JP2013057961A - Zoom lens and imaging apparatus including the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a zoom lens obtaining good image quality, which is small sized and having little deterioration in optical performance due to a manufacturing error such as relative shifting of shafts in respective lenses and even when vibration insulation is carried out.SOLUTION: The zoom lens is composed of lens groups which are: a positive first lens group L1; a negative second lens group L2; a positive third lens group L3; a positive fourth lens group L4; and a positive fifth lens group L5 in this order from an object side. In this case, when zooming from a wide angle end to a telephoto end, the image forming position is varied by having the second lens group L2 moved to an image surface IP side as well as having the spacing between respective lens groups varied and the third lens group L3 is moved in the direction having the same perpendicular component as the optical axis. The third lens group L3 is composed of: a 3a lens group L3a having positive refractive power; an aperture diaphragm SP; and a 3b lens group L3b in this order from the object side. The 3a lens group L3a is composed of one lens component having positive refractive power. The 3b lens group L3b includes a negative lens. When the focal distances for the 3a lens group L3a and the 3b lens group L3b are respectively f3a and f3b, the relation: -0.1<f3a/f3b<0.1 is satisfied.

Description

  The present invention relates to a zoom lens and an image pickup apparatus having the same, such as an image pickup apparatus using a solid-state image pickup device such as a video camera, an electronic still camera, a broadcast camera, a surveillance camera, or a camera using a silver salt film. It is suitable for an imaging device.

  In recent years, imaging devices such as a video camera using a solid-state imaging device, a digital still camera, a broadcasting camera, a surveillance camera, and a camera using a silver salt film have been improved in function, and the entire device has been downsized.

  A photographing optical system used therefor is required to be a zoom lens having a short overall lens length, a compact size, a high zoom ratio (high zoom ratio), and a high resolving power.

  As a zoom lens that meets these requirements, a positive lead type zoom lens in which a lens group having a positive refractive power is disposed on the object side is known. For example, a zoom lens having a rear group including first, second, and third lens groups having positive, negative, and positive refractive power in order from the object side to the image side and one or more lens groups that follow is known. (Patent Documents 1 to 6).

  In these zoom lenses, the second lens group having a negative refractive power moves mainly toward the image plane during zooming from the wide-angle end to the telephoto end, thereby performing a main zooming action. In this type of zoom lens, the lens configuration of the third lens group is important for obtaining high optical performance over the entire zoom range.

  In Patent Document 1, the third lens group is composed of one or more positive lenses and negative lenses, respectively, and the aperture stop is disposed immediately before the third lens group.

  In Patent Documents 2 to 5, the third lens group is composed of three lenses, and the aperture stop is disposed between the lenses of the third lens group.

  As a result, high optical performance is obtained over the entire zoom range.

  Also, in Patent Document 5, in order to correct image blur when the zoom lens vibrates, the third lens group is moved so as to have a component in a direction perpendicular to the optical axis (orthogonal direction) to correct blur of the photographed image. doing.

  In Patent Document 6, image blur when the zoom lens vibrates is corrected by moving a part of the lens group constituting the third lens group in a direction perpendicular to the optical axis.

JP 7-270684 A JP 2003-050351 A JP-A-8-94931 JP 2006-301193 A JP 2006-189627 A JP 2006-84740 A

  In recent years, there is a strong demand for a zoom lens used in an imaging apparatus that has a high zoom ratio and that the entire lens system is small.

  In general, in a zoom lens, if the refractive power of each lens group is increased, the amount of movement of each lens group for obtaining a predetermined zoom ratio can be reduced, so that a high zoom ratio and a shortened total lens length are achieved. Can do.

  However, if the refractive power of each lens group is simply increased, the assembly accuracy of each lens group becomes severe. For example, in the zoom lenses disclosed in Patent Documents 1 to 5, when the third lens group that greatly affects the optical performance is assembled, if the optical axis of each lens of the third lens group is relatively shifted, the image performance is reduced. May deteriorate.

  For this reason, appropriately setting the lens configuration of the third lens group is very important in reducing the size and performance of the positive lead type zoom lens described above.

  Digital cameras, video cameras, and the like are required to obtain high optical performance even when there is camera shake or vibration.

  The present invention is small in size, has little degradation in optical performance due to manufacturing errors such as relative optical axis misalignment of each lens, and can suppress degradation in optical performance due to decentration aberrations during vibration compensation, resulting in good image quality. An object of the present invention is to provide a zoom lens that can achieve the above.

The zoom lens according to the present invention includes, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive lens having a positive refractive power. The fourth lens group includes a fifth lens group having a positive refractive power, and during zooming from the wide-angle end to the telephoto end, the second lens group moves to the image plane side, and the interval between the lens groups changes. The zoom lens moves the third lens group in a direction having a component perpendicular to the optical axis to change the imaging position, and the third lens group has a positive refractive power in order from the object side to the image side. 3a lens group L3a, an aperture stop, and a 3b lens group L3b. The 3a lens group L3a is composed of a lens component having one positive refractive power, and the 3b lens group L3b is a negative lens. The focus of the 3a lens unit L3a and the 3b lens unit L3b Distance respectively f3a, when the f3b,
-0.1 <f3a / f3b <0.1
It satisfies the following conditional expression.

  According to the present invention, the optical system is small, there is little deterioration in optical performance due to a manufacturing error such as a relative optical axis shift (relative axis shift) of each lens, and even if vibration compensation (anti-vibration) is performed. A zoom lens capable of obtaining good image quality can be obtained.

