JP5280231B2 - Zoom lens system, interchangeable lens device, and camera system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a zoom lens system including a compact focusing lens group, and having a small image magnification change in moving the focusing lens group. <P>SOLUTION: The zoom lens system includes, in the order starting from an object side to an image side, a first lens group G1 with negative power, a second lens group G2 with positive power, a third lens group G3, and a fourth lens group G4. The first lens group G1 includes, in order from the object side to the image side: the first lens element L1, with negative power and a negative meniscus shape the concave face of which is oriented toward the image side; a second lens element L2 with negative power and a negative meniscus shape, the concave face of which is oriented on the image side; and a third lens element L3 with a negative power and negative meniscus shape, the concave face of which is oriented toward the image side. At least one of the lens elements constituting the first lens group G1 is an aspheric lens. <P>COPYRIGHT: (C)2010,JPO&amp;INPIT

Description

  The present invention relates to a zoom lens system, and more particularly to a zoom lens system suitable as an imaging lens system used in an interchangeable lens apparatus of a so-called interchangeable lens digital camera. The present invention also relates to an interchangeable lens apparatus and a camera system that incorporate the zoom lens system.

  In recent years, interchangeable lens digital camera systems are rapidly spreading. An interchangeable-lens digital camera system (also simply referred to as “camera system”) includes a camera body having an image sensor such as a charge coupled device (CCD) and a complementary metal-oxide semiconductor (CMOS), and an optical image on a light receiving surface of the image sensor. And an interchangeable lens device including an imaging lens system for forming the lens. Patent Documents 1 to 8 disclose zoom lens systems applicable to such an interchangeable lens digital camera.

On the other hand, there is a camera system having a function of displaying image data generated by a photographing lens system and an image sensor on a display device such as a liquid crystal display of the camera body (hereinafter referred to as “live view function”) (for example, Patent Document 9 And Patent Document 10).
JP 2005-284097 A JP 2005-352057 A JP 2006-221092 A JP 2005-316396 A JP 2006-267425 A JP 2007-219315 A JP 2008-3195 A JP 2008-15251 A JP 2000-1111789 A JP 2000-333064 A

  The camera systems described in Patent Document 9 and Patent Document 10 perform a focusing operation by the contrast AF method when the live view function is operated. The contrast AF is a focusing operation based on the contrast value of image data from the image sensor. Hereinafter, the operation of contrast AF will be described.

  First, the camera system vibrates the focusing lens group at a high speed in the optical axis direction (hereinafter referred to as “wobbling”) to detect a deviation direction from the in-focus state. After wobbling, the camera system detects a signal component in a specific frequency band of the image area from the output signal of the imaging sensor, and calculates the optimum position of the focusing lens group that is in focus. Thereafter, the camera system moves the focusing lens group to the optimum position to complete the focusing operation. When performing a focusing operation continuously with a moving image or the like, the camera system repeats this series of operations.

  In general, moving images are displayed at a high speed of, for example, about 30 frames / second so as not to cause a sense of incongruity due to flicker or the like. Therefore, the moving image shooting in the interchangeable lens digital camera must basically be performed at the same 30 frames / second. For this reason, the focusing lens group needs to be driven at a high speed of 30 Hz during wobbling.

  However, if the weight of the focusing lens group is large, the motor and the actuator that move the focusing lens group at high speed will be large. For this reason, there exists a problem that the maximum diameter of a lens-barrel will become large. However, in the zoom lens systems described in Patent Documents 1 to 8, it is difficult to say that the focusing lens group is lightweight.

  In the interchangeable lens digital camera, it is necessary to pay attention to the fact that the size of the image corresponding to the subject changes during wobbling. The change in the size of the image is mainly caused by the change in the focal length of the entire lens system due to the movement of the focusing lens group in the optical axis direction. If the change in shooting magnification due to wobbling is large, the photographer will feel uncomfortable.

  An object of the present invention is to provide a zoom lens system in which the focusing lens group is compact and the image magnification change is small when the focusing lens group is moved, an interchangeable lens apparatus having the zoom lens system, and a camera system.

A zoom lens system according to the present invention is a zoom lens system that includes a plurality of lens groups and performs zooming by changing the interval between the lens groups. Negative zoom power is sequentially applied from the object side to the image side. A first lens group, a second lens group having a positive power, a third lens group having a positive power, and a fourth lens group having a negative power . The first lens unit has, in order from the object side to the image side, a negative meniscus first lens element having a negative power and a concave surface facing the image side, and a negative power and a concave surface on the image side. A negative meniscus second lens element with negative power, a negative meniscus third lens element with negative power and a concave surface facing the image side, a fourth lens element with negative power, And a fifth lens element having power . At least one of the lens elements constituting the first lens group is an aspheric lens.

Further, an interchangeable lens device according to the present invention is a lens connected to a camera body including the zoom lens system and an image sensor that receives an optical image formed by the zoom lens system and converts it into an electrical image signal. A mounting portion.

  Furthermore, a camera system according to the present invention receives an optical image formed by the zoom lens system, which is detachably connected to the interchangeable lens apparatus including the zoom lens system and the interchangeable lens apparatus via a camera mount unit. And a camera body including an image sensor for converting into an electrical image signal.

  According to the present invention, it is possible to provide a zoom lens system having a compact focusing lens group and a small image magnification change when the focusing lens group is moved, an interchangeable lens apparatus having a zoom lens system, and a camera system.

  1, 3, 5, 7, 9, and 11 are lens arrangement diagrams of the zoom lens systems according to Embodiments 1, 2, 3, 4, 5, and 6, respectively. 1 represents a zoom lens system.

In each figure, (a) shows the lens configuration at the wide angle end (shortest focal length state: focal length f _W ),
(B) shows the lens configuration at the intermediate position (intermediate focal length state: focal length f _M = √ (f _W * f _T )), and (c) shows the telephoto end (longest focal length state: focal length f _T ) Each lens configuration is shown. Also, in each figure, the broken line arrows provided between FIGS. (A) and (b) are obtained by connecting the positions of the lens groups in the wide-angle end, the intermediate position, and the telephoto end in order from the top. Straight line. The wide-angle end and the intermediate position, and the intermediate position and the telephoto end are simply connected by a straight line, which is different from the actual movement of each lens group. Further, in each figure, an arrow attached to the lens group represents focusing from an infinitely focused state to a close object focused state. That is, the moving direction during focusing from the infinitely focused state to the close object focused state is shown.

  In FIGS. 1, 3, 5, 7, 9, and 11, an asterisk * attached to a specific surface indicates that the surface is aspherical. Further, in each drawing, a symbol (+) and a symbol (−) attached to a symbol of each lens group correspond to a symbol of power of each lens group. Furthermore, in each figure, the straight line described on the rightmost side represents the position of the image plane S. On the object side of the image plane S, a parallel flat plate P equivalent to an optical low-pass filter, a face plate of an image sensor, or the like is provided. Furthermore, in each figure, the straight line described between adjacent lens elements represents the position of the aperture stop A.

(Embodiment 1)
The zoom lens system according to Embodiment 1 includes, in order from the object side to the image side, a first lens group G1 having negative power, a second lens group G2 having positive power, and a first lens group having positive power. 3 lens group G3, 4th lens group G4 which has negative power, and 5th lens group G5 which has positive power are provided.

  The first lens group G1 includes, in order from the object side to the image side, a negative meniscus first lens element L1 having a convex surface facing the object side, and a negative meniscus second lens element L2 having a convex surface facing the object side. A negative meniscus third lens element L3 having a convex surface facing the object side, a biconcave fourth lens element L4, and a positive meniscus fifth lens element L5 having a convex surface facing the object side. . The image side surface of the third lens element L3 is aspheric.

  The second lens group G2 includes, in order from the object side to the image side, a negative meniscus sixth lens element L6 with a convex surface facing the object side, and a positive meniscus seventh lens element L7 with a convex surface facing the object side. It consists of. The sixth lens element L6 and the seventh lens element L7 are cemented.

  The third lens group G3 includes, in order from the object side to the image side, a negative meniscus eighth lens element L8 having a convex surface directed toward the object side, a biconvex ninth lens element L9, and a biconcave first lens element L9. It comprises a ten-lens element L10, a biconvex eleventh lens element L11, a positive meniscus twelfth lens element L12 having a convex surface facing the image side, and a biconvex thirteenth lens element L13. The eighth lens element L8 and the ninth lens element L9 are cemented, and the tenth lens element L10 and the eleventh lens element L11 are cemented.

