JPH0990225A - Zoom lens with hand shake correcting function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To suppress an eccentric aberration such as partial defocusing and an off-axis image point movement error while maintaining compactness and to make possible hand shake correction which hold high optical performance over the entire zoom area while holding the compactness by using the whole 2nd group as one zoom group for the hand shake correction and satisfying specific a conditional formula. SOLUTION: The zoom lens which includes a 1st group Gr1 with positive refracting power, the 2nd group Gr2 with positive refracting power, and a 3rd group Gr3 with negative refracting power corrects a hand shake by making the whole 2nd group Gr2 eccentric in parallel. Then the inequality 0.15<ϕ1 /ϕ2 <0.35 is satisfied. Here, ϕ1 is the refracting power of the 1st group Gr1 and ϕ2 is the refracting part of the 2nd group Gr2. When this conditional inequality is satisfied, the astigmatism of the 1st group Gr1 and the astigmatism of the 2nd group Gr2 cancel each other, so the partial defocusing can be suppressed.

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 particularly, to a lens 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 having a camera shake correction function suitable for a shutter camera.

[0002]

2. Description of the Related Art Hitherto, most of the causes of failure in photography have been camera shake and out of focus. However, in recent years, most cameras have adopted an autofocus mechanism, and as the focus accuracy of the autofocus mechanism has improved, the failure of photography due to out-of-focus has been almost eliminated. On the other hand, the lens that comes standard with the camera is
We are moving from single focus lenses to zoom lenses,
At the same time, high magnification and telephoto have been achieved, and the possibility of camera shake is extremely high. As a result, at present, it is no exaggeration to say that the cause of failure in photography is due to camera shake, and for this reason, the camera shake correction function is becoming indispensable for zoom lenses.

As a zoom lens having a camera shake correction function, there has been proposed one which performs camera shake correction by decentering a part of the lenses (Japanese Patent Laid-Open No. 1-116619, 2-10).
3014, 2-93620, 4-362909, 4-212916, 6-9
5039, 6-265827, etc.).

[0004]

A zoom lens having a camera shake correction function has good optical performance in a standard state (hereinafter, also referred to as "pre-eccentricity state"), as well as a corrected state.
Even in (hereinafter, also referred to as “post-eccentricity state”), it is necessary to suppress the occurrence of aberration (hereinafter referred to as “eccentric aberration”) due to decentering of the lens and maintain the optical performance. However, in the above-mentioned conventional example, it is difficult to obtain sufficiently satisfactory optical performance in the entire zoom range because the optical performance is largely deteriorated due to decentering. Moreover, since the number of lenses is large, it is difficult to achieve a high zoom ratio and compact size.

The present invention has been made in view of these points, and an object thereof is a high zoom ratio and compact zoom lens, which is capable of image stabilization while maintaining high optical performance in the entire zoom range. It is to provide a zoom lens having a correction function.

[0006]

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 positive refractive power in order from the object side. In a zoom lens including a second lens unit having a negative refractive power and a third lens unit having a negative refractive power, camera shake correction is performed by decentering the entire second lens unit in parallel, and the following conditional expression (1) is satisfied. It is characterized by 0.15 <φ ₁ / φ ₂ <0.35 (1) where φ _{1 is} the refracting power of the first group φ ₂ is the refracting power of the second group.

The parallel eccentricity means to move a part of the optical system in a direction perpendicular (or almost perpendicular) to the optical axis. In the present invention, the entire second group (that is, all the lenses of the second group), which is one of the zoom groups, is used as an optical system (hereinafter referred to as a “correction lens group”) for performing parallel decentering for camera shake correction. I am using. Normally, the zoom groups are corrected for aberrations within each group, and therefore, according to this configuration, there is a conventional example (for example, JP-A-2-03014, JP-A-2-93620, JP-A-4-362909, and JP-A-6-95039).
No. 6-265827), it is possible to satisfactorily correct not only the aberration in the standard state but also the eccentric aberration. In contrast,
If camera shake correction is performed by decentering some of the lenses that make up the zoom group, then that part of the lenses must also correct aberrations, and the entire zoom group must also correct aberrations. And the total length becomes large.

