WO2001027677A1 - Zoom lens and video camera comprising the same - Google Patents

Abstract

A first group of lenses (11) having a positive refractive power and fixed with respect to the image plane, a second group of lenses (12) having a negative refractive power and a variable power action when moving along the optical axis, a diaphragm (15) fixed with respect to the image plane (17), a third group of lenses (13) having a positive refractive power, and a fourth group of lenses (14) having a positive refractive power and movable along the optical axis so as to keep the image plane (17) moved when the second group of lenses (12) and the object move in a fixed position from a reference plane are arranged in this order from the object. The second group of lenses (12) comprises two negative lenses and a positive lens; the third group of lenses (13) comprises two positive lenses and a negative lens; and the fourth group of lenses (14) comprises a lens. Each of the second to fourth groups (12 to 14) has at least one aspherical surface. With this configuration of as few as ten lenses, aberrations including the chromatic aberration can be corrected well, realizing a zoom lens having an angle of field of 62° or more.

Description

 Description Zoom lens and video camera using the same

 The present invention relates to a zoom lens and a video camera using the same. More particularly, the present invention relates to a compact aspherical zoom lens having a camera shake correction function having an angle of view at a wide-angle end of 62 degrees or more and a video camera using the same. Background art

 With the recent popularization of the DV format in consumer video cameras, it is essential to achieve both small size and high image quality. Accordingly, there is a strong demand for a wide-angle zoom lens having a high optical quality, a short overall optical length, and a large angle of view.

 For example, Japanese Patent Application Laid-Open No. Heisei 9-2181392 discloses that high-quality images have an angle of view at the wide-angle end of 59.2 degrees to 60.7 degrees and a zoom ratio of about 10 times. A zoom lens is disclosed.

However, the zoom lens disclosed in the above-mentioned publication achieves miniaturization and high image quality with a lens configuration as small as 10 sheets, but the angle of view at the wide-angle end is about 61 degrees or less. In order to achieve a larger angle of view while maintaining high image quality, it is necessary to use 10 or more lenses or to increase the overall optical length, so that a larger angle of view is required. However, there is a problem that it is impossible to realize a small zoom lens having the following characteristics. Disclosure of the invention The present invention has been made in order to solve the above-mentioned problems in the prior art, and has various lens aberrations including chromatic aberrations, with a small lens configuration, and has an angle of view of 62 degrees or more, and An object of the present invention is to provide a zoom lens having a camera shake correction function, and to provide a small, high-quality video camera using the zoom lens.

In order to achieve the above object, a first configuration of a zoom lens according to the present invention has a positive refractive power, which is arranged in order from the object side to the image plane side, and is fixed to the image plane. One lens group, a second lens group that has negative refractive power and performs zooming by moving on the optical axis, an aperture fixed with respect to the image plane, and a positive refractive power A third lens group, and a fourth lens group having a positive refractive power and moving on the optical axis such that the image plane, which fluctuates due to the movement of the second lens group and the object, is kept at a fixed position from the reference plane. Wherein the second lens group includes three lenses, two negative lenses and one positive lens, and includes at least one aspherical surface. The three lens group consists of three lenses, two positive lenses and one negative lens, and at least The fourth lens unit includes a positive lens including at least one aspherical surface, and the fourth lens group includes at least one aspherical surface. According to the first configuration of this zoom lens, the third lens group is composed of three lenses, two positive lenses and one negative lens, so that the zoom lens is small and has a wide range from the wide-angle end to the standard position. A zoom lens in which spherical aberration is well corrected is realized. In addition, by arranging at least one aspherical surface in each of the second to fourth lens groups with a small lens diameter and adopting the optimal aspherical shape and lens type, a small lens configuration is possible. It is possible to realize a compact zoom lens having an angle of view equal to or greater than degrees and various aberrations including chromatic aberration being satisfactorily corrected. In addition, since the lenses constituting the second to fourth lens groups all have small lens diameters, the aspherical lenses included in these lens groups are included. Can be easily manufactured.

 Further, in the first configuration of the zoom lens according to the present invention, the second lens group includes a first negative lens, a second negative lens, and a positive lens that are sequentially arranged from an object side. It is preferable that it is constituted by three lenses including a lens.

 In the first configuration of the zoom lens according to the present invention, the second lens group includes a first negative lens, a second negative lens, and a positive lens, which are arranged in order from the object side. Preferably, it is composed of three lenses.

 Further, in the first configuration of the zoom lens of the present invention, the third lens group includes a first positive lens, a second positive lens, and a negative lens which are arranged in order from the object side. It is preferable that it is constituted by three lenses including a lens.

 In the first configuration of the zoom lens according to the present invention, the third lens group includes a first positive lens, a second positive lens, and a negative lens, which are arranged in order from the object side. Preferably, it is composed of three lenses.

 In the first configuration of the zoom lens of the present invention, when the focal length of the second lens group is f 2 and the focal length of the entire system at the wide-angle end is fw, the following condition (Equation 1) is satisfied. Is preferably satisfied.

 [Number 1]

 1.0 <I f 2 \ / f w <2.0

According to this preferred example, it is possible to realize a zoom lens capable of correcting the curvature of field to be small in spite of the wide angle, and capable of being downsized. In this case, it is preferable that the following condition (Equation 2) is satisfied. [Number 2]

 I f 2 I / f w <1.7

 According to this preferred example, the amount of movement of the second lens group can be reduced while the field curvature is further reduced.

 In the first configuration of the zoom lens according to the present invention, the second lens group includes a first negative lens, a second negative lens, and a positive lens, which are arranged in order from the object side. The second negative lens has an aspherical surface on the object side, has a local radius of curvature near the optical axis of the aspherical surface of R 10, and an outer periphery of the aspherical surface. When the local radius of curvature of the part is R 11, it is preferable that the following (Equation 3) is satisfied.

 [Number 3]

 0.8 <| R11 I / I R10 | <3.0

 According to this preferred example, coma can be favorably corrected on the wide-angle side, and spherical aberration can be favorably corrected on the telephoto side. In this case, it is preferable that the following condition (Equation 4) is satisfied.

 [Number 4]

 I R 1 1 I Z I R 10 I

 According to this preferred example, it is possible to satisfactorily correct external coma aberration that causes coma flare at the periphery of the screen on the wide-angle side.

 In the first configuration of the zoom lens of the present invention, when the focal length of the third lens unit is f 3 and the focal length of the entire system at the wide-angle end is fw, the following condition (Equation 5) is satisfied. Is preferably satisfied.

 [Number 5]

 2.5 <f 3 / f w <4.0

According to this preferred example, it is possible to secure a back focus in which a crystal filter or an IR cut filter can be inserted. In addition, a zoom lens that can be downsized can be realized. In this case, it is preferable that the following condition (Equation 6) is satisfied.

 [Number 6]

 2.6 <f 3 / f w <3.6

 According to this preferred example, it is possible to secure an air gap enough to insert a quartz filter, an IR cut filter, or the like while maintaining good field curvature.

 Further, in the first configuration of the zoom lens according to the present invention, the object-side surface of the lens closest to the object that forms the third lens group is an aspheric surface, and the vicinity of the optical axis of the aspheric surface Assuming that the local radius of curvature is R 20 and the local radius of curvature of the outer peripheral portion of the aspheric surface is R 21, it is preferable that the following condition (Equation 7) is satisfied.

 [Number 7]

 1. 0 5 <R 2 1 / R 2 0 <2.0

 According to this preferred example, it is possible to realize a zoom lens in which the spherical aberration in the entire zoom region is satisfactorily corrected. In this case, it is preferable that the following condition (Equation 8) is satisfied.

 [Equation 8]

 1.KR 2 1 / R 20 <1.7

 According to this preferred example, the spherical aberration generated by the axial marginal ray can be corrected, so that the flare generated near the center of the screen can be satisfactorily corrected.

In the first configuration of the zoom lens of the present invention, the absolute value of the radius of curvature of the image side surface of the concave lens included in the third lens group is R 30, and the focal length of the third lens group is f 3 In this case, it is preferable that the following condition (Equation 9) is satisfied. [Number 9]

 0.3 5 <R 30 / f 3 <0.6

 According to this preferred example, it is possible to realize a zoom lens in which the frame difference of the light beam outside the principal ray of the off-axis light is favorably corrected. In this case, it is preferable that the following condition (Equation 10) is satisfied.

 [Number 1 0]

 0.40 <R 30 / f 3

 According to this preferred example, inward coma, which is a flare component, can also be satisfactorily corrected.

 In the first configuration of the zoom lens of the present invention, when the focal length of the fourth lens unit is f 4 and the focal length of the entire system at the wide-angle end is fw, the following (Equation 11) is obtained. Preferably, the conditions are satisfied.

 [Number 1 1]

 2.3 <f 4 / f w <3.0

 According to this preferred example, a back focus in which a crystal filter, an IR cut filter, and the like can be inserted can be secured, and a zoom lens that can be downsized can be realized. In this case, it is preferable that the following condition (Equation 12) is satisfied.

 [Number 1 2]

 2.4 <f 4 / f w <2.9

 If f 4 fw is less than 2.4, the assembly tolerance may become tight even if a crystal filter or IR cut filter can be inserted. When f 4Zf w is 2.9 or more, the distance between the third lens unit and the fourth lens unit becomes narrow because the moving amount of the fourth lens unit increases, and similarly, the assembly tolerance may become tight. is there.

Further, in the first configuration of the zoom lens of the present invention, the fourth lens When the object-side surface of the lens group is an aspheric surface, the local radius of curvature near the optical axis of the aspheric surface is R 40, and the local radius of curvature of the outer peripheral portion of the aspheric surface is R 41. It is preferable that the following condition (Equation 13) is satisfied.

 [Number 1 3]

 1.3 3 R 4 1 R 4 0 1.6

 According to this preferred example, it is possible to realize a zoom lens in which the frame difference of the light flux inside the principal ray of the off-axis light is favorably corrected.

 In the first configuration of the zoom lens of the present invention, the aperture diameter of the aperture decreases with an increase in the focal length of the entire system, and the aperture diameter at the telephoto end is St, and the aperture diameter at the wide-angle end is Assuming that S w, it is preferable that the following condition (Equation 14) is satisfied.

 [Number 1 4]

 S t / S w <0. 9 2

 According to this preferred example, deterioration of aberration at the long focal length side, particularly at the telephoto end, can be reduced.

 In general, deterioration of the optical performance of the zoom lens during zooming can be reduced by adjusting the aberration performance of each lens unit. In other words, compared to the type that moves some lenses inside the lens group perpendicular to the optical axis, moving the entire lens group that has the same optical performance reduces camera shake with less aberration degradation. A zoom lens with functions can be realized. In this case, the amount of movement of the third lens group at the focal length f of the entire system at the time of camera shake correction is Y, the amount of movement of the third lens group at the telephoto end is Yt, and the focal length at the telephoto end is ft. At this time, it is preferable that the following conditions (Equation 15) and (Equation 16) are satisfied.

 [Number 1 5]

Y t> Y [Number 1 6]

 (Y / Y t) / (f / f t) <1.5

 According to this preferred example, it is possible to realize camera shake correction with less deterioration in optical performance. In this case, it is preferable that the following condition (Equation 17) is satisfied.

 [Number 1 7]

 (Y / Y t) / (f / f t) <1.2

 If (Y / Y t) / (f / ft) is 1.2 or more, the image may seem to jump when a disturbance occurs, and the panning is conspicuous.

Further, a first configuration of the video camera of the present invention is a video camera provided with a zoom lens, wherein the first configuration of the zoom lens of the present invention is used as the zoom lens. According to the first configuration of the video camera, a small-sized and wide-angle video camera can be realized. ₍ The second configuration of the zoom lens of the present invention is arranged in order from the object side to the image plane side.) A first lens group having a positive refractive power and fixed with respect to the image plane, and a second lens group having a negative refractive power and performing a zooming action by moving on the optical axis. An aperture fixed with respect to an image plane; a third lens group having a positive refractive power; and an image plane having a positive refractive power, the image plane varying with movement of the second lens group and the object. A fourth lens unit that moves on the optical axis so as to keep the lens unit at a fixed position from the first lens unit, wherein the second lens unit includes a first negative lens, which is arranged in order from the object side, The three lenses consisting of the second negative lens and the cemented lens of the positive lens The third lens group includes at least one aspheric surface, and the third lens group includes a first positive lens arranged in order from the object side, a refractive index of 1.55 or less, and a refractive index of 65 or more. Of a second positive lens and a negative lens having a negative Abbe number And at least one aspherical surface, and the fourth lens group includes at least one aspherical surface.