  The fourth lens group G4 is composed of a negative meniscus fourteenth lens element L14 with the convex surface facing the object side.

  The fifth lens group G5 includes, in order from the object side to the image side, a negative meniscus fifteenth lens element L15 having a convex surface directed toward the object side, and a biconvex sixteenth lens element L16. The fifteenth lens element L15 and the sixteenth lens element L16 are cemented. The image side surface of the sixteenth lens element L16 is aspheric.

During zooming, the air gap between the first lens group G1 and the second lens group G2 is shorter at the telephoto end than at the wide-angle end, and the air gap between the second lens group G2 and the third lens group G3 is shorter at the telephoto end than at the wide-angle end. The air gap between the third lens group G3 and the fourth lens group G4 is shorter at the telephoto end than at the wide angle end, and the air gap between the fourth lens group G4 and the fifth lens group G5 is longer at the telephoto end than at the wide angle end. In addition, the plurality of lens groups move along the optical axis. More specifically, during zooming from the wide-angle end to the telephoto end, the first lens group G1 moves to the image side along the optical axis, and the second lens group G2, the third lens group G3, and the fourth lens group G4 Move to the object side along the optical axis. The fifth lens group G5 is fixed with respect to the image plane S during zooming. The aperture stop A moves to the object side together with the second lens group G2.

  In focusing from the infinitely focused state to the close-joined focused state, the fourth lens group G4 moves to the image side along the optical axis.

(Embodiment 2)
The zoom lens system according to Embodiment 2 includes, in order from the object side to the image side, a first lens group G1 having negative power, a second lens group G2 having positive power, and a first lens group having positive power. 3 lens group G3, 4th lens group G4 which has negative power, and 5th lens group G5 which has positive power are provided.

  The first lens group G1 includes, in order from the object side to the image side, a negative meniscus first lens element L1 having a convex surface facing the object side, and a negative meniscus second lens element L2 having a convex surface facing the object side. A negative meniscus third lens element L3 having a convex surface facing the object side, a biconcave fourth lens element L4, and a positive meniscus fifth lens element L5 having a convex surface facing the object side. . The fourth lens element L4 and the fifth lens element L5 are cemented. The image side surface of the third lens element L3 is aspheric.

  The second lens group G2 includes, in order from the object side to the image side, a negative meniscus sixth lens element L6 with a convex surface facing the object side, and a positive meniscus seventh lens element L7 with a convex surface facing the object side. It consists of. The sixth lens element L6 and the seventh lens element L7 are cemented.

  The third lens group G3 includes, in order from the object side to the image side, a negative meniscus eighth lens element L8 having a convex surface directed toward the object side, a biconvex ninth lens element L9, and a biconcave first lens element L9. It comprises a ten-lens element L10, a biconvex eleventh lens element L11, a positive meniscus twelfth lens element L12 having a convex surface facing the image side, and a biconvex thirteenth lens element L13. The eighth lens element L8 and the ninth lens element L9 are cemented, and the tenth lens element L10 and the eleventh lens element L11 are cemented.

  The fourth lens group G4 is composed of a negative meniscus fourteenth lens element L14 with the convex surface facing the object side.

  The fifth lens group G5 includes, in order from the object side to the image side, a negative meniscus fifteenth lens element L15 having a convex surface directed toward the object side, and a biconvex sixteenth lens element L16. The fifteenth lens element L15 and the sixteenth lens element L16 are cemented. The image side surface of the sixteenth lens element L16 is aspheric.

  During zooming, the air gap between the first lens group G1 and the second lens group G2 is shorter at the telephoto end than at the wide-angle end, and the air gap between the second lens group G2 and the third lens group G3 is shorter at the telephoto end than at the wide-angle end. The air gap between the third lens group G3 and the fourth lens group G4 is shorter at the telephoto end than at the wide angle end, and the air gap between the fourth lens group G4 and the fifth lens group G5 is longer at the telephoto end than at the wide angle end. In addition, the plurality of lens groups move along the optical axis. More specifically, during zooming from the wide-angle end to the telephoto end, the first lens group G1 moves to the image side along the optical axis, and the second lens group G2, the third lens group G3, and the fourth lens group G4 Move to the object side along the optical axis. The fifth lens group G5 is fixed with respect to the image plane S during zooming. The aperture stop A moves to the object side together with the second lens group G2.

  In focusing from the infinitely focused state to the close-joined focused state, the fourth lens group G4 moves to the image side along the optical axis.

(Embodiment 3)
The zoom lens system according to Embodiment 3 includes, in order from the object side to the image side, a first lens group G1 having negative power, a second lens group G2 having positive power, and a first lens group having positive power. 3 lens group G3, 4th lens group G4 which has negative power, and 5th lens group G5 which has positive power are provided.

  The first lens group G1 includes, in order from the object side to the image side, a negative meniscus first lens element L1 having a convex surface facing the object side, and a negative meniscus second lens element L2 having a convex surface facing the object side. A negative meniscus third lens element L3 having a convex surface facing the object side, a biconcave fourth lens element L4, and a positive meniscus fifth lens element L5 having a convex surface facing the object side. . The fourth lens element L4 and the fifth lens element L5 are cemented. The image side surface of the third lens element L3 is aspheric.

  The second lens group G2 includes, in order from the object side to the image side, a negative meniscus sixth lens element L6 with a convex surface facing the object side, and a positive meniscus seventh lens element L7 with a convex surface facing the object side. It consists of. The sixth lens element L6 and the seventh lens element L7 are cemented.

  The third lens group G3 includes, in order from the object side to the image side, a plano-concave eighth lens element L8 with a concave surface facing the image side, a biconvex ninth lens element L9, and a biconcave first lens element L9. It consists of a ten-lens element L10, a biconvex eleventh lens element L11, and a biconvex twelfth lens element L12. The eighth lens element L8 and the ninth lens element L9 are cemented, and the tenth lens element L10 and the eleventh lens element L11 are cemented.

  The fourth lens group G4 is composed of a negative meniscus thirteenth lens element L13 with the convex surface facing the object side.

  The fifth lens group G5 includes, in order from the object side to the image side, a biconcave fourteenth lens element L14 and a biconvex fifteenth lens element L15. The fourteenth lens element L14 and the fifteenth lens element L15 are cemented. The image side surface of the fifteenth lens element L15 is aspheric.

  During zooming, the air gap between the first lens group G1 and the second lens group G2 is shorter at the telephoto end than at the wide-angle end, and the air gap between the second lens group G2 and the third lens group G3 is between the wide-angle end and the telephoto end. The air gap between the third lens group G3 and the fourth lens group G4 is shorter at the telephoto end than at the wide angle end, and the air gap between the fourth lens group G4 and the fifth lens group G5 is at the telephoto end from the wide angle end. The plurality of lens groups move along the optical axis so as to be longer. More specifically, during zooming from the wide-angle end to the telephoto end, the first lens group G1 moves to the image side along the optical axis, and the second lens group G2, the third lens group G3, and the fourth lens group G4 Move to the object side along the optical axis. The fifth lens group G5 is fixed with respect to the image plane S during zooming. The aperture stop A moves to the object side together with the second lens group G2.

  In focusing from the infinitely focused state to the close-joined focused state, the fourth lens group G4 moves to the image side along the optical axis.

(Embodiment 4)
The zoom lens system according to Embodiment 4 includes, in order from the object side to the image side, a first lens group G1 having negative power, a second lens group G2 having positive power, and a first lens group having positive power. 3 lens group G3, 4th lens group G4 which has negative power, and 5th lens group G5 which has positive power are provided.

  The first lens group G1 includes, in order from the object side to the image side, a negative meniscus first lens element L1 having a convex surface facing the object side, and a negative meniscus second lens element L2 having a convex surface facing the object side. A negative meniscus third lens element L3 having a convex surface facing the object side, a biconcave fourth lens element L4, and a positive meniscus fifth lens element L5 having a convex surface facing the object side. . The fourth lens element L4 and the fifth lens element L5 are cemented. The image side surface of the third lens element L3 is aspheric.