Generally, decentration aberration is expressed as an aberration in which the aberration of the correction lens group and the aberration of the group before the correction lens group are combined (this will be described later). Therefore, when the second lens group is used as the correction lens group as in the present invention, the aberrations of the first lens group and the second lens group affect decentering aberrations. For example, one-sided blur, which is one of the eccentric aberrations, is mainly determined by the astigmatism of the first and second groups, and the off-axis image point movement error, which is one of the eccentric aberrations, is mainly It is determined by the distortion aberration of the second group and the second group.

If the conditional expression (1) is satisfied, the first group and the second group
Since the astigmatisms cancel each other out with the group, the occurrence of one-sided blur is suppressed. Further, the distortion aberrations of the first and second groups are corrected by the values of opposite signs to correct the distortion aberrations in the pre-eccentric state. However, if the conditional expression (1) is satisfied, the distortions of the opposite signs will be corrected. Since the aberration has an advantageous effect on the off-axis image point movement error at the time of camera shake correction, the occurrence of the off-axis image point movement error can be suppressed.

If the upper limit of conditional expression (1) is exceeded, the ratio of the refractive power of the first lens group to the second lens group becomes large. For this reason, the amount of aberration burden on the first group increases, and as a result, it becomes difficult to suppress the occurrence of one-sided blur that was canceled by the first group and the second group. On the other hand, if the lower limit of conditional expression (1) is exceeded, the ratio of the refractive power of the first lens group to the second lens group becomes small. for that reason,
The amount of distortion aberration generated in the first lens unit also decreases, and as a result, it becomes difficult to suppress the off-axis image point movement error at the wide-angle end.

A zoom lens having a camera shake correction function of the second invention is characterized in that, in the constitution of the first invention, the following conditional expression (2) is further satisfied. 0.2 <φ ₁ / φ ₂ <0.3 (2)

The axial coma aberration, which is one of the decentering aberrations, is mainly determined by the coma aberrations of the first and second groups. If the conditional expression (2) is satisfied, the amount of coma aberration generated in the first group can be appropriately maintained, so that the axial coma aberration at the telephoto end can be suppressed to be small.

According to a third aspect of the present invention, there is provided a zoom lens having an image stabilization function, wherein in the configuration of the first aspect, the second group includes a positive lens and a negative lens, and the following conditional expression (3), It is characterized by satisfying (4). νd (N) <30.0 …… (3) νd (P)> 55.0 …… (4) where νd (N): Abbe's number of the negative lens in the second group νd (P): Positive in the second group This is the Abbe number of the lens.

If the correction lens group is not color-corrected, axial lateral chromatic aberration, which is one of decentering aberrations, occurs. If the second lens group includes the positive and negative lenses that satisfy the above conditional expressions (3) and (4), color correction of the second lens group can be performed, and axial lateral chromatic aberration can be corrected well. it can.

Next, the definition of aberration deterioration of an optical system having a camera shake correction function (hereinafter referred to as "camera shake correction optical system") like the zoom lens according to the first to third inventions is defined as follows.
This will be described with reference to FIG. Eccentric aberration shown in the figure (off-axis image point movement error, one-sided blur, axial coma and axial lateral chromatic aberration)
Causes image deterioration of the image stabilization optical system.

[Off-axis image point movement error] {FIG. 25 (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. 25 (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 standard state (pre-eccentric state), and 4 represents a camera shake correction direction.