 Further, a third configuration of the zoom lens of the present invention includes a first lens group, which is arranged in order from the object side, has a positive refractive power and is fixed with respect to an image plane, and a negative refractive power. A second lens group having a zooming effect by moving on the optical axis, a stop fixed to the image plane, a third lens group having a positive refractive power, and a positive refraction. A fourth lens group having a power and moving on the optical axis so as to keep the image plane, which fluctuates due to the movement of the object, at a fixed position from the reference plane. The second lens group is composed of three lenses including a first negative lens and a cemented lens of a second negative lens and a positive lens, which are arranged in order from the object side. , Including at least one aspherical surface, wherein the third lens group is arranged in order from the object side, A positive lens, a second positive lens having a refractive index of 1.55 or less and an Abbe number of 65 or more, and a negative lens, and at least one surface The fourth lens group includes at least one aspherical surface.

A fourth configuration of the zoom lens according to the present invention includes a first lens group, which is arranged in order from the object side, has a positive refractive power and is fixed with respect to an image plane, and has a negative refractive power. A second lens group having a zooming effect by moving on the optical axis, a stop fixed to the image plane, a third lens group having a positive refractive power, and a positive refraction. A fourth lens group having a power and moving on the optical axis so as to keep the image plane, which fluctuates due to the movement of the object, at a fixed position from the reference plane. The second lens group includes at least three lenses including a first negative lens, a second negative lens, and a positive lens, which are arranged in order from the object side. The third lens group includes one aspherical surface, and the third lens group is arranged in order from the object side. A first positive lens and a second positive lens having a refractive index of 1.55 or less and an Abbe number of 65 or more are provided. And at least one aspherical surface, and the fourth lens group includes at least one aspherical surface. And

 According to the second to fourth configurations of these zoom lenses, by optimizing the lens type, the arrangement of the aspheric surfaces, and the shape of the aspheric surfaces, various aberrations including chromatic aberration can be reduced with a lens configuration as small as 10 lenses. Correction can be made well. In addition, since the diameters of the lenses constituting the second lens group, the third lens group, and the fourth lens group are all small, aspheric lenses included in these lens groups can be easily manufactured. Also, since the third lens group is composed of three lenses, two positive lenses and one negative lens, it is compact and has good spherical aberration from the wide-angle end to the standard position. Thus, a corrected zoom lens can be realized.

 Also, the condition that the second positive lens constituting the third lens group has a refractive index of 1.55 or less and an Abbe number of 65 or more provides good axial color difference and field curvature over the entire zoom range. It is effective in correcting to.

 In any of the second to fourth configurations of the zoom lens of the present invention, when the focal length of the second lens group is f 2 and the focal length of the entire system at the wide-angle end is fw, It is preferable that the following condition (Equation 18) is satisfied.

 1.0 <I f 2 I / f w <2.0

 In this case, it is preferable that the following condition (Equation 19) is satisfied.

 [Number 1 9]

I f 2 I / f w <1.7 In any one of the second to fourth configurations of the zoom lens of the present invention, the object-side surface of the second negative lens forming the second lens group is an aspheric surface, and the aspheric surface is provided. When the local radius of curvature near the optical axis is R 10 and the local radius of curvature of the outer peripheral portion of the aspheric surface is R 11, it is preferable that the following condition (Equation 20) is satisfied.

 [Number 2 0]

 0.8 <<| R 1 1 | / | R 1 0 | <3. 0

 In this case, it is preferable that the following condition (Equation 21) is satisfied.

 [Number 2 1]

 I R 1 1 I / I R 1 0 | <2.9

In any one of the second to fourth configurations of the zoom lens of the present invention, when the focal length of the third lens group is f 3 and the focal length of the entire system at the wide-angle end is fw, It is preferable that the following condition (Expression 22) is satisfied _c [Expression 2 2]

 2.5 <f 3 / f w <4.0

 In this case, it is preferable that the following condition (Equation 23) is satisfied.

 [Number 2 3]

 2.6 <f 3 / f w <3.6

 In any one of the second to fourth configurations of the zoom lens of the present invention, the focal length of the entire system at the wide-angle end is fw, the first positive lens that forms the third lens group, and When the air gap between the positive lens and the second positive lens is d 31, it is preferable that the following condition (Equation 24) is satisfied.

 [Number 24]

0.02 <d31 / fw <0.50 According to this preferred example, axial chromatic aberration can be satisfactorily corrected with a glass material having no practical problem while maintaining a manufacturable lens interval. In addition, it is preferable that the following condition (Equation 25) is satisfied.

 [Number 2 5]

 d 3 1 / f w <0.40

 According to this preferred example, axial chromatic aberration can be further favorably corrected.

 Further, in any one of the second to fourth configurations of the zoom lens of the present invention, the object-side surface of the lens closest to the object that constitutes the third lens group is an aspheric surface, When the local radius of curvature near the optical axis of the aspherical surface is R 20, and the local radius of curvature of the outer peripheral portion of the aspherical surface is R 21, it is preferable that the following condition is satisfied. .

 [Number 2 6]

 1.05 <R21 / R2 0 <2.0

 In this case, it is preferable that the following condition (Equation 27) is satisfied.

 [Number 2 7]

 1. 1 R 2 1 / R 2 0 <1.7

 In any one of the second to fourth configurations of the zoom lens of the present invention, the absolute value of the radius of curvature of the image side surface of the concave lens included in the third lens group is R 30, and the third lens When the focal length of the group is f3, it is preferable that the following condition (Equation 28) is satisfied.

 [Number 2 8]

 0.35 <R3 0 / f3 <0.6

In this case, it is preferable that the following condition (Equation 29) is satisfied. [Number 2 9]

 0.4 0 <R 3 0 / f 3

 In any one of the second to fourth configurations of the zoom lens of the present invention, when the focal length of the fourth lens group is f 4 and the focal length of the entire system at the wide-angle end is fw, It is preferable that the following condition (Equation 30) is satisfied.

 2.3 <f 4 / f w <3.0

In this case, it is preferable that the following condition (Equation 31) is satisfied: _t [Equation 31]

 2.4 <f 4 / f w <2.9

 Further, in any one of the second to fourth configurations of the zoom lens of the present invention, the object-side surface of the fourth lens unit is an aspheric surface, and the local curvature of the aspheric surface near an optical axis is provided. When the radius is R 40 and the local radius of curvature of the outer peripheral portion of the aspheric surface is R 41, it is preferable that the following condition (Equation 3 2) is satisfied.

 1.3 <R 4 1 / R 4 0 <1.6

 In any one of the second to fourth configurations of the zoom lens according to the present invention, the stop diameter of the stop decreases as the focal length of the entire system increases, and the stop diameter at the telephoto end is S. When t and the aperture diameter at the wide-angle end are Sw, it is preferable that the following condition (Equation 33) is satisfied.

 [Number 3 3]

 S t / S w <0.92

Further, in any one of the second to fourth configurations of the zoom lens of the present invention, the entire third lens group is perpendicular to the optical axis in accordance with the shake amount obtained from the shake amount detector. It is preferable to have a function of correcting the movement of the image due to camera shake by moving the camera in the direction indicated by the arrow. According to this preferred example, Compared to the type that moves some lenses inside the lens group perpendicularly to the optical axis, a zoom lens with a camera shake correction function that causes less aberration deterioration by moving the entire lens group that has the same optical performance Can be realized. In this case, the amount of movement of the third lens group at the focal length f of the entire system at the time of camera shake correction is Y, the amount of movement of the third lens group at the telephoto end is Yt, and the focal length at the telephoto end is Yt. When ft is satisfied, it is preferable that the following conditions (Equation 34) and (Equation 35) are satisfied.

 [Number 34]

 Y t> Y

 [Number 3 5]

 (Y / Y t) / (f / f t) <1.5

 In this case, it is preferable that the following condition (Equation 36) is satisfied.

 [Number 3 6]

 (Y / Y t) / (f / f t) <l. 2

 A second configuration of the video camera according to the present invention is a video camera equipped with a zoom lens, wherein any one of the second to fourth configurations of the zoom lens according to the present invention is used as the zoom lens. It is characterized by. According to the second configuration of the video camera, a small-sized and wide-angle video camera can be realized. BRIEF DESCRIPTION OF THE FIGURES

 FIG. 1 is an arrangement diagram illustrating a configuration of a zoom lens according to a first embodiment of the present invention.

FIG. 2 is an arrangement diagram illustrating a configuration of a zoom lens according to a second embodiment of the present invention. FIG. 3 is an arrangement diagram showing a configuration of a zoom lens according to a third embodiment of the present invention.

 FIG. 4 is an arrangement diagram showing a configuration of a zoom lens having a camera shake correction function according to a fourth embodiment of the present invention.

 FIG. 5 is a layout diagram showing a configuration of a video camera according to the fifth embodiment of the present invention.

 FIG. 6 is an aberration performance diagram at the wide-angle end according to the first embodiment of the present invention.

 FIG. 7 is an aberration diagram at a standard position of the zoom lens according to the first embodiment of the present invention.

 FIG. 8 is an aberration performance diagram at the telephoto end of the zoom lens according to the first embodiment of the present invention.

 FIG. 9 is an aberration performance diagram at the telephoto end of the zoom lens according to Embodiment 1 of the present invention at the time of 0.3-degree camera shake correction.

 FIG. 10 is an aberration performance diagram at the wide-angle end of the zoom lens according to Embodiment 2 of the present invention.

 FIG. 11 is an aberration performance diagram at a standard position of the zoom lens according to the second embodiment of the present invention.

 FIG. 12 is an aberration diagram at the telephoto end of the zoom lens according to the second embodiment of the present invention.

 FIG. 13 is an aberration performance diagram at the telephoto end of the zoom lens according to Embodiment 2 of the present invention at the time of 0.3-degree camera shake correction.

 FIG. 14 is an aberration performance diagram at the wide-angle end of the zoom lens according to Embodiment 3 of the present invention.

 FIG. 15 is an aberration performance diagram at a standard position of the zoom lens according to the third embodiment of the present invention.

FIG. 16 shows aberration performance at the telephoto end of the zoom lens according to Embodiment 3 of the present invention. FIG.

 FIG. 17 is an aberration performance diagram at the telephoto end of the zoom lens according to Embodiment 3 of the present invention at the time of 0.3-degree camera shake correction.

 FIG. 18 is an aberration diagram at the wide-angle end of the zoom lens according to Example 4 of the present invention.

 FIG. 19 is an aberration performance diagram at a standard position of the zoom lens according to Embodiment 4 of the present invention.

 FIG. 20 is an aberration performance diagram at the telephoto end of the zoom lens according to Embodiment 4 of the present invention.

 FIG. 21 is an aberration performance diagram at the telephoto end of the zoom lens according to Embodiment 4 of the present invention at the time of 0.3-degree camera shake correction.

 FIG. 22 is an aberration diagram at the wide-angle end of the zoom lens according to Example 5 of the present invention.

 FIG. 23 is an aberration performance diagram at a standard position of the zoom lens according to Example 5 of the present invention.

 FIG. 24 is an aberration performance diagram at the telephoto end of the zoom lens according to Embodiment 5 of the present invention.

 FIG. 25 is an aberration performance diagram at the time of correcting a camera shake by 0.3 degrees at the telephoto end of the zoom lens according to Embodiment 5 of the present invention.

 FIG. 26 is an aberration diagram at the wide-angle end of the zoom lens according to Embodiment 6 of the present invention.

 FIG. 27 is an aberration performance diagram at a standard position of the zoom lens according to Embodiment 6 of the present invention.

 FIG. 28 is an aberrational diagram at the telephoto end of the zoom lens according to Embodiment 6 of the present invention.

FIG. 29 shows 0.3 degrees at the telephoto end of the zoom lens according to Embodiment 6 of the present invention. FIG. 9 is an aberration performance diagram at the time of camera shake correction.

 FIG. 30 is an aberrational diagram at the wide-angle end of the zoom lens according to Embodiment 7 of the present invention.

