JP2004110079A - Zoom lens having vibration proof function and television camera having zoom lens - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a zoom lens having a vibration proof function and capable of obtaining a still image by optically correcting blurs of the still image which may be generated when the zoom lens is vibrated and to provide a television camera having the zoom lens. <P>SOLUTION: In the zoom lens comprising a 1st group having positive refractive power and fixed at the time of variable power operation, a 2nd group having negative refractive power and prepared for variable power operation, a 3rd group having positive refractive power and prepared for correcting image surface variation followed by variable power operation, and a 4th group having positive refractive power and fixed at the time of variable power operation which are arranged successively from the object side, a 4th S group consisting of a part of lens group constituting the 4th group and having negative refractive power is moved in a plane approximately vertical to the optical axis to correct blurs of a photographed image which may be generated when the zoom lens is vibrated and the 4th E group for changing the focal distance of the whole system is arranged on the image surface side as compared with the 4th S group so as to be inserted/ejected. <P>COPYRIGHT: (C)2004,JPO

Description

The present invention relates to a zoom lens having an image stabilizing function and a television camera having the same, and corrects image blur when the zoom lens vibrates by moving vertically a part of lens groups in a lens system. When obtaining a still image, by appropriately defining the configuration such as the refractive power arrangement of the entire system and the arrangement of the variable power moving group, over the entire variable power range, especially had good optical performance even during vibration isolation, It is suitable for television cameras, photographic cameras, video cameras, and the like.

ズ ー ム Conventionally, large-diameter, high-magnification zoom lenses having high optical performance have been required for television cameras, photographic cameras, video cameras, and the like.

In addition to this, operability and mobility are particularly important in a color television camera for broadcasting, and in response to the demand, a small CCD (solid-state image pickup device) of 2/3 inch or 1/2 inch has been used. It has become mainstream.

(4) Since the CCD has a substantially uniform resolution over the entire imaging range, a zoom lens using the CCD is required to have a substantially uniform resolution from the center of the screen to the periphery of the screen.

For example, it is demanded that various aberrations such as coma, astigmatism, distortion, etc. are corrected well and that the entire screen has high optical performance. Furthermore, it is demanded that it has a large aperture, a wide angle, a high zoom ratio, a small size and light weight, and that it has a long back focus because a color separation optical system and various filters are arranged in front of the imaging means. ing.

抑制 Furthermore, suppression of image blur due to vibration or camera shake, which occurs particularly when using an imaging system having a long focal length, has become a major problem, and there has been an increasing demand for an image stabilization function that does not cause image blur. Under such circumstances, various types of anti-vibration systems have been conventionally proposed.

In Japanese Patent Application Laid-Open No. 61-223819, in a photographing system in which a refraction-type variable apex prism is arranged on the most object side, the vibration of the photographing system in which the refraction-type variable apex angle prism is arranged corresponds to the vibration of the photographing system. By changing the prism apex angle of the refraction type variable apex angle prism, the image is stabilized.

In Japanese Patent Application Laid-Open Nos. 1-116619 and 2-124521, vibration of a photographing system is detected using an acceleration sensor or the like, and a part of a lens group of the photographing system is moved along an optical axis according to a signal obtained at this time. There is a method of obtaining a still image by vibrating in a direction perpendicular to the image.

Japanese Unexamined Patent Publication No. 7-92431 discloses a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a fourth lens unit having a positive refractive power. A zoom lens having two lens groups, wherein the fourth group comprises two lens groups, a front group having a positive refractive power and a rear group having a positive refractive power, and the front group is moved in a direction perpendicular to the optical axis. Thus, the blur of the photographed image when the zoom lens vibrates is corrected.

Japanese Patent Application Laid-Open No. H10-90601 discloses a first group of positive refractive power, a second group of negative refractive power, a third group of positive refractive power, a fourth group of negative refractive power, A fifth lens group having a fifth refractive power, wherein the fourth group is moved in a direction perpendicular to an optical axis to correct a blur of a photographed image when the zoom lens vibrates. I have.

