JP3387307B2 - Zoom lens with camera shake correction function - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a zoom lens having a camera shake correction function, and more specifically, it is capable of preventing image blur caused by camera shake (for example, vibration during hand-held shooting of a camera). The present invention relates to a zoom lens suitable as a standard / standard high-magnification zoom lens for a reflex camera.

[0002]

2. Description of the Related Art Conventionally, various zoom lenses having a camera shake correction function have been proposed. For example, JP-A-5-23
Japanese Laid-Open Patent Publication No. 2410 proposes a zoom lens having a positive, negative, positive, and positive four-group configuration, in which the entire second group is moved in the direction perpendicular to the optical axis to perform camera shake correction.
Japanese Patent Application Laid-Open No. 7-991124 proposes a zoom lens which has a positive, negative, positive, and positive four-group configuration in which the entire third group is moved in the direction perpendicular to the optical axis to perform camera shake correction.

[0003]

The zoom lens proposed in Japanese Patent Application Laid-Open No. 5-232410 and Japanese Patent Application Laid-Open No. 7-991124 has a working angle of view close to the telephoto end, and therefore cannot be used as a standard zoom. The optics are too large and unsuitable.
Also, since the entire zoom group is moved in the direction perpendicular to the optical axis for camera shake correction, the weight of the lens to be moved is large and the lens frame portion that holds the lens is also large. There is. For this reason, a large load is applied to the camera shake drive system that performs camera shake correction drive, and the resulting increase in the size of the camera shake drive system and the delay in response to eccentricity pose problems.

As described above, a standard zoom lens and a standard high-magnification zoom lens which are compact and capable of excellent image stabilization have not yet been known. In view of the above, the present invention provides a standard / standard high-magnification zoom lens that has an image stabilization function, a lens group that moves for image stabilization is light in weight, and the overall length is short and compact, and that has high depiction performance. The purpose is to do.

[0005]

In order to achieve the above object, a zoom lens having an image stabilizing function according to a first aspect of the present invention comprises a first group having a positive refractive power and a negative refractive power in order from the object side. A zoom lens that includes a second lens unit having a positive refractive power and a third lens unit having a positive refracting power to perform zooming by changing the distance between the zoom lens units, and at the time of zooming from the wide-angle end to the telephoto end. The first group moves to the object side, and any one of the second and subsequent zoom groups is divided into a front group and a rear group in order from the object side, and the front group or the rear group is set with respect to the optical axis. performs image stabilization by moving in a vertical direction, the front
It is characterized in that the distance between the group and the rear group does not change upon zooming and satisfies the following conditional expression (1). 2.1 <f1 / fW <4.3 (1) where f1 is the focal length of the first lens group, and fW is the focal length of the entire system at the wide-angle end.

The zoom lens having the image stabilization function of the second invention is the first lens having a positive refractive power in order from the object side.
A zoom lens including a group, a second group having a negative refracting power, and a third group having a positive refracting power, and performing zooming by changing the distance between the groups, At the time of zooming to the telephoto end, the first group moves to the object side, the second group is divided into a front group and a rear group in order from the object side, and the front group or the rear group with respect to the optical axis. Image stabilization is performed by moving in the vertical direction, and the front group and the rear group
It is characterized in that the interval does not change upon zooming and satisfies the conditional expression (1).

A zoom lens having a camera shake correction function according to a third aspect of the present invention comprises a first zoom lens having a positive refractive power in order from the object side.
A zoom lens including a group, a second group having a negative refracting power, and a third group having a positive refracting power, and performing zooming by changing the distance between the groups, Upon zooming to the telephoto end, the first group moves to the object side, the third group is divided into a front group and a rear group in order from the object side, and the front group or the rear group is set with respect to the optical axis. Image stabilization is performed by moving in the vertical direction, and the front group and the rear group
It is characterized in that the interval does not change upon zooming and satisfies the conditional expression (1).

The zoom lens having the image stabilizing function according to the fourth aspect of the present invention is the first lens having a positive refractive power in order from the object side.
A group, a second group having a negative refracting power, a third group having a positive refracting power, and a fourth group having a positive refracting power, and the magnification is changed by changing an interval between the groups. The first lens group moves toward the object side during zooming from the wide-angle end to the telephoto end, and the fourth lens group is divided into a front lens group and a rear lens group in order from the object side. Image stabilization is performed by moving the lens group or the rear group in the direction perpendicular to the optical axis, and the distance between the front group and the rear group changes during zooming.
Without satisfying the above condition (1).

The first to fourth inventions are, in order from the object side, a first group having a positive refracting power and a negative lens group so as to be suitable as a standard zoom lens for a single-lens reflex camera or a standard high-magnification zoom lens. It includes a second group having a refractive power and a third group having a positive refractive power. With a zoom lens that includes positive, negative, and positive types as described above, the degree of freedom of movement of the zoom group can be effectively used for aberration correction, so even though it is a high-power zoom lens that includes a wide-angle range, It is possible to obtain good imaging performance over all of the above.

Further, since the first lens unit moves to the object side during zooming from the wide-angle end to the telephoto end, a retro type lens is used at the wide-angle end.
At the telephoto end, a telephoto type structure will be adopted. Therefore, a sufficient back focus can be secured and an optical system having a short total length can be achieved.
Furthermore, if the second group and the third group are configured to move to the object side during zooming from the wide-angle end to the telephoto end, the degree of freedom of movement of the zoom group is increased, which is advantageous for aberration correction and the total length is increased. It is possible to obtain a shorter optical system.

Further, in this type of zoom lens, since each zoom group positively performs zooming, the aberration burden on each zoom group becomes considerably large. Therefore, it is very difficult to correct the aberration of each zoom group with only one single lens or one cemented lens. Therefore, it is desirable to configure each zoom group with a plurality of lenses.

The conditional expression (1) relates to the focal length of the first lens unit, and by satisfying this conditional expression (1), good imaging performance can be obtained without impairing compactness. If the upper limit of conditional expression (1) is exceeded, the focal length of the first lens group becomes large, which is advantageous for aberration correction, but the lens outer diameter of the first lens group becomes large and the first lens group moves during zooming. Since this causes an increase in the amount, it becomes difficult to obtain a compact optical system. By setting the upper limit of conditional expression (1) to 3.8 and satisfying this, a more compact optical system can be obtained. When the value goes below the lower limit of the conditional expression (1), the aberration generated in the first group becomes very large, and it becomes difficult to correct the aberration in the other groups. By setting the lower limit of conditional expression (1) to 2.5 and satisfying the lower limit, a better imaging performance can be obtained.

In the above first to fourth inventions, it is desirable that the following conditional expression (2) is further satisfied. By satisfying conditional expression (2), it is possible to make a high-power zoom lens including a wide-angle range compact and to improve its imaging performance. 0.65 <fR / fW <1.8 (2) where fR is the combined focal length of the third and subsequent zoom groups at the wide-angle end.

Conditional expression (2) relates to the combined focal length at the wide-angle end of the third and subsequent zoom groups. Conditional expression
When the value exceeds the upper limit of (2), it is advantageous for aberration correction, but the length of the third and subsequent lens groups becomes long, resulting in loss of compactness. If the upper limit of conditional expression (2) is set to 1.3 and this is satisfied, a more compact optical system can be obtained. If the lower limit of conditional expression (2) is exceeded, an excessive aberration will occur because the combined focal length at the wide-angle end of the third and subsequent zoom groups will be too short, and it will be difficult to correct it with other zoom groups. become. By setting the lower limit of conditional expression (2) to 0.8 and satisfying the lower limit, a better imaging performance can be obtained.

Generally, in a zoom photographing optical system for a single-lens reflex camera, the first lens group is the largest lens group, and the lens weight is also considerably large. As in the first to fourth inventions, a first group having a positive refracting power, a second group having a negative refracting power, and a third group having a positive refracting power are provided in order from the object side. The first zoom lens equipped
The lens weights of the groups are much larger than the lens weights of the second and subsequent zoom groups. For this reason, it is not preferable to move the first lens group in the direction perpendicular to the optical axis (that is, to perform parallel eccentricity) to correct the camera shake because the camera shake drive system becomes large.