Lens cross-sectional view at the wide angle end according to Numerical Example 1 of the present invention Aberration diagram at the wide angle end according to Numerical Example 1 of the present invention. Aberration diagram at the intermediate zoom position in Numerical Example 1 of the present invention Aberration diagram at the telephoto end according to Numerical Example 1 of the present invention. Lens sectional view at the wide angle end according to Numerical Embodiment 2 of the present invention Aberration diagram at wide-angle end according to Numerical Example 2 of the present invention Aberration diagram at intermediate zoom position in Numerical Example 2 of the present invention Aberration diagram at the telephoto end according to Numerical Example 2 of the present invention Lens cross-sectional view at the wide-angle end according to Numerical Embodiment 3 of the present invention Aberration diagram at wide-angle end according to Numerical Example 3 of the present invention Aberration diagram at intermediate zoom position according to Numerical Example 3 of the present invention Aberration diagram at the telephoto end according to Numerical Example 3 of the present invention Lens sectional view at the wide-angle end according to Numerical Embodiment 4 of the present invention Aberration diagram at wide-angle end according to Numerical Example 4 of the present invention Aberration diagram at intermediate zoom position according to Numerical Example 4 of the present invention Aberration diagram at the telephoto end according to Numerical Example 4 of the present invention Lens sectional view at the wide angle end according to Numerical Embodiment 5 of the present invention Aberration diagram at wide-angle end according to Numerical Example 5 of the present invention Aberration diagram at intermediate zoom position according to Numerical Example 5 of the present invention Aberration diagram at the telephoto end according to Numerical Example 5 of the present invention Lens sectional view at the wide-angle end according to Numerical Embodiment 6 of the present invention Aberration diagram at wide-angle end according to Numerical Example 6 of the present invention Aberration diagram at intermediate zoom position in Numerical Example 6 of the present invention Aberration diagram at the telephoto end according to Numerical Example 6 of the present invention. Lens sectional view at the wide-angle end according to Numerical Embodiment 7 of the present invention Aberration diagram at wide-angle end according to Numerical Example 7 of the present invention Aberration diagram at intermediate zoom position according to Numerical Example 7 of the present invention Aberration diagram at the telephoto end according to Numerical Example 7 of the present invention. Lens sectional view at the wide-angle end according to Numerical Embodiment 8 of the present invention Aberration diagram at wide-angle end according to Numerical Embodiment 8 of the present invention Aberration diagram at intermediate zoom position according to Numerical Example 8 of the present invention Aberration diagram at the telephoto end according to Numerical Example 8 of the present invention. Schematic diagram of essential parts when the zoom lens of the present invention is applied to a digital camera. Schematic diagram of essential parts when the zoom lens of the present invention is applied to a video camera.

  Embodiments of the zoom lens of the present invention and an image pickup apparatus having the same will be described below.

The zoom lens according to the present invention includes, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and one or more lenses. It consists of a rear group having a positive refractive power as a whole including the group.

Then, the second lens group moves to the image plane side, and zooming from the wide-angle end to the telephoto end is performed by changing the interval between the lens groups.

  The third lens group is moved in a direction having a component perpendicular to the optical axis (in the direction perpendicular to the embodiment) to displace the image position (image formation position). That is, vibration isolation is performed.

  1 is a cross-sectional view of a main part of the zoom lens of Reference Example 1, and FIGS. 2 to 4 are a wide angle end (short focal length end), an intermediate focal length, and a telephoto end (long focal length end) of the zoom lens of Reference Example 1, respectively. FIG.

  5 is a cross-sectional view of a main part of the zoom lens of Reference Example 2, and FIGS. 6 to 8 are aberration diagrams of the zoom lens of Reference Example 2 at the wide-angle end, the intermediate focal length, and the telephoto end, respectively.

  FIG. 9 is a cross-sectional view of the main part of the zoom lens of Reference Example 3, and FIGS. 10 to 12 are aberration diagrams of the zoom lens of Reference Example 3 at the wide-angle end, intermediate focal length, and telephoto end, respectively.

  13 is a cross-sectional view of the main part of the zoom lens of Reference Example 4, and FIGS. 14 to 16 are aberration diagrams of the zoom lens of Reference Example 4 at the wide-angle end, intermediate focal length, and telephoto end, respectively.

  FIG. 17 is a cross-sectional view of a main part of the zoom lens of Reference Example 5, and FIGS. 18 to 20 are aberration diagrams of the zoom lens of Reference Example 5 at the wide angle end, the intermediate focal length, and the telephoto end, respectively.

  FIG. 21 is a cross-sectional view of the main part of the zoom lens of Reference Example 6, and FIGS. 22 to 24 are aberration diagrams of the zoom lens of Reference Example 6 at the wide-angle end, intermediate focal length, and telephoto end, respectively.

  FIG. 25 is a cross-sectional view of a main part of the zoom lens of Example 1, and FIGS. 26 to 28 are aberration diagrams of the zoom lens of Example 1 at the wide angle end, the intermediate focal length, and the telephoto end, respectively.

  FIG. 29 is a cross-sectional view of a principal part of the zoom lens of Example 2, and FIGS. 30 to 32 are aberration diagrams of the zoom lens of Example 2 at the wide-angle end, the intermediate focal length, and the telephoto end, respectively.

  FIG. 33 and FIG. 34 are schematic views of a main part of a camera (imaging device) provided with the zoom lens of the present invention.

  The zoom lens of each embodiment is a photographic lens system used in an imaging apparatus such as a video camera or a digital camera. In the lens cross-sectional view, the left side is the subject side (object side) (front), and the right side is the image side (rear).

  In the lens cross-sectional view, i indicates the order of the lens groups from the object side, and Li is the i-th lens group. Lr is the rear group.

  SP is an aperture stop. The aperture stop SP is disposed in the third lens unit L3 in the zoom lens of each embodiment.

  G is an optical block corresponding to an optical filter, a face plate (parallel flat glass), a quartz low-pass filter, an infrared cut filter, and the like.

  IP is an image plane, and when used as a photographing optical system of a video camera or a digital still camera, an imaging plane of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor is placed.

  In the aberration diagrams, d and g are d-line and g-line, ΔM and ΔS are meridional image surface, sagittal image surface, and lateral chromatic aberration are represented by g-line. ω is a half angle of view, and Fno is an F number.

  In the following embodiments, the wide-angle end and the telephoto end refer to zoom positions when the zoom lens unit is positioned at both ends of a range in which the mechanism can move on the optical axis.

  The arrows indicate the movement trajectory of each lens unit during zooming from the wide-angle end to the telephoto end. The zoom lens of each embodiment includes, in order from the object side to the image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, and a third lens unit L3 having a positive refractive power. doing. Further, the rear lens unit Lr has a positive refractive power as a whole in the entire zoom range including one or more lens units following this.