In Japanese Patent Application Laid-Open No. Hei 5-232410, in a telephoto zoom lens having four lens groups of first to fourth groups having positive, negative, positive, and positive refractive powers in order from the object side, a second group is provided. It is moved in the direction perpendicular to the optical axis to perform vibration isolation.

In Japanese Patent Application Laid-Open No. 7-152002, in a zoom lens having four lens groups of first to fourth groups having negative, positive, negative, and positive refractive power in order from the object side, the third group is perpendicular to the optical axis. It moves in the direction to perform vibration isolation.

In Japanese Patent Application Laid-Open No. 7-199124, in a four-unit variable magnification optical system including four lens units having positive, negative, positive, and positive refractive powers, the entire third unit is moved in a direction perpendicular to the optical axis. We are performing vibration isolation.
JP-A-61-223819 JP-A-1-116619 JP-A-2-124521 JP-A-7-92431 JP-A-10-90601 JP-A-5-232410 JP-A-7-152002 JP-A-7-199124

In general, an image stabilizing optical system is arranged in front of a photographing system, a drive control of a part of the movable lens group of the image stabilizing optical system eliminates blurring of a photographed image, and a method of obtaining a still image increases the size of the entire apparatus. In addition, there is a problem that a moving mechanism for moving the movable lens group becomes complicated.

In an optical system that performs image stabilization using a variable apex angle prism, there is a problem that the amount of eccentric magnification chromatic aberration increases during image stabilization, especially on the telephoto side.

On the other hand, an optical system that performs image stabilization by decentering some of the lenses of the imaging system in a direction perpendicular to the optical axis has the advantage that no special optical system is required for image stabilization. There is a problem in that a space for a lens to be used is required, and the amount of eccentric aberration generated during image stabilization increases.

Japanese Patent Laid-Open No. 7-92431 discloses a four-unit variable magnification optical system including four lens units having positive, negative, positive, and positive refractive powers. In a zoom lens that performs image stabilization by moving it vertically, the image stabilization lens group is a positive lens group having a relatively large effective diameter. There was a tendency to increase in size.

Japanese Patent Laid-Open No. Hei 10-90601 discloses a zoom lens having a five-lens configuration including five lens units having positive, negative, positive, negative, and positive refractive powers, in which a fourth unit is moved in a direction perpendicular to the optical axis. In a zoom lens that performs image stabilization, the drive control mechanism tends to be complicated because the fourth group moves in the optical axis direction during zooming.

The present invention corrects blurring of a photographed image by eccentrically driving a part of lens groups of an optical system in a direction perpendicular to an optical axis, and by appropriately arranging each lens element, particularly the vibration-proof lens group. It is an object of the present invention to provide a zoom lens having a vibration-proof function suitable for a so-called four-group zoom lens, which can be downsized and satisfactorily correct various aberrations and eccentric aberrations, and a television camera having the same.

The zoom lens having an image stabilizing function according to the first aspect of the present invention includes a first lens unit having a fixed positive refractive power and a second lens unit having a negative refractive power for zooming when zooming in order from the object side. A zoom lens having a third lens unit having a positive refractive power for correcting an image plane variation caused by magnification, and a fourth lens unit having a fixed positive refractive power during zooming; Moving the fourth S group having a negative refractive power composed of the lens units in a plane substantially perpendicular to the optical axis to correct blurring of a captured image when the zoom lens vibrates;
It is characterized in that a fourth-E unit for changing the focal length of the entire system is removably disposed on the image surface side with respect to the fourth-S unit.

According to the present invention, as described above, when correcting a blur of a captured image by eccentrically driving a part of the lens groups of the optical system in a direction perpendicular to the optical axis, by appropriately arranging each lens element, In particular, to achieve a zoom lens having a vibration-proof function suitable for a so-called four-group zoom lens and a television camera having the same, which enables downsizing of the vibration-proof lens group and favorably corrects various aberrations and eccentric aberrations. Can be.

In addition, according to the present invention, in a so-called four-unit zoom lens, the arrangement of the refractive power of the entire system and the arrangement of the variable-power moving unit are defined, and the configuration of the fourth unit is specified. It is possible to achieve a zoom lens that has high optical performance even at times, and the entire mechanism is small and lightweight and has an anti-vibration function.