Further, as in the first to fourth inventions, in order from the object side, the first group having a positive refractive power, the second group having a negative refractive power, and the first group having a positive refractive power. A zoom lens including three groups generally has an aperture stop in the second and subsequent groups. Since the on-axis light flux and the off-axis light flux are densely gathered near the aperture stop, the lens diameter is reduced near the aperture stop. The zoom groups of the second group and the subsequent groups are located near the aperture stop in zooming from the wide-angle end to the telephoto end, so that it is possible to make the lens diameter relatively small. Therefore, as in the first to fourth inventions, the use of the small and lightweight lenses constituting the second and subsequent zoom groups for camera shake correction does not increase the load on the camera shake drive system and causes the camera shake. It is suitable for making corrections.

However, if the camera shake correction is performed by decentering the entire zoom group of the second and subsequent zoom groups in parallel, the weight of the lens and the lens frame portion to be decentered in parallel increases, so that the camera shake driving system is affected. The burden also increases. Therefore, in the first to fourth inventions, any one of the second and subsequent zoom groups is divided into a front group and a rear group in order from the object side, and the front group or the rear group is a lens group for image stabilization (hereinafter The "shake correction group") is configured to perform the shake correction by moving in the direction perpendicular to the optical axis (that is, by causing parallel eccentricity). With this configuration, it is possible to reduce the weight of the lens and the lens frame portion that are moved for camera shake correction, and as a result, it is possible to reduce the load on the camera shake drive system.

Regarding the positional relationship between the camera shake correction group and the aperture stop, it is preferable that the following conditional expression (3) is satisfied in all zoom regions. D / f <1.2 (3) where D is the distance from the surface closest to the aperture stop in the image stabilization group to the aperture stop, and f is the focal length of the entire system.

If the upper limit of conditional expression (3) is exceeded, the camera shake correction group will be greatly separated from the aperture stop, and the passing positions of the on-axis light beam and the off-axis light beam will be separated. As a result, the lens diameter increases and the lens weight increases, which increases the load on the camera shake drive system.

When the lens group is moved in the direction perpendicular to the optical axis for camera shake correction, the light beam passes where the light beam does not pass in the normal state (pre-eccentric state) and in the camera shake correction state (post-eccentric state). It will be. This light beam may become a harmful light beam and deteriorate the imaging performance. Therefore, it is desirable to block harmful light rays during image stabilization by providing a fixed aperture on the object side of the image stabilization group, in the image stabilization group, or on the image side of the image stabilization group, and thus even in the image stabilization state. Good imaging performance can be obtained.

Further, it is desirable that focusing on a near object is performed by a camera shake correction group or a zoom group having a camera shake correction group. This makes it possible to realize the focusing drive system and the camera shake drive system for camera shake correction by using a common drive member, which is very advantageous in terms of cost.

Generally, the aberration at the time of camera shake is represented by a combination of the aberration caused by the optical system located in front of the optical system decentered for camera shake correction and the aberration of the optical system itself decentered for camera shake correction. be able to. When the camera shake correction group is composed of one lens, the optical system located in front of the camera shake correction group has a larger number of lenses than the camera shake correction group, so that the degree of freedom of aberration correction is large. Therefore, it is possible to correct both the aberration in the normal state and the aberration at the time of camera shake by the optical system located in front of the camera shake correction group. However, since the camera shake correction group has a small degree of freedom for aberration correction, if its refracting power is too large, the aberrations that occur in the camera shake correction group will be extremely large, and aberration correction in normal conditions should be suppressed with other lenses. Becomes difficult.

Therefore, when the image stabilizing group is composed of one lens, it is preferable that the following conditional expression (4) is satisfied. | Pd | / fW <2.30 (4) where Pd is the refractive power of the image stabilization group.

If the upper limit of conditional expression (4) is exceeded, the refractive power of the image stabilization group becomes too large, so that the aberrations generated only in the image stabilization group become excessive and the aberrations in the normal state (pre-eccentric state) are corrected. Difficult to do. Also, conditional expression (4)
By setting the upper limit of to 1.6 and satisfying this, it is possible to obtain an optical system with further aberration correction.

When the camera shake correction group is decentered in parallel during camera shake, axial lateral chromatic aberration, which is one of decentering aberrations, occurs.
In order to suppress this, it is desirable that the camera shake correction group be color-corrected. However, when the camera shake correction group is composed of one lens, chromatic aberration inevitably occurs in the camera shake correction group. If the number of lenses in the image stabilizing group is increased by adding a lens in order to suppress this, the image stabilizing group becomes large. Therefore, it is desirable to use a cemented lens of a positive lens and a negative lens as the camera shake correction group. 1
By using a single cemented lens, it is possible to realize a color-corrected, lightweight image stabilization group.

When using the image stabilizing group consisting of one cemented lens, it is desirable that the following conditional expression (5) is satisfied when the image stabilizing group has a positive refractive power, and the image stabilizing group has a negative refractive power. If you have the following conditional expression (6)
It is desirable to satisfy. νp> νn… (5) νp ＜ νn… (6) where νp is the Abbe number of the positive lens in the image stabilization group (junction lens), νn is the Abbe number of the negative lens in the image stabilization group (junction lens) is there.

<< Decentering Aberration and Decentering Aberration Coefficient >> Next, the definition of aberration deterioration of an optical system having a camera shake correcting function (hereinafter referred to as “camera shake correcting optical system”) like the zoom lens according to the present invention is defined in FIG. It will be described based on. The decentration aberrations (off-axis image point movement error, one-sided blur, axial coma and axial lateral chromatic aberration) shown in the same figure cause image deterioration of the image stabilizing optical system.

[Off-axis image point movement error] {FIG. 17 (A)} In a decentered optical system, a distortion error due to decentering occurs in addition to the normal distortion aberration. For this reason, in the image stabilization optical system, when the image point on the axis (that is, the center of the screen) is corrected to completely stop, the image point off-axis does not completely stop, and an image blur occurs. In FIG. 17 (A), 1 is the film surface, 2
Represents an image point in a corrected state (post-eccentric state), 3 represents an image point in a normal state (pre-eccentric state), and 4 represents a camera shake correction direction.

Here, the optical axis is the x-axis direction, the camera shake direction is the y-axis direction (that is, the camera shake correction direction 4 is also the y-axis direction), and Y
(y ', z', θ) is the Y coordinate of the actual image point at the image stabilization angle θ of the ray whose paraxial image point is (y ', z') (so that the image point on the axis stops completely Since Y is corrected to Y (0,0, θ) = 0. }, The following expression (a) is established. ΔY (y ', z', θ) ＝ Y (y ', z', θ) -Y (y ', z', 0) …… (a)

[0030] Unless otherwise specified, the off-axial image point movement error of the image point on the y-axis [Delta] Y _Y 'and axial image point for an image point on the z-axis movement error [Delta] Y _Z' are each the following formula ( b) and the formula
It is represented by (c). The 0.7 field is about 12 mm for the new standard 24 mm film. ΔY _Y '＝ {ΔY (0.7field, 0,0.7 °) + ΔY (-0.7field, 0,0.7 °)} / 2 …… (b) ΔY _Z ' ＝ ΔY (0,0.7field, 0.7 °)… … (C)

[One-sided blur] {FIG. 17 (B)} In FIG. 17 (B), 5 represents an image plane asymmetric with respect to the optical axis AX, and 6
Represents an image plane symmetrical to the optical axis. Due to the asymmetry of the optical system, the image plane 5 is asymmetric with respect to the optical axis AX. As a result, the generated meridional one-sided blur ΔM ′ and the sagittal one-sided blur ΔS ′ are represented by the following equations (d) and (e), respectively. ΔM '= {meridional value (y' = 0.7field, z = 0, θ = 0.7 °) -meridional value (y '=-0.7field, z = 0, θ = 0.7 °)} / 2 (d) ΔS '= {Sagittal value (y' = 0.7field, z = 0, θ = 0.7 °) -Sagittal value (y '=-0.7field, z = 0, θ = 0.7 °)} / 2 ...... (e)