Here, the optical axis is the x-axis direction and 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 ') (Because the image point on the axis is completely corrected, , Always Y (0,0, θ) = 0. }, The following expression (a) is established. ΔY (y ', z', θ) ＝ Y (y ', z', θ) -Y (y ', z', 0) …… (a)

[0018] 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). 0.7field is about 1 for 35mm film
It is 5 mm. 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. 25 (B)} In FIG. 25 (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. 25 (C)} In FIG. 25 (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 (Upprer Zornal, θ = 0.7 °) + Y (Lower Zornal, θ = 0.7 °)} / 2 …… (f)

[Axial Lateral Chromatic Aberration] {FIG. 25 (D)} Since the image point shifts due to the difference in wavelength, when the optical system is asymmetric, the 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 paper "Third-order aberration theory of an optical system having eccentricity" (June 1990)
JOEM) shows its 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] Based on FIG. 26 showing the relationship between the optical system and the coordinates, the method of obtaining the eccentric aberration coefficient will be described below. 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 displacement 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 also appears on the axis, 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 Matsui's paper, 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. In contrast,
As shown in FIG. 27 (B), (M ₁ : light beam before image stabilization,
M _2: light beam after camera shake compensation), image stabilization in the optical system in the (ideally), the passing position of the light beam on the object side of the decentering lens LS would change and after camera shake compensation before and 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 of the above-mentioned article by 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. 28. Therefore, the off-axis image point movement error and the one-sided blur greatly differ from those when there is no rotation. In FIG. 28,
OS ₁ represents the object surface before image stabilization, and OS ₂ represents the object surface after image stabilization.

[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 equations (2A) to (2
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 Shake Aberration Coefficient When the Correction Lens Group is Decentered in Parallel] The above equations (1A) to (1H) show the case where only one surface ν is decentered. Therefore, equations (1A) to (1H) are further transformed into equations when a plurality of surfaces i to j are eccentric. When the correction lens group is decentered in parallel, the decentering 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 disappears similarly. 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 correction lens group (Petzval sum) (μ = i → j) ΣPμ: sum of P of the correction lens group. (PE) i to j = (αj'-αi) P _R -αi · P _D where () _{R is} the sum of aberration coefficients after the correction lens group () _D is the sum of aberration coefficients of the correction lens group .

As described above, the following equations (3A) to (3F) are obtained by converting the image point movement amount into one on the object plane and transforming into an 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. 30 (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 equation: 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・ Cosφω 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.

When converting on the image plane and setting N _k '= 1 and N = 1, 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), formula: ΔY _Upper = Fl × θ × R ² × (3 ・ IIE / ΔE) = ΔY _Lower , and the on-axis coma AXCM is It is represented by the 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) Marginal 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 expressions (3A) to (3F) into the expressions (9A) to (9E) representing the camera shake aberration coefficient, the following expressions (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 correction lens group () _R : Sum of aberration coefficient after the correction lens group (object side) A = Αi / (αj'-αi) (Here, the correction lens 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. }, Since it is a coefficient of (camera shake correction angle) / (lens eccentricity amount), aim at an almost predetermined value (however, the sign differs depending on whether the correction lens group is positive or negative).
Therefore, A is the angle of incidence of the marginal ray on the correction lens group (viewed from the image side), and A # is proportional to the angle of incidence of the chief ray. If h # or h does not change much in the correction lens group, H
# Represents the ratio between the chief ray h # and the marginal ray h.

Since the decentering aberration coefficients in the above equations (10A) to (10E) are defined in the inversion system, they must be returned to the non-inversion 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 correction lens group and non-inverting system () _F : Sum of aberration coefficients before correction lens group A = -αn '/ (αn'-αm) A # ＝ αn'# / (αn'-αm) H ＝-(αn '#-αm #) / (αn'-αm) ＝-(Σhμ # ・ φμ) / ( Σhμ
・ Φμ) ΔE = -2 (αn'-αm) (correction lens group m → n, inversion j ← i).

From the above equations (11A) to (11E), the following can be understood. First, as described above, in the method of the above-mentioned article by Matsui, the correction lens group (that is, the decentering lens LS) and the optical system after that are related to the optical performance, but the equations (11A) to (11E) are used. In (), the correction lens group and the optical system before that are related to the optical performance. Second, the off-axis image point movement error tends to increase in a wide-angle system (the focal length Fl of the correction lens group is a denominator), and one-sided blur and axial coma tend to increase in a telephoto system.