First, regarding the occurrence of eccentric aberration in a zoom lens having an anti-vibration function according to the present invention when a subsystem in an optical system is decentered in a direction orthogonal to the optical axis, the 23rd Applied Physics The explanation is based on the method presented by Matsui in the lecture (1962).

When a part of the lens group p of the taking lens is decentered in parallel by E, the aberration amount Δ′Y of the whole system is represented by the aberration amount ΔY before the decentering and the eccentric aberration amount ΔY generated by the eccentricity as shown in the equation (a). (E). Here, the eccentric aberration ΔY (E) is represented by a first-order eccentric coma (IIE), a first-order eccentric astigmatism (IIIE), a first-order eccentric field curvature (PE), as shown in the equation (b). It is represented by first-order eccentric distortion (VE1), first-order eccentric distortion additional aberration (VE2), and first-order origin shift ΔE.

Further, the aberrations from (IIE) to (ΔE) in equations (c) to (h) are caused by the incidence of axial marginal rays on the decentered lens group of paraxial rays when the focal length of the entire system is normalized to 1. Let αp and αp ′ be the angles and the exit angles respectively, and the incident angle of the principal ray passing through the center of the pupil is

Is expressed using the aberration coefficients Ip, IIp, IIIp, Pp, and Vp of the eccentric lens group and the aberration coefficients Iq, IIq, IIIq, Pq, and Vq of the lens system on the image side of the eccentric lens group.

Similarly, when the lens unit P is parallel decentered by E, the chromatic aberration amount ΔcYa of the entire system is, as shown in the equation (i), the aberration ΔcY before the parallel decentering and the aberration ΔcY (E) caused by the decentering. Become sum.

Here, the aberration ΔcY before the parallel decentering and the eccentric aberration ΔcY (E) are calculated by using the axial chromatic aberration L, the lateral chromatic aberration T, and the first-order eccentric chromatic aberration Te as in the equations (j) and (k), respectively. Can be represented.

Further, the first-order eccentric chromatic aberration coefficient (TE) in the equation (1) is represented by Lq, the chromatic aberration coefficients Lp and Tp of the lens group P, and the chromatic aberration coefficient of the entire lens group disposed closer to the image plane side than the lens group to be decentered in parallel. It can be expressed using Tq.

う ち Of these, the image movement due to eccentricity is represented by the first-order origin movement (ΔE), and (IIE), (IIIE), (PE), and (TE) affect the imaging performance.

First, in order to reduce the occurrence of eccentric aberration, it is necessary to reduce the amount of eccentricity E of the lens unit P as shown in the equation (b).

In order to make the eccentric aberration coefficient of the lens group P shown in the equations (c) to (g) minute, the various aberration coefficients Ip, IIp, IIIp, Pp, and Vp of the lens group P are set to small values, or It is necessary to set the aberration coefficients in a well-balanced manner so as to cancel each other.

In particular, the converted inclination of the paraxial ray that enters the lens group p to be parallel decentered and exits from the lens group p so that the eccentric aberration coefficients shown in the above equations (c) to (g) have small values. It is necessary to appropriately set the value of the third-order aberration coefficient and the value of the third-order aberration coefficient of the entire lens group q arranged on the image plane side of the lens group p.

That is, in order to remove the deterioration of the center image that occurs when the lens group is decentered in the direction perpendicular to the optical axis, the first-order decentered coma mainly represented by the expression (c) is favorably corrected, and In order to satisfactorily correct the one-sided blur that occurs when parallel eccentricity occurs at the same time, it is necessary to satisfactorily correct mainly the first-order eccentric field curvature shown in the equation (d).

Of course, it is naturally necessary to satisfactorily correct other aberrations as well.

In order to minimize the eccentric chromatic aberration coefficient (TE) shown in the equation (1), it is necessary to appropriately set the chromatic aberration coefficients of the lens group p and the entire lens group q disposed on the image plane side thereof.

ズ ー ム The zoom lens having the image stabilizing function of the present invention is configured in consideration of the above points.

Next, the features of the zoom lens having the image stabilizing function of the present invention will be described.

