JPH09230239A - Zoom lens provided with camera shake correcting function - Google Patents

Abstract

PROBLEM TO BE SOLVED: To excellently correct aberration both in a normal state and in a correcting state and to make entire length short so that the lens may be compact by constituting the lens to satisfy specified conditional expressions. SOLUTION: This zoom lens is constituted of a 1st group Gr1 having positive refractive power, a 2nd group Gr2 and a 3rd group Gr3 having negative refractive power, a 4th group Gr4 having the positive refractive power, and a 5th group Gr5 having the negative refractive power in order from an object side; and zooming is performed by changing an interval between the respective groups. Camera shake is corrected by decentering the 2nd group Gr2 in parallel (that means, by moving it in the direction perpendicular to an optical axis AX). In such a case, the following conditional expressions are satisfied: 0.2<|fL/fW|<0.4, 0.2<|f2/fW|<4.0. In the expressions, fL represents the focal distance of the final group, fW the focal distance of an entire optical system at a wide angle end, and f2 the focal distance of the 2nd group Gr2.

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 telephoto zoom lens for a reflex camera.

[0002]

2. Description of the Related Art Hitherto, most of the causes of failure in photographing have been camera shake and out of focus. However, in recent years,
As most cameras have adopted an autofocus mechanism and the focus accuracy of the autofocus mechanism has improved, the failure to take a photograph due to out-of-focus has been almost eliminated. On the other hand, the lens standardly equipped in the camera is shifting from a single focus lens to a zoom lens, and along with it, higher magnification and telephoto are achieved, and the possibility of camera shake is extremely high. As a result, it is no exaggeration to say that the failure to take a photograph is due to camera shake, and for this reason, a camera shake correction function has become indispensable in the taking optical system.

Various zoom lenses having a camera shake correction function have been conventionally known. For example, in Japanese Patent Laid-Open No. 6-337375, the entire second group is moved in the direction perpendicular to the optical axis in a positive / negative / negative / positive / negative or positive / negative / positive / positive / negative five-group configuration. Therefore, a telephoto zoom lens has been proposed that compensates for camera shake. In JP-A-5-232410,
There has been proposed a telephoto zoom lens which has a positive, negative, positive, and positive four-group configuration and which performs camera shake correction by moving the entire second group in the direction perpendicular to the optical axis. In addition, the commercially available zoom lens with a shake correction function has a positive, negative, positive, negative, positive, and negative six-group configuration, and by moving the entire second group in the direction perpendicular to the optical axis Are known to do.

[0004]

However, the above-described conventional zoom lens having a camera shake correction function has a problem that the total length at the wide-angle end and the total length at the telephoto end are too large. Even with a zoom lens having a camera shake correction function, if it is too large compared to a lens without a camera shake correction function, it is very disadvantageous in terms of portability and handleability, which is not preferable. Further, a zoom lens having a camera shake correction function has good optical performance in a normal state (hereinafter also referred to as “pre-eccentric state”), and also in a correction state (hereinafter also referred to as “post-eccentric state”). It is necessary to suppress the occurrence of aberration due to decentering of the lens (hereinafter referred to as “decentering aberration”) and maintain good optical performance.

The present invention has been made in view of these points, and an object thereof is to have various functions in both a normal state and a corrected state, in which various aberrations are satisfactorily corrected, and a short length and a compact camera shake correction function are provided. It is to provide a zoom lens.

[0006]

In order to achieve the above object, a zoom lens having an image stabilization function of the first invention has 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 and a final lens unit having a negative refractive power closest to the image side, and performs zooming by changing the interval between the lens units. When the magnification is doubled, the first group and the last group move to the object side, and the second group is moved in the direction perpendicular to the optical axis to perform camera shake correction, and the following conditions are satisfied. . 0.2 <| fL / fW | <0.4 (1) 0.2 <| f2 / fW | <4.0 (2) However, fL: focal length of the final lens group, fW: focal length of the entire system at the wide-angle end, f2: It is the focal length of the second lens group.