Third, if the aberration coefficients of the correction lens group and the groups before it are made small, the aberration deterioration at the time of decentering becomes small, 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 upon 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 correction lens group is to the diaphragm, the smaller h # on each surface and the smaller H #.

[0052]

DETAILED DESCRIPTION OF THE INVENTION A zoom lens embodying the above-described first to third inventions will be described below with reference to the drawings.
1, FIG. 5, FIG. 9, FIG. 13, FIG. 17, and FIG.
It is a lens block diagram respectively corresponding to 6th Embodiment. Each lens configuration diagram shows the lens arrangement at the wide-angle end [W], and arrows m1, m2A, m2, and m3 in the diagram indicate the first group Gr1, the second group Gr2, the diaphragm A, and the second group Gr2. ，
The movements of the third lens unit Gr3 from the wide-angle end (W) to the telephoto end (T) are schematically shown.

In the first embodiment, in order from the object side, the first group Gr1 composed of a negative meniscus lens concave to the object side and a biconvex positive lens, and a negative meniscus lens concave to the image side {ν
d (N) = 23.66} and a positive meniscus lens convex on the image side {ν
It is composed of a second group Gr2 composed of d (P) = 70.44}, an aperture stop A, and a third group Gr3 composed of a positive meniscus lens convex to the image side and a biconcave negative lens. The second group G
Both surfaces of the negative meniscus lens in r2 and the third group Gr2
Both sides of the positive meniscus lens in are aspherical surfaces.

In the second embodiment, in order from the object side, a first group Gr1 including a negative meniscus lens concave to the image side and a positive meniscus lens convex to the object side, a biconcave negative lens and a biconvex positive lens. Lens and negative meniscus lens concave on image side
{νd (N) = 21.00} and biconvex positive lens {νd (P) = 69.07}
And a diaphragm A, and a third group Gr3 including a positive meniscus lens having a convex surface on the image side and a negative meniscus lens having a concave surface on the object side. Both surfaces of the biconcave lens in the second group Gr2, the image side surface of the cemented lens in the second group Gr2, and both surfaces of the positive meniscus lens in the third group Gr2 are aspherical surfaces.

In the third embodiment, in order from the object side, a first group Gr1 including a negative meniscus lens concave to the image side and a positive meniscus lens convex to the object side, and a biconcave negative lens and convex to the object side. Positive meniscus lens, negative meniscus lens concave on the image side {νd (N) = 21.00} and biconvex positive lens {ν
The second lens unit Gr2 composed of a cemented lens with d (P) = 69.07}
And a diaphragm A, and a third group Gr3 including a positive meniscus lens having a convex surface on the image side and a negative meniscus lens having a concave surface on the object side. Incidentally, both surfaces of the biconcave lens in the second group Gr2, the image side surface of the cemented lens in the second group, and the third
Both surfaces of the positive meniscus lens in the group Gr2 are aspherical surfaces.

In the fourth and fifth embodiments, in order from the object side, the first group Gr1 is composed of a negative meniscus lens concave on the image side and a positive meniscus lens convex on the object side,
Biconcave negative lens, biconvex positive lens, negative meniscus lens concave on the image side {νd (N) = 21.00} and biconvex positive lens
The second group Gr consisting of a cemented lens with {νd (P) = 69.07}
2, a diaphragm A, and a third group Gr3 including a positive meniscus lens having a convex surface on the image side and a biconcave negative lens. Both surfaces of the biconcave lens in the second group Gr2, the image side surface of the cemented lens in the second group Gr2, and both surfaces of the positive meniscus lens in the third group Gr2 are aspherical surfaces.

In the sixth embodiment, in order from the object side, the first group Gr1 including a negative meniscus lens concave to the object side and a biconvex positive lens, and a negative meniscus lens concave to the image side {ν
d (N) = 23.66}, a second group Gr2 consisting of an aperture A and a positive meniscus lens {νd (P) = 70.44} convex to the image side, and a positive meniscus lens convex to the image side and a biconcave negative lens. And the third group Gr3. The second group Gr
Both surfaces of the negative meniscus lens in 2 and both surfaces of the positive meniscus lens in the third group Gr2 are aspherical surfaces.