The zoom lens having an image stabilizing function according to the present invention includes a first lens unit having a fixed positive refractive power, a second lens unit having a negative refractive power for zooming, and zooming in order from the object side. A zoom lens having a third lens unit having a positive refractive power for correcting an image plane variation and a fourth lens unit having a positive refractive power fixed at the time of zooming, wherein a part of the fourth lens unit is included. The fourth S group having the negative refractive power is moved in a plane substantially perpendicular to the optical axis to correct the blur of the photographed image when the zoom lens vibrates.

The fourth S group has one negative lens and one positive lens, and the incident conversion inclination angle to the lens surface closest to the object which constitutes the fourth S group is α, and the fourth S group is formed. Α ′, the average Abbe number of the material of the negative lens constituting the fourth S group is v n (4S), and the material of the material of the positive lens constituting the fourth S group is When the average Abbe number is νp (4S),
α′−α <−0.45 ‥‥‥ (1)
νn (4S) −νp (4S)> 10 ‥‥‥ (2)
The following conditional expression is satisfied.

The fourth group has, in order from the object side, a fourth F group having a negative refractive power including the fourth S group and a fourth R group having a positive refractive power, and the material of the positive lens constituting the fourth R group Is the average Abbe number of the lens and the average value of the Abbe number of the material of the negative lens is vn (4R).
νp (4R) −νn (4R)> 10 ‥‥‥ (3)
The following conditional expression is satisfied.

Further, the second unit changes in the area including the imaging magnification of -1 at the time of zooming, and the change of the lateral magnification is Z2. When the zoom ratio is changed within the area including 1 × and the zoom ratio is Z,
5 <Z2 ‥‥‥ (4)
0.15 <Z2 / Z ‥‥‥ (5)
The following conditional expression is satisfied.

{Circle around (4)} A fourth-E unit that changes the focal length of the entire system is disposed so as to be able to be inserted and removed from the fourth-S unit on the image side.

The fourth unit has a fourth lens unit having a negative refractive power and a fourth lens unit having a positive refractive power. The fourth lens unit includes two lenses, a negative lens and a positive lens, or a negative lens and a positive lens, and The fourth lens unit is composed of three negative lenses, and the fourth lens group is moved in a direction perpendicular to the optical axis to correct a blur of a captured image when the zoom lens vibrates.

At this time, when the incident conversion inclination angle to the lens surface closest to the object side forming the fourth F group is α and the conversion conversion inclination angle from the most image side lens surface forming the fourth F group is α ′, Is satisfied.

According to the present invention, the optical system has high optical performance even during image stabilization over the entire zoom range, and the configuration of the entire system and the arrangement of the image stabilizing lens groups for appropriately reducing the size of the image stabilizing apparatus are appropriately set.

FIG. 27 shows a conceptual diagram of a zoom lens having an image stabilizing function. Here, F is a focus group (front lens group) having a positive refractive power as the first group.

V is a variator of negative refracting power for zooming as the second unit, and zooms from the wide-angle end (wide) to the telephoto end (tele) by monotonously moving on the optical axis to the image plane side. It is carried out.

C is a compensator having a positive refractive power, and moves non-linearly on the optical axis toward the object side in order to correct an image plane variation accompanying zooming. The variator V and the compensator C constitute a variable power system. SP is a stop, and R is a fixed relay group having a positive refractive power as a whole as a fourth group. The relay group R includes a fourth F group having a negative refractive power and a fourth R group having a positive refractive power.

As shown in FIG. 27, the image point 1 'formed by the lens groups F to C does not change during zooming. Therefore, considering the imaging relationship of only the relay group R, the arrangement and the paraxial tracking value change. It is constant regardless of times. Therefore, by arranging the image stabilizing lens group on the image side of the zooming movable group and fixed at the time of zooming, it is possible to prevent fluctuations of the respective eccentric aberration coefficients due to zooming.

In addition, by making the image stabilizing lens group a group of negative refractive power on the image side of the group of positive refractive power, the effective diameter of the image stabilizing lens group is reduced to reduce the size and weight, and the entire image stabilizing apparatus is reduced. The size is reduced.