The zoom lens having the camera shake correction function of the second invention is the first lens having positive refractive power in order from the object side.
From a group, a second group having a negative refractive power, a third group having a positive or negative refractive power, a fourth group having a positive refractive power, and a fifth group having a negative refractive power A zoom lens having a five-group configuration, in which zooming is performed by changing the distance between the respective groups, wherein the zoom lens is the first lens when zooming from the wide-angle end to the telephoto end.
Group and the fifth group move to the object side, and camera shake correction is performed by moving the second group in the direction perpendicular to the optical axis, and the following conditional expressions (1a) and (2) are given. Characterized by satisfaction. 0.2 <| f5 / fW | <0.4 (1a) where f5 is the focal length of the fifth lens unit.

The first and second inventions each include, in order from the object side, a first group having a positive refracting power and a second group having a negative refracting power, and the negative refracting power is closest to the image side. With the final group to have. In such a type of zoom lens, the degree of freedom of movement of the zoom group can be effectively used for aberration correction, so that good imaging performance can be obtained over the entire zoom range.

Further, since the first lens group and the last lens group (that is, the lens group closest to the image side) move to the object side during zooming from the wide-angle end to the telephoto end, they have a sufficient back focus,
Moreover, a compact zoom optical system can be achieved. In particular, since the final lens group has a negative refractive power, it is possible to achieve both sufficient back focus and compactness. Further, if the second group and the third group are moved 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 has a shorter overall length. The system can be obtained.

In the second invention, a first group having a positive refractive power and a second group having a negative refractive power are arranged in this order from the object side.
5 comprising a third group having a positive or negative refractive power, a fourth group having a positive refractive power, and a fifth group having a negative refractive power
In the zoom lens having the group configuration, the first group and the fifth group are configured to move to the object side during zooming from the wide-angle end to the telephoto end, so that a very compact telephoto zoom lens can be obtained.

The conditional expressions (1) and (1a) define the size of the focal length of the final lens group. If the upper limits of the conditional expressions (1) and (1a) are exceeded, the refractive power of the final lens group becomes weak and the proportion of the lens that contributes to zooming becomes small, resulting in a large zoom movement amount. When the amount of zoom movement increases, the overall length increases, and compactness is lost. Conditional expression
If the upper limits of (1) and (1a) are set to 0.38 to satisfy this, a more compact zoom optical system can be obtained. If the lower limits of conditional expressions (1) and (1a) are exceeded, the refracting power of the final group becomes too strong, and a very large aberration occurs.
It becomes difficult to suppress the aberration in other groups. Conditional expression
If the lower limits of (1) and (1a) are set to 0.27 to satisfy this, it is possible to obtain a zoom optical system with even better imaging performance.

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 and second inventions, a first refracting power having a positive refracting power in order from the object side.
A group and a second group having negative refracting power, and a final group having negative refracting power is provided on the most image side, and zooming is performed by changing the interval between each group, from the wide-angle end to the telephoto end. Even in a zoom lens in which the first group and the last group move to the object side during zooming, the lens weight of the first group is much larger than the lenses of the second and subsequent 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.

Therefore, in the first and second inventions, camera shake correction is performed by moving the second group in the direction perpendicular to the optical axis. Since the lens diameter of the second group is much smaller and the weight of the lens is lighter than that of the first group, if the second group is used for camera shake correction, camera shake correction can be performed without burdening the camera shake drive system. it can. Further, the second group is characterized in that the amount of movement in zooming from the wide-angle end to the telephoto end is smaller than that of the other groups. This is a very advantageous condition when performing image stabilization,
Also in that respect, there is an advantage in using the second group for camera shake correction. In addition, in a fourth embodiment (Example 4) described later, the second group is fixed during zooming. In this way, it is preferable that the second lens group, which is the camera shake correction group, is fixed during zooming, because it is advantageous to arrange the camera shake drive system in the lens barrel.