  In the zoom lenses of Reference Examples 1 to 6 as the rear group Lr, the fourth lens group L4 having one positive refractive power is configured. In the zoom lenses of Examples 1 and 2 as the rear group Lr, the second lens group includes a fourth lens unit L4 having a positive refractive power and a fifth lens unit L5 having a positive refractive power.

  In each embodiment, the third lens unit L3 includes, in order from the object side to the image side, a positive refractive power third lens unit L3a including one lens component having positive refractive power, an aperture stop SP, and at least one negative aperture. It is composed of a 3b lens group L3b having a lens.

  By configuring the third lens unit L3 in this way, the distance between the second lens unit L2 and the third lens unit L3 that is the minimum at the telephoto end is set so that the aperture stop SP is positioned immediately before the third lens unit L3. Can be shortened.

  As a result, since the zooming efficiency of the second lens unit L2, which is the main zooming lens unit, is improved, it is easy to reduce the total lens length while achieving a high zoom ratio.

  In general, in the lens group close to the aperture stop SP, the effective lens diameter is determined by the diameter of the axial light beam, so it is particularly necessary to correct spherical aberration and axial chromatic aberration.

  In addition, in this lens group, the height of the light beam through which the off-axis light beam passes is high throughout the entire zoom range, so it is necessary to correct the field curvature well from the wide-angle end to the telephoto end.

  In order to correct such a plurality of different aberrations, the third lens unit L3 is composed of one or more positive lenses and negative lenses as a whole.

  In a plurality of lens surfaces close to each other in the optical system, there is little change in the light beam height. For this reason, correction of similar aberrations is easy, but it is difficult to effectively correct different aberrations such as spherical aberration and field curvature.

  Therefore, in the third lens unit L3, the wider the distance between the 3a lens unit L3a and the 3b lens unit L3b, the better. According to this, the difference in the height of light rays passing through the two lens units is increased. As a result, aberration correction becomes easy.

  On the other hand, if the distance between the two lens groups is increased, the total lens length increases, which is not preferable for downsizing the optical system.

  Therefore, in each embodiment, an aperture stop SP is disposed between the third-a lens unit L3a and the third-b lens unit L3b. As a result, the distance between the 3a lens unit L3a and the 3b lens unit L3b necessary for aberration correction is effectively obtained, and the entire lens system is reduced in size while satisfactorily correcting aberrations.

  In each embodiment, the 3a lens unit L3a and the 3b lens unit L3b are moved in a direction having a component perpendicular to the optical axis to displace the image position. In other words, the vibration of the photographed image when the zoom lens vibrates is corrected to prevent vibration.

  The aperture stop SP may be moved integrally with the 3a lens unit L3a and the 3b lens unit L3b during image blur correction or may be fixed.

  In each embodiment, the third lens unit L3 includes, in order from the object side to the image side, a third-a lens unit L3a having a positive refractive power, an aperture stop SP, and a third-b lens unit L3b. The third-a lens unit L3a includes one lens component having a positive refractive power. The third lens group L3b has a negative lens. The focal lengths of the third-a lens unit L3a and the third-b lens unit L3b are f3a and f3b, respectively.

At this time,
-0.1 <f3a / f3b <0.1 (1)
The following conditional expression is satisfied.

  Here, the technical meaning of conditional expression (1) will be described.

  Conditional expression (1) relates to the ratio of the refractive power (reciprocal of the focal length) of the third-a lens unit L3a and the third-b lens unit L3b.

  The third lens unit L3 corrects a plurality of aberrations such as spherical aberration, axial chromatic aberration, and field curvature over the entire zoom range in cooperation with the third lens unit L3a and the third lens unit L3b with the aperture stop SP interposed therebetween. doing.

  Therefore, when the third a lens unit L3a and the third b lens unit L3b are displaced relative to each other in the lens unit, the relative height of the light beam passing through the third b lens unit L3b with respect to the third a lens unit L3a is changed. For this reason, the aberration correction balance between the two lens groups is lost, and the image performance deteriorates.

  Since the third-a lens unit L3a has a positive refractive power, the focal length f3a takes a positive value in the conditional expression (1).

  Even if the refractive power of the third lens group L3b exceeds the lower limit of the conditional expression (1) and becomes too large in the negative direction, or conversely exceeds the upper limit and becomes too large in the positive direction, the third lens. When the relative axis shifts in the group L3, the variation in the height of the light beam passing through the third b lens group L3b increases. For this reason, the deterioration of the image performance is increased.

  The ratio of the refractive powers of the 3a lens unit L3a and the 3b lens unit L3b is also related to the optical performance during image stabilization (image blur correction).

  At the time of image stabilization, the third lens unit L3 is decentered in a direction having a component perpendicular to the optical axis with respect to the lens system, so that decentration aberration occurs.

  A particular problem with decentration aberrations during image stabilization is decentration coma and one-sided blur due to image plane tilt.

  If the lower limit and the upper limit of conditional expression (1) are exceeded and the refractive power of the third lens unit L3b is too large, the decentration coma aberration and the image plane tilt will be too great when the third lens unit L3 is decentered. It is difficult to achieve good optical performance over the entire screen during image stabilization.

  In each embodiment, the zoom lens has a good image quality suitable for vibration compensation (anti-vibration) because it is small in size and has a small optical performance due to a manufacturing error such as a relative axis shift of each lens. Have gained.

  In each embodiment, by configuring each lens group as described above, there is a zoom lens that can reduce an optical performance due to a manufacturing error due to a relative axis shift of each lens and can obtain a good image even during image stabilization. can get. In each embodiment, it is more preferable to satisfy one or more of the following conditions.

  The focal length at the wide-angle end of the rear group Lr is denoted by fr. Here, the focal length fr is the combined focal length of the fourth and fifth lens groups L4 and L5 when the rear group Lr includes the fourth and fifth lens groups L4 and L5.

  The Abbe number of the material of one negative lens G3bn of the third b lens unit L3b is νd3bn.

  The third-a lens unit L3a is composed of one positive lens G3ap, and the Abbe number of the material of the positive lens G3ap is νd3ap.