  The second lens group G2 includes, in order from the object side to the image side, a negative meniscus sixth lens element L6 with a convex surface facing the object side, and a positive meniscus seventh lens element L7 with a convex surface facing the object side. It consists of. The sixth lens element L6 and the seventh lens element L7 are cemented. The image side surface of the seventh lens element L7 is aspheric.

  The third lens group G3 includes, in order from the object side to the image side, a negative meniscus eighth lens element L8 having a convex surface directed toward the object side, a biconvex ninth lens element L9, and a biconcave first lens element L9. It consists of a ten-lens element L10, a biconvex eleventh lens element L11, and a biconvex twelfth lens element L12. The eighth lens element L8 and the ninth lens element L9 are cemented, and the tenth lens element L10 and the eleventh lens element L11 are cemented.

  The fourth lens group G4 is composed of a negative meniscus thirteenth lens element L13 with the convex surface facing the object side.

  The fifth lens group G5 includes, in order from the object side to the image side, a biconcave fourteenth lens element L14 and a biconvex fifteenth lens element L15. The fourteenth lens element L14 and the fifteenth lens element L15 are cemented. The image side surface of the fifteenth lens element L15 is aspheric.

  During zooming, the air gap between the first lens group G1 and the second lens group G2 is shorter at the telephoto end than at the wide-angle end, and the air gap between the second lens group G2 and the third lens group G3 is shorter at the telephoto end than at the wide-angle end. The air gap between the third lens group G3 and the fourth lens group G4 does not substantially change between the wide-angle end and the telephoto end, and the air gap between the fourth lens group G4 and the fifth lens group G5 is larger than the wide-angle end. The plurality of lens groups move along the optical axis so as to be longer. More specifically, during zooming from the wide-angle end to the telephoto end, the first lens group G1 moves to the image side along the optical axis, and the second lens group G2, the third lens group G3, and the fourth lens group G4 Move to the object side along the optical axis. The fifth lens group G5 is fixed with respect to the image plane S during zooming. The aperture stop A moves to the object side together with the second lens group G2.

  In focusing from the infinitely focused state to the close-joined focused state, the fourth lens group G4 moves to the image side along the optical axis.

(Embodiment 5)
The zoom lens system according to Embodiment 5 includes, in order from the object side to the image side, a first lens group G1 having negative power, a second lens group G2 having positive power, and a first lens group having positive power. 3 lens group G3, 4th lens group G4 which has negative power, and 5th lens group G5 which has positive power are provided.

The first lens group G1 includes, in order from the object side to the image side, a negative meniscus first lens element L1 having a convex surface facing the object side, and a negative meniscus second lens element L2 having a convex surface facing the object side. A negative meniscus third lens element L3 having a convex surface facing the object side, a biconcave fourth lens element L4, and a positive meniscus fifth lens element L5 having a convex surface facing the object side. . The fourth lens element L4 and the fifth lens element L5 are cemented. The image side surface of the third lens element L3 is aspheric.

  The second lens group G2 includes, in order from the object side to the image side, a negative meniscus sixth lens element L6 with a convex surface facing the object side, and a positive meniscus seventh lens element L7 with a convex surface facing the object side. It consists of. The sixth lens element L6 and the seventh lens element L7 are cemented. The image side surface of the seventh lens element L7 is aspheric.

  The third lens group G3 includes, in order from the object side to the image side, a biconcave eighth lens element L8, a biconvex ninth lens element L9, a biconcave tenth lens element L10, It consists of a convex eleventh lens element L11 and a biconvex twelfth lens element L12. The eighth lens element L8 and the ninth lens element L9 are cemented, and the tenth lens element L10 and the eleventh lens element L11 are cemented.

  The fourth lens group G4 is composed of a negative meniscus thirteenth lens element L13 with the convex surface facing the object side.

  The fifth lens group G5 includes, in order from the object side to the image side, a negative meniscus fourteenth lens element L14 having a convex surface directed toward the object side, and a biconvex fifteenth lens element L15. The image side surface of the fifteenth lens element L15 is aspheric.

  During zooming, the air gap between the first lens group G1 and the second lens group G2 is shorter at the telephoto end than at the wide-angle end, and the air gap between the second lens group G2 and the third lens group G3 is shorter at the telephoto end than at the wide-angle end. The air gap between the third lens group G3 and the fourth lens group G4 does not substantially change between the wide-angle end and the telephoto end, and the air gap between the fourth lens group G4 and the fifth lens group G5 is larger than the wide-angle end. The plurality of lens groups move along the optical axis so as to be longer. More specifically, during zooming from the wide-angle end to the telephoto end, the first lens group G1 moves to the image side along the optical axis, and the second lens group G2, the third lens group G3, and the fourth lens group G4 Move to the object side along the optical axis. The fifth lens group G5 is fixed with respect to the image plane S during zooming. The aperture stop A moves to the object side together with the second lens group G2.

  In focusing from the infinitely focused state to the close-joined focused state, the fourth lens group G4 moves to the image side along the optical axis.

(Embodiment 6)
The zoom lens system according to Embodiment 6 includes, in order from the object side to the image side, a first lens group G1 having negative power, a second lens group G2 having positive power, and a first lens group having positive power. 3 lens group G3 and 4th lens group G4 which has negative power are provided.

  The first lens group G1 includes, in order from the object side to the image side, a negative meniscus first lens element L1 having a convex surface facing the object side, and a negative meniscus second lens element L2 having a convex surface facing the object side. A negative meniscus third lens element L3 having a convex surface facing the object side, a biconcave fourth lens element L4, and a positive meniscus fifth lens element L5 having a convex surface facing the object side. . The fourth lens element L4 and the fifth lens element L5 are cemented. The object side surface of the second lens element L2 is aspheric.

  The second lens group G2 includes, in order from the object side to the image side, a biconvex sixth lens element L6 and a negative meniscus seventh lens element L7 with a convex surface facing the image side. The sixth lens element L6 and the seventh lens element L7 are cemented. The object side surface of the sixth lens element L6 is aspheric.

  The third lens group G3 includes, in order from the object side to the image side, a negative meniscus eighth lens element L8 with a convex surface facing the object side, a biconvex ninth lens element L9, and a convex surface facing the object side. And a positive meniscus tenth lens element L10. The eighth lens element L8 and the ninth lens element L9 are cemented.

  The fourth lens group G4 includes, in order from the object side to the image side, a positive meniscus eleventh lens element L11 with a convex surface facing the image side, and a negative meniscus twelfth lens element L12 with a convex surface facing the image side. And a biconcave thirteenth lens element L13 and a biconvex fourteenth lens element L14. The twelfth lens element L12 and the thirteenth lens element L13 are cemented. The object side surface of the eleventh lens element L11 is aspheric.

  During zooming, the air gap between the first lens group G1 and the second lens group G2 is shorter at the telephoto end than at the wide angle end, and the air gap between the second lens group G2 and the third lens group G3 is longer at the telephoto end than at the wide angle end. Each lens group moves along the optical axis so that the air gap between the third lens group G3 and the fourth lens group G4 is longer at the telephoto end than at the wide-angle end. More specifically, during zooming from the wide-angle end to the telephoto end, the first lens group G1 moves to the image side along the optical axis, and the second lens group G2, the third lens group G3, and the fourth lens group G4 Move to the object side along the optical axis. The aperture stop A moves to the object side together with the third lens group G3.

  Further, during focusing from the infinitely focused state to the close-joined focused state, the second lens group G2 moves toward the image side along the optical axis.

  Hereinafter, conditions to be satisfied by the zoom lens system according to each embodiment will be described. In the zoom lens system according to each embodiment, a plurality of conditions to be satisfied are defined, but a zoom lens system configuration that satisfies as many conditions as possible is most desirable. However, by satisfying individual conditions, it is possible to obtain a zoom lens system that exhibits the corresponding effects.

It is desirable that the zoom lens system according to each embodiment satisfies the following conditions.
−0.65 <f _W / f ₁ <−0.45 (1)
here,
f ₁ : focal length of the first lens group,
f _W : focal length at the wide-angle end of the entire system,
It is.