Conditional expression (2) defines the size of the focal length of the second lens unit. If the upper limit of conditional expression (2) is exceeded, the refractive power of the second lens unit will become too weak, and as a result,
The movement in the direction perpendicular to the optical axis of the group makes the sensitivity of moving the image point too weak. Therefore, the second
The amount of movement of the group becomes large. The upper limit of conditional expression (2)
If you set it to 2.0 and meet this, the second
The amount of movement of the group can be further reduced. On the other hand, if the lower limit of conditional expression (2) is exceeded, the refractive power of the second lens unit will become too strong, and the amount of aberration in both the normal state and the corrected state of camera shake will increase. It becomes difficult to hold down. By setting the lower limit of conditional expression (2) to 0.3 and satisfying the lower limit, more excellent imaging performance can be obtained.

In the first and second inventions, it is desirable that the following conditional expression (3) is further satisfied. f1 / fW <1.10 (3) where f1: is the focal length of the first lens unit.

Conditional expression (3) defines the size of the focal length of the first lens unit. If the upper limit of conditional expression (3) is exceeded, the refractive power of the first lens unit becomes weak, and the amount of movement during zooming increases. Therefore, the overall length becomes large and the lens diameter also increases, so that compactness is lost. If the upper limit of conditional expression (3) is set to 1.00 to satisfy this condition, a more compact zoom optical system can be obtained.

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 be harmful and degrade the imaging performance. Therefore, the object side of the second group that is the image stabilization group, the second group, or the second group.
It is desirable to block a harmful ray at the time of camera shake correction by providing a fixed diaphragm on the image side of the group. As a result, good imaging performance can be obtained even in the camera shake correction state.

Further, it is desirable that focusing on a near object is performed by the second group which is 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.

Image stabilization group at the time of camera shake (that is, the second
The amount of movement of the group) (hereinafter referred to as “image stabilization movement amount”) is
It is preferable that the wide-angle end and the telephoto end of the zoom do not change much. In this respect, it is desirable in the first and second inventions that the following conditional expression (4) is further satisfied. 0.4 <MT / MW <2.5 (4) However, MT: shake compensation movement amount at the telephoto end, MW: shake compensation movement amount at the wide-angle end.

When the upper limit or the lower limit of the conditional expression (4) is exceeded, the amount of camera shake correction movement greatly differs between the wide-angle end and the telephoto end of the zoom. When calculating the amount of camera shake correction at any focal length, Calculation errors are likely to occur.

When the camera shake correction group is decentered in parallel during camera shake, axial lateral chromatic aberration, which is one of the eccentric aberrations, occurs,
In order to suppress this, it is desirable that the second group, which is the camera shake correction group, be color-corrected. For that purpose, for example, it is desirable to satisfy the following conditional expression (5). νp> νn (5) where νp is the Abbe number of the positive lens in the camera shake correction group (second group), and νn is the Abbe number of the negative lens in the camera shake correction group (second group).

<< Eccentric Aberration and Eccentric Aberration Coefficient >> 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 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)

[0025] Unless otherwise specified, 'off-axial image point movement error [Delta] Y _Z on and an image point on the z-axis' axial image point movement error [Delta] Y _Y for an image point on the y-axis, each of the following formula ( b) and the formula
It is represented by (c). The 0.7 field is about 12 mm for the new photographic 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 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] A 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 (image lateral deviation) (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 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 the aberration is deteriorated due to the 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] From the above reason, the image point movement amount 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.

With respect to the other aberration coefficients, the terms in the middle of Σ similarly disappear. 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 camera shake correction group (Petzval sum) (μ = i → j) ΣPμ: Sum of P of the camera shake correction group. (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 it 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 becomes 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・ 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.

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) 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 equations (3A) to (3F) into equations (9A) to (9E) representing the above-mentioned 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 (object side) the image stabilization group 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 inversion system, these 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 camera shake correction group and non-inversion 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 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 image stabilization group is to the aperture, the smaller h # on each surface and the smaller H #.