  The third lens group L3b has a positive lens G3bp, and the focal length of the positive lens G3bp is f3bp.

  The imaging magnifications at the wide-angle end and the telephoto end of the third lens unit L3b are β3bw and β3bt, respectively.

  The distance between the third-a lens unit L3a and the third-b lens unit L3b is dab, and the maximum effective diameter of the aperture stop at the wide-angle end is Dsp.

  However, the effective diameter Dsp is the diameter of the circular opening when the opening area is satisfied when the opening is not circular.

  The focal length of the first lens unit L1 is f1, and the focal lengths at the wide-angle end and the telephoto end of the entire lens system are fw and ft, respectively.

  The imaging magnifications at the wide-angle end and the telephoto end of the second lens unit L2 are β2w and β2t, respectively.

At this time,
3.2 <fr / fw <6.4 (2)
20 <νd3bn <33 (3)
55 <νd3ap (4)
0.7 <f3a / f3bp <1.3 (5)
0.8 <β3bt / β3bw <1.2 (6)
0.1 <dab / Dsp <1.6 (7)
1.2 <f1 / (fw · ft) ^1/2 <3.0 (8)
0.6 <(β2t / β2w) / (ft / fw) <1.6 (9)
It is preferable to satisfy one or more of the following conditions.

  Next, the technical meaning of each conditional expression described above will be described.

  Conditional expression (2) is an expression for an appropriate length (back focus) from the last lens surface of the rear group Lr to the image plane at the wide-angle end.

  If the upper limit of conditional expression (2) is exceeded and the focal length of the rear lens group Lr becomes long, the back focus becomes too long and the overall length of the lens becomes large.

  Conversely, when the lower limit of conditional expression (2) is exceeded and the focal length of the rear group Lr becomes too short, the back focus becomes too short.

  As a result, it is difficult to secure a sufficient space for placing a face plate, a low-pass filter, and the like placed on the light incident surface side of a solid-state imaging device such as a CCD sensor or a CMOS sensor.

  Further, since the amount of aberration generated in the rear group Lr increases, it is necessary to increase the number of lenses, and the entire lens system becomes large, which is not good.

  Conditional expression (3) is for favorably correcting chromatic aberration. If the upper limit of conditional expression (3) is exceeded and the dispersion of the material of the negative lens G3bn of the third lens unit L3b becomes too small, the achromaticity with the third lens unit L3a having a positive refractive power becomes insufficient. This is not good because the axial chromatic aberration deteriorates in the entire zoom range.

  If the dispersion of the material of the negative lens G3bn of the third lens group L3b exceeds the lower limit value of the conditional expression (3) and becomes too large, the negative lens is determined from the achromatic condition with the third lens group L3a having a positive refractive power. The refractive power given to G3bn becomes small.

  As a result, it becomes insufficient to correct spherical aberration, axial chromatic aberration, field curvature in the entire zoom range, and the like to be corrected in the entire third lens unit L3.

  Conditional expression (4) is for favorably correcting chromatic aberration. Constructing the third-a lens unit L3a with a single positive lens has the advantage of reducing the size of the entire lens system and reducing the weight of the lens unit that is moved during image stabilization.

  When the lower limit value of conditional expression (4) is exceeded, chromatic aberration generated in the 3a lens unit L3a becomes too large to be corrected by the 3b lens unit L3b.

  Conditional expression (5) defines the ratio of the focal length of the 3a lens unit L3a having positive refractive power and the focal length of at least one positive lens G3bp of the 3b lens unit L3b. This is a formula for correcting well.

  When the upper limit of conditional expression (5) is exceeded and the refractive power of the positive lens G3bp of the 3b lens unit L3b becomes too large, the spherical aberration generated in the positive lens G3bp becomes larger on the negative side, and this becomes the third lens. It becomes difficult to correct with the negative lens G3bn of the group L3b.

  Conversely, when the lower limit of conditional expression (5) is exceeded, the curvature of the image surface becomes too large from the intermediate image height to the maximum image height over the entire zoom range, making it difficult to obtain high optical performance over the entire screen.

  Conditional expression (6) is an expression that defines the zoom ratio (ratio of imaging magnification) of the 3b lens unit L3b.

  Even if the zoom ratio of the 3b lens unit L3b exceeds the upper limit value and the lower limit value of the conditional expression (6) and becomes too larger than 1.2 or smaller than 0.8, the 3a lens unit The variation of the spherical aberration due to the relative axis shift of the third b lens unit L3b with respect to L3a becomes too large. As a result, it is difficult to manufacture each lens group.

  Conditional expression (7) relates to the distance dab between the 3a lens unit L3a and the 3b lens unit L3b and the effective diameter Dsp when the aperture stop SP is opened.

  If the upper limit of conditional expression (7) is exceeded and the distance dab between the 3a lens unit L3a and the 3b lens unit L3b becomes too large, the entire lens system becomes large, which is not good.

  Conversely, if the distance dab becomes too narrow beyond the lower limit of conditional expression (7), the difference in the height of off-axis rays passing through the third lens unit L3a and the third lens unit L3b becomes too small. It becomes difficult to correct field curvature well over the entire zoom range.

  Also, when the number of lenses of the 3b lens unit L3b or the number of aspheric surfaces is increased to correct the field curvature, the variation in field curvature due to the relative axis shift between the 3a lens unit L3a and the 3b lens unit L3b may occur. It becomes too big and difficult to manufacture.

  Conditional expression (8) relates to the focal length of the first lens unit L1.

  When the upper limit of conditional expression (8) is exceeded and the focal length f1 of the first lens unit L1 becomes too long, the zooming effect due to the movement of the second lens unit L2 is reduced, and the second lens unit L2 accompanying zooming is reduced. This is not good because the amount of movement becomes too long and the total lens length increases.

  Conversely, if the lower limit of conditional expression (8) is exceeded and the focal length f1 of the first lens unit L1 becomes too short, the spherical aberration becomes too under and the axial chromatic aberration worsens at the telephoto end.

  Conditional expression (9) defines the zoom ratio of the second lens unit L2.