Condition (1) defines the ratio between the focal length of the entire system and the focal length of the first lens group. If the lower limit of condition (1) is not reached, it will be difficult to correct astigmatism and distortion, and it will be difficult to improve the performance of the image periphery. If the upper limit of the condition (1) is exceeded , the total lens length becomes large and the diameter of the first lens group becomes large, which makes it difficult to reduce the size.

It is desirable that the zoom lens system according to each embodiment satisfies the following conditions.
0.1 <f _W / f ₂ <0.3 (2)
here,
f ₂ : focal length of the second lens group,
f _W : focal length at the wide-angle end of the entire system,
It is.

Condition (2) defines the ratio between the focal length of the entire system and the focal length of the second lens group. If the upper limit of the condition (2) is exceeded, the total lens length becomes large and it becomes difficult to reduce the size, and at the same time, it is difficult to correct so-called coma aberration in the intermediate to telephoto range. If the lower limit of the condition (2) is not reached, the effect of field curvature correction obtained by dividing the refractive power into the second lens group and the subsequent third lens group and changing the interval by zooming is lost. It becomes difficult to improve the performance of the image periphery.

It is desirable that the zoom lens system according to each embodiment satisfies the following conditions.
0.25 <f _W / f ₃ <0.5 (3)
here,
f ₃ : focal length of the third lens group,
f _W : focal length at the wide-angle end of the entire system,
It is.

  Condition (3) defines the ratio between the focal length of the entire system and the focal length of the third lens group. If the upper limit of the condition (3) is exceeded, it becomes difficult to correct spherical aberration and coma aberration related to the performance near the axis, and the distance between the lens groups before and after the third lens group is insufficient. The configuration becomes difficult. If the lower limit of condition (3) is not reached, the amount of movement of the third lens group during zooming becomes large, and it becomes difficult to reduce the size.

It is desirable that the zoom lens system according to each embodiment satisfies the following conditions.
−0.1 <f _W / f ₄ <−0.05 (4)
here,
f ₄ : focal length of the fourth lens group,
f _W : focal length at the wide-angle end of the entire system,
It is.

Condition (4) defines the ratio between the focal length of the entire system and the focal length of the fourth lens group. If the lower limit of condition (4) is not reached, the change in astigmatism and the like due to the decentration error of the fourth lens group increases, and the positive power also increases in the third lens group on the object side, resulting in decentration error and the like. Since the change in coma tends to be large, the necessary cost at the time of production increases, which is not preferable. If the upper limit of condition (4) is exceeded , the amount of movement of the fourth lens group at the time of focusing increases, making it difficult to reduce the size.

It is desirable that the zoom lens system according to each embodiment satisfies the following conditions.
0.01 <f _W / f ₅ <0.15 (5)
here,
f ₅ : focal length of the fifth lens group,
f _W : focal length at the wide-angle end of the entire system,
It is.

  Condition (5) defines the ratio between the focal length of the entire system and the focal length of the fifth lens group. If the upper limit of the condition (5) is exceeded, it approaches perfect telecentricity, so the diameter of the fifth lens group becomes large, and as a result, miniaturization becomes difficult. Further, if the lower limit of the condition (5) is not reached, the distance from telecentricity is increased, and in particular, the light incident angle to the peripheral image sensor increases, which is not preferable in terms of the characteristics of the image sensor.

It is desirable that the zoom lens system according to each embodiment satisfies the following conditions.
DIS _W <−8 (6)
here,
DIS _W : Distortion aberration (%) at the maximum image height at the wide-angle end,
It is.
The distortion aberration DIS _W is obtained by the following equation.
DIS _W = (Y′−Y) / Y × 100 (unit%)
(Y ': real image height Y: ideal image height)

  If the upper limit of condition (6) is exceeded, distortion will be overcorrected and it will be difficult to correct coma and astigmatism, making it difficult to reduce the size.

It is desirable that the zoom lens system according to each embodiment satisfies the following conditions.
2.3 <(R ₁₁ + R ₁₂ ) / (R ₁₁ −R ₁₂ ) <10 (7)
here,
R ₁₁ : Object side radius of curvature of the lens element closest to the object side in the first lens group,
R ₁₂ : image-side radius of curvature of the lens element closest to the object side in the first lens group,
It is.

  Condition (7) defines the shape of the lens element closest to the object in the first lens group. If the upper limit of the condition (7) is exceeded, the diameter of the lens element becomes large, and it becomes difficult to process the lens element, which makes it difficult to reduce the size and at the same time increases the manufacturing cost. On the other hand, if the lower limit of the condition (7) is not reached, a large amount of negative distortion occurs, so that distortion correction is insufficient.

It is desirable that the zoom lens system according to each embodiment satisfies the following conditions.
2.3 <(R ₂₁ + R ₂₂ ) / (R ₂₁ −R ₂₂ ) <10 (8)
here,
R ₂₁ : Object side radius of curvature of the second lens element from the object side in the first lens group,
R ₂₂ : image-side radius of curvature of the second lens element from the object side in the first lens group,
It is.

  Condition (8) defines the shape of the second lens element from the object side in the first lens group. If the upper limit of the condition (8) is exceeded, the diameter of the lens element becomes large, and it becomes difficult to process the lens element, which makes it difficult to reduce the size and at the same time increases the manufacturing cost. On the other hand, if the lower limit of the condition (8) is not reached, a large amount of negative distortion occurs, so that distortion correction is insufficient.

It is desirable that the zoom lens system according to each embodiment satisfies the following conditions.
2.3 <(R ₃₁ + R ₃₂ ) / (R ₃₁ −R ₃₂ ) <10 (9)
here,
R ₃₁ : Object side radius of curvature of the third lens element from the object side in the first lens group,
R ₃₂ : image-side radius of curvature of the third lens element from the object side in the first lens group,
It is.

  Condition (9) defines the shape of the third lens element from the object side in the first lens group. If the upper limit of the condition (9) is exceeded, the diameter of the lens element becomes large, and it becomes difficult to process the lens element, which makes it difficult to reduce the size and at the same time increases the manufacturing cost. On the other hand, if the lower limit of the condition (9) is not reached, a large amount of negative distortion occurs, so that distortion correction is insufficient.

It is desirable that the zoom lens system according to each embodiment satisfies the following conditions.
1.4 <DL / YM <2.5 (10)
(However, 100 <2ω _W <140)
here,
DL: effective diameter of the lens surface closest to the image side,
YM: maximum image height at the wide-angle end,
ω _W : Half angle of view (°) at wide angle end
It is.

  Condition (10) defines the ratio between the effective diameter of the lens surface closest to the image and the maximum image height. If the upper limit of the condition (10) is exceeded, the lens diameter on the most image side becomes large, and it becomes difficult to reduce the size. If the lower limit of the condition (10) is not reached, it is necessary to lengthen the back focus in order to avoid an increase in the light incident angle, and it is difficult to reduce the size.

It is desirable that the zoom lens system according to each embodiment satisfies the following conditions.
1.2 <BF _W /YM<1.6 (11)
here,
BF _W : Back focus at the wide angle end,
YM: maximum image height at the wide-angle end,
ω _W : Half angle of view (°) at wide angle end
It is.

  Condition (11) defines the ratio between the back focus at the wide-angle end and the maximum image height. If the upper limit of the condition (11) is exceeded, the retrofocus type characteristics become large and it becomes difficult to correct distortion, and it is difficult to reduce the size. If the lower limit of the condition (11) is not reached, the shadow of foreign matter (dust) adhering to the lens surface closest to the image becomes conspicuous on the photographed image. For example, the handling of the interchangeable lens device becomes complicated.

  Each lens group of the zoom lens system according to each embodiment includes only a refractive lens element that changes incident light by refraction (that is, a lens that is deflected at an interface between media having different refractive indexes). A diffractive lens element that deflects incident light by diffracting action, a refraction / diffractive hybrid lens element that deflects incident light by combining diffractive action and refracting action, and refracting incident light in a medium Each lens group may be configured by any one kind or a combination of plural kinds of refractive index distribution type lens elements which are deflected by a refractive index distribution.

(Embodiment 7)
FIG. 13 is a schematic configuration diagram of a lens interchangeable digital camera system according to the seventh embodiment.

  A lens-interchangeable digital camera system 100 (hereinafter simply referred to as “camera system”) according to the present embodiment includes a camera body 101 and an interchangeable lens apparatus 201 that is detachably connected to the camera body 101.