Each of the first to sixth embodiments is a positive / positive / negative three-group zoom lens, and camera shake correction is performed by decentering the entire second group Gr2 in parallel. In this way, the second group Gr2 whose aberration is corrected as the zoom group
It is very advantageous to correct the decentering aberration as described above by using as a correction lens group.

In the first to sixth embodiments, the first group G
The refractive power ratio φ ₁ / φ ₂ between r1 and the second lens unit Gr2 is defined by the conditional expression
Since (1) and (2) are satisfied, one-sided blur, off-axis image point movement error, and axial coma aberration can be corrected well. Further, since the second lens unit Gr2 includes the positive lens and the negative lens that satisfy the conditional expressions (3) and (4), it is possible to excellently correct the axial lateral chromatic aberration.

By the way, in the positive / negative two-group zoom lens which moves so that the group spacing widens during zooming to the telephoto side, when the first lens group is a correction lens group, lateral chromatic aberrations occur at wide angle and at telephoto. The magnitudes of the lateral chromatic aberrations are greatly different from each other, and the axial lateral chromatic aberration due to decentering is added to this when the camera shake is corrected, so that the total lateral chromatic aberration becomes unacceptably large. On the other hand, in the first to sixth embodiments,
The first positive lens group G that moves so as to widen the group distance during zooming to the telephoto side before the correction lens group (second lens group Gr2)
Since r1 is arranged, lateral chromatic aberration can be corrected well.

Further, by making the refracting power of the first lens unit Gr1 positive, a conventional example (for example, Japanese Patent Laid-Open Nos. 1-116619 and 4-2129).
Compared with No. 16), it is possible to satisfactorily correct distortion and suppress the off-axis image point movement error to a small value. In contrast, the first
When the refractive power of the group Gr1 is negative, a large negative negative distortion is generated in the first group Gr1, and the off-axis image point movement error becomes positively large.

In the first to fifth embodiments, the second lens group Gr2, which is a correction lens group, has a negative / positive configuration.
Since the diaphragm A is disposed on the image side, the second lens unit Gr
By 2, the distortion becomes negative (aberration coefficient V is positive). Since the off-axis image point movement error due to this is positive, it is possible to more effectively eliminate the negative off-axis image point movement error, which is always caused by rotational blur, than in the conventional example (for example, Japanese Patent Laid-Open No. 1-116619). .

The negative front lens group which constitutes the second lens unit Gr2 produces negative distortion and large positive spherical aberration (aberration coefficient I is negative), and camera shake on the telephoto side. This will cause an axial coma during correction. However, since the surface of the second lens unit Gr2 closest to the diaphragm A generates spherical aberration in the negative direction without generating distortion, the spherical aberration in the correction lens unit is reduced, and at the time of image stabilization on the telephoto side. The axial coma of can be reduced. This is because the surface of the second lens unit Gr2 closest to the diaphragm A is a convex surface toward the image side, and when the surface of the second lens unit Gr2 closest to the diaphragm A is convex toward the image side, this surface is a diaphragm. This is because it will be located near A.

[0064]

EXAMPLES Hereinafter, the structure of the zoom lens having the image stabilization function according to the first to third aspects of the present invention will be described more specifically with reference to construction data, aberration performance and the like. Examples 1 to 6 given here as examples are
It is an example corresponding to each of the above-described first to sixth embodiments (FIGS. 1, 5, 5, 9, 13, 17 and 21). 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, and di (i = 1,2,3, ...) is the i-th surface counted from the object side. Shows the axial upper surface spacing (here, the state before eccentricity is shown), where Ni (i = 1,2,3, ...) and νi (i = 1,2,3, ...) are the objects. The refractive index (Nd) and Abbe number (νd) for the d-line of the i-th lens counted from the side are shown. Further, the focal length f and the F number FNo of the entire system from the wide-angle end [W] to the intermediate focal length state [M] to the telephoto end [T] are also shown. In each example, the radius of curvature ri
A surface marked with * indicates that the surface is composed of an aspherical surface, and is defined by the following formula 1 representing the surface shape of the aspherical surface.