  If the zoom ratio of the second lens unit L2 exceeds the upper limit value of the conditional expression (9), the third lens unit L3 becomes a strong reduction lens system, and the most object side lens surface of the 3a lens unit L3a. The incident angle of the outermost ray of the on-axis light beam incident on is too large.

  As a result, the spherical aberration occurring in the 3a lens unit L3a becomes too under at the wide angle end, and it becomes difficult to correct this in the entire third lens unit L3. At the same time, the variation of the spherical aberration due to the relative axis shift between the 3a lens unit L3a and the 3b lens unit L3b becomes too large, making it difficult to manufacture.

  Conversely, if the zoom ratio of the second lens unit L2, which is the main zoom lens unit, becomes too small beyond the lower limit of conditional expression (9), the variable power sharing of the rear lens unit Lr after the third lens unit L3. Is too big. As a result, it is necessary to increase the number of lenses in the rear group Lr, which is not good because the total lens length increases.

  Preferably, the numerical ranges of conditional expressions (1) to (9) are set as follows.

-0.1 <f3a / f3b <0.08 (1a)
3.4 <fr / fw <6.0 (2a)
25 <νd3bn <32 (3a)
55 <νd3ap <75 (4a)
0.75 <f3a / f3bp <1.3 (5a)
0.9 <β3bt / β3bw <1.1 (6a)
0.2 <dab / Dsp <0.8 (7a)
1.4 <f1 / (fw · ft) ^1/2 <2.7 (8a)
0.7 <(β2t / β2w) / (ft / fw) <1.5 (9a)
More preferably, when the numerical ranges of the conditional expressions (1a) to (9a) are set as follows, the effects of the conditional expressions described above can be further increased.

−0.08 <f3a / f3b <0.08 (1b)
3.5 <fr / fw <5.6 (2b)
25 <νd3bn <30 (3b)
58 <νd3ap <72 (4b)
0.75 <f3a / f3bp <1.25 (5b)
0.95 <β3bt / β3bw <1.05 (6b)
0.3 <dab / Dsp <0.6 (7b)
1.5 <f1 / (fw · ft) ^1/2 <2.5 (8b)
0.8 <(β2t / β2w) / (ft / fw) <1.4 (9b)
More specifically, it is more preferable that the upper limit value of conditional expression (1b) is 0.07 and the upper limit value of conditional expression (2b) is 5.4.

  In each of the other examples, it is preferable that the third-a lens unit L3a includes a single positive lens G3ap, and at least one surface of the positive lens G3ap is aspherical.

  According to this, it becomes easy to satisfactorily correct spherical aberration and astigmatism over the entire zoom range.

  In addition, the second lens unit L2 includes, in order from the object side to the image side, a negative lens having a convex meniscus shape on the object side, a negative lens having a concave surface on the image side, and a convex surface on the object side. It is preferable that the lens is composed of a positive lens.

  The second lens unit L2, which is the main variable power lens unit, has such a lens configuration, so that it has sufficient refractive power necessary for variable power and various aberrations such as field curvature and distortion caused by zooming. It becomes easy to correct well.

  In addition, one lens group constituting the rear group Lr is preferably moved so as to have a convex locus toward the object side during zooming from the wide-angle end to the telephoto end.

  By using such a locus, it becomes easy to effectively use the space between the third lens unit L3 and the image plane and effectively shorten the entire lens length.

  Next, features of each reference example and each example will be described. In addition, the lens configuration of each reference example and each example will be described. The lens configuration will be described assuming that it is arranged from the object side to the image side unless otherwise specified.

  In the zoom lenses of Reference Examples 1 to 4 shown in FIGS. 1, 5, 9, and 13, zooming is performed by changing the interval between the lens groups.

  During zooming from the wide-angle end to the telephoto end, the second lens unit L2 moves to the image plane side and performs main magnification.

  During zooming, the first and third lens groups L1 and L3 do not move.

  The fourth lens unit L4 is moved to correct the image plane variation accompanying zooming, and focusing is performed.

  By making the movement locus accompanying zooming of the fourth lens unit L4 a convex locus toward the object side, the space between the third lens unit L3 and the fourth lens unit L4 can be effectively used, and the total lens length can be shortened. It is achieved effectively. Here, the convex trajectory is a trajectory in which the fourth lens group moves toward the image side after zooming from the wide-angle end to the telephoto end (a trajectory convex toward the object side). It is desirable to be.

  Further, when focusing from an infinitely distant object to a close object at the telephoto end, a rear focus method is employed in which the fourth lens unit L4 is moved forward as indicated by an arrow 4c.

  A solid line curve 4a and a dotted line curve 4b relating to the fourth lens unit L4 are moving trajectories for correcting image plane fluctuations associated with zooming from the wide-angle end to the telephoto end when focusing on an object at infinity and an object at close distance, respectively. Is shown.

  Next, the lens configurations of Reference Examples 1 to 4 will be described.

  The first lens unit L1 includes a cemented lens of a negative meniscus lens G11 having a convex object side surface and a positive lens G12, and a positive meniscus lens G13 having a convex object side surface.

  By configuring the first lens unit L1 with the three lenses having such a shape, spherical aberration, axial chromatic aberration, lateral chromatic aberration, and the like are favorably corrected with a high zoom ratio.

  The second lens unit L2 includes a negative meniscus lens G21 having a convex object side surface, a negative lens G22 having a concave surface on the image side, and a positive lens G23 having a convex surface on the object side. . The second lens unit L2 is composed of three lenses having such a shape, and aberration variations associated with zooming are suppressed.

  The third lens unit L3 includes a third lens unit L3a configured by a positive lens G31 having a convex surface on the object side, a negative lens G32 having a concave surface on the image side, and a positive lens G33 having a biconvex shape. The third lens unit L3b includes the third lens group L3b. The third b lens unit L3b may have one or more negative lenses.

  The third-a lens unit L3a may be composed of a lens component such as a cemented lens of a positive lens and a negative lens in addition to a single positive lens.

  The 3a lens unit L3a and the 3b lens unit L3b are arranged with a predetermined air interval for satisfactorily correcting field curvature in the entire zoom range in addition to spherical aberration and longitudinal chromatic aberration.