  The camera body 101 receives an optical image formed by the zoom lens system 202 of the interchangeable lens apparatus 201, and displays an image sensor 102 that converts the optical image into an electrical image signal, and an image signal converted by the image sensor 102. A liquid crystal monitor 103 and a camera mount unit 104 are included. On the other hand, the interchangeable lens device 201 includes a zoom lens system 202 according to any one of Embodiments 1 to 8, a lens barrel that holds the zoom lens system 202, and a lens that is connected to the camera mount unit 104 of the camera body. And a mount unit 204. The camera mount unit 104 and the lens mount unit 204 electrically connect not only a physical connection but also a controller (not shown) in the camera body 101 and a controller (not shown) in the interchangeable lens device 201. It also functions as an interface that enables mutual signal exchange.

  Since the camera system 100 according to the present embodiment includes the zoom lens system 202 according to any one of the first to eighth embodiments, a good optical image can be displayed during focusing in a live view state.

  Hereinafter, numerical examples in which the zoom lens systems according to Embodiments 1 to 6 are specifically implemented will be described. As will be described later, Numerical Examples 1 to 6 correspond to Embodiments 1 to 6, respectively. In each numerical example, the unit of length in the table is “mm”, and the unit of angle of view is “°”. In each numerical example, r is a radius of curvature, d is a surface interval, nd is a refractive index with respect to the d line, and vd is an Abbe number with respect to the d line. In each numerical example, the surface marked with * is an aspherical surface, and the aspherical shape is defined by the following equation.

ただし、数式中の各項によって表される事項は以下の通りである。
Ｚ：光軸からの高さがｈの非球面上の点から、非球面頂点の接平面までの距離
ｈ：光軸からの高さ
ｒ：頂点曲率半径
κ：円錐定数
Ａｎ：ｎ次の非球面係数

However, the items represented by the terms in the formula are as follows.
Z: distance from a point on the aspherical surface whose height from the optical axis is h to the tangential plane of the aspherical vertex h: height from the optical axis r: vertex radius of curvature κ: conic constant An: n-th non-dimensional Spherical coefficient

  2, 4, 6, 8, 10, and 12 are longitudinal aberration diagrams of the zoom lens system according to Numerical Examples 1, 2, 3, 4, 5, and 6, respectively, in an infinitely focused state.

  In each longitudinal aberration diagram, (a) shows the aberration at the wide angle end, (b) shows the intermediate position, and (c) shows the aberration at the telephoto end. Each longitudinal aberration diagram shows spherical aberration (SA (mm)), astigmatism (AST (mm)), and distortion (DIS (%)) in order from the left side. In the spherical aberration diagram, the vertical axis represents the F number (indicated by F in the figure), the solid line is the d line (d-line), the short broken line is the F line (F-line), and the long broken line is the C line (C- line). In the astigmatism diagram, the vertical axis represents the image height (indicated by H in the figure), the solid line represents the sagittal plane (indicated by s), and the broken line represents the meridional plane (indicated by m in the figure). is there. In the distortion diagram, the vertical axis represents the image height (indicated by H in the figure).

(Numerical example 1)
The zoom lens system of Numerical Example 1 corresponds to Embodiment 1 shown in FIG. Table 1 shows surface data of the zoom lens system of Numerical Example 1, Table 2 shows aspheric data, Table 3 shows various data, Table 4 shows single lens data, Table 5 shows zoom lens group data, and Zoom Lens Group magnification is shown in Table 6.

Table 1 (Surface data)

Surface number rd nd vd
Object ∞
1 32.61610 2.00000 1.80420 46.5
2 20.03180 6.25890
3 28.62190 1.80000 1.80420 46.5
4 16.57000 2.64120
5 20.52130 1.70000 1.80800 40.9
6 * 11.47060 7.78130
7 -302.25460 1.05000 1.49700 81.6
8 17.88820 0.26000
9 18.09470 4.00840 1.80610 33.3
10 60.79620 Variable
11 19.24800 0.70000 1.74330 49.2
12 6.77140 2.24910 1.67270 32.2
13 170.51120 1.89140
14 (Aperture) ∞ Variable
15 3979.65950 0.70000 1.84666 23.8
16 13.78260 2.33950 1.51680 64.2
17 -21.54820 1.31900
18 -9.53570 0.80000 1.51680 64.2
19 21.19960 2.89150 1.49700 81.6
20 -15.02470 0.20000
21 -58.86510 1.97180 1.49700 81.6
22 -20.72310 0.20000
23 41.66740 3.23430 1.49700 81.6
24 -20.80500 Variable
25 26.65630 0.80000 1.51823 59.0
26 17.53640 Variable
27 84.08090 0.90000 1.80518 25.5
28 27.44430 3.57720 1.52300 70.1
29 * -39.99340 BF
Image plane ∞

Table 2 (Aspherical data)

6th page
K = -4.01413E-01, A4 = -2.82803E-05, A6 = -1.13654E-07, A8 = -7.54243E-10
A10 = 5.36525E-12, A12 = -3.87978E-14
29th page
K = 0.00000E + 00, A4 = 5.16711E-05, A6 = 2.64198E-07, A8 = -6.34113E-09
A10 = 9.00687E-11, A12 = -4.31222E-13

Table 3 (various data)

Zoom ratio 1.89190
Wide angle Medium telephoto Focal length 7.2006 9.9053 13.6229
F number 4.00268 3.85380 4.09472
Angle of view 59.0156 48.7020 38.1410
Image height 10.8150 10.8150 10.8150
Total lens length 95.5429 90.8643 89.7896
BF 15.38321 15.38860 15.39895
d10 19.2075 9.1749 1.9157
d14 1.9913 2.0522 1.2990
d24 2.5261 2.0100 1.8500
d26 5.1612 10.9650 18.0524
Entrance pupil position 19.8078 18.7380 17.5657
Exit pupil position -50.9354 -68.0300 -85.0516
Front principal point position 26.2266 27.4671 29.3411
Rear principal point position 88.3423 80.9590 76.1668

Table 4 (Single lens data)

Lens Start surface Focal length
1 1 -69.4814
2 3 -52.4229
3 5 -35.1378
4 7 -33.9445
5 9 30.6741
6 11 -14.3986
7 12 10.4247
8 15 -16.3366
9 16 16.6409
10 18 -12.6150
11 19 18.1737
12 21 63.2652
13 23 28.4087
14 25 -101.9601
15 27 -50.9622
16 28 31.6971

Table 5 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 -14.89596 27.49980 9.27046 14.76759
2 11 40.61921 4.84050 -0.45077 0.77074
3 15 22.48920 13.65610 11.20519 17.60033
4 25 -101.96007 0.80000 1.58769 1.84449
5 27 80.78660 4.47720 2.60670 4.21608

Table 6 (Zoom lens group magnification)

Group Start surface Wide angle Medium telephoto
1 1 0.00000 0.00000 0.00000
2 11 -7.04498 9.51959 3.52410
3 15 0.06774 -0.06597 -0.23278
4 25 1.25623 1.31323 1.38290
5 27 0.80635 0.80628 0.80616

(Numerical example 2)
The zoom lens system of Numerical Example 2 corresponds to Embodiment 2 shown in FIG. Surface data of the zoom lens system of Numerical Example 2 are shown in Table 7, aspherical data in Table 8, various data in Table 9, single lens data in Table 10, zoom lens group data in Table 11, and zoom lens. Group magnification is shown in Table 12.