[0065]

[Equation 1]

[Mathematical formula-see original document] In the equation 1, 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: quadric surface parameter Ai: i It is an aspherical coefficient.

Example 1 f = 30.8 to 60.0 to 117.0 FNo = 3.62 to 6.00 to 10.20 [radius of curvature] [axis upper surface spacing] [refractive index] [Abbe number] r1 -22.717 d1 3.300 N1 1.83400 ν1 37.34 r2- 37.666 d2 0.100 r3 89.680 d3 4.500 N2 1.48749 ν2 70.44 r4 -30.724 d4 2.089 to 17.459 to 28.627 r5 * 14.090 d5 1.750 N3 1.84506 ν3 23.66 r6 * 12.141 d6 1.950 r7 -65.411 d8 6.650 N4 1.48749 ν4 70.44 r8 (Aperture) d9 14.110 ~ 6.949 ~ 2.330 r10 * -37.504 d10 3.790 N5 1.58340 ν5 30.23 r11 * -15.804 d11 1.640 r12 -10.949 d12 0.800 N6 1.80420 ν6 46.50 r13 1168.811 Σd = 41.679 ~ 49.888 ~ 56.437

[0068]

Example 2 f = 30.5 to 59.9 to 117.3 FNo = 3.55 to 5.70 to 9.51 [curvature radius] [axis upper surface spacing] [refractive index] [Abbe number] r1 25.212 d1 1.257 N1 1.84666 ν1 23.82 r2 19.707 d2 0.550 r3 19.140 d3 3.614 N2 1.51680 ν2 64.20 r4 63.742 d4 3.141 ~ 17.316 ~ 26.985 r5 * -23.452 d5 1.021 N3 1.76683 ν3 49.47 r6 * 17.387 d6 1.571 r7 19.156 d7 2.082 N4 1.83350 ν4 21.00 r8 -127.503 d8 1.532 1.83350 ν5 21.00 r10 9.685 d10 0.008 r11 9.685 d11 3.850 N6 1.51178 ν6 69.07 r12 * -12.135 d12 0.864 r13 ∞ (diaphragm) d13 16.897 ~ 8.075 ~ 2.300 r14 * -31.921 d14 2.907 N7 1.84506 ν7 23.66 r15 * -19.779 -d15 2.435 11.582 d16 0.943 N8 1.75450 ν8 51.57 r17 -222.772 Σd = 44.007 to 49.361 to 53.255

[0070]

Example 3 f = 30.5 to 59.8 to 117.1 FNo = 3.80 to 5.97 to 9.66 [radius of curvature] [axis upper surface spacing] [refractive index] [Abbe number] r1 28.011 d1 1.257 N1 1.84666 ν1 23.82 r2 22.944 d2 0.550 r3 23.538 d3 3.614 N2 1.51680 ν2 64.20 r4 59.650 d4 3.141 ~ 26.220 ~ 42.357 r5 * -26.374 d5 1.021 N3 1.76683 ν3 49.47 r6 * 13.055 d6 1.571 r7 15.871 d7 2.082 N8 1.83350 ν4 21.00 r8 284.961 d8 ν5 21.00 r10 8.545 d10 0.008 r11 8.545 d11 3.850 N6 1.51178 ν6 69.07 r12 * -11.786 d12 0.864 r13 ∞ (diaphragm) d13 19.066 ~ 9.061 ~ 2.300 r14 * -36.635 d14 2.907 N7 1.75520 ν7 27.51 r15 * -18.055 d15 2.435 r16 d16 0.943 N8 1.77250 ν8 49.77 r17 -101.766 Σd = 46.176 to 59.251 to 68.626

[0072]