 FIG. 31 is an aberration performance diagram at a standard position of the zoom lens according to Embodiment 7 of the present invention.

 FIG. 32 is an aberrational diagram at the telephoto end of the zoom lens according to Embodiment 7 of the present invention.

 FIG. 33 is an aberration performance diagram of the zoom lens according to Embodiment 7 of the present invention at the telephoto end at the time of 0.3-degree camera shake correction.

 FIG. 34 is an aberration diagram at the wide-angle end of the zoom lens according to Embodiment 8 of the present invention.

 FIG. 35 is an aberration performance diagram at a standard position of the zoom lens according to Embodiment 8 of the present invention.

 FIG. 36 is an aberrational diagram at the telephoto end of the zoom lens according to Embodiment 8 of the present invention.

 FIG. 37 is an aberration performance diagram at the time of correcting a camera shake by 0.3 degrees at the telephoto end of the zoom lens according to Embodiment 8 of the present invention.

 FIG. 38 is an aberration diagram at the wide-angle end of the zoom lens according to Embodiment 9 of the present invention.

 FIG. 39 is an aberration performance diagram at a standard position of the zoom lens according to Embodiment 9 of the present invention.

 FIG. 40 is an aberration diagram at the telephoto end of a zoom lens according to Embodiment 9 of the present invention.

 FIG. 41 is an aberration performance diagram at the telephoto end of the zoom lens according to Embodiment 9 of the present invention at the time of 0.3-degree camera shake correction.

FIG. 42 shows aberrations at the wide-angle end of the zoom lens according to the tenth embodiment of the present invention. It is a Noh figure.

 FIG. 43 is an aberration performance diagram at a standard position of the zoom lens according to Example 10 of the present invention.

 FIG. 44 is an aberrational performance diagram at the telephoto end of the zoom lens according to the tenth embodiment of the present invention.

 FIG. 45 is an aberration performance diagram at the telephoto end of the zoom lens of Embodiment 10 of the present invention at the time of 0.3-degree camera shake correction. BEST MODE FOR CARRYING OUT THE INVENTION

 Hereinafter, the present invention will be described more specifically with reference to embodiments.

 [First Embodiment]

 FIG. 1 is an arrangement diagram illustrating a configuration of a zoom lens according to a first embodiment of the present invention. As shown in FIG. 1, the zoom lens according to the present embodiment includes a first lens group arranged in order from the object side (the left side in FIG. 1) to the image plane 17 side (the right side in FIG. 1). 1 1, 2nd lens group 1 2, aperture 15, 3rd lens group 1 3, 4th lens group 1 4, optical aperture and single pass filter. Equivalent to filter and CCD face plate It is composed of a flat plate 16.

The first lens group 11 has a positive refractive power, and is fixed with respect to the image plane 17 both during zooming and during focusing. The second lens group 12 is composed of three lenses including a first negative lens and a cemented lens of a second negative lens and a positive lens arranged in order from the object side. It has a negative refractive power. The second lens group 12 is a lens group that performs a zooming action by moving on the optical axis. The third lens group 13 includes three lenses including a first positive lens and a cemented lens of a second positive lens and a negative lens, which are arranged in order from the object side. During zooming and focusing, it is fixed with respect to the image plane 17. The fourth lens group 14 is composed of a single lens having a positive refractive power, and keeps the second lens group 12 and the image plane 17 that fluctuates due to the movement of the object at a fixed position from the reference plane. Move on the optical axis. That is, the fourth lens group 14 simultaneously moves the image by zooming and adjusts the focus by moving on the optical axis.

 The second positive lens constituting the third lens group preferably has a refractive index of 1.55 or less and an Abbe number of 65 or more. By satisfying these conditions, it is possible to satisfactorily correct axial chromatic aberration and field curvature over the entire zoom range.

 When the focal length of the second lens group 12 is f 2 and the focal length of the entire system at the wide-angle end is fw, it is desirable that the following condition (Equation 37) is satisfied.

 [Number 3 7]

 1.0 <I f 2 I / f w <2.0

The above (Equation 37) is a conditional expression regarding the power of the second lens group 12. I 2 | when / ^/ is 1.0 or less, it becomes difficult to correct curvature of field. If If 2 I Zfw is 2.0 or more, the amount of movement of the second lens unit 12 during zooming becomes large, so that the overall length becomes long, and it becomes difficult to realize a compact zoom lens. Further, by satisfying the following condition (Equation 38), the moving amount of the second lens unit can be reduced while the field curvature is further reduced.

 [Number 38]

 I f 2 I / f w <l. 7

The object-side surface of the second negative lens constituting the second lens group 12 is an aspheric surface, the local radius of curvature near the optical axis of the aspheric surface is R 10, and the outer peripheral portion of the aspheric surface Let R 11 be the local radius of curvature of It is desirable that the conditions be satisfied.

 [Number 39]

 0.8 <<| R 1 1 | / | R 10 | <3.0

 When IR 11 I Ί R 10 I is 3.0 or more, the outer coma aberration of the light beam outside the principal ray of off-axis light is large on the wide angle side, and the spherical aberration is insufficiently corrected on the telephoto side. . If the IR 11 IIR 10 I is less than 0.8, spherical aberrations are excessively corrected, especially on the telephoto side, and large inner coma occurs near the standard position, making it impossible to obtain good aberration correction. . Furthermore, by satisfying the following condition (Equation 40), it is possible to satisfactorily correct external coma aberration that causes coma flare at the periphery of the image on the wide-angle side.

 [Number 40]

 I R 11 I / I R 10 I <2.9

 When the focal length of the third lens group 13 is f 3 and the focal length of the entire system at the wide-angle end is f w, it is desirable that the following condition (Equation 41) is satisfied.

 [Number 41]

 2.5 <f 3 / f w <4.0

The above (Equation 41) is a conditional expression regarding the power of the third lens group 13. When f3 / fw becomes 2.5 or less, a back focus in which a crystal filter, an IR cut filter, and the like can be inserted. It is difficult to secure Also, when f 3Zfw exceeds 4.0, the overall length becomes long, and it is difficult to realize a small zoom lens. Further, by satisfying the following condition (Equation 42), it is possible to secure an air gap enough to insert a crystal filter or an IR cut filter while maintaining good field curvature. [Number 42]

 2.6 <f 3 / f w <3.6

 As described above, the third lens group 13 includes three lenses including two positive lenses and one negative lens. With this lens configuration, it is possible to realize a zoom lens that is small and that has a good correction of spherical aberration from the wide-angle end to the standard position.

 When the air distance between the first positive lens and the second positive lens constituting the third lens group 13 is d 31 and the focal length of the entire system at the wide-angle end is fw, It is desirable that the condition of 43) is satisfied.

 [Number 43]

 0.02 <d3 1 / f w 0.5

 If d31 / fw is less than 0.02, two lenses may contact each other due to a manufacturing error, and the lens surface may be damaged. On the other hand, when dSlZfw is 0.5 or more, it is difficult to satisfactorily correct longitudinal chromatic aberration with a glass material having no practical problem. Further, by satisfying the following condition (Equation 44), axial chromatic aberration can be further favorably corrected.

 [Number 44]

 d 3 1 / f w <0.40

 Furthermore, the object-side surface of the lens located closest to the object and constituting the third lens group 13 is an aspheric surface, the local radius of curvature near the optical axis of the aspheric surface is R 20, and the aspheric surface When the local radius of curvature of the outer peripheral portion is R 21, it is desirable that the following condition (Equation 45) is satisfied.

 [Number 45]

 1.05 <R21 / R2 0 <2.0

The above (Equation 45) is a conditional expression relating to the aspherical surface of the object-side surface of the lens located closest to the object side, which constitutes the third lens unit 13, and has a favorable spherical aberration. Defines the range to be corrected. When 1 ^ 2 1! ^ 20 is less than 1.05, negative spherical aberration occurs, and when R2 1ZR20 exceeds 2.0, overcorrection results in positive spherical aberration. . Furthermore, by satisfying the following condition (Equation 46), it is possible to correct the spherical aberration generated by the on-axis marginal ray, so that the flare generated near the center of the screen can be corrected well. it can.

 [Number 46]

 1.1 <R 21 / R 20 <1.7

 Further, when the absolute value of the radius of curvature of the image side surface of the concave lens included in the third lens group 13 is R 30, and the focal length of the third lens group 13 is f 3, the following condition (Equation 47) is satisfied. It is desirable to be satisfied.

 [Number 47]

 0.3 5 <R 30 / f 3 <0.6

The conditional expression (Equation 47) defines the range in which the coma of the light beam outside the principal ray of the off-axis light is favorably corrected. ! ^ 3 0 / ^/ 3 When becomes 0.6 or more, frames of inward occurs at zooming intermediate position, when R 3 0 3 is 0.3 5 or less, the frame outward occurs. Further, by satisfying the following condition (Equation 48), inward coma aberration, which is a flare component, can be corrected well.

 [Number 48]

 0.40 <R 30 / f 3

 When the focal length of the fourth lens group 14 is f 4 and the focal length of the entire system at the wide-angle end is f w, it is desirable that the following condition (Equation 49) is satisfied.

 [Number 49]

2.3 <f 4 / f w <3.0 (Equation 49) above is a conditional expression for the power of the fourth lens group 14. When <f 4Z fw is 2.3 or less, the back focus that can introduce a crystal filter, an IR cut filter, and the like is set. It is difficult to secure. If f 4 / fw is 3.0 or more, the amount of movement of the fourth lens group 14 during focusing becomes large, and it is difficult to realize a small zoom lens. Further, it is desirable to satisfy the following condition (Equation 50).

 [Number 50]

 2.4 <f 4 / f w <2.9

 If f 4Z f w is 2.4 or less, the assembly tolerance may become tight even if a crystal filter or an IR cut filter can be inserted. When f4 / fw is 2.9 or more, the distance between the third lens group and the fourth lens group is reduced due to an increase in the amount of movement of the fourth lens group. There is.

 The object-side surface of the lens of the fourth lens group 14 is an aspheric surface, and the local radius of curvature near the optical axis of the aspheric surface is R 40, and the local radius of curvature of the outer peripheral portion of the aspheric surface is R When 41 is set, it is desirable that the following condition (Equation 51) is satisfied.

 [Number 5 1]

 1.3 <R 41 / R 40 <1.6

 The above (Equation 29) is a conditional expression relating to the aspherical surface of the object-side surface of the fourth lens group 14, and defines the range in which the coma of the light flux inside the principal ray of the off-axis light is favorably corrected. Things. When the length is 140 or less, an inward frame is generated, and when the R41ZR40 is 1.6 or more, an outward frame is generated.

Also provided on the object side of the third lens group 13 and fixed to the image plane 17 When the aperture diameter of the aperture 15 decreases as the focal length of the entire system increases, and the aperture diameter at the telephoto end is St and the aperture diameter at the wide-angle end is Sw, the following condition (Equation 5 2) is satisfied. Is preferably satisfied.

 [Number 5 2]

 S t / S w <0.92

 When St / Sw is 0.92 or more, the deterioration of aberration at the long focal length side, particularly at the telephoto end, becomes large.

 Further, it is desirable to correct the fluctuation of the image due to camera shake by moving the entire third lens group 13 perpendicular to the optical axis. As a result, deterioration of chromatic aberration during correction can be reduced.

 Also, the amount of movement of the third lens group 13 (correction lens) at the focal length f of the entire system at the time of camera shake correction is Y, the amount of movement of the third lens group 13 (correction lens) at the telephoto end is Yt, When the focal length at the end is ft, it is desirable that the following conditions (Equation 53) and (Equation 54) are satisfied.

 [Number 5 3]

 Y t> Y

 [Number 54]

 (Y / Y t) / (f / f t) <1.5

 The above (Equation 53) and (Equation 54) are conditional expressions relating to the amount of movement of the third lens group 13 (correction lens). In the case of a zoom lens, when the correction angle is constant over the entire zoom range, the larger the zoom ratio, the larger the amount of movement of the correction lens, and conversely, the smaller the zoom ratio, the smaller the amount of movement of the correction lens. If the values deviate from the limits of (Equation 53) and (Equation 54), the correction will be excessive and the deterioration of the optical performance including monochromatic aberration will increase.