[On-axis coma] {FIG. 17 (C)} In FIG. 17 (C), 7 represents an axial luminous flux, and 8 represents an axial chief ray. As shown in the figure, the axial light beam 7 is not symmetrical with respect to the axial principal ray 8, and coma aberration occurs. The axial coma AXCM generated in the axial luminous flux 7 is expressed by the following equation (f). AXCM = {Y (Upper Zornal, θ = 0.7 °) + Y (Lower Zornal, θ = 0.7 °)} / 2 …… (f)

[Axial Lateral Chromatic Aberration] {FIG. 17 (D)} Since the image point shifts due to the difference in wavelength, when the optical system is asymmetric, a shift occurs even in the axial light. The axial lateral chromatic aberration that occurs in the axial chief ray is represented by the following equation (g). (Axial lateral chromatic aberration) = {Y (g line, θ = 0.7 °) -Y (d line, θ = 0.7 °)} …… (g)

Regarding the above-mentioned eccentric aberration, Yoshiya Matsui's article "Third-order aberration theory of an optical system having eccentricity" (1990)
June, JOEM) shows the application method. This method is suitable when the photographic lens is decentered due to mounting error, but it should be applied directly to the image stabilization optical system where the coaxial relationship between the object plane and the photographic lens and image plane is misaligned. I can't. Therefore, in order to enable the method of the above paper to be directly applied to the image stabilization optical system, the aberration of the actual image stabilization optical system is converted into a normal third-order aberration coefficient by performing conversion of the equations described below. Express.

[Application of Eccentric Aberration Coefficient to Shake Correction Optical System] The method of obtaining the eccentric aberration coefficient will be described below with reference to FIG. 18 showing the relationship between the optical system and the coordinates. First, the formula is defined as follows. tanω ・ cosφω ＝ Y / g $ tanω ・ sinφω ＝ Z / g $ R ・ cosφR ＝ (g $ / g) ・ Y * R ・ sinφR ＝ (g $ / g) ・ Z * g and g $ are entrance pupils Surface, object side principal plane to object plane
(Object surface) The distance to the OS, ω is the angle formed by the straight line connecting the object point and the object-side principal point H with the reference axis, and φω is its azimuth, and R
Is the entrance pupil radius converted on the object-side principal plane and φR is the azimuth.
It's muth.

The νth surface from the object side is Y with respect to the reference axis.
Image plane (image plane) I when decentered by a small amount Eν
The image point movement amounts ΔY and ΔZ on S are expressed by the following equations (1A) and (1B). ΔY ＝-(Eν / 2α _k ') ・ [(ΔE) ν + (N ・ tanω) ²・ {(2 + cos2φω) ・ (VE1) ν- (VE2) ν} + 2R ・ (N ・ tanω) ・((2cos (φR-φω) + cos (φR + φω)) ・ (IIIE) ν + cosφR ・ cosφω ・ (PE) ν} + R ²・ (2 + cos2φR) ・ (IIE) ν] …… (1A ) ΔZ ＝-(Eν / 2α _k ') ・ [(N ・ tanω) ²・ sin2φω ・ (VE1) ν + 2R ・ (N ・ tanω) ・ (sin (φR + φω) ・ (IIIE) ν + sinφR ・sinφω ・ (PE) ν} + R ²・ sin2φR ・ (IIE) ν] …… (1B)

Where (ΔE) ν: prism action (lateral deviation of image) (VE1) ν, (VE2) ν: rotationally asymmetric distortion (IIIE) ν, (PE) ν: rotationally asymmetric astigmatism, image Surface inclination (IIE) ν: If the rotationally asymmetric coma aberration that also appears on the axis is taken, each decentering aberration coefficient that represents the effect of decentering is also ν
It is expressed by the following equations (1C) to (1H) according to the aberration coefficient of the lens surface from the second surface to the image surface (#: subscript indicating the object surface). In the case of rotational eccentricity, it is expressed by the same formula as the formulas (1A) to (1H). (ΔE) ν = -2 (αν'-αν) …… (1C) (VE1) ν ＝ [{αν '・ (μ = ν + 1 → k) ΣVμ}-{αν ・ (μ = ν → k) ΣVμ}]-[{αν '# ・ (μ = ν + 1 → k) ΣIIIμ}-{αν # ・ (μ = ν → k) ΣIIIμ}] …… (1D) (VE2) ν ＝ {αν'#・ (Μ = ν + 1 → k) ΣPμ}-{αν # ・ (μ = ν → k) ΣPμ} …… (1E) (IIIE) ν ＝ [{αν '・ (μ = ν + 1 → k) ΣIIIμ}-{αν ・ (μ = ν → k) ΣIIIμ}]-[{αν '# ・ (μ = ν + 1 → k) ΣIIμ}-{αν # ・ (μ = ν → k) ΣIIμ}]… … (1F) (PE) ν ＝ {αν '・ (μ = ν + 1 → k) ΣPμ}-{αν ・ (μ = ν → k) ΣPμ} …… (1G) (IIE) ν ＝ [{αν '・ (Μ = ν + 1 → k) ΣIIμ}-{αν ・ (μ = ν → k) ΣIIμ}]-[{αν'# ・ (μ = ν + 1 → k) ΣIμ}-{αν # ・(μ = ν → k) ΣIμ}] …… (1H)

However, in order to apply the decentering aberration coefficient to the image stabilization optical system, the image plane IS is changed to the object plane OS by reversing the optical system.
It is necessary to replace with, and use the aberration coefficient from the image plane IS. In other words, the image point movement amount must be converted to that on the object plane OS. The reason will be described below.

The first reason is that there is a difference in the light beam passage position due to eccentricity. As shown in FIG.
₍₁ : before decentering, L ₂ : after decentering), and in the method of the above-mentioned article by Yoshiya Matsui, the passing position of the ray on the image plane IS side of the decentering lens LS changes depending on the decentering lens LS. Therefore, the aberration coefficients of the eccentric lens LS and the eccentric lens LS to the image plane IS are related to the eccentric aberration coefficient. On the other hand, as shown in FIG. 19B (M ₁ : light beam before image stabilization, M ₂ : light beam after image stabilization), the image stabilization optical system
(Ideally), the passing position of the light beam on the object side of the decentering lens LS changes between before and after the image stabilization.
Therefore, the eccentric lens LS and the aberration coefficient on the object side of the eccentric lens LS are related to the eccentric aberration coefficient.

The second reason is that aberration deterioration occurs due to rotational conversion of the object surface. In the method described by Yoshiya Matsui, both the object plane OS ₁ and the image plane IS do not move, but in the image stabilization optical system, the object plane OS ₁ rotates as shown in FIG. Therefore, the off-axis image point movement error and the one-sided blur greatly differ from those when there is no rotation. In FIG. 20, OS ₁ represents the object surface before camera shake correction, and OS ₂ represents the object surface after camera shake correction.

[Aberration Coefficient of Inverted System and Aberration Coefficient of Non-Inverted System] For the above-mentioned reason, the amount of movement of the image point must be converted to that on the object surface. Therefore, each of the formulas (1A) to (1H) The coefficient
The following formulas (2A) to (2) represented based on FIG. 21 (non-inverting system)
Convert according to J). In addition, ^R () is an inversion symbol, N
Represents the refractive index. ^R α = ^R N / ^R g $ = -α '…… (2A) ^R α # = α'# …… (2B) ^R αμ '＝-αν …… (2C) ^R αμ'# ＝ αν # …… (2D) ^R Pμ ＝ Pν …… (2E)… Same ^R φμ ＝ φν …… (2F)… Same ^R Iμ ＝ Iν …… (2G)… Same ^R IIμ ＝ -IIν …… (2H)… Inverse ^R IIIμ ＝ IIIν …… (2I)… Same ^R Vμ ＝ -Vν …… (2J)… Inverse

[Eccentric Aberration Coefficient and Camera Shake Aberration Coefficient When Parallel Shake Correction Group is Decentered] The above equations (1A) to (1H) show the case where only one surface ν is eccentric. Therefore, equations (1A) to (1H) are further transformed into equations when a plurality of surfaces i to j are eccentric. When the camera shake correction group is decentered in parallel, the eccentric amounts Ei to Ej of the decentered surfaces i to j are equal,
The aberration coefficient can be treated as the sum as shown by the formula: (ΔE) i to j = (ν = i → j) Σ {-2 · (αν'-αν)}.
Then, from αν ′ = αν + 1, the formula: (ΔE) i to j = −2 · (αj′-αi) is obtained.