Example 4 f = 30.5 to 79.8 to 146.5 FNo = 3.70 to 6.53 to 10.41 [curvature radius] [axial upper surface spacing] [refractive index] [Abbe number] r1 22.624 d1 1.257 N1 1.84666 ν1 23.82 r2 18.445 d2 0.550 r3 19.004 d3 3.614 N2 1.51680 ν2 64.20 r4 56.594 d4 3.141 ~ 27.977 ~ 34.796 r5 * -21.530 d5 1.021 N3 1.76683 ν3 49.47 r6 * 15.336 d6 1.571 r7 20.341 d7 2.082 N4 1.83350 ν4 21.00 r8 -136.741 d8 1.53350 1.83350 ν5 21.00 r10 9.390 d10 0.008 r11 9.390 d11 3.850 N6 1.51178 ν6 69.07 r12 * -11.578 d12 0.864 r13 ∞ (diaphragm) d13 17.629 ~ 6.811 ~ 2.300 r14 * -32.645 d14 2.907 N7 1.84506 ν7 23.66 r15 * -20.094 d15 2.435 r 11.915 d16 0.943 N8 1.75450 ν8 51.57 r17 514.713 Σd = 44.740 to 58.757 to 61.065

[0074]

Example 5 f = 30.5 to 79.7 to 146.5 FNo = 3.80 to 7.30 to 9.72 [curvature radius] [axis upper surface spacing] [refractive index] [Abbe number] r1 26.352 d1 1.257 N1 1.84666 v1 23.82 r2 21.759 d2 0.550 r3 23.022 d3 3.614 N2 1.51680 ν2 64.20 r4 78.180 d4 3.141 to 26.120 to 43.662 r5 * -18.203 d5 1.021 N3 1.76683 ν3 49.47 r6 * 14.738 d6 1.571 r7 27.055 d7 2.082 N5 1.88350 ν4 21.00 r8 -58.168 d8 1.83350 ν5 21.00 r10 9.558 d10 0.008 r11 9.558 d11 3.850 N6 1.51178 ν6 69.07 r12 * -11.143 d12 0.864 r13 ∞ (aperture) d13 19.024 ~ 7.420 ~ 2.300 r14 * -65.675 d14 2.907 N7 1.58340 ν7 30.23 r15 * -21.703 d15 2.435 12.366 d16 0.943 N8 1.69680 ν8 56.47 r17 105.660 Σd = 46.134 to 57.509 to 69.932

[0076]

Example 6 f = 30.8 to 59.1 to 116.8 FNo = 3.62 to 5.80 to 9.77 [curvature radius] [axis upper surface spacing] [refractive index] [Abbe number] r1 -38.866 d1 3.300 N1 1.83400 ν1 37.34 r2- 60.281 d2 0.100 r3 93.663 d3 4.500 N2 1.48749 ν2 70.44 r4 -53.568 d4 2.089 ~ 23.137 ~ 38.894 r5 * 13.709 d5 1.800 N3 1.84506 ν3 23.66 r6 * 10.600 d6 1.500 r7 ∞ (diaphragm) d7 1.500 r8 -690.355.44 d4 6.650 N4 r9 -10.284 d9 15.028 ~ 7.525 ~ 2.330 r10 * -52.093 d10 3.790 N5 1.58340 ν5 30.23 r11 * -15.537 d11 1.640 r12 -10.769 d12 0.800 N6 1.80420 ν6 46.50 r13 2240.243 Σd = 42.697 ~ 56.242 ~ 66.804

[0078]

Table 1 shows the refractive powers and the refractive power ratios of the respective groups in Examples 1 to 6.

[0080]

[Table 1]

2, FIG. 6, FIG. 10, FIG. 14, FIG. 18, and FIG. 22 are longitudinal aberration diagrams corresponding to Examples 1 to 6, respectively. In each drawing, [W] indicates the aberration in the wide-angle end, [M] indicates the intermediate focal length state (middle), and [T] indicates the aberration in the standard 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, FIG. 19 and FIG.
And 24 are lateral aberration diagrams corresponding to the wide-angle end [W] and the telephoto end [T] of Examples 1 to 6, respectively, and the second group Gr.
2 shows lateral aberrations of the light fluxes on the meridional surface before the decentering [A] and after the decentering [B]. Aberration diagram after each eccentricity [B]
Is the camera shake correction angle of the second lens unit Gr2 θ = 0.7 deg (= 0.012217)
Aberrations in the corrected state (3 rad) are shown.

