equations.

In the above equation, x is a shift in the optical axis direction at a position of height h from the optical axis when the vertex of the lens surface is used as a reference, and k is a conic coefficient, A, B, C, D Is the aspheric coefficient, and r is the radius of curvature of the reference sphere. In the table, “E-n” represents “× 10 ⁻ⁿ ”, for example “2.2283E-05” represents “2.2283 × 10 ⁻⁵ ”. Since these symbols are the same in the following embodiments, the description thereof will be omitted in the second and subsequent embodiments.

In all the following values, the described focal length f, radius of curvature R, lens surface distance D, and other lengths are “mm” unless otherwise specified. Even in proportional reduction, the same optical performance can be obtained, and the present invention is not limited to this. Since these symbols are the same in the following embodiments, the description thereof will be omitted in the second and subsequent embodiments.

In each aberration diagram, Fno is an F value, C is a C line (wavelength λ = 656.3 nm), d is a d line (wavelength λ = 587.6 nm), g is a g line (wavelength λ = 435.8 nm), ΔM Denotes a d-line meridional image plane, and ΔS denotes a d-line sagittal image plane. Since these symbols are the same in the following embodiments, the description thereof is omitted.

FIG. 10 is a lens configuration diagram at the wide-angle end of the large-aperture zoom lens having an image stabilization function according to Example 3.

The third-b lens component L3b can perform image blur correction by moving an image on the image plane I in a direction substantially perpendicular to the optical axis by moving the lens component L3b in a direction substantially perpendicular to the optical axis. In order from a negative biconcave lens and a positive biconvex lens.

FIG. 11 is a longitudinal aberration diagram when focusing on infinity at the wide-angle end of the large-aperture zoom lens having an image stabilization function according to Example 2. FIG. 12 is a longitudinal aberration diagram when focusing on infinity at the telephoto end of the large-aperture zoom lens having an image stabilization function according to Example 2. FIG. 13 is a lateral aberration diagram in a normal state when focusing on infinity at the wide-angle end of the large-aperture zoom lens having the image stabilization function according to Example 1. FIG. 14 shows an image stabilization lens group as an optical axis in order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing on infinity at the wide-angle end of a large-aperture zoom lens having an image stabilization function according to Example 2. On the other hand, a lateral aberration diagram at the time of anti-vibration is shown by moving +0.123 mm in the vertical direction. In Example 2, the anti-vibration lens group is the third-b lens component L3b. FIG. 15 shows the image stabilization lens group as an optical axis in order to perform image blur correction corresponding to an incident angle of −0.2 ° when focusing on infinity at the wide angle end of the large-aperture zoom lens having the image stabilization function according to the second embodiment. The lateral aberration diagram at the time of anti-vibration moved by −0.123 mm in the vertical direction with respect to FIG. FIG. 16 is a lateral aberration diagram in a normal state when focusing on infinity at the telephoto end of the large-aperture zoom lens having an image stabilization function according to Example 2. FIG. 17 illustrates a case where the image stabilization lens group is arranged on the optical axis in order to perform image blur correction corresponding to an incident angle of 0.2 ° at the infinite focus at the telephoto end of the large-aperture zoom lens having the image stabilization function according to the second embodiment. The lateral aberration diagram at the time of anti-vibration is shown by moving +0.255 mm in the vertical direction. FIG. 18 illustrates a case where the image stabilizing lens group is used to perform image blur correction corresponding to an incident angle of −0.2 ° at the infinite focus at the telephoto end of the large-aperture zoom lens having the image stabilizing function according to the second embodiment. The lateral aberration diagram at the time of vibration isolation when moved by −0.255 mm in the direction perpendicular to the axis is shown.

Table 2 below shows specification values of the large-aperture zoom lens having the image stabilization function according to Example 2.

FIG. 19 is a lens configuration diagram at the wide-angle end of the large-aperture zoom lens having an image stabilization function according to Example 3.

The third-b lens component L3b can perform image blur correction by moving an image on the image plane I in a direction substantially perpendicular to the optical axis by moving the lens component L3b in a direction substantially perpendicular to the optical axis. In order from a negative biconcave lens and a positive biconvex lens.