According to the present invention, the condition that the fourth lens unit is small and lightweight and the optical performance is optimal as a vibration-proof lens unit is regulated. The eccentricity E4s of the image stabilizing lens group required to obtain the predetermined image blur correction amount ΔY on the image plane is expressed by the following equation assuming that R = 0, ω = 0, αk ′ = 1 from the equation (b). expressed.

E4s = −ΔY / {2 (ΔE)}｝ (m)
Since the primary origin movement (ΔE) is expressed by the equation (h), the eccentricity E4s for obtaining the necessary image blur correction amount ΔY is determined by the incident conversion inclination α of the axial marginal ray to the image stabilizing lens group and the emission. It is defined by the converted inclination angle α ′.

Therefore, if the expression (1) is not satisfied, the amount of movement of the image stabilizing lens group increases rapidly due to an increase in the amount of eccentricity E4s, and the effective diameter of the image stabilizing lens group in consideration of eccentricity increases. The driving force suddenly increases, and the entire mechanism becomes larger. Further, since the occurrence of eccentric aberration increases with an increase in the amount of eccentricity E4s, the optical performance during image stabilization is not good.

From the relations of (c) to (g), in order to correct the eccentric aberration caused by the anti-vibration lens group, it is necessary to appropriately control each aberration coefficient sharing value of the anti-vibration lens group. Therefore, unless the anti-vibration lens group is composed of at least one positive lens and one negative lens, it becomes difficult to control each aberration coefficient sharing value of the anti-vibration lens group, and it becomes difficult to correct eccentric aberration. Various eccentric aberrations such as eccentric coma and eccentric field curvature are likely to occur.

From the relationship of the formula (1), in order to correct the eccentric chromatic aberration caused by the image stabilizing lens group, it is necessary to appropriately control each chromatic aberration coefficient sharing value of the image stabilizing lens group.

Therefore, if the relationship between the average Abbe number νp (4S) of the positive lens and the average Abbe number vn (4S) of the negative lens does not satisfy the expression (2), the anti-vibration lens will be used. Control of each chromatic aberration coefficient of the group becomes difficult, correction of eccentric chromatic aberration becomes difficult, and color asymmetry tends to occur during image stabilization.

The present invention specifies the conditions as the fourth R group suitable for optical performance as a zoom lens having an image stabilizing function.

From the relations of the equations (c) to (g), in order to correct the eccentric aberration caused by the image stabilizing lens group (fourth S group), it is necessary to appropriately assign the respective aberration coefficient sharing values of the image plane side group of the image stabilizing lens group. Need to be controlled.

Therefore, unless the fourth R group disposed on the image plane side of the image stabilizing lens group is composed of at least one positive lens and at least one negative lens, it becomes difficult to control each aberration coefficient and to suppress eccentric aberration. As a result, various eccentric aberrations such as eccentric coma and eccentric field curvature are likely to occur during image stabilization.

From the relationship of equation (1), in order to correct the eccentric chromatic aberration caused by the image stabilizing lens group, it is necessary to appropriately control the chromatic aberration coefficient sharing value of the group on the image plane side of the image stabilizing lens group.

Therefore, if νp (4R) and νn (4R) do not satisfy the expression (3), it becomes difficult to control each chromatic aberration coefficient of the fourth R group disposed on the image side of the image stabilizing lens group. Becomes difficult to suppress the eccentric chromatic aberration, and color asymmetry tends to occur during image stabilization.

The present invention is a condition for efficiently achieving a high zoom ratio of 40 times or more by increasing the change in the lateral magnification in the third group as well as the second group.

な い と Unless conditional expressions (4) and (5) are satisfied, it becomes difficult to obtain a zoom lens having a high zoom ratio.

The present invention stipulates that an optical system that shifts the zoom range to the telephoto side or the wide-angle side by a method such as unit switching, such as a built-in extender, is provided on the image side of the image stabilizing lens group. This eliminates the need to change the control of the image stabilizing lens group. Before and after the focal length conversion by the 4E group, the arrangement of the image stabilizing lens group on the object side does not change, so that the eccentricity E of the image stabilizing lens group for obtaining the predetermined correction angle θ does not change, and the image stabilizing lens does not change. There is no need to change group control.