Near the telephoto end, the angle of view is narrow, so if Y exceeds Yt, the performance will deteriorate and the image will become unnatural. The above (Equation 54) mainly specifies the upper limit of the camera shake on the wide-angle side. When (YZY t) Z (f / ft) becomes 1.5 or more, the correction becomes excessive, and the deterioration of the optical performance is reduced. growing. Also, the screen after correction will be unnatural.

 By satisfying the above (Equation 53) and (Equation 54), it is possible to realize a zoom lens having a natural image stabilization function with less deterioration in optical performance.

 Further, it is desirable to satisfy the following condition (Equation 55).

 [Number 5 5]

 (Y / Y t) / (f / f t) <1.2

 If (Y / Y t) / (f / ft) is 1.2 or more, the image may seem to jump when a disturbance occurs, and the panning is conspicuous.

 [Second embodiment]

 FIG. 2 is an arrangement diagram illustrating a configuration of a zoom lens according to a second embodiment of the present invention. As shown in FIG. 2, the zoom lens according to the present embodiment includes a first lens group 2 arranged in order from the object side (the left side in FIG. 2) to the image plane 27 side (the right side in FIG. 2). 1, a second lens group 22, an aperture 25, a third lens group 23, a fourth lens group 24, and a flat plate 26 equivalent to an optical low-pass filter and a CCD face plate Has been done.

The first lens group 21 has a positive refractive power, and is fixed with respect to the image plane 27 both during zooming and during focusing. The second lens group 22 is composed of three lenses including a first negative lens and a cemented lens of a second negative lens and a positive lens, which are arranged in order from the object side. It has a negative refractive power. This second lens group 22 moves on the optical axis. This is a lens group that performs a zooming action by moving. The third lens group 23 is composed of three lenses including a first positive lens, a second positive lens, and a negative lens arranged in order from the object side. Sometimes it is fixed relative to the image plane 27. The fourth lens group 24 is composed of one lens having a positive refractive power, and the second lens group 22 and the image plane 27 that fluctuates due to the movement of the object are located at a fixed position from the reference plane. Move on the optical axis to keep. That is, the fourth lens group 24 simultaneously moves the image by zooming and adjusts the force by moving on the optical axis.

 As in the first embodiment, the second positive lens forming the third lens group 23 preferably has a refractive index of 1.55 or less and an Abbe number of 65 or more. Also, it is desirable that the conditions of (Equation 37) to (Equation 55) are satisfied.

 [Third Embodiment]

 FIG. 3 is an arrangement diagram showing a configuration of a zoom lens according to a third embodiment of the present invention. As shown in FIG. 3, the zoom lens according to the present embodiment includes a first lens group arranged in order from the object side (the left side in FIG. 3) to the image plane 37 side (the right side in FIG. 3). 3 1, 2nd lens group 3 2, aperture 3 5, 3rd lens group 3 3, 4th lens group 34, and flat plate 36 equivalent to an optical low-pass filter and CCD face plate It is configured.

The first lens group 31 has a positive refractive power, and is fixed with respect to the image plane 37 both during zooming and during focusing. The second lens group 32 is composed of three lenses including a first negative lens, a second negative lens, and a positive lens arranged in order from the object side. Has bending power. This second lens group 32 moves along the optical axis. Therefore, it is a lens group that performs a zooming action. The third lens group 33 is composed of three lenses including a first positive lens and a cemented lens of a second positive lens and a negative lens arranged in order from the object side. At the time of doubling and focusing, it is fixed with respect to the image plane 37. The fourth lens group 34 is composed of a single lens having a positive refractive power. The second lens group 32 and the image plane 37 that fluctuates due to the movement of the object are fixed at a certain position from the reference plane. On the optical axis to keep That is, the fourth lens group 34 simultaneously moves the image by zooming and adjusts the force by moving on the optical axis.

 As in the first embodiment, the second positive lens constituting the third lens group 33 preferably has a refractive index of 1.55 or less and an Abbe number of 65 or more. Also, it is desirable that the conditions of (Equation 37) to (Equation 55) are satisfied.

 [Fourth embodiment]

FIG. 4 is an arrangement diagram showing a configuration of a zoom lens having a camera shake correction function according to a fourth embodiment of the present invention. As shown in FIG. 4, in the zoom lens having the image stabilization function according to the present embodiment, the first lens group 41 and the second lens constituting the zoom lens according to the first to third embodiments. A group 42, an aperture 45, a third lens group 43, a fourth lens group 44, a flat plate 46 equivalent to an optical low-pass filter, and an imaging element 47 are arranged in this order. In addition, a detector 48 is connected to the third lens group 43 via a driving device 49 having a driving circuit. Here, the detector 48 detects a camera shake amount. The driving device 49 moves the third lens group 43 in two directions perpendicular to the optical axis. As a result, it is possible to realize a zoom lens having a small and high-precision camera shake correction function. [Fifth Embodiment]

 FIG. 5 is a layout diagram showing a configuration of a video camera according to the fifth embodiment of the present invention. The video camera according to the present embodiment includes the zoom lens 51, the image sensor 52, and the signal processing circuit 53 according to the first to fourth embodiments. As a result, a small and wide-angle video camera can be realized.

 Hereinafter, the present invention will be described in more detail with reference to specific examples.

 (Example 1)

 The following (Table 1) shows specific examples of the zoom lens according to the first embodiment.

 [Table 1] Group surface r d n

 1 3 5 5 3 3 0-7 0 1 .8 4 6 6 6 2 3.9

 2 1 5 4 4 9 5. 0 5 1 .6 9 6 8 0 5 5.6

 1 3 —4 1 9 2 3 2 0. 1 2

 4 1 3 6 6 9 2.70 .1.7 7 2 5 0 A 9.6

 5 3 5 8 5 7 Variable

 6 3 5 8 5 7 0 .4 0 1 .8 3 4 0 0 37.2

 7 3 8 3 2 2. 3 8

 2 8 1 6 5 5 2 0 .5 5 1 .6 6 5 4 7 5 5.2

 9 5 2 5 0 1 .7 5 1 .8 4 6 6 6 2 3.9

 1 0 -8 7 8 7 2 Variable

 Aperture 1 1 1. 0 0

 1 2 6 0 9 5 2.75 5 1 .6 0 6 0 2 5 7.5

3 1 3-1 0 7 0 0 0. 4 5

 1 4 8 7 2 0 1 .7 5 1 .4 8 7 4 9 7 0 .4

1 5-4 9 5 7 8 0.4 .0 1 .8 4 6 6 6 23.9

1 6 5 0 5 6 Variable

 4 1 7 6 5 7 5 2.3 0 1 .5 1 4 5 0 6 3.1

 1 8 1 1 9 .0 8 2 Variable

 5 1 9 α 2.3 0 1 .5 1 6 3 3 6 4.1

20 In Table 1 above, r (mm) is the radius of curvature of the lens, d (mm) is the thickness of the lens or the air gap of the lens, and n is the bending of each lens with respect to the d-line. The refractive index and the re are the Abbe numbers of each lens with respect to the d-line, respectively (the same applies to Examples 2 to 10 below).

 Further, the aspherical shape is defined by the following (Equation 56) (the same applies to the following Examples 2 to L0).

但し、 [Number 56]

However,

 SAG: Distance from the aspherical vertex to the point on the aspheric surface at height H from the optical axis

 H: Height from optical axis

R: radius of curvature of aspherical vertex

K: conical constant

D, E: Aspheric coefficient

 The following (Table 2) shows the aspherical shape of the zoom lens according to the present embodiment <[Table 2]

Also, Table 3 below shows the values when the object point is located 2 m from the lens tip as an example of the air gap that can be changed by zooming. <Also, the following Table 3 shows the focus. Shows the aperture diameter that changes with distance. [Table 3]

上記 （表 3) において、 標準位置は第 3レンズ群 1 3と第 4レンズ群 14とが最接近する位置である。 また、 f 、 FZN〇、 ω (度） は、 上 記 （表 1 ) に示すズームレンズの広角端、 標準位置、 望遠端における焦 点距離、 Fナンバー、 入射半画角を表している。 上記 （表 3) から分か るように、 本実施例の広角端の画角は 6 5. 6 0度である。

In the above (Table 3), the standard position is the position where the third lens group 13 and the fourth lens group 14 come closest to each other. F, FZN〇, and ω (degrees) represent the focal length, F-number, and half angle of incidence at the wide-angle end, standard position, and telephoto end of the zoom lens shown in Table 1 above. As can be seen from the above (Table 3), the angle of view at the wide-angle end in this embodiment is 65.60 degrees.

 As shown in the above (Table 1), the second positive lens of the third lens group 13 has a refractive index of 1.55 or less and an Abbe number of 65 or more. In addition, axial chromatic aberration and field curvature over the entire zoom range are well corrected.

The following (Table 4) shows specific numerical values corresponding to (Equation 37) to (Equation 55) in this example.

[Table 4]

(1) f21 / fw = 1.006

 (2) R 1 1 1/1 R 1 0 1 = = 0.85 2

 (3) f 3 / f w = 2.675

 (4) d1 3 / f3: 0.12 2

 (5) R 1 2 / R 2 0 ― = 1.5 1 8

 (6) R 30 / f 3: 0.5 1 2

 (7) f 4 / f w = 2.65 5

 (8) R 4〗 / R 4 0 = 1. 4 64

 (9) S t / S w: 0.75 8

 (1 0) Y (Y t = 0 8 8)

 Wide-angle end Standard position

 0. 0 1 9 0. 092

(1 1) (YXY t) / (i / ί

上記 （表 4) に示すように、 本実施例は、 第 2レンズ群 1 2の焦点距 離 f 2が上記 （数 3 7) を満足し、 広角であるにもかかわらず、 像面湾 曲が小さく補正された小型のズームレンズを実現することができる。 また、 本実施例におけるズームレンズは、 第 2レンズ群 1 2が、 物体 側から順に配置された、 第 1の負レンズと、 第 2の負レンズと正レンズ との接合レンズとからなる 3枚のレンズによって構成されている。 また, 第 2の負レンズの物体側の面が非球面であり、 特に、 当該非球面の光軸 近傍の局所的曲率半径 R 1 0と当該非球面の外周部の局所的曲率半径 R 1 1とが上記 （表 4) に示す値を有し、 上記 （数 3 9) の条件式が満足 されている。 これにより、 広角側でのコマ収差と、 望遠側での球面収差 とが良好に補正されている。

As shown in the above (Table 4), in the present embodiment, the focal length f 2 of the second lens group 12 satisfies the above (Equation 37), and despite the wide angle, the curvature of the image surface is large. , A small zoom lens with small correction can be realized. Further, the zoom lens according to the present embodiment includes three lenses including a first negative lens, and a cemented lens of a second negative lens and a positive lens, in which the second lens group 12 is arranged in order from the object side. Lens. Also, the object-side surface of the second negative lens is an aspheric surface, and in particular, a local radius of curvature R 10 near the optical axis of the aspheric surface and a local radius of curvature R 11 of the outer peripheral portion of the aspheric surface Have the values shown in the above (Table 4), and the conditional expression (Equation 39) is satisfied. Thus, the coma on the wide-angle side and the spherical aberration on the telephoto side are satisfactorily corrected.

Also, the zoom lens in the present embodiment is as shown in the above (Table 4). The focal length f3 of the third lens group 13 satisfies the above (Equation 41), and a small zoom lens with a back focus that can insert a crystal filter or IR cut filter is realized. ing.

 In the zoom lens of the present embodiment, the third lens group 13 is composed of three lenses including a first positive lens and a cemented lens of a second positive lens and a negative lens, and is compact and compact. In addition, a zoom lens in which the spherical aberration from the wide-angle end to the standard position is satisfactorily corrected is realized. Further, in the zoom lens of the present embodiment, the air distance d 31 between the first positive lens and the second positive lens constituting the third lens group 13 and the focal length fw of the entire system at the wide-angle end. Have the values shown in the above (Table 4), and the above (Equation 43) is satisfied. As a result, axial chromatic aberration is favorably corrected while maintaining a manufacturable lens interval.

 In the zoom lens according to the present embodiment, both surfaces of the lens which is the most object side of the third lens group 13 are aspherical surfaces. The local radius of curvature R 20 and the local radius of curvature R 21 of the outer periphery of the aspheric surface have the values shown in the above (Table 4), and the above (Equation 45) is satisfied. As a result, spherical aberration over the entire zoom range is successfully corrected.