FIG. 20 is a longitudinal aberration diagram when focusing on infinity at the wide-angle end of the large-aperture zoom lens having an image stabilization function according to Example 3. FIG. 21 is a longitudinal aberration diagram at the telephoto end of the large aperture zoom lens having the image stabilization function according to Example 3 at the time of focusing on infinity. FIG. 22 is a lateral aberration diagram in a normal state at the time of focusing on infinity at the wide-angle end of the large-aperture zoom lens having an image stabilization function according to Example 3. FIG. 23 shows an image stabilization lens group as an optical axis in order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing at infinity at the wide angle end of a large-aperture zoom lens having an image stabilization function according to Example 3. On the other hand, a lateral aberration diagram at the time of anti-vibration is shown by moving +0.127 mm in the vertical direction. In Example 3, the anti-vibration lens group is the third-b lens component L3b. FIG. 24 shows the image stabilization lens group as an optical axis in order to perform image blur correction corresponding to an incident angle of −0.2 ° when focusing at infinity at the wide-angle end of the large-aperture zoom lens having the image stabilization function according to Example 3. The lateral aberration diagram at the time of anti-vibration moved by −0.127 mm in the vertical direction with respect to FIG. FIG. 25 is a lateral aberration diagram in a normal state when focusing on infinity at the telephoto end of the large-aperture zoom lens having an image stabilization function according to Example 3. FIG. 26 shows an image stabilization lens group as an optical axis in order to perform image blur correction corresponding to an incident angle of 0.2 ° at the infinite focus at the telephoto end of the large-aperture zoom lens having the image stabilization function according to the third embodiment. On the other hand, a lateral aberration diagram at the time of anti-vibration is shown by moving +0.261 mm in the vertical direction. FIG. 27 illustrates a case where the image stabilizing lens group is used to perform image blur correction corresponding to an incident angle of −0.2 ° at the infinite focus at the telephoto end of the large-aperture zoom lens having the image stabilizing function according to the third embodiment. The lateral aberration figure at the time of vibration isolation which moved -0.261 mm perpendicularly to the axis is shown.

Table 3 below shows specification values of the large-aperture zoom lens having the image stabilization function according to Example 3.

FIG. 28 is a lens configuration diagram at the wide-angle end of the large-aperture zoom lens having an image stabilization function according to Example 4.

The third-b lens component L3b can perform image blur correction by moving an image on the image plane I in a direction substantially perpendicular to the optical axis by moving the lens component L3b in a direction substantially perpendicular to the optical axis. In order from a negative biconcave lens and a positive biconvex lens.

FIG. 29 is a longitudinal aberration diagram of the large-aperture zoom lens having an image stabilization function according to Example 4 when focusing on infinity at the wide angle end. FIG. 30 is a longitudinal aberration diagram at the telephoto end of the large aperture zoom lens having the image stabilization function according to Example 4 when focusing on infinity. FIG. 31 is a lateral aberration diagram in a normal state when focusing on infinity at the wide-angle end of a large-aperture zoom lens having an image stabilization function according to Example 4. FIG. 32 shows an image stabilization lens group as an optical axis in order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing at infinity at the wide-angle end of a large-aperture zoom lens having an image stabilization function according to Example 4. On the other hand, a lateral aberration diagram at the time of anti-vibration is shown by moving +0.121 mm in the vertical direction. In Example 4, the anti-vibration lens group is the third-b lens component L3b. FIG. 33 is a diagram illustrating an example in which an anti-vibration lens group is used as an optical axis in order to perform image blur correction corresponding to an incident angle of −0.2 ° when focusing at infinity at the wide angle end of a large-aperture zoom lens having an anti-vibration function according to Example 4. The lateral aberration figure at the time of vibration proof which moved to -0.121 mm perpendicularly | vertically with respect to is shown. FIG. 34 is a transverse aberration diagram at normal time when focusing on infinity at the telephoto end of a large-aperture zoom lens having an image stabilization function according to Example 4. FIG. 35 is a diagram illustrating an example in which the image stabilizing lens group is arranged on the optical axis in order to perform image blur correction corresponding to an incident angle of 0.2 ° at the infinite focus at the telephoto end of the large-aperture zoom lens having the image stabilizing function according to Example 4. The lateral aberration diagram at the time of anti-vibration is shown by moving +0.262 mm in the vertical direction. FIG. 36 illustrates a case where a vibration-proof lens group is irradiated with light in order to perform image blur correction corresponding to an incident angle of −0.2 ° when focusing at infinity at the telephoto end of a large-aperture zoom lens having a vibration-proof function according to Example 4. The lateral aberration figure at the time of vibration isolation which moved -0.262 mm perpendicularly to the axis is shown.

Table 4 below shows specification values of the large-aperture zoom lens having the image stabilization function according to Example 4.

FIG. 37 is a lens configuration diagram at the wide-angle end of the large-aperture zoom lens having an image stabilization function according to Example 5.

The third-b lens component L3b can perform image blur correction by moving an image on the image plane I in a direction substantially perpendicular to the optical axis by moving the lens component L3b in a direction substantially perpendicular to the optical axis. In this order, the lens comprises a cemented lens of a negative biconcave lens and a positive meniscus lens.