The zoom lens having an image stabilizing function according to the present invention is provided with an image stabilizing function by appropriately setting the refractive power arrangement of the entire system and the zooming movement group, and appropriately setting the configurations of the image stabilizing lens group and the image side lens group. While reducing the size and weight of the lens group, the effect of the eccentricity of the image stabilizing lens group on the optical performance is minimized even during zooming, and the optical performance is maintained well during the image stabilization.

Next, a specific configuration of the zoom lens having the image stabilizing function of the present invention will be described.

FIG. 1 is a sectional view of a lens at a wide angle end according to Numerical Embodiment 1 of the present invention. In FIG. 1, F is a focus group (front lens group) having a positive refractive power as a first group. V is a variator of negative refracting power for zooming as the second unit, and zooms from the wide-angle end (wide) to the telephoto end (tele) by monotonously moving on the optical axis to the image plane side. It is carried out.

C is a compensator having a positive refractive power, and moves non-linearly on the optical axis toward the object side in order to correct an image plane variation accompanying zooming. The variator V and the compensator C constitute a variable power system.

SP is a stop, and R is a fixed relay group having a positive refractive power as a fourth group. P denotes a color separation prism, an optical filter, or the like, and is shown as a glass block in FIG.

Next, the features of the fourth group of the zoom lens having an image stabilizing function according to the present invention will be described. The fourth lens unit is composed of a fourth lens unit having a negative refractive power and a fourth lens unit having a positive refractive power. The fourth lens unit as a whole is a fourth lens unit having a negative refractive power. It has a function to move in the direction perpendicular to the direction.

The fourth group S is composed of one negative lens and one positive lens. The converted incident tilt angle of the light beam to the fourth group S is α, the converted output tilt angle of the light beam is α ′, Assuming that the average value of the Abbe number of the material is νn (4S) and the average value of the Abbe number of the material of the positive lens is νP (4S), the value of each expression is as follows, and the above conditional expression (1) And (2) are satisfied.

α'-α = -0.503
νn (4S) −νp (4S) = 22.7 (νn (4S) = 46.6
νp (4S) = 23.9)
The fourth R group includes five positive lenses and three negative lenses. The average value of the Abbe number of the material of the positive lens is νp (4R), and the average of the Abbe number of the material of the negative lens is When the value is vn (4R), the value of each expression is as follows, and satisfies the conditional expression (3).

νn (4R) −νP (4R) = 12.1 (νp (4R) = 53.5
νn (4R) = 41.4)
The decentering aberration coefficients corresponding to the expressions (c) to (h) and (1) are p for the image stabilizing lens group (fourth S group in this embodiment), and p is the lens group on the image side of the image stabilizing lens group. Table 1 shows q.

By appropriately setting the input / output conversion inclination angle of the image stabilizing lens group and the sharing value of each aberration coefficient of the image side lens group of the image stabilizing lens group and the image stabilizing lens group, each eccentric aberration coefficient of the image stabilizing lens group Is minute.

変 化 The change Z2 in the lateral magnification of the second lens unit is 9.21, and the zoom ratio is 44.1, which satisfies the conditional expressions (4) and (5).

FIGS. 2 to 5 show longitudinal aberration diagrams of the numerical example 1 at the wide angle end, f = 69.79 mm, f = 257.37 mm, and the telephoto end.

6 to 9 show lateral aberration diagrams of the numerical example 1 at the wide-angle end, f = 69.79 mm, f = 257.37 mm, the image height at the telephoto end is 0 mm, and ± 4 mm.

FIGS. 10 to 13 show lateral aberrations at the wide angle end, f = 69.79 mm, f = 257.37 mm, and the image height 0 mm and ± 4 mm when the image stabilizing lens group is shifted at the telephoto end in Numerical Example 1. Is shown.

In the present embodiment, the fourth S group is constituted by the entire fourth F group as a lens group for image stabilization. However, the number of constituent members of the fourth F group is increased and the lens group is divided into a plurality of parts, and a part of the lens group is set as the fourth S group. It is also easy.