For other aberration coefficients, the term in the middle of Σ similarly disappears. For example, (PE) i ~ j = (μ = i → j) Σ {αν '・ (μ = ν + 1 → k) ΣPμ-αν ・ (μ = ν → k) ΣPμ} = αj' ・ (μ = j + 1 → k) ΣPμ-αi ・ (μ = i → k) ΣPμ Further transformation, (PE) i〜j ＝ (αj'-αi) ・ (μ = j + 1 → k) ΣPμ-αi ・(μ = i → j) ΣPμ where (μ = j + 1 → k) ΣPμ: Sum of P after the image stabilization group (Petzval sum) (μ = i → j) ΣPμ: P of image stabilization group It is a sum. (PE) i to j = (αj'-αi) P _R -αi · P _D where () _{R is} the sum of aberration coefficients after the image stabilization group () _D : is the sum of aberration coefficients of the image stabilization group .

As described above, the following equations (3A) to (3F) are obtained by converting the image point movement amount into that on the object plane and transforming into the equation when a plurality of surfaces i to j are eccentric. The decentering aberration coefficient represented by) is obtained. Then, by redefining each eccentric aberration coefficient as in equations (3A) to (3F), equations (1A) to (1H) can be used as they are as an equation representing the image point movement amount on the object surface. . (ΔE) i~j = -2 · ( αj'-αi) ...... (3A) (VE1) i~j = (αj'-αi) · V R - (αj '# - αi #) · III R - (αi ・ V _D -αi # ・ III _D ) …… (3B) (VE2) i〜j ＝ (αj # -αi #) ・ P _R -αi # ・ P _D … (3C) (IIIE) i〜j ＝ (αj'-αi) ・ III _R- (αj '#-αi #) ・ II _R- (αi ・ III _D -αi # ・ II _D ) ...… (3D) (PE) i〜j ＝ (αj' _{-αi) · P R -αi · P} D ...... (3E) (IIE) i~j = (αj'-αi) · II R - (αj '# - αi #) · I R - (αi · II D -αi # ・ I _D ) …… (3F)

[Off-axis image point movement error] Next, the off-axis image point movement error will be described. The eccentric aberration coefficient (of the inverted system) is ΔE, V
E1, VE2, IIIE, PE, IIE. The image point movement due to eccentricity on the object surface (before rotation conversion on the object surface) is {in the principal ray (R = 0)} and expressed by the following equations (4A) and (4B). Note that equations (4A), (4
In B), R in the equations (1A) and (1B) is set to R = 0. ΔY # ＝-(E / 2α ' _k ) ・ [ΔE + (N ・ tanω) ²・ {(2 + cos ² φω) VE1-VE2}] …… (4A) ΔZ # ＝-(E / 2α') ・{(N ・ tanω) ²・ sin2φω) ・ VE1} …… (4B)

Based on the above equations (4A) and (4B), the following equation (4
C) and (4D) are obtained (axial light, tan ω = 0). ΔY ₀ # ＝-(E / 2α ' _k ) ・ ΔE …… (4C) ΔZ ₀ # ＝ 0 …… (4D)

Next, the rotation conversion will be described with reference to FIG. From FIG. 22 (A), the equation: Y # = g $ _k · tanω holds. According to the sine theorem, Y '# / {sin (π / 2-ω')} ＝ (Y # + ΔY # -ΔY ₀ #) / {sin (π / 2 + ω '
-θ)}, and ΔY '# after rotation conversion is the following formula: ΔY'# ＝ (Y '#)-(Y #) ＝ [Y # ・ cosω' + {(ΔY #)-(ΔY ₀ #)} ・ Cosω'-Y # ・ cos (ω'-
θ)] / cos (ω'-θ). Only the numerator of this equation is transformed. [Y # ・ cosω '+ {(ΔY #)-(ΔY ₀ #)} ・ cosω'-Y # ・ cos (ω'-θ)] = Y # ・ cosω' + {(ΔY #)-(ΔY ₀ #)} ・ Cosω'-Y # ・ cosθ ・ cosω'-Y # ・ sinθ ・ sin nω '＝ (1-cosθ) ・ Y # ・ cosω' + {(ΔY #)-(ΔY ₀ #)} ・ cosω '-Y # ・ sin θ ・ sin ω' where θ is small and can be ignored compared to the other two terms,
^{(1-cosθ) ≒ θ 2} /2, a sin [theta ≒ theta. Also, cosω '/ {c
os (ω'-θ)} ≈ 1 and sin ω '/ {cos (ω'-θ)} ≈ tanω.

Therefore, the formula: ΔY '# ≈ (ΔY # -ΔY ₀ #)-Y # · θ · tanω is obtained. (ΔY # −ΔY ₀ #) represents the parallel decentering off-axis image point movement error, and Y # · θ · tan ω represents the additional term due to rotation (not related to the aberration coefficient). However, since ω at this time is on the XY cross section, ΔY '# ≈ (ΔY # -ΔY ₀ #)-Y # ・ θ ・ tanω ・ cosφω ...... (5A).

Next, the conversion to the image plane IS will be described with reference to FIG. The scaling factor β is represented by the formula: β = g $ ₁ / g $ _k = α _k ′ / α ₁ . Here, α ₁ = 1 / g $ ₁ . On the other hand, the image plane IS
And the object surface OS are related by the formula: Y = β ・ Y #, and Y # and ΔY # are in the form of 1 / α _k '× (), so they are transformed as follows. To do. Y ＝ β ・ Y # ＝ (α _k '/ α ₁ ) ・ (1 / α _k ') × () ＝ g $ ₁ × () where g $ _k ′ → ∞, g $ ₁ ＝- It becomes Fl. Therefore,
Formula: Y ＝ -Fl × () ＝-Fl × α _k '× Y # holds.

Next, the off-axis image point movement error on the image plane will be described. The eccentricity E can be calculated from the equation (4C) and α _k '= 1 / g _k ' $ by the following equation: θ = ΔY ₀ # / g $ _k '= E ・ ΔE / 2 E = 2 ・ θ / ΔE expressed. The camera shake correction angle θ is normalized so as to be constant (0.7 deg = 0.0122173 rad).

Due to parallel eccentricity (no rotation conversion), ΔY =
When (ΔY # -ΔY ₀ #) is converted to the image plane, (where N ・ tanω = Φ / F
l, Φ ² = Y ² + Z ² ) and the following equations (6A) to (6D) are obtained. ΔY = (θ ・ Φ ² / Fl) ・ [{(2 + cos2 ・ φω) ・ VE1-VE2} / ΔE] …… (6A) ΔZ ＝ (θ ・ Φ ² / Fl) ・ [{(sin2 ・ φω ) ・ VE1-VE2} / ΔE] …… (6B) Y ₊ image point, Y ₋ image point {φω = 0, π} in equations (6A) and (6B): ΔY _Y ＝ (θ ・ Y ² / Fl ) ・ {(3 ・ VE1-VE2) / ΔE} …… (6C) Z image point {φω = π / 2} of formulas (6A) and (6B): ΔY _Z = (θ ・ Z ² / Fl) ・{(VE1-VE2) / ΔE} ...... (6D)

Next, rotation conversion is performed. Y # ＝-Y / (Fl ×
α _k '), so -Y # ・ θ ・ tanω ・ cosφω in formula (5A) is expressed as: -Y # ・ θ ・ tanω ・ cosφω ＝ Y / (Fl × α _k ') ・ θ ・ tanω・ Cosφ
ω holds. At Y ₊ image point and Y _- image point, φω = 0, π, and
tanω / α _k '= Y, so -Y # ・ θ ・ tanω ・ cosφ at the image plane
ω = Y ² · θ / Fl. Adding this to equation (6C) gives
(6E) is obtained. On the other hand, at the Z image point, since φω = π / 2, -Y # · θ · tanω · cos φω = 0 on the image plane. By adding this to the equation (6D), the following equation (6F) is obtained. ΔY _Y '= (θ ・ Y ² / Fl) ・ {(3 ・ VE1-VE2-ΔE) / ΔE} …… (6E) ΔY _Z ' ＝ ΔY _Z …… (6F)

[One-sided blur] Next, one-sided blur will be described. Expression (1
From (A) and (1B), ΔM is {(first order term of R) φR = 0} × g $ _k 'of ΔY
And ΔS is {(first-order term of R) φR = π / 2} × g $ _k 'of ΔZ. First, on the object OS before rotation (where α _k '= N _k ' /
g $ _k ', E / 2 = θ / ΔE is used. ), Formula: ΔM # = (-g $ _k ' ²・ θ / N _k ') × 2 ・ R ・ (N ・ tanω) ・ cosφω ・ {(3 ・ I
IIE + PE) / ΔE} holds. Then, after rotation, the formula: ΔM '# ≈ΔM # + θY # holds.