 In the zoom lens according to the present embodiment, the absolute value R 30 of the radius of curvature of the image side surface of the concave lens included in the third lens group 13 and the focal length f 3 of the third lens group 13 are as shown in the above table. It has the value shown in 4) and satisfies the above (Equation 47). As a result, the coma of the light beam outside the principal ray of the off-axis light is satisfactorily corrected.

In the zoom lens according to the present embodiment, as shown in the above (Table 4), the focal length f 4 of the fourth lens group 14 satisfies the above (Equation 49), and a crystal filter, an IR cut filter, etc. Can insert a back A small zoom lens with a secured focus has been realized.

 In the zoom lens according to the present embodiment, the object-side surface of the lens of the fourth lens unit 14 is an aspheric surface, and the local radius of curvature R 40 near the optical axis of the aspheric surface and the aspheric surface. The local radius of curvature R 41 of the outer peripheral portion of the spherical surface has the value shown in the above (Table 4), and the above (Equation 51) is satisfied. As a result, the coma of the light beam inside the principal ray of the off-axis light is favorably corrected.

 In the zoom lens of this embodiment, the stop diameter of the stop 15 fixed with respect to the image plane provided on the object side of the third lens group 13 is, as shown in (Table 3) above, It decreases with an increase in the focal length of the system, and the ratio between the aperture diameter St at the telephoto end and the aperture diameter Sw at the wide-angle end has the value shown in Table 4 above. That is, the above (Equation 52) is satisfied, and the aberration at the long focal length side, particularly at the telephoto end, is favorably corrected.

 In the present embodiment, the entire third lens group 13 is moved perpendicularly to the optical axis to correct the image fluctuation at the time of camera shake, and the chromatic aberration during correction is small. It is suppressed.

 In the present embodiment, the movement amount Y of the third lens group 13 (correction lens) at the wide-angle end, the standard position, and the telephoto end and the focal length f of the entire system are calculated as shown in Table 4 above. This satisfies the above (Equation 53) and (Equation 54), whereby deterioration of various aberrations at the time of correction is suppressed to a small value.

6 to 8 show aberration performance diagrams of the zoom lens shown in (Table 1) at the wide-angle end, the standard position, and the telephoto end. In each of the drawings, (a) is a diagram of spherical aberration with respect to d-line. (B) is a diagram of astigmatism, where a solid line indicates sagittal field curvature and a broken line indicates meridional field curvature. (C) is a diagram of distortion, (d) is a diagram of axial chromatic aberration, a solid line shows a value for d-line, a short dashed line shows a value for F-line, and a long dashed line shows a value for C-line, respectively. ing. (E) is a diagram of chromatic aberration of magnification. The short dashed line shows the value for the F line, and the long dashed line shows the value for the C line. The explanations of (a) to (e) above are given in Fig. 10 to Fig. 12, Fig. 14 to Fig. 16, Fig. 18 to Fig. 20, Fig. 22 to Fig. 24, Fig. 26 to Fig. 28, Fig. The same applies to 30 to FIG. 32, FIG. 34 to FIG. 36, FIG. 38 to FIG.

 FIG. 9 shows an aberration performance chart at the telephoto end at the time of 0.3-degree camera shake correction. In FIG. 9, (f) is the relative image height 0.75, (g) is the center of the screen,

(h) shows a diagram of the lateral aberration at a relative image height of 0.75, respectively. The solid line shows the value for the d line, the short dashed line shows the value for the F line, and the long dashed line shows the value for the C line. The above explanations of (f) to (h) are the same for FIGS. 13, 17, 21, 25, 29, 33, 37, 41, and 45. as can be seen from the _c Figure 6-9 is, the zoom lens of this embodiment, when quiescent, shows both excellent aberration performance at image stabilization.

 (Example 2)

 Table 5 below shows other specific examples of the zoom lens according to the first embodiment. The first lens group 11, the second lens group 12, and the aperture 15 are omitted because they are the same as the above (Table 1) of the first embodiment.

 [Table 5]

 1st, 2nd, and aperture are the same as in [Table 1]

 Group plane r d n

 1 2 6. 8 8 7 2. 7 5 1.6. 0 6 0 2 5 7.5

 3 1 3 — 1〗. 8 9 7 1 .2 5 1 .4 9 7 0 0 8 1 .2 1 8. 1 4 8 1 .7 5

 1 5-4 9.9 0 9 0 .4 0 1 .8 4 6 6 6 23.9

 1 6 5. 3 4 5 Variable

 4 1 7 6. 1 5 2.3 0 1.5 1 4 5 0 6 3.1 1 8-1 6.5 1 5 Variable

 1 9 2. 3 0 1 .5 1 6 3 3 6 4.1

5 2 0 The following (Table 6) shows the aspherical shape of the zoom lens according to the present example. <[Table 6]

Further, in the following (Table 7), as an example of a variable air gap by zooming, measured from the tip of the lens to the position of 2 m shows a value when there is object point _(also in the following (Table 7), the focal Shows the aperture diameter that changes with distance.

 [Table 7]

上記 （表 7) から分かるように、 本実施例の広角端の画角は 6 5. 7 度である。

As can be seen from the above (Table 7), the angle of view at the wide-angle end in this embodiment is 65.7 degrees.

 As shown in Table 5 above, the second positive lens of the third lens group 13 has a refractive index of 1.55 or less and an Abbe number of 65 or more. are doing.

The following (Table 8) shows specific numerical values corresponding to (Equation 37) to (Equation 55) in this example. [Table 8]

 (1 0) Y (Y t = 0.199)

上記 （表 8) に示すように、 本実施例におけるズームレンズは、 上記 (数 3 7) 〜 （数 5 5) の条件を満足している。

As shown in the above (Table 8), the zoom lens according to the present embodiment satisfies the conditions of (Equation 37) to (Equation 55).

 FIGS. 10 to 12 show aberration performance diagrams of the zoom lens shown in (Table 7) at the wide-angle end, the standard position, and the telephoto end. Fig. 13 shows the aberration performance at the telephoto end at the time of 0.3-degree camera shake correction. As can be seen from FIGS. 10 to 13, the zoom lens according to the present example shows good aberration performance.

 (Example 3)

The following (Table 9) shows still another specific example of the zoom lens according to the first embodiment. The first lens group 11, the second lens group 12, and the aperture 15 are omitted because they are the same as the above (Table 1) of the first embodiment. [Table 9] Group, 2 groups, aperture same as [Table 1]

下記 （表 1 0) に、 本実施例におけるズームレンズの非球面形状を示 す。

The following (Table 10) shows the aspherical shape of the zoom lens according to the present example.

 [Table 10]

また、 下記 （表 1 1 ) に、 ズーミングによって可変な空気間隔の実施 例として、 レンズ先端から測って 2 mの位置に物点がある場合の値を示 す。 また、 下記 （表 1 1 ) に、 焦点距離とともに変化する絞り径を示す < [表 1 1 ]

Also, the following (Table 11) shows the values when the object point is 2 m from the front of the lens as an example of the variable air spacing by zooming. Also, the following (Table 11) shows the aperture diameter that changes with the focal length. <[Table 11]

 Wide angle standard

 f 3.6 9 2 1 6. 8 3 6 3 4. 7 8 7

 F / N 0 1 .8 6 3 2.3 5 3 2.1 2

 2 ω 6 5.5 4 1 5. 0 6 7.28

 Aperture diameter 6.2 0 5. 0 0 4.7 0

 d 1 6 4. 9 9 1 2. 0 4 0 4. 2 6 7

d 1 8 1 .0 0 9 3.96 2 1 .7 3 3 As can be seen from the above (Table 11), the angle of view at the wide-angle end in this embodiment is 65.5 degrees.

 As shown in Table 9 above, the second positive lens of the third lens group 13 has a refractive index of 1.55 or less and an Abbe number of 65 or more. are doing.

 The following (Table 12) shows specific numerical values corresponding to the above (Equation 37) to (Equation 55) in this example.

 [Table 1 2]

(1) I f 2 I / f w 1. 0 0

 (2) I R 1 1 I / | R 1 0 0.85

 (3) f 3 / f w 2.64

 (4) d1 3 / f3 0.02

 (5) R 1 2 / R 2 0 1 .2 0

 (6) R30 / f300.50

 (7) f 4 / f w 2.83

 (8) R 1 / R 4 0 .1.5 1

 (9) St ZS w 0.75

(1 0) Y (Y t = 0.18 1)

上記 （表 1 2) に示すように、 本実施例におけるズームレンズは、 上 記 （数 3 7) 〜 （数 5 5) の条件を満足している。 (ID (YZY t) / (f / ft)

As shown in the above (Table 12), the zoom lens according to the present embodiment satisfies the above-mentioned conditions (Formula 37) to (Formula 55).

Figures 14 to 16 show aberration performance charts of the zoom lens shown in (Table 11) at the wide-angle end, the standard position, and the telephoto end. Fig. 17 shows the aberration performance at the telephoto end when correcting camera shake by 0.3 degrees. From Fig. 14 to Fig. 17 As can be seen, the zoom lens according to the present example shows good aberration performance.

 (Example 4)

 The following (Table 13) shows other specific examples of the zoom lens according to the first embodiment.

 [Table 13]

 Group r O η V

1 3 3.6 2 8 0.7 .0 1 .8 4 6 6 6 2 3.9

 n

 L 1.13 2 .00 U 1.6 .6 6 6 0 55.6

1 3 — 2 3 7. 8 4 8 0. 1 2

 A 1 2.68 8 1 2.15 1 .7 7 2 5 0 49.6

 0 3 4. 6 3 5

 6 3 1-7 2 0 0 .4 0 1 .8 3 4 0 0 37.2

7 3.5 8 6 2. 0 3

 2 8-5. 6 8 6 0.5 0.5 1. 6 6 5 4 7 5 5.2

 9 4.96 6 2 1 .6 0 1 .8 4 6 6 6 2 3.9

1 0 -5 7. 6 8 4 Variable

 Aperture 1 1 0.7.0

 1 2 5.5 2 9 2. 6 5 1 6 0 6 0 2 5 7.5

3 1 3-1 1 .5 6 5 0.4 9

 1 4 7.5 1 1 1 .5 0 1 .5 1 6 3 3 6 4-1

1 5 — 2 0 8.8 3 9 0 .4 0 1 .8 4 6 6 6 23.9

1 6 4. 4 1 1 Variable

 4 1 7 6. 3 8 9 2. 1 7 1 .5 1 5 0 6 3.1

 1 8 -4 1 .3 1 0 Variable

 5 1 9 2. 3 0 1 .5 1 6 3 3 6 4-1

 20 oo The following (Table 14) shows the aspherical shape of the zoom lens in this example.

 [Table 4] Surface 8 12 13 17

^{Κ -8.85745 10-1 - 9.63946X10 - 1 -1.06899X10} 3.59590 X

D one ^{2.97423X10 - 4 - 2.78126X10- 4 - 3.83685X10} - 4 -8.56767 10- 4

Ε -7.76949Χ10— ⁵ 2.49843X10-6 1.07074 X 10 " ⁵ -2.88677 Χ10" ⁵ Also, the following (Table 15) shows the values when the object point is 2 m from the lens tip as an example of the variable air spacing by zooming. Also, the following (Table 15) shows the aperture diameter that changes with the focal length. <The standard positions in the following (Table 15) are the third lens group 13 and the fourth lens group.

14 is the closest position. In the following (Table 15), f (mm) and F / ΝΟω (degrees) are the focal length, F-number, half-incidence at the wide-angle end, standard position, and telephoto end of the zoom lens in (Table 13) above. Is the corner.

 [Table 15]

上記 （表 1 5 ) から分かるように、 本実施例の広角端の画角は約 6 4 度である。

As can be seen from the above (Table 15), the angle of view at the wide-angle end in this embodiment is about 64 degrees.

 -When the focal length of the second lens unit 12 is f 2 and the focal length of the entire system at the wide-angle end is fw, | f 2 | Z fw is as follows (Table 16). It has the values shown.

 That is, the condition of the above (Equation 37) is satisfied, and a compact zoom lens in which the field curvature is corrected to be small despite the wide angle is realized.