  Then, by arranging the aperture stop SP at this air interval, the space in the third lens unit L3 is efficiently used to shorten the entire lens length.

  Since the aperture stop SP is disposed in the third lens unit L3, the second lens unit L2 and the third lens unit are disposed at the telephoto end as compared with the case where the aperture stop SP is disposed in front of the third lens unit L3. The distance L3 can be shortened, and the total lens length is shortened.

  The positive lens G31 corrects spherical aberration favorably by making the object-side surface an aspherical surface.

  In Reference Examples 1 and 2, the object side surface of the positive lens G33 is aspherical so that mainly spherical aberration and astigmatism are corrected favorably.

  In Reference Examples 3 and 4, the image side surface of the positive lens G31 is aspherical so that mainly spherical aberration and astigmatism are corrected favorably.

  The fourth lens unit L4 includes a cemented lens in which a biconvex positive lens G41 and a meniscus negative lens G42 having a convex surface on the image surface side are bonded together. By using the cemented lens of the positive lens G41 and the negative lens G42, aberration variation during movement accompanying zooming and focusing is suppressed.

  In Reference Example 5 shown in FIG. 17, zooming is performed by changing the interval between the lens groups.

  By moving the first lens unit L1 at the telephoto end so as to be positioned on the object side as compared with the wide angle end, a large zoom ratio can be obtained while keeping the entire lens length at the wide angle end small.

  During zooming from the wide-angle end to the telephoto end, the second lens unit L2 moves to the image plane side and performs main magnification.

  During zooming, the third lens unit L3 does not move. The movement of the fourth lens unit L4 is the same as in Reference Examples 1 to 4.

  In Reference Example 5, during zooming from the wide-angle end to the telephoto end, in addition to the second lens unit L2 and the fourth lens unit L4, the first lens unit L1 is moved along a locus that is convex toward the image plane side. The zooming effect of the second lens unit L2 is enhanced to achieve a high zoom ratio of 17 times or more.

  In Reference Example 6 shown in FIG. 21, zooming is performed by changing the interval between the lens groups.

  By moving the first lens unit L1 at the telephoto end so as to be positioned on the object side as compared with the wide angle end, a large zoom ratio can be obtained while keeping the entire lens length at the wide angle end small.

  During zooming from the wide-angle end to the telephoto end, the second lens unit L2 moves to the image plane side and performs main magnification.

  During zooming from the wide-angle end to the telephoto end, the third lens unit L3 moves with a convex locus on the object side. The movement of the fourth lens unit L4 is the same as in Reference Examples 1 to 4.

  In Reference Example 6, by moving all four lens groups during zooming, the zooming effect of the second lens unit L2, which is the main zooming lens unit, is further enhanced, and during zooming with the third lens unit L3 The effect of correcting the field curvature fluctuation is enhanced.

  As a result, the zoom lens of Reference Example 6 achieves a high zoom ratio of 16 times or more and a wide angle of view.

  In Examples 1 and 2 shown in FIGS. 25 and 29, zooming is performed by changing the interval between the lens groups.

  By moving the first lens unit L1 at the telephoto end so as to be positioned on the object side as compared with the wide angle end, a large zoom ratio can be obtained while keeping the entire lens length at the wide angle end small.

  During zooming from the wide-angle end to the telephoto end, the second lens unit L2 moves to the image plane side and performs main magnification.

  During zooming from the wide-angle end to the telephoto end, the third lens unit L3 moves along a locus convex toward the object side. The fourth lens unit L4 does not move during zooming.

  The fifth lens unit L5 uses a movement locus that accompanies zooming as a convex locus toward the object side, thereby effectively using the space between the fourth lens unit L4 and the fifth lens unit L5 and shortening the total lens length. It is achieved effectively.

  Here, the convex trajectory is a trajectory in which the third lens unit or the fifth lens unit moves to the image side after moving to the object side (zoom to the object side) during zooming from the wide-angle end to the telephoto end. A convex trajectory is desirable.

  Further, when focusing from an infinitely distant object to a close object at the telephoto end, the fifth lens unit L5 is moved forward as indicated by an arrow 5c. Note that the fourth lens unit L4 may be driven in an auxiliary manner during focusing.

  In that case, fluctuations in aberrations associated with focusing can be reduced.

  The solid line curve 5a and the dotted line curve 5b of the fifth lens unit L5 shown in the lens cross-sectional view respectively correct image plane fluctuations caused by zooming from the wide-angle end to the telephoto end when focusing on an object at infinity and a short-distance object. The movement trajectory is shown.

  In Examples 1 and 2, during zooming, the second lens unit L2 performs main magnification, and the first lens unit L1, the third lens unit L3, and the fifth lens unit L5 are moved to change the lens unit. By doubling the sharing, a high zoom ratio of 15 times or more is achieved.

  The lens configurations of the first lens unit L1, the second lens unit L2, and the third lens unit L3 are the same as those in Examples 5 and 6.

  The fourth lens group includes a positive lens G41 having a convex object-side surface.

  The fifth lens unit L5 includes a cemented lens in which a biconvex positive lens G51 and a meniscus negative lens G52 having a convex image side surface are bonded together. By using a cemented lens of the positive lens G51 and the negative lens G52, aberration variation during movement associated with zooming and focusing is suppressed.

  In each example and each reference example, the F number shown in the numerical examples described later is obtained by controlling the size of the effective diameter of the aperture stop SP during zooming from the wide-angle end to the telephoto end.

  As a result, flare light components that affect off-axis imaging performance are cut from the zoom intermediate range to the telephoto end, and image quality is improved over the entire zoom range.

  The effective aperture diameter of the aperture stop SP is the maximum at the wide angle end.

  Further, in the imaging apparatus using the solid-state imaging device, distortion correction due to zooming in each embodiment and each reference example may be electronically corrected when digitally processing a captured image.

  Next, Numerical Examples 1 to 8 respectively corresponding to Reference Examples 1 to 6 and Examples 1 and 2 of the present invention are shown.

  In each numerical example, i indicates the order of the surfaces from the object side. ri is the radius of curvature of the i-th optical surface. di is a surface interval between the i-th surface and the (i + 1) -th surface. ndi and νdi respectively indicate the refractive index and Abbe number of the i-th medium with respect to the d-line.