Assuming that N _k '= 1 and N = 1 while transforming on the image plane, the equation: ΔM' = β ² · ΔM '# = -g $ ₁ ² · θ × 2 · R · tanω · cosφω・ {(3 ・ IIIE + PE) / ΔE} + β ・ Y ・ θ is obtained, and the object surface OS is ∞ (where g $ ₁ = -Fl, β →
0, tanω = Y / Fl, φω = 0. ), A formula (7A) expressing the meridional half-blurred ΔM ′ is obtained. Similarly, the equation (7B) expressing the sagittal one-sided blur ΔS ′ is obtained. ΔM '=-2 ・ Fl ・ Y ・ θ ・ R ・ {(3 ・ IIIE + PE) / ΔE} …… (7A) ΔS' ＝-2 ・ Fl ・ Y ・ θ ・ R ・ {(IIIE + PE) / ΔE} ...... (7B)

[On-axis coma] Next, the on-axis coma will be described.
Based on equation (1A), the coma due to eccentricity of ω = 0, Upper is
Formula: ΔY _Upper # = ΔY # (ω = 0, φ _R = 0) −ΔY # (ω = 0, R = 0) ＝-E / (2 ・ α ') × R ² × 3 ・ IIE , Ω = 0, the coma due to the eccentricity of Lower (same as ΔY _Upper # including the sign) is expressed by the formula: ΔY _Lower # = ΔY # (ω = 0, φ _R = π) −ΔY # (ω = 0, R = 0) = − E / (2 · α ′) × R ² × 3 · IIE

Since ω = 0, the axial coma hardly changes with rotation conversion. By converting from the object surface OS to the image surface IS (ΔY = β ・ ΔY #, E / 2 = θ / ΔE), the formula: ΔY _Upper = Fl × θ × R ² × (3 ・ IIE / ΔE) = ΔY _Lower And the axial coma AXCM is expressed by the following equation (8A). AXCM = (ΔY _Upper + ΔY _Lower ) / 2 = ΔY _Upper ...... (8A)

Equations (6E), (6F), obtained as described above,
A part of (7A), (7B), and (8A) is newly added by the following formulas (9A) to (9A).
It is defined as the camera shake aberration coefficient represented by E). Off-axis image point movement error of y-axis image point VE _Y = {(3 ・ VE1-VE2-ΔE) / ΔE} (9A) Off-axis image point movement error of z-axis image point VE _Z = { (VE1-VE2) / ΔE}… (9B) Meridional one-sided blur ……………… IIIE _M = {(3 ・ IIIE + PE) / ΔE}… (9C) Sagittal one-sided blur …………………… IIIE _S = {(IIIE + PE) / ΔE}… (9D) On-axis coma ……………………………… IIE _A = {(3 ・ IIE) / ΔE}… (9E)

By substituting the equations (3A) to (3F) into the equations (9A) to (9E) representing the camera shake aberration coefficient and rearranging, the following equations (10A) to (10E) representing the camera shake aberration coefficient are obtained. To be VE _Y = -1 / 2 ・ {3V _R -3V _D・ A + 2- (3 ・ III _R + P _R ) ・ H # + (3 ・ III _D + P _D ) ・ A #} …… (10A) VE _Z = -1 / 2 ・ {V _R -V _D・ A- (III _R + P _R ) ・ H # + (III _D + P _D ) ・ A #} ...... (10B) IIIE _M = -1 / 2 ・_{{(3 · III R + P} R) - (3 · III D + P D) · A-3 · II R · H # + 3 · II D · A #} ...... (10C) IIIE S = -1 / 2・ {(III _R + P _R )-(III _D + P _D ) ・ A-II _R・ H # + II _D・ A #} …… (10D) IIE _A = -3/2 ・ (II _R + II _D・ AI _R・ H # + I _D・ A #) (10E) However, () _D : Sum of aberration coefficients of the image stabilization group () _R : Sum of aberration coefficients after the image stabilization group (object side) A = Αi / (αj'-αi) (Here, the camera shake correction groups are i to j.) A # = αi # / (αj'-αi) H # = (αi '#-αi #) / (αj' -αi).

ΔE = -2 · (αj'-αi) is {where (αj'-αi)
Is ± 0.0122173 at 0.7 ° / mm. }, (Camera shake correction angle) / (lens eccentricity) coefficient, so aim at almost a predetermined value (however, the sign differs depending on whether the camera shake correction group is positive or negative). Therefore, A is the angle of incidence of the marginal ray on the image stabilization group (as seen from the image side), and A # is proportional to the angle of incidence of the chief ray. When h # and h do not change much in the image stabilization group, H # represents the ratio between the chief ray h # and the marginal ray h.

Since each eccentric aberration coefficient in the above equations (10A) to (10E) is defined in the inverting system, these must be returned to the non-inverting system again. Therefore, when the coefficients in the equations (10A) to (10E) are returned to the non-inversion system using the above equations (2A) to (2J), the following equations (11A) to (11E) are obtained. VE _Y = + 1/2 ・ {3V _F -3V _D・ A-2 + (3 ・ III _F + P _F ) H #-(3 ・ III _D + P _D ) ・ A #} …… (11A) VE _Z ＝ + 1/2 ・ {V _F -V _D・ A + (III _F + P _F ) H #-(III _D + P _D ) ・ A #} …… (11B) IIIE _M ＝ -1 / 2 ・ {(3 _{· III F + P F) -} (3 · III D + P D) · A + 3 · II F · H # -3 · II D · A #} ...... (11C) IIIE S = -1 / 2 · {( III _F + P _F )-(III _D + P _D ) ・ A + II _F・ H # -II _D・ A #} …… (11D) IIE _A ＝ + 3/2 ・ (II _F -II _D・ A + I _F / H # -I _D / A #) (11E) However, () _D : Sum of aberration coefficients of camera shake correction group and non-inverting system () _F : Sum of aberration coefficients before camera shake correction group A = -αn '/ (αn'-αm) A # ＝ αn'# / (αn'-αm) H ＝-(αn '#-αm #) / (αn'-αm) ＝-(Σhμ # ・ φμ) / ( Σhμ
・ Φμ) ΔE = -2 (αn'-αm) (m → n for image stabilization group, inversion j ← i).

From the above equations (11A) to (11E), the following can be understood. First, as described above, in the method of Yoshiya Matsui, the image stabilization group (that is, the decentering lens LS) and the optical system after that are related to the optical performance.
In (11E), the image stabilization group and the optical system before it are related to the optical performance. Second, the off-axis image point movement error is wide-angle system.
The focal length Fl of the image stabilization group becomes larger in the denominator, and one-sided blur and axial coma tend to become larger in the telephoto system.

Thirdly, if the aberration coefficient of the camera shake correction group and the group before it are reduced, the aberration deterioration at the time of decentering is reduced, but the coefficient VE _Y of the off-axis image point movement error ΔY _Y 'is Constant (expression
-2 in {} in (11A) remains. This is the object plane OS and the image plane IS
And are terms that occur because of a tilted relationship due to rotational blur. The off-axis image point movement error due to this constant term (-2) is
It becomes very large in wide-angle systems. For example, focal length Fl = 38mm
Then, the off-axis image point movement error ΔY _Y '= -72 μm, which cannot be ignored. Further, the off-axis image point movement error due to the constant term (-2) remains even if each aberration coefficient is "0". Therefore,
It is desirable to set each aberration coefficient so as to cancel the constant term (-2).