Further, the zoom lens according to the present embodiment includes a first negative lens in which the second lens group 12 is arranged in order from the object side, and a second negative lens and a positive lens. The second negative lens has an aspherical surface on the object side, has a local radius of curvature near the optical axis of R10, and has a local outer peripheral portion. When the radius of curvature is R11, IR11IIR10I has the values shown in the following (Table 16).

 That is, the condition of (Equation 39) is satisfied, and excellent correction of coma on the wide-angle side and spherical aberration on the telephoto side is realized.

 In the zoom lens of the present embodiment, when the focal length of the third lens group 13 is f 3 and the focal length of the entire system at the wide-angle end is fw, f 3Z fw is shown in the following (Table 16). Have a value.

 That is, the condition of the above (Equation 41) is satisfied, a back focus capable of inserting a crystal filter, an IR cut filter, etc. is secured, and a small zoom lens is realized.

 Further, in the zoom lens according to the present embodiment, the object-side surface of the lens closest to the object side of the third lens group 13 is an aspheric surface, the local radius of curvature near the optical axis is R 20, Assuming that the local radius of curvature of the part is R 21, R 21 / R 20 has the values shown in the following (Table 16).

 That is, the above-mentioned (Equation 45) is satisfied, and a zoom lens in which spherical aberration over the entire zoom region is satisfactorily corrected is realized.

 Further, when the radius of curvature of the image side surface of the concave lens included in the third lens group 13 is R 30, and the focal length of the third lens group 13 is f 3, the zoom lens according to the present embodiment has RS OZ fS has the value shown in the following (Table 16).

 That is, the zoom lens in which the above condition (Equation 47) is satisfied and the coma of the light beam outside the principal ray of the off-axis light is well corrected is realized.

The zoom lens according to the present embodiment has a focal length of the fourth lens group 14. When the distance is f 4 and the focal length of the entire system at the wide-angle end is fw, f 4Z fw has the value shown in the following (Table 16).

 That is, the condition of the above (Equation 49) is satisfied, a back focus in which a crystal filter, an IR cut filter, and the like can be inserted is secured, and a compact zoom lens is realized.

 Further, in the zoom lens according to the present embodiment, the surface of the fourth lens unit 14 on the object side is aspheric, the local radius of curvature near the optical axis is R 40, and the local radius of curvature of the outer peripheral portion is R 40. Assuming that R41, R41ZR40 has the value shown in the following (Table 16).

 That is, a zoom lens that satisfies the above condition (Equation 51) and satisfactorily corrects the coma of the light flux inside the principal ray of the off-axis light is realized.

 Also, as shown in the above (Table 15), the zoom lens according to the present embodiment has an aperture diameter of the aperture 15 fixed to the image plane 17 provided on the object side of the third lens group 13. Decreases as the focal length of the entire system increases, and when the stop diameter at the telephoto end is St and the stop diameter at the wide-angle end is Sw, the value of St /. Sw is as shown in Table 16 below. Have.

 That is, the condition of the above (Equation 52) is satisfied, and the zoom lens in which the aberration at the long focal length side, particularly at the telephoto end is favorably corrected is realized. Further, the zoom lens according to the present embodiment corrects image fluctuations due to camera shake by moving the entire third lens group 13 perpendicularly to the optical axis, thereby reducing the deterioration of chromatic aberration during correction. ing.

Further, the zoom lens in this embodiment is configured such that the movement amount of the third lens group 13 (correction lens) at the focal length f of the entire system at the time of camera shake correction is Y, and the movement amount of the third lens group 13 at the telephoto end is Y. When Yt and the focal length at the telephoto end are ft, Y, Yt and (Y / Yt) Z (f / ft) are as follows (Table 16) Has the values shown in FIG.

 That is, the conditions of (Equation 53) and (Equation 54) are satisfied, and a zoom lens with little deterioration of various aberrations at the time of correction is realized.

 [Table 16]

 (1) I f 2 I / fw = 1.022

 (2) I R 1 1 I / I R 1 0 I = 0.86 3

 (3) f 3Zf w = 2.74

 (4) R 21 / R 2 0 = 1.66 1

 (5) R 30 / f 3 = 0. 4 7 2

 (6) f / f w = 2.609

 (7) R 1 / R 4 0 = 1.5 0 1

 (8) S tZSw 0.72

 (9) Y ((Y t = 0.169)

 Wide angle y standard position

 0. 0 1 8 0. 085

Y / Y t) / (f Zf t)

 Wide angle standard position

 0.891.10 Figures 18 to 20 show aberration performance diagrams at the wide-angle end, standard position, and telephoto end of the zoom lens shown in Table 13 above. FIG. 21 shows an aberration performance diagram at the telephoto end at the time of 0.3-degree camera shake correction. As can be seen from FIGS. 18 to 21, the zoom lens according to the present embodiment shows good aberration performance both at rest and when camera shake is corrected.

 (Example 5)

The following (Table 17) shows still another specific example of the zoom lens according to the first embodiment. [Table 17]

 The following (Table 18) shows the aspherical shape of the zoom lens in this example.

 [Table 18]

In addition, the following (Table 19) shows the values when the object point is 2 m from the lens tip as an example of the variable air spacing by zooming. The following (Table 19) shows the aperture diameter that changes with the focal length. The standard position in the following (Table 19) is the position where the third lens group 13 and the fourth lens group 14 are closest. It is. Below (Table 19), f (mm), F / NO ω (degrees) is the focal length, F-number, and half angle of incidence at the wide-angle end, the standard position, and the telephoto end of the zoom lens described in (Table 17).

 [Table 19]

上記 （表 1 9) から分かるように、 本実施例の広角端の画角は約 6 5 度である。

As can be seen from the above (Table 19), the angle of view at the wide-angle end in this embodiment is about 65 degrees.

The following (Table 20) shows values of I I2Iίw and the like for the zoom lens of this example.

[Table 20]

 (1) I f 2 I / fw = 1. 0 6 1

 (2) 1 R 1 1 1/1 R 1 0 1 = 0.86 6

 (3) f 3 / f w = 2.84 4

 (4) R 2 1 / R 2 0 = 1.5. 5 1 2

 (5) R 3 0 / f 3 = 0.4 5 3

 (6) f 4 / f w = 2.7 0 9

 (7) R 1 / R 4 0 = 1 4 2 4

 (8) S t / S w = 0.7 2 4

(9) Y (Y t = 0.1 6 9)

(1 0) (Y / Y t) / (f Zf t)

 As shown in the above (Table 20), the conditions of (Equation 37) to (Equation 42) and (Equation 45) to (Equation 55) are satisfied also in the zoom lens of this example.

 FIGS. 22 to 24 show aberration performance diagrams of the zoom lens shown in (Table 19) at the wide-angle end, the standard position, and the telephoto end. Fig. 25 shows the aberration performance chart at the telephoto end when correcting camera shake by 0.3 degrees. As can be seen from FIGS. 22 to 25, the zoom lens according to the present example shows good aberration performance both at rest and when camera shake is corrected.

 (Example 6)

The following (Table 21) shows still another specific example of the zoom lens according to the first embodiment. [Table 2 1]

 Group 囬 r α n

 1 3 3.3 1 5 U. / U 1.84 6 6 6 2 3.9

 2 1 .00 1 3.8 3 1.6 9 6 8 0 5 5.6

 1 3-24 9.28 2 0.12

 4 1 2.6 1 7 2.1 7 1.7 7 25 0 4 9.6

 5 3 3. 9 06 Variable

 6 3 0.000 U-4 U 1.8 3 4 0 0 37.2

 7 3.5 2 1 2-U 4

 2 8-5.71 1ϋ, b1.66 5 4 7 55.2

 9 4.7 5 0 1.60 1.84 6 6 6 2 3.9

 1 0 -6 1.4.4 0 Variable

 Aperture 1 1 1.00

 1 2 5.5 5 9 2 2.b b 1.60 6 0 2 5 7.5

3 1 3-1 0.59 8 0.4 4

 1 8.002 1.60 1.54 07 2 4 7.2

1 5-1 9.54 4 0.4 0 1.84 6 6 6 2 3.9

1 6 4. 6 00 Variable

 4 1 7 6. 0 9 6 2. 1 7 1. 5 1 4 5 0 6 3.1

 1 8 1 1 7.4 9 1 Variable

 1 9 oo 2.30 1.5 1 6 3 3 64. 1

5 20 oo The following (Table 22) shows the aspherical shape of the zoom lens in this example.

 [Table 22]

また、 下記 （表 2 3) に、 ズーミングによって可変な空気間隔の実施 例として、 レンズ先端から測って 2 mの位置に物点がある場合の値を示 す。 また、 下記 （表 2 3) に、 焦点距離とともに変化する絞り径を示す' 下記 （表 2 3) における標準位置は、 第 3レンズ群 1 3と第 4レンズ群 1 4とが最接近する位置である。 下記 （表 2 3) 中、 ί (mm)、 ¥ / N〇、 ω (度） は、 上記 （表 2 1 ) のズームレンズの広角端、 標準位置. 望遠端における焦点距離、 Fナンバー、 入射半画角である。

Also, the following (Table 23) shows the values when the object point is 2 m from the front of the lens as an example of the variable air spacing by zooming. Also, the following (Table 23) shows the aperture diameter that changes with the focal length. The standard position in (Table 23) below is the position where the third lens group 13 and the fourth lens group 14 are closest. It is. Below (Table 23), 、 (mm), ¥ / N〇 and ω (degrees) are the focal length, F-number, and half angle of view at the wide-angle end and standard position.

 [Table 23]

上記 （表 2 3) から分かるように、 本実施例の広角端における画角は 約 6 3度である。

As can be seen from the above (Table 23), the angle of view at the wide-angle end in this embodiment is about 63 degrees.

The following (Table 24) shows values of I I2I / に 関 す る w and the like for the zoom lens of this example.

[Table 24]

 (1) I f 2 I / f w = 1.008

 (2) R 11 I / I R 10 I = o. 8 6 6

 (3) f 3 / f w = 2.7 3 1

 (4) R 21 / R 20 = 1.600

 (5) R 30 / f 3 = 0.490

 (6) f 4 / f w = 2.6 6 3 8

 (7) R 1 / R 4 0 = 1.505

 (8) S t / S w = 0.74 6

(9) Y (Y t = 0 1 6 8)

 As shown in (Table 24) above, also in the zoom lens of this example, the conditions of (Equation 37) to (Equation 42) and (Equation 45) to (Equation 55) are satisfied. .

 Figures 26 to 28 show aberration performance diagrams of the zoom lens shown in (Table 23) at the wide-angle end, the standard position, and the telephoto end. Fig. 29 shows the aberration performance chart at the telephoto end when correcting camera shake by 0.3 degrees. As can be seen from FIGS. 26 to 29, the zoom lens according to the present embodiment shows good aberration performance both at rest and when camera shake is corrected.

 (Example 7)

The following (Table 25) shows specific examples of the zoom lens according to the second embodiment. [Table 25]

 The following (Table 26) shows the aspherical shape of the zoom lens in this example.

 [Table 26]

また、 下記 （表 2 7) に、 ズーミングによって可変な空気間隔の実施 例として、 レンズ先端から測って 2mの位置に物点がある場合の値を示 す。 また、 下記 （表 2 7) に、 焦点距離とともに変化する絞り径を示す ' [表 2 7]

The following (Table 27) shows the values when the object point is 2 m from the front of the lens as an example of the variable air spacing by zooming. Also, the following (Table 27) shows the aperture diameter that changes with the focal length. [Table 27]

上記 （表 2 7) から分かるように、 本実施例の広角端の画角は 6 9. 5度である。

As can be seen from the above (Table 27), the angle of view at the wide-angle end in this embodiment is 69.5 degrees.

 As shown in Table 25 above, the second positive lens of the third lens group 23 has a refractive index of 1.55 or less and an Abbe number of 65 or more. Have.

The following (Table 28) shows specific numerical values corresponding to (Equation 37) to (Equation 55) in this example.