[0059]

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 and m5 are the first group Gr1, the second group Gr2, and the third group G
The zoom movements from the wide-angle end [W] to the telephoto end [T] of r3, the aperture stop S, the fourth lens unit Gr4, and the fifth lens unit Gr5 are schematically shown.

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 negative refractive power. When,
The zoom lens includes a fourth group Gr4 having a positive refracting power and a fifth group Gr5 having a negative refracting power, and performs zooming by changing the interval between the groups. Then, the camera shake correction is to decenter the second group Gr2 in parallel.
(That is, move in the direction perpendicular to the optical axis AX)
Done by

In the second to fourth embodiments, 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 first group Gr2 having a positive refractive power. Group 3 Gr
3, a fourth group Gr4 having a positive refracting power and a fifth group Gr5 having a negative refracting power, and is a zoom lens which performs zooming by changing the interval between the groups. Then, the camera shake correction is performed by decentering the second lens unit Gr2 in parallel.

In each embodiment, since the second lens unit Gr2 having a small lens diameter and a light weight is used for camera shake correction, the burden on the camera shake drive system is also reduced. Moreover, the zoom movement of each group, the power arrangement, and the configuration satisfying each conditional expression are effective in shortening the overall length and making it compact and obtaining excellent imaging performance. The fourth
In the embodiment, the second lens unit Gr2, which is a camera shake correction unit, is fixed during zooming, which is advantageous in disposing the camera shake drive system in the lens barrel.

[0063]

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. Further, Table 1 shows corresponding values of the conditional expressions (1) to (4) in each example.

Example 1 f = 83.0 to 160.0 to 234.0 FNO = 4.60 to 5.81 to 5.78 [curvature radius] [axis upper surface interval] [refractive index] [Abbe number] <first group Gr1 ... Positive> r1 97.345 d1 1.700 N1 1.61293 ν1 36.96 r2 48.265 d2 6.460 N2 1.49310 ν2 83.58 r3 -1091.036 d3 0.100 r4 57.984 d4 3.820 N3 1.49310 ν3 83.58 r5 810.051 d5 3.300 to 26.272 to 39.846 <2nd group Gr2… Negative> r6 -830 N4 r6 -73.4. 53.93 r7 34.239 d7 3.000 r8 39.600 d8 2.750 N5 1.67339 ν5 29.25 r9 -3349.859 d9 2.000 r10 -35.714 d10 1.215 N6 1.51728 ν6 69.43 r11 -29.097 d11 2.000 ~ 4.000 ~ 6.000 <3rd group Gr3 ... negative> r12 15-24.999 d12. 1.51728 ν7 69.43 r13 -30.588 d13 20.453 ~ 4.949 ~ 1.000 <Aperture S, 4th group Gr4 ... Positive> r14 ∞ (Aperture S) d14 1.380 r15 60.430 d15 1.300 N8 1.84666 ν8 23.82 r16 26.308 d16 2.460 r17 41.552 d17 2.840 N9 1.51680 ν 64.20 r18 -115.365 d18 0.400 r19 36.133 d19 4.550 N10 1.51680 ν10 64.20 r20 -42.506 d20 19.811 to 9.140 to 0.900 <No. 5th group Gr5 ... Negative> r21 214.395 d21 1.080 N11 1.71300 ν11 53.93 r22 23.976 d22 1.540 r23 -181.698 d23 3.480 N12 1.67339 ν12 29.25 r24 -18.797 d24 1.130 N13 1.75450 ν13 51.57 r25 ∞ Σd = 89.815 to 88.611〜