Fourthly, in order to reduce the deterioration of aberration at the time of decentering, it is necessary to reduce each aberration coefficient and also reduce the coefficients A, A #, H #, etc. related to the aberration coefficient. A, A #
As for, the denominator α _n '-α _m should be increased, but this is directly connected to ΔE = -2 (α _n ' -α _m ), so if it is too large, the blur correction sensitivity (how many mm the lens decenters) And how many times the light beam is bent) becomes too high, and mechanical driving accuracy is required. Regarding H #, the closer the image stabilization group is to the aperture, the smaller h # on each surface and the smaller H #.

[0064]

BEST MODE FOR CARRYING OUT THE INVENTION A zoom lens having an image stabilization function according to the present invention will be described below with reference to the drawings. FIG. 1, FIG. 5, FIG. 9, and FIG. 13 are lens configuration diagrams in a normal state (pre-eccentric state) corresponding to the first to fourth embodiments, respectively, and the lens arrangement at the wide-angle end [W]. Is shown. Also, in each lens configuration diagram, ri (i = 1,2,3, ...) is the radius of curvature of the i-th surface counted from the object side, and di (i = 1,2,3, ...).
Indicates the i-th axial upper surface distance counted from the object side.
Arrows m1, m2, m3 in FIG. 1, FIG. 5, FIG. 9, and FIG.
m4 is a first lens unit Gr1, a second lens unit Gr2, a diaphragm S and a third lens unit.
From the wide-angle end [W] of the group Gr3 and the fourth group Gr4 to the telephoto end
The zoom movements to [T] are schematically shown, and the arrow m5 in FIG. 1 schematically shows the zoom movements from the wide-angle end [W] to the telephoto end [T] of the fifth lens unit Gr5. Shows.

In the first embodiment, in order from the object side, the first group Gr1 having a positive refractive power, the second group Gr2 having a negative refractive power, and the third group Gr3 having a positive refractive power. When,
The zoom lens includes a fourth group Gr4 having a positive refractive power and a fifth group Gr5 having a negative refractive power, and performs zooming by changing the distance between the groups. In the first embodiment, the second group Gr2 is divided into a front group GrA and a rear group GrB in order from the object side, and the rear group GrB is decentered in parallel (that is, moved in the direction perpendicular to the optical axis AX). Camera shake correction is performed.

In the second to fourth embodiments, the first group Gr1 having a positive refracting power, the second group Gr2 having a negative refracting power, and the first group having a positive refracting power are arranged in this order from the object side. Group 3 Gr
3 and a fourth group Gr4 having a positive refractive power,
This is a zoom lens that performs zooming by changing the distance between each group.

In the second embodiment, the third group Gr3 is divided into the front group GrA and the rear group GrB in order from the object side, and the front group GrA is decentered in parallel to perform camera shake correction. In the third embodiment, the fourth group Gr4 is divided into a front group GrA and a rear group GrB in order from the object side, and the front group GrA is divided.
Shake correction is performed by eccentricizing.
In the fourth embodiment, the camera shake correction is performed by dividing the second lens unit Gr2 into a front lens unit GrA and a rear lens unit GrB in order from the object side and by eccentricizing the rear lens unit GrB in parallel.

Further, in the second and third embodiments, an aspherical surface (that is, a surface having a radius of curvature r16 in the second embodiment, the third surface, which is the image stabilizing side of the front group GrA, which is the camera shake correction group, is used. In the first embodiment, the front group Gr has a radius of curvature r22).
A lens adjacent to the image side of A has an aspherical surface that cancels the aspherical surface of the front lens unit GrA (that is, a surface having a radius of curvature r17 in the second embodiment, and a radius of curvature in the third embodiment. r23 surface). That is, the surfaces of the front group GrA and the rear group GrB that face each other are aspherical surfaces that cancel each other out. This makes it possible to excellently correct aberrations caused by camera shake without changing the performance during normal shooting.

In each of the embodiments, the camera shake correction group that is decentered in parallel for camera shake correction is a light weight front group GrA or rear group G that constitutes the second group Gr2 to the fourth group Gr4.
Since it is rB, the burden on the camera shake drive system is also reduced. Moreover, the power arrangement and zoom movement configuration are effective for shortening the overall length and making it compact. Furthermore, by satisfying the above-mentioned conditional expressions, it is possible to obtain high rendering performance without impairing compactness. It has become.

[0070]

EXAMPLES The structure of a zoom lens having a camera shake correction function embodying the present invention will be described more specifically below with reference to construction data, aberration performance and the like. Examples 1 to 4 given as examples here are the first to first examples described above.
These are examples corresponding to the fourth embodiment (FIGS. 1, 5, 5, 9 and 13). Then, in the construction data of each example, ri (i = 1,2,3, ...) is the radius of curvature of the i-th surface counted from the object side, di (i = 1,2,3 ,. .) Indicates the i-th shaft upper surface distance (here, the state before eccentricity is shown) counted from the object side, and Ni (i = 1,2,3, ...), νi
(i = 1,2,3, ...) Indicates the refractive index (Nd) and Abbe number (νd) of the i-th lens with respect to the d-line counting from the object side.
Also, in the construction data, the axial upper surface spacing that changes due to zooming is the actual surface spacing between each group at the wide-angle end [W] -middle (intermediate focal length state) [M] -telephoto end [T], The focal length f and the F number FNO of the entire system corresponding to each state are also shown.

In each of the examples, the surface with the radius of curvature ri marked with * indicates that it is a surface composed of an aspherical surface, and is defined by the following expression (AS) representing the surface shape of the aspherical surface. Shall be done. X = C ・ Y ² / {1+ (1-ε ・ C ²・ Y ² ) ^1/2 } + A4 ・ Y ⁴ + A6 ・ Y ⁶ + A8 ・ Y ⁸ + A10 ・
Y ¹⁰ + A12 ・ Y ¹² (AS) where X: displacement from the reference plane in the optical axis direction, Y: height in the direction perpendicular to the optical axis, C: paraxial curvature, ε: quadratic Surface parameter, A4, A6, A8, A10, A12: 4th order, 6th order, 8th order, 10th order and 12th order aspherical surface coefficient.

Further, Table 1 shows the conditional expression in each embodiment.
The corresponding values from (1) to (4) are shown.

Example 1  f = 30.6 to 64.7 to 165.1 FNO = 4.60 ~ 5.23 ~ 5.81    [Radius of curvature] [Spacing on top of axis] [Refractive index] [Abbe number] <First group Gr1 ... Positive> r1 89.595                     d1 1.530 N1 1.84666 ν1 23.82 r2 50.523                     d2 6.970 N2 1.58913 ν2 61.11 r3 885.692                     d3 0.127 r4 47.852                     d4 5.695 N3 1.51680 ν3 64.20 r5 218.621                     d5 0.467 ~ 17.796 ~ 41.243 <Second group Gr2 ... Negative>   {Front group GrA} r6 73.128                     d6 1.020 N4 1.85000 ν4 40.04 r7 14.317                     d7 4.420 r8 -404.817                     d8 2.550 N5 1.75000 ν5 25.14 r9 -31.873                     d9 1.020 N6 1.77 250 ν6 49.77 r10 36.869                     d10 1.105 r11 22.548                     d11 2.635 N7 1.76182 ν7 26.55 r12 212.813                     d12 1.530   {Rear group GrB ... Image stabilization group} r13 -45.353                     d13 1.000 N8 1.75 450 ν8 51.57 r14 38.340                     d14 1.000 N9 1.80518 ν9 25.43 r15 171.510                     d15 17.275 ~ 8.731 ~ 1.714 <Aperture S, third group Gr3 ... Positive> r16 ∞ (Aperture S)                     d16 1.062 r17 33.590                     d17 2.125 N10 1.51680 ν10 64.20 r18 145.888                     d18 0.085 r19 28.299                     d19 2.720 N11 1.51823 ν11 58.96 r20 -4683.183                     d20 0.127 r21 40.246                     d21 2.380 N12 1.51680 ν12 64.20 r22 -101.132                     d22 2.125 r23 -26.751                     d23 1.020 N13 1.84666 ν13 23.82 r24 397.583                     d24 4.505 ~ 1.969 ~ 1.360 <4th group Gr4 ... Positive> r25 43.689                     d25 2.550 N14 1.51823 ν14 58.96 r26 -52.186                     d26 0.127 r27 35.901                     d27 2.890 N15 1.51823 ν15 58.96 r28 -32.031                     d28 3.187 r29 * -70.884                     d29 0.030 N16 1.51790 ν16 52.31 r30 -58.398                     d30 1.190 N17 1.85000 ν17 40.04 r31 23.219                     d31 1.020 r32 68.181                     d32 2.550 N18 1.67339 ν18 29.25 r33 -66.682                     d33 1.700 ~ 9.782 ~ 0.628 <Fifth group Gr5 ... Negative> r34 -41.406                     d34 1.598 N19 1.67000 ν19 57.07 r35 -98.910                   Σd = 81.338 ~ 95.669 ~ 102.335