  The back focus (BF) is a value obtained by converting the distance from the last lens surface to the paraxial image surface into air. The total lens length is defined as a value obtained by adding back focus (BF) to the distance from the front lens surface to the final lens surface. The unit of length is mm.

  Also, when K is the eccentricity, A4, A6, A8 are aspheric coefficients, and the displacement in the optical axis direction at the position of the height H from the optical axis is x based on the surface vertex, the aspheric shape is

Is displayed.

Where R is the paraxial radius of curvature. Also for example, a display of the "E-Z" means ^{"10 -Z".} Table 1 shows the correspondence with the above-described conditional expressions in each numerical example. f represents a focal length, Fno represents an F number, and ω represents a half angle of view.

[Numerical Example 1]
Surface data surface number rd nd νd
1 42.952 1.15 1.84666 23.9
2 21.753 4.20 1.60311 60.6
3 -322.228 0.18
4 19.297 2.65 1.69680 55.5
5 53.195 (variable)
6 51.889 0.70 1.88300 40.8
7 5.592 2.16
8 -24.811 0.60 1.71300 53.9
9 12.701 0.75
10 10.804 1.40 1.92286 18.9
11 39.919 (variable)
12 * 9.298 2.50 1.58313 59.4
13 ∞ 1.30
14 (Aperture) ∞ 2.20
15 47.126 0.60 1.76182 26.5
16 9.220 0.26
17 * 11.034 2.25 1.58313 59.4
18 -56.284 (variable)
19 15.643 2.40 1.80 400 46.6
20 -12.062 0.55 1.84666 23.9
21 -97.799 (variable)
22 ∞ 2.50 1.51633 64.1
23 ∞ 1.51
Image plane ∞

Aspheric data 12th surface
K = 5.31511e-001 A 4 = -1.75571e-004 A 6 = -2.15369e-006 A 8 = -3.16337e-008
17th page
K = -1.73310e + 000 A 4 = -1.50969e-005

Various data Zoom ratio 11.77
Wide angle Medium Telephoto focal length 4.94 23.49 58.17
F number 1.85 2.70 3.00
Angle of view 28.11 6.41 2.60
Image height 2.64 2.64 2.64
Total lens length 59.50 59.50 59.50
BF
8.55 11.93 5.57

d 5 0.70 14.29 18.58
d11 18.59 5.00 0.71
d18 5.81 2.43 8.79
d21 5.39 8.78 2.42

Zoom lens group data group Start surface Focal length
1 1 29.81
2 6 -6.29
3 12 16.70
4 19 17.84

[Numerical Example 2]
Surface data surface number rd nd νd
1 36.365 1.20 1.84666 23.9
2 21.206 4.90 1.60311 60.6
3 -905.732 0.20
4 19.948 3.25 1.60311 60.6
5 56.239 (variable)
6 59.921 0.70 1.88300 40.8
7 5.627 2.30
8 -18.930 0.60 1.77250 49.6
9 13.123 0.73
10 11.845 1.40 1.92286 18.9
11 88.886 (variable)
12 * 9.223 2.60 1.58313 59.4
13 614.034 1.30
14 (Aperture) ∞ 2.20
15 127.180 0.60 1.76182 26.5
16 10.130 0.32
17 * 11.718 2.10 1.58313 59.4
18 -30.178 (variable)
19 14.871 2.30 1.69680 55.5
20 -18.738 0.60 1.84666 23.9
21 -72.687 (variable)
22 ∞ 2.10 1.51633 64.1
23 ∞ 1.45
Image plane ∞

Aspheric data 12th surface
K = -3.29687e-001 A 4 = -3.30543e-005 A 6 = -5.72043e-007 A 8 = 6.00834e-009
17th page
K = -2.09746e + 000 A 4 = -4.52812e-005 A 6 = -4.39745e-007

Various data Zoom ratio 13.74
Wide angle Medium Telephoto focal length 5.00 23.59 68.70
F number 1.85 2.70 3.00
Angle of view 28.20 6.48 2.23
Image height 2.68 2.68 2.68
Total lens length 63.36 63.36 63.36
BF 8.27 13.13 5.63

d 5 0.75 14.53 19.37
d11 19.33 5.55 0.70
d18 7.71 2.86 10.36
d21 5.44 10.30 2.80

Zoom lens group data group Start surface Focal length
1 1 31.30
2 6 -5.86
3 12 16.45
4 19 19.95

[Numerical Example 3]
Surface data surface number rd nd νd
1 39.914 1.15 1.84666 23.9
2 21.357 4.90 1.60311 60.6
3 -798.513 0.18
4 20.011 3.05 1.69680 55.5
5 57.339 (variable)
6 53.625 0.70 1.88300 40.8
7 5.288 2.25
8 -17.244 0.60 1.78800 47.4
9 14.154 0.60
10 11.629 1.40 1.92286 18.9
11 108.219 (variable)
12 * 9.466 2.80 1.58313 59.4
13 * -54.703 1.20
14 (Aperture) ∞ 2.10
15 52.536 0.60 1.80518 25.4
16 9.082 0.30
17 14.702 1.60 1.69680 55.5
18 -40.832 (variable)
19 13.434 2.00 1.69680 55.5
20 -15.798 0.55 1.80518 25.4
21 -72.463 (variable)
22 ∞ 1.50 1.51633 64.1
23 ∞ 1.76
Image plane ∞

Aspheric data 12th surface
K = -2.05475e-001 A 4 = -5.07587e-005 A 6 = -6.87140e-007 A 8 = 1.11739e-008
Side 13
K = -6.32108e + 001 A 4 = 6.09935e-005

Various data Zoom ratio 14.60
Wide angle Medium Telephoto focal length 4.67 22.19 68.20
F number 1.85 2.95 3.30
Angle of View 29.86 6.89 2.25
Image height 2.68 2.68 2.68
Total lens length 61.06 61.06 61.06
BF 7.34 12.09 4.61

d 5 0.70 14.25 19.01
d11 19.02 5.47 0.70
d18 8.02 3.27 10.75
d21 4.59 9.34 1.86

Zoom lens group data group Start surface Focal length
1 1 30.05
2 6 -5.62
3 12 15.49
4 19 17.95