"L o 1

 Clothing o i

(1) 1 f 2 1 / f w = 1.2.5 5 4

 (2) 1 R 1 1 1/1 R 1 0 1 = 1.0.764

 (, 3 ^ ノ) -J / 1

 (4) d 1 3 / f 3 = 0.03

 (5) R 1 2 / R 2 0 = 1.5 3 7

 (6) R 3 0 / f 3 = 0.4 6 6

 (7) f 4 / f w = 2.4 4 5

 (8) R 1 / R 40 = 1.3 4 6

 (9) S t / S w = 0.8 4 6

(1 0) Y (Y t = 0 1 8 5)

上記 （表 28) に示すように、 本実施例におけるズームレンズは、 上 記 （数 3 7) 〜 （数 5 5) の条件式を満足している。 (1 1) (YZY t) Z (f Zf t)

As shown in the above (Table 28), the zoom lens of this example satisfies the above-mentioned conditional expressions (37) to (55).

 FIGS. 30 to 32 show aberration performance diagrams of the zoom lens shown in (Table 27) at the wide-angle end, the standard position, and the telephoto end. FIG. 33 shows the aberration performance chart at the telephoto end when correcting 0.3-degree camera shake. As can be seen from FIG. 30 to FIG. 33, the zoom lens according to the present example shows good aberration performance.

 (Example 8)

The following (Table 29) shows other specific examples of the zoom lens according to the second embodiment. [Table 29] Group surface rd η

 1 1 36.5 2 3 1 .1 0 1 .8 4 6 6 6 2 3.9

 2 1 5.4 7 1 5.4 0 1 6 9 6 8 0 5 5.6

 1 3-2 4 4 3.99 9 4 0. 1 2

 4 1 4. 1 7 9 2.90 0 1.1.8 1 6 0 0 46.7

 5 3 7.2 7 3 Variable

 6 8 5.0 0 0 0 .4 5 1 .8 3 4 0 0 37.2

 7 3.6 7 5 2. 3 7

 2 8 1 9.8 6 5 0 .5 5 1 .6 6 5 4 7 5 5.2

 Q 4.6 1 6 1 .9 5 1 .8 4 6 6 6 2 3.9

 1 0 2 5 7. 5 3 6 Variable

 $ x '1 1

 ノ 1 1 0.7.0

 1 2 5.5 2 4 2.2 0 1.6 0 6 0 2 5 7.5

3 1 3 — 1 6. 3 1 0. 1 0

 1 4 7.40 1 1 .5 0 1 .5 8 9 1 3 6 1 .2

1 5 — 1 3.5 5 8, 3 0 1 .8 4 6 6 6 2 3.9

1 6 1 1 5.7 7 0 0 .4 0

 1 7 4.4 0 9 Variable

 4 1 8 6. 0 7 6 1 .6 0 1-6 0 6 0 2 5 7.6

 1 9 — 1 7. 1 8 3 Variable

 5 2 0 2. 3 0 1 .5 1 6 3 3 6 4.1

 2 1 oo The following (Table 30) shows the aspherical shape of the zoom lens in this example.

 [Table 30]

十' 下記 （表 3 1 ) に、 ズーミングによって可変な空気間隔の実施 例として、 レンズ先端から測って 2mの位置に物点がある場合の値を示 す。 また、 下記 （表 3 1) に、 焦点距離とともに変化する絞り径を示す < 下記 （表 3 1) における標準位置は、 第 3レンズ群 2 3と第 4レンズ群 2 4とが最接近する位置である。 下記 （表 3 1 ) 中、 f (mm), F / ΝΟ、 ω (度） は、 上記 （表 2 9) のズームレンズの広角端、 標準位置、 望遠端における焦点距離、 Fナンバー、 入射半画角である。

10 'The following (Table 31) shows an example of an air gap that can be changed by zooming when the object point is 2 m from the lens tip. Also, the following (Table 31) shows the aperture diameter that changes with the focal length. <The standard positions in the following (Table 31) are the third lens group 23 and the fourth lens group. 24 is the closest position. In the following (Table 31), f (mm), F / ΝΟ, and ω (degrees) are the focal length at the wide-angle end, the standard position, the telephoto end, the F-number, and the half-incidence of the zoom lens described in (Table 29). The angle of view.

 [Table 3 1]

上記 （表 3 1 ) から分かるように、 本実施例の広角端における画角は 約 6 9度である。

As can be seen from the above (Table 31), the angle of view at the wide-angle end in this embodiment is about 69 degrees.

The following (Table 32) shows values such as If2IIw for the zoom lens of this example.

[Table 3 2]

 (1) I f 2 I / f w 2 54

 (2) I R 1 1 I / I R 1 0 5 9 5

 (3) f 3 / f w 1 4 3

 (4) R 1 20 = 50 3

 (5) R 30 / f 3 4 6 0

 (6) f 4 / f w 4 9 1

 (7) R 4 1 / R 4 0 = 3 6 1

 (8) St No Sw 84 6

 (9) <(Y t = 0.176)

 Wide-angle end Standard position

 0. 0 1 9 0. 089

(YZY t) / (f / f t)

 Wide-angle end Standard position

 1. 02 1. 07 As shown in the above (Table 32), also in the zoom lens of this embodiment, the above (Equation 37) to (Equation 42) and (Equation 45) to (Equation 55) can be used. The condition has been met.

 Figures 34 to 36 show aberration performance diagrams of the zoom lens shown in (Table 31) at the wide-angle end, the standard position, and the telephoto end. FIG. 37 shows the aberration performance chart at the telephoto end when correcting 0.3-degree camera shake. As can be seen from FIG. 34 to FIG. 37, the zoom lens according to the present example shows good aberration performance both at rest and when camera shake is corrected.

 (Example 9)

The following (Table 33) shows specific examples of the zoom lens according to the third embodiment. [Table 33]

 Group plane r d n

 1 1 .9 7 4 1 .2 0 1 .o 4 b b b 2 3-9

2 1 8.3 9 5 7.40 to 6 9 6 8 0 5 5.6

1 3 8] 4.3 1 9 0.1 2

 4 1 6.4 4 0 3.55 to 8 1 6 0 0 46.7

5 3 9.5 0 0 Variable

 6 8 0. 0 0 0 0.4 0 1.7 ./Z Ό 49.6

 7 4.3 0 4 2-9 4

 2 8 1 8.3 3 4 0.50 to 6 6 b 4/5 5.2

 9 8.1 3 8 0. 4 0

 1 0 1 0.3 9 8 1.7 0 1 .8 4 6 6 6 2 3-9

 1 1 -2 8. 3 7 8 Variable

 Aperture 1 2 0.7.0

 1 3 8. 3 7 7 1.6 .0 1.6 .0.60 0.257.5

 3 1 A-1 3.5 4 5 0 .1 0

 1 5 4. 5 0 9 2. 2 0 to 4 7 7 0 0 8 1.2

 1 6 -2 6. 3 3 0 0 .4 0 1 .8 0 5 1 8 2 5.4

 1 7 4. 1 3 1 Variable

 4 1 8 6.6 0 7 1 .8 0 1 .6 6 5 4 7 5 5.2

 1 9 -2 2.9.2 2 2 Variable

 2 0 2.3 0 1 .5 1 6 3 3 6 4.2

 5 2 1 The following (Table 34) shows the aspherical shape of the zoom lens in this example.

 [Table 34]

また、 下記 （表 3 5) に、 ズーミングによって可変な空気間隔の実施 例として、 レンズ先端から測って 2 mの位置に物点がある場合の値を示 す。 また、 下記 （表 3 5) に、 焦点距離とともに変化する絞り径を示す < [表 3 5]

Also, the following (Table 35) shows the values when the object point is located 2 m from the lens tip as an example of the variable air spacing by zooming. Also, the following (Table 35) shows the aperture diameter that changes with the focal length. [Table 35]

 As can be seen from the above (Table 35), the angle of view at the wide-angle end in this embodiment is 72.9 degrees.

 As shown in the above (Table 33), the second positive lens of the third lens group 33 has a refractive index of 1.55 or less and an Abbe number of 65 or more. Have.

The following (Table 36) shows specific numerical values corresponding to the above (Equation 37) to (Equation 55) in this example.

[Table 3 6]

(1) I f 2 I / f w 6

 (2) I R 1 1 I / I R 1 0 2 8

 (3) f 3 / f w 3 5

 (4) d1 3 / f3 0 0

 (5) R 1 2 / R 2 0 1 1

 (6) R 3 0 / f 3 0 4

 (7) f 4 / f w 2 7

 (8) R 1 / R 4 0 1 3

 (9) St / S w 0.88

 (1 0) Y (Y t = 0. 1 8 8)

上記 （表 36) に示すように、 本実施例におけるズームレンズは、 上 記 （数 37) 〜 （数 5 5) の条件を満足している。

As shown in the above (Table 36), the zoom lens in this example satisfies the above-mentioned conditions (Expression 37) to (Expression 55).

 Figures 38 to 40 show aberration performance charts of the zoom lens shown in (Table 35) at the wide-angle end, at the standard position, and at the telephoto end. FIG. 41 shows an aberration performance chart at the telephoto end at the time of 0.3-degree camera shake correction. As can be seen from FIGS. 38 to 41, the zoom lens according to the present example shows good aberration performance.

 (Example 10)

The following (Table 37) shows other specific examples of the zoom lens according to the third embodiment. [Table 37]

 The following Table 38 shows the aspherical shape of the zoom lens in this example.

 [Table 38]

The following table (Table 39) shows the values when the object point is 2 m from the front of the lens as an example of the variable air spacing by zooming. Also, the following (Table 39) shows the aperture diameter that changes with the focal length. <The standard position in the following (Table 39) is the position where the third lens group 33 and the fourth lens group 34 come closest. Below (Table 39), f (mm), FX N〇 and ω (degrees) are the focal length at the wide-angle end, the standard position, the telephoto end, the F-number, and the half angle of incidence of the zoom lens described in (Table 37).

 [Table 3 9]

上記 （表 3 9) から分かるように、 本実施例の広角端における画角は 約 7 3度である。

As can be seen from the above (Table 39), the angle of view at the wide-angle end in this embodiment is about 73 degrees.

The following (Table 40) shows values such as If2IIw for the zoom lens of this example.

[Table 40]

(1) f 2 I κ w 6 1 7

 (2) 1 R 1 1 1 Z 1 R 1 0 1 = 5 5 7

 (3) f 3 / f w 4 7 7

 (4) R 21 / R 20 = 24 4

 (5) R 30 / f 3 1 0

 (6) f 4 / f w 7 54

 (7) R 1 / R 4 0 = 3 5 0

 (8) S t / S w 7 1 0

 (9) <(Y t = 0.176)

 Wide-angle end Standard position

 0_ 0 1 9 0, 089

(Y / Y t) Z (f Zf

 Wide-angle end Standard position

 1.07 1.07

As shown in the above (Table 40), also in the zoom lens of this example, the conditions of (Equation 37) to (Equation 42) and (Equation 45) to (Equation 55) are satisfied. .

 Figures 42 to 44 show aberration performance diagrams of the zoom lens shown in (Table 39) at the wide-angle end, at the standard position, and at the telephoto end. Fig. 45 shows the aberration performance chart at the telephoto end when correcting camera shake by 0.3 degrees.

 As can be seen from FIGS. 42 to 45, the zoom lens according to the present embodiment exhibits good aberration performance both at rest and during camera shake correction. Industrial applicability

The zoom lens of the present invention can be used for a video camera and the like. According to the zoom lens of the present invention, various components including chromatic aberration can be achieved with a small lens configuration. Achieved a zoom lens with good aberration correction, an angle of view of 62 degrees or more, and a camera shake correction function, and a compact, high-quality video camera using this zoom lens. Can be realized.