Table 7 (Surface data)

Surface number rd nd vd
Object ∞
1 32.47020 2.00000 1.80420 46.5
2 20.03180 6.27370
3 28.59860 1.80000 1.80420 46.5
4 16.57000 2.70090
5 20.52130 1.70000 1.80800 40.9
6 * 11.44550 8.07250
7 -100.75020 1.00000 1.49700 81.6
8 19.58010 4.00410 1.80610 33.3
9 92.88670 Variable
10 18.85950 0.70000 1.74330 49.2
11 6.74340 2.25040 1.67270 32.2
12 116.25340 1.89560
13 (Aperture) ∞ Variable
14 595.95060 0.70000 1.84666 23.8
15 13.82680 2.34620 1.51680 64.2
16 -21.12650 1.32080
17 -9.70390 0.80000 1.51680 64.2
18 20.99080 2.87260 1.49700 81.6
19 -15.71880 0.20000
20 -58.64710 1.97850 1.49700 81.6
21 -20.62270 0.20000
22 41.46940 3.23800 1.49700 81.6
23 -20.82360 Variable
24 26.64750 0.80000 1.51823 59.0
25 17.53290 Variable
26 81.82020 0.90000 1.80518 25.5
27 27.27070 3.58130 1.52300 70.1
28 * -40.37930 BF
Image plane ∞

Table 8 (Aspherical data)

6th page
K = -3.93507E-01, A4 = -2.91092E-05, A6 = -9.83771E-08, A8 = -1.09494E-09
A10 = 7.89710E-12, A12 = -4.73408E-14
28th page
K = 0.00000E + 00, A4 = 5.27176E-05, A6 = 2.51049E-07, A8 = -5.97520E-09
A10 = 8.53715E-11, A12 = -4.07934E-13

Table 9 (various data)

Zoom ratio 1.88982
Wide angle Medium telephoto Focal length 7.2052 9.9040 13.6166
F number 4.00224 3.85285 4.09430
Angle of view 59.1763 48.7875 38.1653
Image height 10.8150 10.8150 10.8150
Total lens length 95.5329 90.8882 89.8292
BF 15.38680 15.39045 15.40348
d9 19.1344 9.1208 1.8888
d13 1.9956 2.0689 1.2998
d23 2.5108 2.0100 1.8500
d25 5.1707 10.9634 18.0525
Entrance pupil position 19.8352 18.7716 17.6109
Exit pupil position -50.5737 -67.7646 -84.7428
Front principal point position 26.2533 27.4959 29.3761
Rear principal point position 88.3277 80.9842 76.2125

Table 10 (Single lens data)

Lens Start surface Focal length
1 1 -70.0446
2 3 -52.4889
3 5 -34.9551
4 7 -32.8954
5 8 30.0453
6 10 -14.4782
7 11 10.5544
8 14 -16.7280
9 15 16.5496
10 17 -12.7277
11 18 18.5672
12 20 62.9126
13 22 28.3825
14 24 -101.9672
15 26 -51.1776
16 27 31.6996

Table 11 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 -14.90085 27.55120 9.28790 14.66851
2 10 42.30042 4.84600 -0.60680 0.62440
3 14 22.37367 13.65610 11.04562 17.23657
4 24 -101.96715 0.80000 1.58811 1.84491
5 26 80.34236 4.48130 2.56393 4.17322

Table 12 (Zoom lens group magnification)

Group Start surface Wide angle Medium telephoto
1 1 0.00000 0.00000 0.00000
2 10 -10.54686 7.04668 3.19613
3 14 0.04533 -0.08923 -0.25690
4 24 1.25690 1.31376 1.38348
5 26 0.80465 0.80460 0.80444

(Numerical Example 3)
The zoom lens system of Numerical Example 3 corresponds to Embodiment 3 shown in FIG. Surface data of the zoom lens system of Numerical Example 3 are shown in Table 13, aspherical data in Table 14, various data in Table 15, single lens data in Table 16, zoom lens group data in Table 17, and zoom lens. Group magnification is shown in Table 18.

Table 13 (Surface data)

Surface data Surface number rd nd vd
Object ∞
1 30.44780 2.00000 1.80420 46.5
2 18.87500 7.34890
3 27.75750 1.92780 1.80420 46.5
4 16.42880 3.26840
5 19.60000 1.55000 1.80470 41.0
6 * 10.89970 7.72330
7 -225.11440 1.89310 1.49700 81.6
8 16.32060 3.99170 1.80610 33.3
9 57.99910 Variable
10 18.84770 0.70000 1.72342 38.0
11 6.23040 2.36850 1.68400 31.3
12 115.54490 1.70700
13 (Aperture) ∞ Variable
14 ∞ 0.70000 1.84666 23.8
15 13.71240 4.78040 1.51823 59.0
16 -15.01690 1.13690
17 -8.82940 0.80000 1.51680 64.2
18 104.27750 3.14800 1.49700 81.6
19 -12.21860 0.20000
20 33.45760 3.28830 1.49700 81.6
21 -21.12350 Variable
22 30.94380 1.00000 1.58144 40.9
23 19.52960 Variable
24 -73.91420 1.00000 1.80518 25.5
25 123.34430 3.41370 1.52500 70.3
26 * -19.50200 BF
Image plane ∞

Table 14 (Aspherical data)

6th page
K = -5.49068E-01, A4 = -1.42254E-05, A6 = -1.04715E-07, A8 = -1.46986E-10
A10 = 3.11013E-12, A12 = -2.87242E-14
26th page
K = 0.00000E + 00, A4 = 8.23200E-05, A6 = -7.52604E-08, A8 = 6.50947E-09
A10 = -9.16057E-11, A12 = 4.80195E-13

Table 15 (various data)

Zoom ratio 1.88906
Wide angle Medium telephoto Focal length 7.2009 9.9186 13.6030
F number 4.03569 3.88161 4.13870
Angle of view 58.9271 47.9004 37.3032
Image height 10.8150 10.8150 10.8150
Total lens length 96.5585 92.8958 92.3358
BF 15.38273 15.38116 15.38602
d9 18.0260 8.4931 1.4460
d13 1.7982 2.1728 1.6710
d21 2.4078 1.7000 1.7108
d23 4.9978 11.2027 18.1760
Entrance pupil position 20.4341 19.4466 18.3521
Exit pupil position -58.3885 -89.5091 -126.2034
Front principal point position 26.9321 28.4273 30.6482
Rear principal point position 89.3576 82.9771 78.7328

Table 16 (Single lens data)

Lens Start surface Focal length
1 1 -66.9043
2 3 -54.1627
3 5 -33.1474
4 7 -30.5391
5 8 27.0196
6 10 -13.1720
7 11 9.5439
8 14 -16.1958
9 15 14.6636
10 17 -15.7133
11 18 22.2055
12 20 26.5851
13 22 -94.0884
14 24 -57.2713
15 25 32.3410

Table 17 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 -14.40374 29.70320 10.19859 16.32686
2 10 37.60170 4.77550 -0.50091 0.78179
3 14 22.69792 14.05360 11.13540 17.51424
4 22 -94.08838 1.00000 1.77131 2.11793
5 24 68.03402 4.41370 5.03396 6.83127

Table 18 (Zoom lens group magnification)

Group Start surface Wide angle Medium telephoto
1 1 0.00000 0.00000 0.00000
2 10 -4.88114 20.55381 4.23608
3 14 0.10003 -0.03110 -0.19604
4 22 1.26498 1.33090 1.40509
5 24 0.80943 0.80945 0.80938

(Numerical example 4)
The zoom lens system of Numerical Example 4 corresponds to Embodiment 4 shown in FIG. The surface data of the zoom lens system of Numerical Example 4 is shown in Table 19, the aspheric data is shown in Table 20, the various data is shown in Table 21, the single lens data is shown in Table 22, the zoom lens group data is shown in Table 23, and the zoom lens. Group magnification is shown in Table 24.