Example 2 f = 82.6 to 160.0 to 234.0 FNO = 4.60 to 5.81 to 6.83 [curvature radius] [axial upper surface spacing] [refractive index] [Abbe number] <first group Gr1 ... Positive> r1 97.792 d1 1.700 N1 1.61293 ν1 36.96 r2 46.299 d2 6.460 N2 1.49310 ν2 83.58 r3 -184.667 d3 0.100 r4 50.563 d4 3.820 N3 1.49310 ν3 83.58 r5 241.312 d5 3.300 ~ 23.941 ~ 31.837 〈2nd group Gr2… Negative〉 r6 -830.4 53.93 r7 33.113 d7 1.000 r8 20.179 d8 2.000 N5 1.51728 ν5 69.43 r9 24.487 d9 2.000〜4.000〜6.000 〈3rd group Gr3 …… positive〉 r10 30.032 d10 1.215 N6 1.51728 ν6 69.43 r11 19.448 d11 1.000 r12 26.836.67 r12 2.750 N7 117.377 d13 23.629 ~ 8.887 ~ 1.306 <Aperture S, 4th group Gr4 ... Positive> r14 ∞ (Aperture S) d14 1.380 r15 73.885 d15 1.300 N8 1.84666 ν8 23.82 r16 28.089 d16 2.460 r17 46.118 d17 2.840 N9 1.51680 ν9 64.20 d18 0.400 r19 34. d19 4.550 N10 1.51680 ν10 64.20 r20 -44.058 d20 17.850 ~ 6.911 ~ 0.874 <5th group Gr5 ... > R21 512.839 d21 1.080 N11 1.71300 ν11 53.93 r22 24.541 d22 1.540 r23 -133.326 d23 3.480 N12 1.67339 ν12 29.25 r24 -17.645 d24 1.130 N13 1.75450 ν13 51.57 r25 ∞ Σd = 88.815~85.775~82.052

Example 3 f = 82.6 to 160.0 to 234.0 FNO = 4.60 to 5.81 to 5.95 [radius of curvature] [axis upper surface spacing] [refractive index] [Abbe number] <first group Gr1 ... Positive> r1 58.900 d1 1.700 N1 1.61293 ν1 36.96 r2 34.284 d2 6.460 N2 1.49310 ν2 83.58 r3 -300.890 d3 0.100 r4 63.185 d4 3.820 N3 1.49310 ν3 83.58 r5 98.931 d5 3.300 to 28.301 to 41.700 <second group Gr2… Negative> r6 -830 N4 r6 -74.4 7.74 53.93 r7 29.553 d7 1.000 r8 23.424 d8 1.215 N5 1.51728 ν5 69.43 r9 39.791 d9 2.500 to 4.000 〜 7.500 〈3rd group Gr3… positive〉 r10 36.855 d10 1.215 N6 1.51728 ν6 69.43 r11 21.931 d11 1.000 r12 29.252 r3 237 2.75 d12 2.750 2. 212.765 d13 29.756 ~ 11.469 ~ 1.306 <Aperture S, 4th group Gr4 ... Positive> r14 ∞ (Aperture S) d14 1.380 r15 62.924 d15 1.300 N8 1.84666 ν8 23.82 r16 28.043 d16 2.460 d17 2.840 N9 1.51680 ν9 64.20 r18 -8619 63d18 0.400 r 32.661 d19 4.550 N10 1.51680 ν10 64.20 r20 -50.825 d20 18.926 ~ 8.308 ~ 0.874 <5th group Gr5 ... Negative> r21 149.097 d21 1.080 N11 1.71300 ν11 53.93 r22 24.519 d22 1.540 r23 -121.815 d23 3.480 N12 1.67339 ν12 29.25 r24 -18.056 d24 1.130 N13 1.75450 ν13 51.57 r25 ∞ Σd = 95.733 to 93.328 to 92.631