FIG. 38 is a longitudinal aberration diagram of the large-aperture zoom lens having an image stabilization function according to Example 5 when focusing on infinity at the wide angle end. FIG. 39 is a longitudinal aberration diagram at the telephoto end of the large aperture zoom lens having the image stabilization function according to Example 5 when focusing on infinity. FIG. 40 is a lateral aberration diagram in a normal state at the time of focusing on infinity at the wide-angle end of the large-aperture zoom lens having an image stabilization function according to Example 1. FIG. 41 shows an image stabilization lens group as an optical axis in order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing at infinity at the wide-angle end of a large-aperture zoom lens having an image stabilization function according to Example 5. On the other hand, a lateral aberration diagram at the time of anti-vibration is shown by moving +0.121 mm in the vertical direction. In Example 5, the anti-vibration lens group is the third-b lens component L3b. FIG. 42 shows the image stabilization lens group as an optical axis in order to perform image blur correction corresponding to an incident angle of −0.2 ° at the infinite focus at the wide angle end of the large-aperture zoom lens having the image stabilization function according to the fifth embodiment. The lateral aberration figure at the time of vibration proof which moved to -0.121 mm perpendicularly | vertically with respect to is shown. FIG. 43 is a lateral aberration diagram at normal time when the telephoto end of the large-aperture zoom lens having an image stabilization function according to Example 5 is in focus at infinity. FIG. 44 is a diagram illustrating an example in which an anti-vibration lens group is used as an optical axis in order to perform image blur correction corresponding to an incident angle of 0.2 ° when focusing on infinity at a telephoto end of a large-aperture zoom lens having an anti-vibration function according to Example 5. The lateral aberration diagram at the time of anti-vibration is shown by moving +0.262 mm in the vertical direction. FIG. 45 shows the image stabilization lens group in order to perform image blur correction corresponding to an incident angle of −0.2 ° at the infinite focus at the telephoto end of the large-aperture zoom lens having the image stabilization function according to Example 5. The lateral aberration figure at the time of vibration isolation which moved -0.262 mm perpendicularly to the axis is shown.

Table 5 below shows specification values of the large-aperture zoom lens having the image stabilization function according to Example 5.

Conditional expression correspondence table

L1 First lens unit L1
L2 Second lens unit L2
L3 Third lens unit L3
L4 Fourth lens unit L4
L3a 3a lens component L3a
L3b 3b lens component L3b
L3c 3c lens component L3c
S aperture stop I image plane d d-line C C-line g g-line Fno F value ΔS sagittal image plane ΔM meridional image plane Y image height

Claims (4)

In order from the object side to the image side, a first lens unit L1 having positive refractive power, a second lens unit L2 having negative refractive power, a third lens unit L3 having positive refractive power, and positive refraction A fourth lens unit L4 having power,
When zooming from the wide-angle side to the telephoto side, the distance between the first lens group L1 and the second lens group L2 is large, and the distance between the second lens group L2 and the third lens group L3 is small, The first lens group L1, the second lens group L2, the third lens group L3, and the fourth lens group L4 are arranged on the optical axis so that the distance between the third lens group L3 and the fourth lens group L4 is reduced. Move along
The third lens unit L3 includes, in order from the object side to the image side, a third-a lens component L3a having a positive refractive power, a third-b lens component L3b having a negative refractive power, and a third-c lens component L3c having a positive refractive power. Consisting of
It is possible to move the image by moving the third b lens component L3b in a direction substantially perpendicular to the optical axis,
When zooming from the wide-angle end to the telephoto end, the F value is fixed regardless of zooming by increasing the aperture diameter.
A large-aperture zoom lens having an anti-vibration function characterized by satisfying the following conditional expression:
(1) 0.29 <ft / (f3 × Fnot) <0.69
(2) 1.35 <| f3b | / f3a <4.33
(3) 0.07 <f3c / | f3bc | <1.04
However,
ft is the focal length of the entire lens system at the telephoto end when focusing on infinity,
f3 is a focal length of the third lens unit L3,
Fnot is the F value of the entire lens system at the telephoto end,
f3a is the focal length of the 3a lens component L3a,
f3b is a focal length of the third b lens component L3b,
f3c is a focal length of the third c lens component L3c,
f3bc is a focal length of a synthesis system of the third b lens component L3b and the third c lens component L3c.
The large-aperture zoom lens (4) having an anti-vibration function according to claim 1, wherein the first lens unit L1 satisfies the following conditional expression: 1.13 <f1 / ft <2.93.
However,
f1 is a focal length of the first lens unit L1,
ft is the focal length when the entire lens system at the telephoto end is in focus at infinity.
3. The large-aperture zoom lens having an image stabilization function according to claim 1, wherein the third b lens component L3b includes at least one aspheric surface.
4. The large-aperture zoom lens having an anti-vibration function according to claim 1, wherein the fourth lens unit L <b> 4 includes at least one aspherical surface and satisfies the following conditional expression. .
(5) 0.877 <f4 / f34w <2.145
However,
f4 is a focal length of the fourth lens unit L4,
f34w is the focal length of the combined system of the third lens unit L3 and the fourth lens unit L3 at the wide angle end.

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