Table 19 (Surface data)

Surface number rd nd vd
Object ∞
1 33.73000 2.00000 1.80420 46.5
2 20.50000 5.85990
3 26.77380 1.80000 1.80420 46.5
4 16.10000 4.64310
5 19.60000 1.55000 1.80470 41.0
6 * 10.69470 8.26910
7 -298.88690 1.26450 1.49700 81.6
8 16.57410 5.66770 1.80610 33.3
9 58.84120 Variable
10 19.49320 0.70000 1.72342 38.0
11 7.80550 4.16820 1.68400 31.3
12 * 65.51100 1.50600
13 (Aperture) ∞ Variable
14 268.54290 0.70000 1.84666 23.8
15 18.67540 2.51990 1.51823 59.0
16 -12.40510 0.78790
17 -9.47110 0.80000 1.51680 64.2
18 12.00420 3.75020 1.49700 81.6
19 -17.26890 0.20000
20 38.76770 2.94440 1.49700 81.6
21 -18.34760 Variable
22 33.88100 1.00000 1.58144 40.9
23 19.79670 Variable
24 -205.25430 1.00000 1.80518 25.5
25 58.31210 3.35500 1.52500 70.3
26 * -23.17480 BF
Image plane ∞

Table 20 (Aspherical data)

6th page
K = -4.41439E-01, A4 = -3.54100E-05, A6 = 1.15587E-07, A8 = -3.74110E-09
A10 = 2.31717E-11, A12 = -9.50173E-14
12th page
K = 0.00000E + 00, A4 = 4.91209E-05, A6 = -2.40723E-06, A8 = 1.65752E-07
A10 = -4.61598E-09, A12 = 0.00000E + 00
26th page
K = 0.00000E + 00, A4 = 7.10598E-05, A6 = 6.08469E-08, A8 = -1.63689E-09
A10 = 4.66337E-11, A12 = -2.92076E-13

Table 21 (various data)

Zoom ratio 1.88910
Wide angle Medium telephoto Focal length 7.2001 9.8960 13.6017
F number 4.05005 4.05027 4.05142
Angle of view 58.9987 48.4820 37.6168
Image height 10.8150 10.8150 10.8150
Total lens length 96.4352 91.3849 91.2929
BF 15.37255 15.84598 15.85089
d9 17.9459 8.0821 1.5843
d13 2.1001 1.9877 1.1500
d21 1.7000 2.0393 1.7000
d23 4.8308 8.9439 16.5218
Entrance pupil position 20.1706 19.2415 18.3453
Exit pupil position -39.9985 -51.4394 -71.3834
Front principal point position 26.4345 27.6821 29.8262
Rear principal point position 89.2352 81.4889 77.6912

Table 22 (Single lens data)

Lens Start surface Focal length
1 1 -69.6856
2 3 -54.2988
3 5 -31.7123
4 7 -31.5544
5 8 27.0070
6 10 -18.4597
7 11 12.5859
8 14 -23.7367
9 15 14.7927
10 17 -10.1157
11 18 14.8816
12 20 25.4941
13 22 -84.1001
14 24 -56.3032
15 25 32.0423

Table 23 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 -14.24164 31.05430 9.85997 16.74252
2 10 44.08317 6.37420 -1.41896 0.69708
3 14 21.93528 11.70240 8.51387 12.79729
4 22 -84.10010 1.00000 1.56191 1.91263
5 24 69.44057 4.35500 4.15667 5.84080

Table 24 (Zoom lens group magnification)

Group Start surface Wide angle Medium telephoto
1 1 0.00000 0.00000 0.00000
2 10 -44.20775 4.97181 2.86917
3 14 0.01098 -0.12954 -0.28937
4 22 1.30241 1.36019 1.45039
5 24 0.80002 0.79320 0.79313

(Numerical example 5)
The zoom lens system of Numerical Example 5 corresponds to Embodiment 5 shown in FIG. The surface data of the zoom lens system of Numerical Example 5 are shown in Table 25, the aspherical data in Table 26, the various data in Table 27, the single lens data in Table 28, the zoom lens group data in Table 29, and the zoom lens. Group magnification is shown in Table 30.

Table 25 (Surface data)

Surface number rd nd vd
Object ∞
1 32.53230 2.00000 1.80420 46.5
2 20.50000 5.29920
3 24.93130 1.80000 1.80420 46.5
4 16.00000 6.77330
5 30.03360 1.93360 1.80470 41.0
6 * 14.19960 6.83460
7 -81.80750 1.29550 1.49700 81.6
8 29.31440 4.06670 1.80610 33.3
9 213.26320 Variable
10 19.05720 0.70000 1.72623 54.8
11 6.93710 3.42900 1.63182 34.7
12 * 696.48680 1.35570
13 (Aperture) ∞ Variable
14 -631.44520 0.70000 1.84666 23.8
15 17.41730 2.50 600 1.53594 50.3
16 -12.21090 1.02130
17 -7.38790 0.80000 1.51742 52.1
18 24.34430 4.39930 1.49700 81.6
19 -10.50450 0.20000
20 55.10800 3.00710 1.49700 81.6
21 -19.57410 Variable
22 40.60470 1.00000 1.58144 40.9
23 23.96040 Variable
24 233.55820 1.00000 1.80518 25.5
25 34.11090 0.77000
26 79.43180 2.32080 1.52500 70.3
27 * -28.67840 BF
Image plane ∞

Table 26 (Aspherical data)

6th page
K = 0.00000E + 00, A4 = -4.43286E-05, A6 = -1.05536E-07, A8 = -2.37863E-09
A10 = 1.94014E-11, A12 = -8.16832E-14
12th page
K = 0.00000E + 00, A4 = -3.18703E-07, A6 = -1.05633E-06, A8 = -1.75650E-08
A10 = 0.00000E + 00, A12 = 0.00000E + 00
27th page
K = 0.00000E + 00, A4 = 6.73656E-05, A6 = 4.76084E-07, A8 = -6.30642E-09
A10 = 5.53166E-11, A12 = 0.00000E + 00

Table 27 (various data)

Zoom ratio 1.88916
Wide angle Medium telephoto Focal length 7.2007 9.8948 13.6032
F number 4.05157 4.05172 4.05114
Angle of view 59.0196 48.8263 38.1892
Image height 10.8150 10.8150 10.8150
Total lens length 98.5596 90.7884 87.2555
BF 15.36996 15.68211 15.43608
d9 20.5242 9.1837 1.4783
d13 3.0469 2.6786 1.4085
d21 1.9738 2.0576 1.7000
d23 4.4326 7.9743 14.0205
Entrance pupil position 21.2510 20.1148 18.9129
Exit pupil position -42.7313 -46.3055 -48.8643
Front principal point position 27.5593 28.4301 29.6382
Rear principal point position 91.3589 80.8936 73.6523

Table 28 (Single lens data)

Lens Start surface Focal length
1 1 -74.4367
2 3 -61.0190
3 5 -35.3977
4 7 -43.2556
5 8 41.7491
6 10 -15.3935
7 11 11.0686
8 14 -20.0096
9 15 13.8012
10 17 -10.8607
11 18 15.4108
12 20 29.4558
13 22 -102.8018
14 24 -49.7209
15 26 40.4334

Table 29 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 -14.95255 30.00290 10.49730 16.54644
2 10 41.90590 5.48470 -0.32700 1.30559
3 14 20.56078 12.63370 9.79278 15.07317
4 22 -102.80183 1.00000 1.57746 1.93084
5 24 181.29625 4.09080 8.72778 10.25289

Table 30 (Zoom lens group magnification)

Group Start surface Wide angle Medium telephoto
1 1 0.00000 0.00000 0.00000
2 10 -6.25432 9.03108 3.39440
3 14 0.06686 -0.06181 -0.21607
4 22 1.21332 1.25115 1.30730
5 24 0.94921 0.94749 0.94885

(Numerical example 6)
The zoom lens system of Numerical Example 6 corresponds to Embodiment 6 shown in FIG. Surface data of the zoom lens system of Numerical Example 6 are shown in Table 31, aspherical data in Table 32, various data in Table 33, single lens data in Table 34, zoom lens group data in Table 35, and zoom lens. Group magnification is shown in Table 36.