Example 4 f = 82.6 to 160.0 to 234.0 FNO = 4.60 to 5.90 to 6.00 [curvature radius] [axis upper surface spacing] [refractive index] [Abbe number] <first group Gr1 ... Positive> r1 61.148 d1 1.700 N1 1.61293 ν1 36.96 r2 34.001 d2 7.500 N2 1.49310 ν2 83.58 r3 -253.109 d3 0.100 r4 60.899 d4 4.200 N3 1.49310 ν3 83.58 r5 95.792 d5 3.300 to 25.514 to 41.021 <second group Gr2… Negative> r6 -85.4 r6 -85.4 53.93 r7 26.983 d7 1.000 r8 22.823 d8 1.215 N5 1.51728 ν5 69.43 r9 40.300 d9 2.500〜4.000〜7.500 〈3rd group Gr3… positive〉 r10 35.792 d10 1.215 N6 1.51728 ν6 69.43 r11 21.684 d11 1.000 r12 29.241 r12 2.750 2. 217.960 d13 29.529 to 12.908 to 1.306 <Aperture S, 4th group Gr4 ... Positive> r14 ∞ (Aperture S) d14 1.380 r15 55.422 d15 1.300 N8 1.84666 ν8 23.82 d16 2.460 r17 47.314 d17 2.840 N9 1.51680 ν9 64.20 r18 -83.181 d18 0.4 34.948 d19 4.550 N10 1.51680 ν10 64.20 r20 -47.390 d20 17.734〜8.310〜0.874 〈5th group Gr5 Negative> r21 198.738 d21 1.080 N11 1.71300 ν11 53.93 r22 24.489 d22 1.540 r23 -114.315 d23 3.480 N12 1.67339 ν12 29.25 r24 -17.995 d24 1.130 N13 1.75450 ν13 51.57 r25 ∞ Σd = 95.734~93.403~93.372

[0068]

[Table 1]

2, FIG. 6, FIG. 10 and FIG. 14 are longitudinal aberration diagrams corresponding to Examples 1 to 4, respectively. In each figure, [W] is the wide-angle end, [M] is the intermediate focal length state (middle),
[T] indicates 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. In addition, the broken line (D
M) 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. It is a lateral-aberration figure, and shows the lateral-aberration about the light flux of the meridional surface before decentering [A] and after decentering [B] of the 2nd group Gr2, respectively. The aberration diagram [B] after each decentering shows that the camera shake correction angle θ of the second group Gr2 is
The aberration in the corrected state of 0.7 ° (= 0.0122173rad) is shown.

[0071]

As described above, according to the present invention, it is possible to realize a zoom lens which has a small length and is compact in size and which is capable of properly correcting various aberrations in both a normal state and a corrected state. it can.

[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 ... 2nd group Gr3 ... 3rd group Gr4 ... 4th group Gr5 ... 5th group S ... Aperture AX ... Optical axis

Claims (2)

[Claims] 1. A first lens element having a positive refractive power in order from the object side.
A zoom lens comprising a group and a second group having a negative refractive power, and a final group having a negative refractive power on the most image side, and performing zooming by changing the distance between the groups. Upon zooming from the wide-angle end to the telephoto end, the first group and the final group move to the object side, and the second group moves vertically to perform optical image stabilization, and A zoom lens with an image stabilization function characterized by satisfying the following condition; 0.2 <| fL / fW | <0.4 0.2 <| f2 / fW | <4.0, where fL: focal length of the final lens group, fW: at wide-angle end The focal length of the entire system, f2: focal length of the second lens group. 2. A first group having a positive refracting power, a second group having a negative refracting power, a third group having a positive or negative refracting power, and a positive refracting power in order from the object side. A zoom lens of a five-group configuration that includes a fourth group that has and a fifth group that has negative refractive power, and that performs zooming by changing the distance between each group. Upon zooming, the first group and the fifth group move to the object side, and the second group moves in the direction perpendicular to the optical axis to perform camera shake correction, and the following conditions are satisfied. And a zoom lens with a camera shake correction function; 0.2 <| f5 / fW | <0.4 0.2 <| f2 / fW | <4.0, where f5 is the focal length of the fifth lens group, and fW is the focal length of the entire system at the wide-angle end. , F2: focal length of the second lens group.