[Aspherical coefficient] r29: ε = 1.0000 A4 = -0.68521 × 10 ^-4 A6 = -0.10299 × 10 ^-6 A8 = -0.23092 × 10 ^-8 A10 = 0.11744 × 10 ^-9 A12 = -0.13601 × 10 ^-11

Example 2  f = 22.6-50.5-78.0 FNO = 4.10 ~ 5.31 ~ 5.73    [Radius of curvature] [Spacing on top of axis] [Refractive index] [Abbe number] <First group Gr1 ... Positive> r1 122.692                     d1 1.300 N1 1.83350 ν1 21.00 r2 51.521                     d2 6.550 N2 1.58913 ν2 61.11 r3 -185.231                     d3 0.100 r4 27.634                     d4 4.250 N3 1.71300 ν3 53.93 r5 57.348                     d5 1.845 ~ 12.466 ~ 19.246 <Second group Gr2 ... Negative> r6 51.452                     d6 1.100 N4 1.80420 ν4 46.50 r7 10.185                     d7 4.400 r8 -30.276                     d8 0.950 N5 1.75 450 ν5 51.57 r9 20.585                     d9 0.300 r10 16.780                     d10 3.700 N6 1.75000 ν6 25.14 r11 -38.497                     d11 0.940 r12 -14.318                     d12 1.300 N7 1.69680 ν7 56.47 r13 -47.972                     d13 9.859 ~ 4.319 ~ 2.000 <Aperture S, third group Gr3 ... Positive> r14 ∞ (Aperture S)                     d14 0.500   {Front group GrA ... Image stabilization group} r15 32.322                     d15 1.500 N8 1.62041 ν8 60.29 r16 * -24.847                     d16 0.500   {Rear group GrB} r17 * -24.847                     d17 1.310 N9 1.62041 ν9 60.29 r18 -24.706                     d18 0.110 r19 24.077                     d19 4.710 N10 1.51742 ν10 52.15 r20 -12.877                     d20 1.360 N11 1.80741 ν11 31.59 r21 133.539                     d21 5.300 ~ 1.467 ~ 1.000 <4th group Gr4 ... Positive> r22 35.194                     d22 4.820 N12 1.51823 ν12 58.96 r23 -17.079                     d23 1.470 r24 * -125.833                     d24 0.100 N13 1.51790 ν13 52.31 r25 -56.309                     d25 1.400 N14 1.80 500 ν14 40.97 r26 39.727                   Σd = 59.674 ~ 60.923 ~ 64.916

[Aspherical coefficient] r16: ε = 1.0000 A4 = 0.33000 × 10 ^-4 r17: ε = 1.0000 A4 = 0.33000 × 10 ^-4 r24: ε = 1.0000 A4 = -0.10469 × 10 ^-3 A6 = -0.34301 × 10 ^-6 A8 = -0.53437 × 10 ^-9 A10 = -0.14584 × 10 ^-10 A12 = -0.75981 × 10 ^-15

Example 3  f = 22.6 to 47.2 to 80.7 FNO = 3.57-4.38-4.63    [Radius of curvature] [Spacing on top of axis] [Refractive index] [Abbe number] <First group Gr1 ... Positive> r1 701.858                     d1 1.339 N1 1.84666 ν1 23.78 r2 50.822                     d2 6.300 N2 1.61272 ν2 58.75 r3 -142.661                     d3 0.118 r4 33.789                     d4 3.937 N3 1.83400 ν3 37.17 r5 86.386                     d5 1.696 ~ 13.804 ~ 21.178 <Second group Gr2 ... Negative> r6 39.339                     d6 1.102 N4 1.83400 ν4 37.17 r7 11.226                     d7 4.804 r8 -26.223                     d8 2.126 N5 1.78472 ν5 25.68 r9 -15.872                     d9 1.024 N6 1.77 250 ν6 49.60 r10 41.165                     d10 0.118 r11 22.587                     d11 3.071 N7 1.78472 ν7 25.68 r12 -27.632                     d12 1.102 r13 -18.584                     d13 1.024 N8 1.81554 ν8 44.36 r14 321.763                     d14 9.368 ~ 4.115 ~ 1.069 <Aperture S, third group Gr3 ... Positive> r15 ∞ (Aperture S)                     d15 1.496 r16 29.194                     d16 3.465 N9 1.61800 ν9 63.39 r17 -40.669                     d17 0.079 r18 27.739                     d18 5.591 N10 1.56873 ν10 63.16 r19 -14.928                     d19 1.181 N11 1.83400 ν11 37.17 r20 102.907                     d20 7.384 ~ 3.742 ~ 2.663 <4th group Gr4 ... Positive>   {Front group GrA ... Image stabilization group} r21 24.467                     d21 2.362 N12 1.58170 ν12 69.75 r22 * -59.882                     d22 0.354   {Rear group GrB} r23 * -59.882                     d23 1.575 N13 1.75450 ν13 51.57 r24 -27.635                     d24 2.756 r25 * -86.973                     d25 1.488 N14 1.74 500 ν14 34.96 r26 34.087                   Σd = 64.862 ~ 68.073 ~ 71.323

[Aspherical surface coefficient] r22: ε = 1.0000 A4 = 0.27748 × 10 ^-4 r23: ε = 1.0000 A4 = 0.25095 × 10 ^-4 r25: ε = 1.0000 A4 = -0.76769 × 10 ^-4 A6 = -0.21795 × 10 ^-6 A8 = 0.57736 × 10 ^-9 A10 = -0.52121 × 10 ^-11 A12 = 0.27373 × 10 ^-13

Example 4  f = 22.6-50.5-78.0 FNO = 4.10 ~ 5.45 ~ 6.20    [Radius of curvature] [Spacing on top of axis] [Refractive index] [Abbe number] <First group Gr1 ... Positive> r1 69.769                     d1 1.300 N1 1.83350 ν1 21.00 r2 45.196                     d2 6.550 N2 1.58913 ν2 61.11 r3 -397.682                     d3 0.100 r4 36.176                     d4 4.250 N3 1.71300 ν3 53.93 r5 44.734                     d5 1.845 ~ 14.591 ~ 25.237 <Second group Gr2 ... Negative>   {Front group GrA} r6 123.224                     d6 1.100 N4 1.80420 ν4 46.50 r7 11.538                     d7 4.400 r8 -72.748                     d8 0.950 N5 1.75 450 ν5 51.57 r9 26.505                     d9 0.300 r10 17.282                     d10 3.700 N6 1.75000 ν6 25.14 r11 -51.639                     d11 0.940   {Rear group GrB ... Image stabilization group} r12 -28.103                     d12 1.300 N7 1.69680 ν7 56.47 r13 64.162                     d13 10.332 ~ 3.957 ~ 2.000 <Aperture S, third group Gr3 ... Positive> r14 ∞ (Aperture S)                     d14 0.500 r15 21.611                     d15 3.310 N8 1.62041 ν8 60.29 r16 -68.274                     d16 0.110 r17 24.544                     d17 4.710 N9 1.51742 ν9 52.15 r18 -13.473                     d18 1.360 N10 1.80741 ν10 31.59 r19 80.836                     d19 5.300 ~ 2.063 ~ 1.000 <4th group Gr4 ... Positive> r20 27.647                     d20 4.820 N11 1.51823 ν11 58.96 r21 -19.138                     d21 1.470 r22 * 1610.591                     d22 0.100 N12 1.51790 ν12 52.31 r23 -292.156                     d23 1.400 N13 1.80 500 ν13 40.97 r24 42.444                   Σd = 60.147 to 63.282 to 70.907

[Aspherical surface coefficient] r22: ε = 1.0000 A4 = -0.10446 × 10 ^-3 A6 = -0.34881 × 10 ^-6 A8 = -0.56963 × 10 ^-9 A10 = -0.14711 × 10 ^-10 A12 = -0.89025 × ^10-15

[0081]

[Table 1]

2, FIG. 6, FIG. 10 and FIG. 14 are longitudinal aberration diagrams corresponding to Examples 1 to 4, respectively. In each drawing, [W] shows the aberration in the wide-angle end, [M] shows the intermediate focal length state (middle), and [T] shows the aberration in the normal state (pre-eccentric state) at the telephoto end. Further, the solid line (d) represents the aberration with respect to the d line, and the broken line (SC) represents the sine condition. Further, the broken line (DM) and the solid line (DS) represent astigmatism on the meridional surface and the sagittal surface, respectively.