Table 31 (Surface data)

Surface number rd nd vd
Object ∞
1 35.59120 2.00000 1.80420 46.5
2 19.60000 6.20930
3 * 46.52590 2.00000 1.80470 41.0
4 18.71380 3.37540
5 25.12170 1.00000 1.80420 46.5
6 18.02350 7.21140
7 -34.36390 1.00000 1.49700 81.6
8 76.37600 2.05840 1.84666 23.8
9 551.50130 Variable
10 * 157.15760 2.55990 1.62628 46.4
11 -6.95040 0.70000 1.71758 55.1
12 -24.79060 Variable
13 (Aperture) ∞ 6.00000
14 99.20010 0.70000 1.84505 24.2
15 20.82540 6.70280 1.55487 64.3
16 -20.27800 0.20000
17 21.98820 1.81340 1.72799 28.1
18 89.55920 Variable
19 * -49.61050 1.88350 1.49700 81.6
20 -16.09080 0.20000
21 -36.25520 0.70000 1.49700 81.6
22 -50.08650 1.00000 1.82611 25.3
23 16.18320 1.15230
24 41.30550 3.13680 1.48890 70.3
25 -21.08640 BF
Image plane ∞

Table 32 (Aspherical data)

Third side
K = 0.00000E + 00, A4 = 1.56544E-05, A6 = 1.56679E-08, A8 = 1.10484E-10
A10 = -6.49881E-13, A12 = 1.43574E-15
10th page
K = 0.00000E + 00, A4 = -1.03960E-06, A6 = -1.13322E-07, A8 = 4.24478E-08
A10 = 0.00000E + 00, A12 = 0.00000E + 00
19th page
K = 0.00000E + 00, A4 = -6.89822E-05, A6 = -4.22724E-07, A8 = 6.04668E-09
A10 = 0.00000E + 00, A12 = 0.00000E + 00

Table 33 (various data)

Zoom ratio 1.94428
Wide angle Medium telephoto Focal length 7.5030 10.4480 14.5880
F number 4.05212 4.05214 4.05235
Angle of view 58.1750 48.3024 37.2049
Image height 10.8150 10.8150 10.8150
Total lens length 100.5550 92.5102 88.7805
BF 19.65911 20.44391 21.39269
d9 22.7797 10.9625 2.4000
d12 4.0409 4.2922 4.2922
d18 2.4721 5.2084 9.0924
Entrance pupil position 18.7789 17.9213 16.8818
Exit pupil position -29.4478 -31.1871 -33.5144
Front principal point position 25.1355 26.2550 27.5940
Rear principal point position 93.0520 82.0622 74.1925

Table 34 (Single lens data)

Lens Start surface Focal length
1 1 -57.4468
2 3 -40.1923
3 5 -84.6334
4 7 -47.5446
5 8 104.5015
6 10 10.6920
7 11 -13.6837
8 14 -31.3205
9 15 19.6603
10 17 39.5850
11 19 47.0403
12 21 -268.6786
13 22 -14.7054
14 24 29.0330

Table 35 (Zoom lens group data)

Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 -12.50248 24.85450 9.28615 14.61265
2 10 50.49791 3.25990 1.86473 3.12977
3 13 20.66907 15.41620 10.95416 14.51666
4 19 -87.88159 8.07260 -5.69078 -4.43423

Table 36 (Zoom lens group magnification)

Group Start surface Wide angle Medium telephoto
1 1 0.00000 0.00000 0.00000
2 10 16.24168 3.38314 2.14987
3 13 -0.02705 -0.17965 -0.39166
4 19 1.36601 1.37494 1.38574

  Table 37 below shows corresponding values for each condition in the zoom lens system according to each numerical example.

Table 37 (Corresponding values of conditions: Numerical Examples 1 to 6)

  The zoom lens system according to the present invention is applicable to digital input devices such as a digital still camera, a digital video camera, a mobile phone device, a PDA (Personal Digital Assistance), a surveillance camera in a surveillance system, a web camera, an in-vehicle camera, It is particularly suitable for a photographing optical system that requires high image quality, such as a digital still camera and a digital video camera.

Lens arrangement diagram showing an infinitely focused state of the zoom lens system according to Embodiment 1 (Example 1) Longitudinal aberration diagram of the zoom lens system according to Example 1 in an infinitely focused state Lens arrangement diagram showing an infinitely focused state of the zoom lens system according to Embodiment 2 (Example 2) Longitudinal aberration diagram of the zoom lens system according to Example 2 in an infinitely focused state Lens arrangement diagram showing an infinitely focused state of the zoom lens system according to Embodiment 3 (Example 3) Longitudinal aberration diagram of the zoom lens system according to Example 3 in an infinitely focused state Lens arrangement diagram showing an infinitely focused state of the zoom lens system according to Embodiment 4 (Example 4) Longitudinal aberration diagram of the zoom lens system according to Example 4 in an infinitely focused state Lens arrangement diagram showing an infinitely focused state of a zoom lens system according to Embodiment 5 (Example 5) Longitudinal aberration diagram of the zoom lens system according to Example 5 in an infinitely focused state Lens arrangement diagram showing an infinitely focused state of a zoom lens system according to Embodiment 6 (Example 6) Longitudinal aberration diagram of the zoom lens system according to Example 6 in focus at infinity Schematic configuration diagram of an interchangeable lens digital camera system according to Embodiment 7

DESCRIPTION OF SYMBOLS 100 Lens interchangeable digital camera system 101 Camera main body 102 Image pick-up element 104 Camera mount part 201 Interchangeable lens apparatus 202 Zoom lens system

Claims (14)

A zoom lens system that includes a plurality of lens groups and performs zooming by changing an interval between the lens groups,
In order from the object side to the image side,
A first lens group having negative power;
A second lens group having positive power;
A third lens group having positive power ;
A fourth lens group having negative power ,
The first lens group is in order from the object side to the image side.
A negative meniscus first lens element having negative power and having a concave surface facing the image side;
A negative meniscus second lens element having negative power and having a concave surface facing the image side;
A negative meniscus third lens element having negative power and having a concave surface facing the image side ;
A fourth lens element having negative power;
A fifth lens element having a positive power,
A zoom lens system, wherein at least one of the lens elements constituting the first lens group is an aspherical lens. 2. The zoom lens system according to claim 1, wherein, during focusing, the second lens group or a lens group disposed on the image side of the second lens group moves in a direction along the optical axis. The zoom lens system according to claim 1, wherein the zoom lens system satisfies the following condition:
2.3 <(R ₁₁ + R ₁₂ ) / (R ₁₁ −R ₁₂ ) <10 (7)
here,
R ₁₁ : Object side radius of curvature of the lens element closest to the object side in the first lens group,
R ₁₂ : image-side radius of curvature of the lens element closest to the object side in the first lens group,
It is. The zoom lens system according to claim 1, wherein the zoom lens system satisfies the following condition:
2.3 <(R ₂₁ + R ₂₂ ) / (R ₂₁ −R ₂₂ ) <10 (8)
here,
R ₂₁ : Object side radius of curvature of the second lens element from the object side in the first lens group,
R ₂₂ : image-side radius of curvature of the second lens element from the object side in the first lens group,
It is. The zoom lens system according to claim 1, wherein the zoom lens system satisfies the following condition:
2.3 <(R ₃₁ + R ₃₂ ) / (R ₃₁ −R ₃₂ ) <10 (9)
here,
R ₃₁ : Object side radius of curvature of the third lens element from the object side in the first lens group,
R ₃₂ : image-side radius of curvature of the third lens element from the object side in the first lens group,
It is.   The zoom lens system according to claim 1, wherein the third lens element is an aspheric lens. The zoom lens system according to claim 1, wherein the aspheric lens included in the first lens group is a glass lens having a spherical object side surface and an aspheric image side surface. The zoom lens system according to any one of claims 1 to 7 , which satisfies the following condition:
DIS _W <−8 (6)
here,
DIS _W : Distortion aberration (%) at the maximum image height at the wide-angle end,
It is. The zoom lens system according to any one of claims 1 to 7 , which satisfies the following condition:
−0.65 <f _W / f ₁ <−0.45 (1)
here,
f ₁ : focal length of the first lens group,
f _W : focal length at the wide-angle end of the entire system,
It is. The zoom lens system according to any one of claims 1 to 7 , which satisfies the following condition:
0.1 <f _W / f ₂ <0.3 (2)
here,
f ₂ : focal length of the second lens group,
f _W : focal length at the wide-angle end of the entire system,
It is. The zoom lens system according to any one of claims 1 to 7 , which satisfies the following condition:
0.25 <f _W / f ₃ <0.5 (3)
here,
f ₃ : focal length of the third lens group,
f _W : focal length at the wide-angle end of the entire system,
It is. The zoom lens system according to any one of claims 1 to 7 , which satisfies the following condition:
−0.1 <f _W / f ₄ <−0.05 (4)
here,
f ₄ : focal length of the fourth lens group,
f _W : focal length at the wide-angle end of the entire system,
It is. A zoom lens system according to claim 1;
An interchangeable lens apparatus comprising: a lens mount unit connected to a camera body including an imaging sensor that receives an optical image formed by the zoom lens system and converts the optical image signal into an electrical image signal. An interchangeable lens device comprising the zoom lens system according to claim 1;
A camera body that includes an imaging sensor that is detachably connected to the interchangeable lens device via a camera mount unit and that receives an optical image formed by the zoom lens system and converts it into an electrical image signal. system.

Images