As described above, in the present embodiment, the arrangement of the refractive power of the entire system, the arrangement of the variable power moving unit, and the arrangement of the lens group for image stabilization in the fourth group are appropriately set, and the lens configuration of the lens group for image stabilization is set. Is set appropriately, and high optical performance is obtained over the entire zoom range, even during image stabilization.

FIG. 14 is a lens cross-sectional view at a wide angle end according to Numerical Example 2 of the present invention. In FIG. 14, F is a focus group (front lens group) having a positive refractive power as a first group.

V is a variator of negative refracting power for zooming as the second unit, and zooms from the wide-angle end (wide) to the telephoto end (tele) by monotonously moving on the optical axis to the image plane side. It is carried out. C is a compensator having a positive refractive power, and moves non-linearly on the optical axis to the object side in order to correct an image plane variation accompanying zooming. The variator V and the compensator C constitute a variable power system.

SP is a stop, and R is a fixed relay group having a positive refractive power as a fourth group. P denotes a color separation prism, an optical filter, or the like, and is shown as a glass block in FIG.

Next, the features of the fourth group of the zoom lens having an image stabilizing function according to the present invention will be described. The fourth lens unit is composed of a fourth lens unit having a negative refractive power and a fourth lens unit having a positive refractive power. The fourth lens unit as a whole is a fourth lens unit having a negative refractive power. It has a function to move in the direction perpendicular to the direction. The fourth S group includes two negative lenses and one positive lens. The converted incident tilt angle of the light beam is α, the converted output tilt angle of the light beam is α ′, and the average Abbe number of the material of the negative lens is set. Assuming that the value is v n (4S) and the Abbe number of the material of the positive lens is v p (4S), the value of each expression is as follows, and satisfies the above conditional expressions (1) and (2).

α'-α = -0.848
νn (4S) −νp (4S) = 12.5 (νn (4S) = 40.8
νp (4S) = 28.3)
The fourth R group includes five positive lenses and three negative lenses. The average value of the Abbe number of the material of the positive lens is νp (4R), and the average of the Abbe number of the material of the negative lens is When the value is vn (4R), the value of each expression is as follows, and satisfies the conditional expression (3).

νn (4R) −νp (4R) = 11.9 (νp (4R) = 53.3
νn (4R) = 41.4)
The decentering aberration coefficients corresponding to the expressions (c) to (h) and (1) are p for the image stabilizing lens group (fourth S group in this embodiment), and p is the lens group on the image side of the image stabilizing lens group. Table 2 shows q.

By appropriately setting the input / output conversion inclination angle of the image stabilizing lens group and the sharing value of each aberration coefficient of the image side lens group of the image stabilizing lens group and the image stabilizing lens group, each eccentric aberration coefficient of the image stabilizing lens group Is minute.

変 化 The change Z2 in the lateral magnification of the second lens unit is 9.21, and the zoom ratio is 44.1, which satisfies the conditional expressions (4) and (5).

FIGS. 15 to 18 show longitudinal aberration diagrams of the numerical example 2 at the wide angle end, f = 69.79 mm, f = 257.37 mm, and the telephoto end.

FIGS. 19 to 22 show lateral aberration diagrams of the numerical example 2 at the wide-angle end, f = 69.79 mm, f = 257.37 mm, the image height at the telephoto end is 0 mm, and ± 4 mm.

23 to 26 show lateral aberration diagrams of the numerical example 2 at the wide-angle end, f = 69.79 mm, f = 257.37 mm, and at the telephoto end, at an image height of 0 mm and ± 4 mm when the image stabilizing lens group is shifted. Is shown.

In the present embodiment, the fourth lens unit is constituted by the entire fourth lens unit. However, it is easy to increase the number of constituent members of the fourth lens unit and to divide the lens unit into a plurality of lens units to form the fourth lens unit as the fourth lens unit.

As described above, in the present embodiment, the refractive power arrangement of the entire system, the arrangement of the variable power moving group, and the arrangement of the image stabilizing group in the fourth group are appropriately set, and the configuration of the image stabilizing group is appropriately set. High optical performance is obtained in the zoom range, even during image stabilization.