FIGS. 3 and 4, FIG. 7 and FIG. 8, FIG. 11 and FIG. 12, FIG. 15 and FIG. 16 correspond to the wide-angle end [W] and the telephoto end [T] of the first to fourth embodiments. FIG. 7 is a lateral aberration diagram, showing lateral aberrations of light fluxes on the meridional surface before decentering [A] and after decentering [B] of the camera shake correction group, respectively. The aberration diagram [B] after each eccentricity shows the camera shake correction angle θ =
The aberration in the corrected state of 0.7 ° (= 0.0122173rad) is shown.

[0084]

As described above, according to the present invention, the lens group that has a camera shake correction function and moves for camera shake correction is light in weight, and the overall length is short and compact, and the drawing performance is high. A standard / standard high-power zoom lens can be realized.

[Brief description of drawings]

FIG. 1 is a lens configuration diagram of a first embodiment (Example 1).

FIG. 2 is a longitudinal aberration diagram of Example 1 before decentering.

FIG. 3 is an aberration diagram showing meridional lateral aberration before and after decentering at the wide-angle end in Example 1.

FIG. 4 is an aberration diagram showing meridional lateral aberrations before and after decentering at the telephoto end according to Example 1;

FIG. 5 is a lens configuration diagram of a second embodiment (Example 2).

FIG. 6 is a longitudinal aberration diagram of Example 2 before decentering.

FIG. 7 is an aberration diagram showing meridional lateral aberration before and after decentering at the wide-angle end in Example 2;

FIG. 8 is an aberration diagram showing meridional lateral aberration before and after decentering at the telephoto end according to Example 2;

FIG. 9 is a lens configuration diagram of a third embodiment (Example 3).

FIG. 10 is a longitudinal aberration diagram for Example 3 before decentering.

FIG. 11 is an aberration diagram showing meridional lateral aberration before and after decentering at the wide-angle end in Example 3;

FIG. 12 is an aberration diagram showing meridional lateral aberration before and after decentering at the telephoto end in Example 3;

FIG. 13 is a lens configuration diagram of a fourth embodiment (Example 4).

14 is a longitudinal aberration diagram of Example 4 before decentering. FIG.

FIG. 15 is an aberration diagram showing meridional lateral aberration before and after decentering at the wide angle end in Example 4;

FIG. 16 is an aberration diagram showing meridional lateral aberration before and after decentering at the telephoto end according to Example 4;

FIG. 17 is a diagram for explaining a factor of image deterioration of the image stabilizing optical system.

FIG. 18 is a diagram for explaining the relationship between the optical system and coordinates.

FIG. 19 is a diagram for explaining a difference in light beam passing position due to eccentricity.

FIG. 20 is a diagram for explaining rotation conversion of an object surface.

FIG. 21 is a diagram for explaining aberration coefficients of inverted and non-inverted systems.

FIG. 22 is a diagram for explaining rotation conversion.

FIG. 23 is a diagram for explaining conversion to an image plane.

[Explanation of symbols]

Gr1 ... 1st group Gr2 ... Second group Gr3 ... Third group Gr4 ... 4th group Gr5 ... Fifth group GrA ... Front group GrB ... Rear group S ... diaphragm AX ... Optical axis

─────────────────────────────────────────────────── ─── Continued Front Page (56) References JP-A-8-136863 (JP, A) JP-A-9-61753 (JP, A) JP-A-9-15502 (JP, A) JP-A-8- 146354 (JP, A) JP-A-6-289298 (JP, A) JP-A-7-199124 (JP, A) JP-A-7-325272 (JP, A) JP-A-6-265827 (JP, A) JP 7-128619 (JP, A) JP 7-92431 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) G02B 15/16

Claims (5)

(57) [Claims] 1. A first group having a positive refracting power, a second group having a negative refracting power, and a third group having a positive refracting power are arranged in order from the object side, and an interval between the respective groups. Is a zoom lens that performs zooming by changing the zoom ratio, wherein the first group moves to the object side during zooming from the wide-angle end to the telephoto end, and any one of the second and subsequent zoom groups is moved to the object side. Then, the front group and the rear group are divided into the front group and the rear group, and the image stabilization is performed by moving the front group or the rear group in the direction perpendicular to the optical axis, and the distance between the front group and the rear group is varied. To
The zoom lens with the image stabilization function, which does not change and satisfies the following conditions; 2.1 <f1 / fW <4.3 0.65 <fR / fW <1.8 , where f1 is the focal length of the first lens group. , FW: Focal length of the entire system at the wide-angle end , fR: Composite focal length of the third and subsequent zoom groups at the wide-angle end
Away . 2. An interval between each group, which includes, in order from the object side, a first group having a positive refractive power, a second group having a negative refractive power, and a third group having a positive refractive power. Is a zoom lens that performs zooming by changing the zoom ratio, wherein the first group moves to the object side during zooming from the wide-angle end to the telephoto end, and the second group moves in order from the object side to the front group and the rear group. divided into preparative performs image stabilization by moving vertically the front group or the rear group relative to the optical axis, the front group
The zoom lens having an image stabilization function, characterized in that the distance between the rear lens group and the rear group does not change during zooming, and satisfies the following conditions: 2.1 <f1 / fW <4.3 0.65 <fR / fW <1.8 However, f1: focal length of the first lens group, fW: focal length of the entire system at the wide-angle end , fR: combined focal length of the third and subsequent zoom lens units at the wide-angle end
Away . 3. An interval between each group, which includes, in order from the object side, a first group having a positive refractive power, a second group having a negative refractive power, and a third group having a positive refractive power. Is a zoom lens that performs zooming by changing the zoom ratio, wherein the first group moves toward the object side during zooming from the wide-angle end to the telephoto end, and the third group moves in order from the object side to the front group and the rear group. divided into preparative performs image stabilization by moving vertically the front group or the rear group relative to the optical axis, the front group
The zoom lens having an image stabilization function, characterized in that the distance between the rear lens group and the rear group does not change during zooming, and satisfies the following conditions: 2.1 <f1 / fW <4.3 0.65 <fR / fW <1.8 However, f1: focal length of the first lens group, fW: focal length of the entire system at the wide-angle end , fR: combined focal length of the third and subsequent zoom lens units at the wide-angle end
Away . 4. A first group having a positive refractive power, a second group having a negative refractive power, a third group having a positive refractive power, and a third group having a positive refractive power in order from the object side. Including 4 groups,
A zoom lens that performs zooming by changing the distance between each group, wherein the first group moves toward the object side during zooming from the wide-angle end to the telephoto end, and the fourth group moves in order from the object side. divided into a group and the rear group performs image stabilization by moving vertically the front group or the rear group relative to the optical axis, the front group
The zoom lens having an image stabilization function, characterized in that the distance between the rear lens group and the rear group does not change during zooming, and satisfies the following conditions: 2.1 <f1 / fW <4.3 0.65 <fR / fW <1.8 However, f1: focal length of the first lens group, fW: focal length of the entire system at the wide-angle end , fR: combined focal length of the third and subsequent zoom lens units at the wide-angle end
Away . 5. The front group or the rear group is referred to as an image stabilization group.
However, the camera shake correction group or the zoom having the camera shake correction group
It is characterized by performing focusing on a close object in a group
The image stabilization function according to any one of claims 1 to 4.
Zoom lens with.