Claims

The scope of the claims 1. A first lens group having a positive refractive power and fixed to the image plane, which is arranged in order from the object side to the image plane side, and a first lens group having a negative refractive power and A second lens group that performs a zooming action by moving, a stop fixed with respect to an image plane, a third lens group that has a positive refractive power, and a second lens group that has a positive refractive power. A fourth lens group that moves on the optical axis so as to keep an image plane, which fluctuates due to movement of the group and the object, at a fixed position from the reference plane, wherein the second lens group includes two lenses. The third lens group includes three negative lenses and one positive lens, and includes at least one aspheric surface. The third lens group includes two positive lenses and one negative lens. And at least one aspherical surface, wherein the fourth lens group has at least one aspherical surface. A zoom lens comprising a positive lens including.  2. The second lens group according to claim 1, wherein the second lens group is composed of three lenses including a first negative lens and a cemented lens of a second negative lens and a positive lens, which are arranged in order from the object side. The zoom lens described.  3. The zoom according to claim 1, wherein the second lens group is composed of three lenses including a first negative lens, a second negative lens, and a positive lens, which are arranged in order from the object side. lens.  4. The third lens group according to claim 1, wherein the third lens group includes three lenses including a first positive lens and a cemented lens of a second positive lens and a negative lens, which are arranged in order from the object side. The zoom lens described. 5. The zoom according to claim 1, wherein the third lens group is composed of three lenses including a first positive lens, a second positive lens, and a negative lens arranged in order from the object side. lens. 6. The zoom lens according to claim 1, wherein the following condition (Equation 57) is satisfied, where f2 is the focal length of the second lens group and fw is the focal length of the entire system at the wide-angle end.  [Number 5 7]  1.0 <I f 2 I / f w <2.0  7. The zoom lens according to claim 6, wherein the following condition (Equation 58) is satisfied.  [Number 5 8]  I f 2 I / f w <1.7  8. The second lens group is composed of three lenses including a first negative lens, a second negative lens, and a positive lens arranged in order from the object side, and the second negative lens When the object-side surface of the lens is an aspheric surface, the local radius of curvature near the optical axis of the aspheric surface is R10, and the local radius of curvature of the outer peripheral portion of the aspheric surface is R11. (Equation 5 9) The zoom lens according to claim 1, wherein the condition is satisfied.  [Number 5 9]  0.8 <| R 11 I / I R IO | <3.0  9. The zoom lens according to claim 8, wherein the following condition (Equation 60) is satisfied.  [Number 6 0]  | R 1 1 | / | R 1 0 | <2.9  10. The zoom lens according to claim 1, wherein when the focal length of the third lens group is f 3 and the focal length of the entire system at the wide-angle end is fw, the following condition (Equation 61) is satisfied.  [Number 6 1] 2.5 <f 3 / f w <4.0 1 1. The zoom lens according to claim 10, wherein the following condition is satisfied.  [Number 6 2]  2.6 <f 3 / f w <3.6  1 2. The object-side surface of the lens closest to the object forming the third lens group has an aspheric surface, the local radius of curvature near the optical axis of the aspheric surface is R 20, and the outer periphery of the aspheric surface The zoom lens according to claim 1, wherein, when a local radius of curvature of the portion is R 21, the following condition (Equation 63) is satisfied.  [Number 6 3]  1.05 <R21 / R2 0 <2.0  1 3. The zoom lens according to claim 12, wherein the following condition is satisfied.  [Number 6 4]  1.KR 2 1 / R 2 0 <1.7  1 4. When the absolute value of the radius of curvature of the image side surface of the concave lens included in the third lens group is R 30, and the focal length of the third lens group is f 3, the following condition (Equation 65) is satisfied. 2. The zoom lens according to claim 1, wherein the zoom lens is formed.  [Number 6 5]  0.3 5 <R 3 0 / f 3 <0.6  15. The zoom lens according to claim 14, wherein the following condition (Equation 66) is satisfied.  [Number 6 6]  0.4 0 <R 3 0 / f 3 1 6. The zoom lens according to claim 1, wherein the following condition (Equation 67) is satisfied, where f4 is the focal length of the fourth lens group, and fw is the focal length of the entire system at the wide-angle end. 2.3 <f 4 / f w <3.0  17. The zoom lens according to claim 16, wherein the following condition is satisfied.  [Number 6 8]  2.4 <f 4 / f w <2.9  1 8. The object-side surface of the fourth lens group is an aspheric surface, the local radius of curvature near the optical axis of the aspheric surface is R40, and the local radius of curvature of the outer peripheral portion of the aspheric surface is R41. 2. The zoom lens according to claim 1, wherein the following condition (Equation 69) is satisfied.  [Number 6 9]  1.3 <R 4 1 / R40 <1.6  1 9. Assuming that the aperture diameter of the aperture decreases as the focal length of the entire system increases, and the aperture diameter at the telephoto end is St and the aperture diameter at the wide-angle end is Sw, the following condition (Equation 70) is satisfied. The zoom lens according to claim 1, which is satisfied.  [Number 7 0]  S t / S w <0.92  20. A function that corrects image movement due to camera shake by moving the entire third lens group perpendicular to the optical axis according to the camera shake obtained from the camera shake detector. The zoom lens according to 1.  2 1. When the amount of movement of the third lens group at the focal length f of the entire system during camera shake correction is Y, the amount of movement of the third lens group at the telephoto end is Yt; and the focal length at the telephoto end is ft. 21. The zoom lens according to claim 20, wherein the following conditions (Equation 71) and (Equation 72) are satisfied.  [Number 7 1] Y t> Y [Number 7 2]  (Y / Y t) / (f / f t) <l. 5  22. The lens according to claim 21 that satisfies the following condition (Equation 73). [Equation 7 3]  (Y / Y t) / (f / f t) <1.2  23. A video camera provided with a zoom lens, wherein the zoom lens according to claim 1 is used as the zoom lens.  24. A first lens unit having a positive refractive power and fixed to the image plane, which is arranged in order from the object side to the image plane side, and a first lens group having a negative refractive power and A second lens group that performs a zooming action by moving, a stop fixed to an image plane, a third lens group that has a positive refractive power, and a second lens group that has a positive refractive power. A zoom lens comprising: a lens group; and a fourth lens group that moves on the optical axis so as to keep the image plane, which fluctuates due to the movement of the object, at a fixed position from the reference plane, wherein the second lens group includes: The optical system includes at least one aspheric surface, including three lenses including a first negative lens and a cemented lens of a second negative lens and a positive lens, which are arranged in order from the object side. The third lens group includes a first positive lens arranged in order from the object side, The lens includes three lenses including a second positive lens having a refractive index and an Abbe number of 65 or more and a cemented lens of a negative lens, and includes at least one aspherical surface. The zoom lens is characterized in that the four lens groups include at least one aspheric surface. 2 5. The first lens group, which has positive refractive power and is fixed to the image plane, is arranged in order from the object side, and has the negative refractive power and moves on the optical axis. A second lens group that performs zooming, and an aperture that is fixed with respect to the image plane A third lens group having a positive refractive power; and a third lens group having a positive refractive power and maintaining the image plane, which fluctuates due to the movement of the second lens group and the object, at a fixed position from a reference plane. A fourth lens group moving on an axis, wherein the second lens group includes a first negative lens, a second negative lens, and a positive lens, which are arranged in order from the object side. The third lens group includes at least one aspheric surface, and includes a first positive lens, which is arranged in order from the object side. The fourth lens includes at least one aspherical surface, and includes three lenses including a second positive lens having a refractive index of 55 or less and an Abbe number of 65 or more, and a negative lens. The group includes at least one aspherical surface. Murrens.  26. The first lens group, which has positive refractive power and is fixed with respect to the image plane, arranged in order from the object side, and has a negative refractive power and moves on the optical axis. A second lens group that performs a zooming action, an aperture fixed with respect to an image plane, a third lens group that has a positive refractive power, and a second lens group and an object that have a positive refractive power A fourth lens group that moves on the optical axis so as to keep an image plane, which fluctuates due to the movement of the lens, at a fixed position from the reference plane, wherein the second lens group is sequentially arranged from the object side. The third lens group includes at least one aspheric surface, and is configured by three lenses including a first negative lens, a second negative lens, and a positive lens, which are disposed. , A first positive lens arranged in order from the object side, a refractive index of 1.55 or less and an Abbe number of 65 or more And at least one aspherical surface, and the fourth lens group has at least one aspherical surface. A zoom lens comprising: 2 7. The focal length of the second lens group is f 2, and the focal point of the whole system at the wide-angle end 27. The zoom lens according to claim 24, wherein the following condition (Equation 74) is satisfied when the distance is fw.  [Number 74]  1.0 <I f 2 I / f w <2.0  28. The zoom lens according to claim 27, wherein the following condition (Equation 75) is satisfied.  [Number 7 5]  1 f 2 I / f w <1.7  2 9. The object-side surface of the second negative lens constituting the second lens group is an aspheric surface, the local radius of curvature near the optical axis of the aspheric surface is R10, and the outer periphery of the aspheric surface is 27. The zoom lens according to claim 24, wherein the following condition (Equation 76) is satisfied when the local radius of curvature of the portion is R11.  [Number 7 6]  0.8 <<| R 1 1 | / | R 1 0 | <3. 0  30. The zoom lens according to claim 29, wherein the following condition (Equation 77) is satisfied.  [Number 7 7]  | R l l l / | R 1 0 l <2.9  3 1. The following condition (Equation 78) is satisfied when the focal length of the third lens group is f3 and the focal length of the entire system at the wide-angle end is fw. Zoom lens.  [Number 7 8]  2.5 <f 3 / f w <4.0  32. The zoom lens according to claim 31, wherein the following condition (Equation 79) is satisfied. [Number 7 9] 2.6 <f 3 / f w <3.6  3 3. When the focal length of the entire system at the wide-angle end is fw, and the air gap between the first positive lens and the second positive lens constituting the third lens group is d31, the following (Equation 8) The zoom lens according to any one of claims 24 to 26, wherein the condition (0) is satisfied.  [Number 8 0]  0.02 <d31 / fw <0.50  34. The zoom lens according to claim 33, wherein the following condition (Equation 81) is satisfied.  [Number 8 1]  d 3 1 / f w <0.40  3 5. The object-side surface of the lens closest to the object forming the third lens group has an aspherical surface, the local radius of curvature near the optical axis of the aspherical surface is R 20, and the outer periphery of the aspherical surface The aspherical zoom lens according to any one of claims 24 to 26, wherein the following condition (Equation 82) is satisfied when a local radius of curvature of the portion is R21.  [Equation 8 2]  1.05 <R21 / R20 <2.0  36. The zoom lens according to claim 35, wherein the following condition is satisfied.  [Equation 8 3]  1.1 <R 2 1 / R 2 0 <1.7 3 7. When the absolute value of the radius of curvature of the image side surface of the concave lens included in the third lens group is R30, and the focal length of the third lens group is f3, the following condition (Equation 84) is satisfied. A zoom lens according to any one of claims 24 to 26. [Number 84]  0.3 5 <R 3 0 / f 3 <0.6  38. The zoom lens according to claim 37, wherein the following condition (Equation 85) is satisfied.  [Equation 8 5]  0.40 <R 3 0 / f 3  39. The lens according to any one of claims 24 to 26, wherein the following condition (Equation 86) is satisfied, where f4 is the focal length of the fourth lens group and fw is the focal length of the entire system at the wide-angle end. Zoom lens.  [Equation 8 6]  2.3 <f 4 / f w <3.0  40. The zoom lens according to claim 39, wherein the following condition is satisfied.  [Equation 8 7]  2.4 <f 4 / f w <2.9  4 1. The object-side surface of the fourth lens group is an aspheric surface, the local radius of curvature near the optical axis of the aspheric surface is R40, and the local radius of curvature of the outer peripheral portion of the aspheric surface is R41. 28. The zoom lens according to claim 24, wherein the following condition (Equation 88) is satisfied.  [Number 8 8]  1.3 <R 4 1 / R 40 <1.6  42. Assuming that the aperture diameter of the aperture decreases as the focal length of the entire system increases, and the aperture diameter at the telephoto end is St and the aperture diameter at the wide-angle end is Sw, the following condition (Equation 89) is satisfied. A zoom lens according to any one of claims 24 to 26. [Number 8 9] S t / S w <0.92  43. A function that corrects image movement at the time of camera shake by moving the entire third lens group perpendicular to the optical axis according to the camera shake obtained from the camera shake detector. The zoom lens according to any one of 24 to 26.  44. When the amount of movement of the third lens group at the focal length f of the entire system at the time of camera shake correction is Y, the amount of movement of the third lens group at the telephoto end is Yt, and the focal length at the telephoto end is ft, 44. The zoom lens according to claim 43, wherein the conditions of (Equation 90) and (Equation 91) are satisfied.  [Number 9 0]  Y t> Y  [Number 9 1]  (Y / Y t) / (f / f t) <l. 5  45. The zoom lens according to claim 44, wherein the following condition (Equation 92) is satisfied.  [Number 9 2]  (Y / Y t) / (f / f t) <1.2  46. A video camera provided with a zoom lens, wherein the zoom lens according to any one of claims 24 to 26 is used as the zoom lens.