Although the above-mentioned Examples 1 to 6 are high-zoom zoom lenses of 4 to 5 times, as can be seen from the respective aberration diagrams, the second group Gr2 is decentered for camera shake correction. However, the aberration deterioration in the entire zoom range [W] to [T] is small. That is, the high aberration performance in the standard state is maintained even in the corrected state. Moreover, since compactness is maintained, the above-described first to sixth embodiments are optimal as, for example, zoom lenses for lens shutter cameras.

[0084]

As described above, according to the first to third inventions, the entire second lens unit, which is one of the zoom lens units, is used for camera shake correction, and the conditional expression (1) is satisfied. Therefore, it is possible to suppress the occurrence of decentering aberrations such as one-sided blur and off-axis image point movement error while maintaining compactness. Therefore, even with a high-magnification zoom lens of 4 times or more, it is possible to perform image stabilization while maintaining compactness and high optical performance over the entire zoom range.

According to the second aspect of the invention, since the conditional expression (2) is satisfied, the axial coma aberration can be satisfactorily corrected. According to the third invention, the conditional expression
Since (3) and (4) are satisfied, it is possible to excellently correct the axial lateral chromatic aberration. Therefore, in either case, it is possible to carry out camera shake correction while maintaining higher optical performance.

[Brief description of drawings]

FIG. 1 is a lens configuration diagram of a first embodiment and a first example.

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 and a second example.

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 and a third example.

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 and a fourth example.

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 lens configuration diagram of a fifth embodiment and an example 5.

FIG. 18 is a longitudinal aberration diagram for Example 5 before decentering.

FIG. 19 is an aberration diagram showing meridional lateral aberration before and after decentering at the wide angle end in Example 5;

FIG. 20 is an aberration diagram showing meridional lateral aberration before and after decentering at the telephoto end in Example 5;

FIG. 21 is a lens configuration diagram of a sixth embodiment and a sixth example.

FIG. 22 is a longitudinal aberration diagram for Example 6 before decentering.

FIG. 23 is an aberration diagram showing meridional lateral aberration before and after decentering at the wide angle end in Example 6;

FIG. 24 is an aberration diagram showing meridional lateral aberration before and after decentering at the telephoto end in Example 6;

FIG. 25 is a diagram for explaining a factor of image deterioration of the image stabilizing optical system.

FIG. 26 is a diagram for explaining the relationship between the optical system and coordinates.

FIG. 27 is a diagram for explaining a difference in light beam passage position due to eccentricity.

FIG. 28 is a diagram for explaining rotation conversion of an object surface.

FIG. 29 is a diagram for explaining aberration coefficients of an inverting system and a non-inverting system.

FIG. 30 is a diagram for explaining rotation conversion.

FIG. 31 is a diagram for explaining conversion to an image plane.

[Explanation of symbols]

 Gr1 ... 1st group Gr2 ... 2nd group Gr3 ... 3rd group A ... Aperture

Claims (3)

[Claims] 1. A first lens having a positive refractive power in order from the object side.
In a zoom lens including a group, a second group having a positive refracting power, and a third group having a negative refracting power, camera shake correction is performed by decentering the entire second group in parallel, and further satisfying the following conditions. 0.15 <φ ₁ / φ ₂ <0.35, where φ _{1 is} the refracting power of the first lens group φ ₂ is the refracting power of the second lens group. 2. The zoom lens having a camera shake correction function according to claim 1, further satisfying the following condition. 0.2 <φ ₁ / φ ₂ <0.3 3. The zoom lens having a camera shake correction function according to claim 1, wherein the second group includes a positive lens and a negative lens, and further satisfies the following condition: νd (N) <30.0 νd (P)> 55.0 where νd (N) is the Abbe number of the negative lens in the second group νd (P) is the Abbe number of the positive lens in the second group.