Next, numerical examples of the present invention will be described. In the numerical examples, ri is the radius of curvature of the i-th lens surface in order from the object side, di is the i-th lens thickness or air space in order from the object side, and ni and νi are the i-th lens in order from the object side. Are the refractive index and Abbe number of the glass.

に お い て In the numerical examples, the last two lens surfaces are glass blocks such as a face plate and a filter.

Sectional view of a lens at a wide angle end according to Numerical Example 1 of the present invention Aberration diagram at the wide-angle end according to Numerical Embodiment 1 of the present invention Aberration diagram at f = 66.68 mm in Numerical Example 1 of the present invention Aberration diagram at f = 360.00 mm in Numerical Embodiment 1 of the present invention Aberration diagram at the telephoto end of Numerical Embodiment 1 of the present invention Transverse aberration diagram at the wide-angle end according to Numerical Embodiment 1 of the present invention Transverse aberration diagram at f = 66.68 mm in Numerical Example 1 of the present invention Lateral aberration diagram at f = 360.00 mm in Numerical Embodiment 1 of the present invention Lateral aberration diagram at the telephoto end in Numerical Embodiment 1 of the present invention Transverse aberration diagram when the image stabilizing lens group is shifted by 3.0 mm at the wide-angle end in Numerical Example 1 of the present invention Lateral aberration diagram when the image stabilizing lens group is shifted by 3.0 mm at f = 66.68 mm in Numerical Example 1 of the present invention. Lateral aberration diagram when the image stabilizing lens group is shifted by 3.0 mm at f = 360.00 mm in Numerical Example 1 of the present invention. Lateral aberration diagram when the image stabilizing lens group is shifted by 3.0 mm at the telephoto end in Numerical Example 1 of the present invention Sectional view of a lens at the wide angle end according to Numerical Example 2 of the present invention Aberration diagram at the wide-angle end according to Numerical Example 2 of the present invention Aberration diagram at f = 69.8 mm in Numerical Example 2 of the present invention Aberration diagram at f = 257.4 mm in Numerical Example 2 of the present invention Aberration diagram at the telephoto end of Numerical Example 2 of the present invention Lateral aberration diagram at wide angle end in Numerical Example 2 of the present invention Lateral aberration diagram at f = 69.8 mm for Numerical Example 2 of the present invention Lateral aberration diagram at f = 257.4 mm in Numerical Example 2 of the present invention Lateral aberration diagram at the telephoto end in Numerical Example 2 of the present invention Lateral aberration diagram when the image stabilizing lens group is shifted by 1.8 mm at the wide angle end in Numerical Example 2 of the present invention Lateral aberration diagram when the image stabilizing lens group is shifted by 1.8 mm at f = 69.8 mm in Numerical Example 2 of the present invention. Lateral aberration diagram when the image stabilizing lens group is shifted by 1.8 mm at f = 257.4 mm in Numerical Example 2 of the present invention. Lateral aberration diagram when the image stabilizing lens group is shifted by 1.8 mm at the telephoto end in Numerical Example 2 of the present invention Schematic diagram of the anti-shake zoom lens of the present invention

Explanation of reference numerals

F Focus group V Variator C Compensator R Relay group 4F 4F group 4S 4S group (anti-vibration lens group)
4R 4R Group P Glass Block SP Aperture

Claims (2)

A first group having a fixed positive refractive power, a second group having a negative refractive power for zooming, and a third group having a positive refractive power for correcting an image plane variation caused by zooming when zooming in order from the object side. A zoom lens having a fourth lens unit having a positive refractive power that is fixed during zooming, and a fourth lens unit having a negative refractive power, which is a part of the fourth lens unit. By moving in a plane substantially perpendicular to the axis and correcting the blur of the captured image when the zoom lens vibrates,
A zoom lens having an image stabilizing function, wherein a fourth lens unit, which changes the focal length of the entire system, is disposed so as to be able to be inserted into and removed from the image plane side from the fourth lens unit. A television camera comprising the zoom lens according to claim 1.