[Numerical Example 4]
Surface data surface number rd nd νd
1 38.075 1.05 1.84666 23.9
2 20.717 4.50 1.60311 60.6
3 -3338.388 0.15
4 20.138 2.75 1.69680 55.5
5 58.612 (variable)
6 41.892 0.65 1.88300 40.8
7 5.139 2.20
8 -17.545 0.60 1.78800 47.4
9 14.246 0.60
10 11.240 1.35 1.92286 18.9
11 81.892 (variable)
12 * 9.098 2.80 1.58313 59.4
13 * -119.202 1.10
14 (Aperture) ∞ 1.80
15 51.286 0.60
16 10.954 0.40
17 22.560 1.60 1.77250 49.6
18 -22.895 (variable)
19 11.964 2.00 1.62299 58.2
20 -15.728 0.55 1.84666 23.9
21 -66.473 (variable)
22 ∞ 2.00 1.51633 64.1
23 ∞ 1.27
Image plane ∞

Aspheric data 12th surface
K = 8.19478e-002 A 4 = -9.95768e-005 A 6 = -9.29329e-007 A 8 = 2.23217e-009
Side 13
K = -5.58423e + 001 A 4 = 1.23446e-004

Various data Zoom ratio 14.61
Wide angle Medium Telephoto focal length 4.67 22.04 68.20
F number 1.85 3.00 3.50
Angle of view 29.86 6.94 2.25
Image height 2.68 2.68 2.68
Total lens length 61.08 61.08 61.08
BF 7.20 12.34 4.44

d 5 0.60 14.34 19.17
d11 19.53 5.79 0.96
d18 9.05 3.91 11.81
d21 4.61 9.75 1.85

Zoom lens group data group Start surface Focal length
1 1 29.98
2 6 -5.67
3 12 15.52
4 19 19.79

[Numerical Example 5]
Surface data surface number rd nd νd
1 46.510 1.15 1.84666 23.9
2 23.512 4.85 1.48749 70.2
3 -135.657 0.15
4 20.748 3.05 1.77250 49.6
5 60.159 (variable)
6 57.389 0.70 1.88300 40.8
7 5.314 2.45
8 -22.650 0.60 1.78800 47.4
9 12.875 0.60
10 10.977 1.40 1.92286 18.9
11 76.541 (variable)
12 * 10.578 2.70 1.54293 70.5
13 * -49.750 1.40
14 (Aperture) ∞ 2.13
15 39.463 0.60 2.00 330 28.3
16 10.885 0.30
17 19.201 1.60 1.77250 49.6
18 -37.845 (variable)
19 14.690 2.00 1.65 160 58.5
20 -10.227 0.55 1.80809 22.8
21 -21.532 (variable)
22 ∞ 2.50 1.51633 64.1
23 ∞ 2.09
Image plane ∞

Aspheric data 12th surface
K = -1.26901e-001 A 4 = 1.93010e-005 A 6 = -1.43378e-007 A 8 = 1.26891e-008
Side 13
K = -3.77645e + 000 A 4 = 1.74602e-004

Various data Zoom ratio 17.05
Wide angle Medium Telephoto focal length 4.00 15.08 68.21
F number 1.85 2.70 3.00
Angle of view 33.83 10.08 2.25
Image height 2.68 2.68 2.68
Total lens length 63.39 61.33 64.37
BF 8.39 12.89 5.58

d 5 0.70 13.26 21.44
d11 20.46 5.84 0.70
d18 7.61 3.11 10.42
d21 4.65 9.15 1.85

Zoom lens group data group Start surface Focal length
1 1 31.84
2 6 -5.86
3 12 17.65
4 19 15.37

[Numerical Example 6]
Surface data surface number rd nd νd
1 33.284 1.10 1.84666 23.9
2 21.289 4.60 1.48749 70.2
3 -2362.697 0.15
4 21.472 2.60 1.62299 58.2
5 80.353 (variable)
6 80.089 0.70 1.83481 42.7
7 5.841 2.90
8 -35.147 0.60 1.69680 55.5
9 10.825 0.60
10 9.712 1.40 1.94595 18.0
11 23.307 (variable)
12 * 8.079 2.30 1.48749 70.2
13 * -45.307 1.30
14 (Aperture) ∞ 2.20
15 -73.979 0.60 1.80518 25.4
16 10.851 0.20
17 18.493 1.60 1.77250 49.6
18 -17.273 (variable)
19 13.406 1.75 1.69680 55.5
20 -31.321 0.55 1.84666 23.9
21 -177.880 (variable)
22 ∞ 2.00 1.51633 64.1
23 ∞ 1.70
Image plane ∞

Aspheric data 12th surface
K = 1.38117e-002 A 4 = -1.66276e-004 A 6 = 9.47481e-007 A 8 = -9.38919e-008
Side 13
K = -6.38981e + 000 A 4 = 1.94512e-004

Various data Zoom ratio 16.21
Wide angle Medium Telephoto focal length 3.70 16.57 60.00
F number 1.85 2.70 3.00
Angle of view 35.09 9.19 2.56
Image height 2.60 2.68 2.68
Total lens length 56.82 57.99 62.22
BF 7.67 12.19 5.01

d 5 0.65 13.31 21.57
d11 20.33 4.67 0.71
d18 3.03 2.68 9.79
d21 4.65 9.18 1.99

Zoom lens group data group Start surface Focal length
1 1 33.55
2 6 -6.08
3 12 14.53
4 19 19.27

[Numerical Example 7]
Surface data surface number rd nd νd
1 34.284 1.10 1.84666 23.9
2 20.765 4.60 1.48749 70.2
3 -832.849 0.18
4 20.562 3.15 1.69680 55.5
5 70.585 (variable)
6 53.905 0.70 1.88300 40.8
7 5.215 2.40
8 -16.257 0.60 1.71300 53.9
9 14.812 0.60
10 11.511 1.40 1.94595 18.0
11 53.886 (variable)
12 * 11.003 2.90 1.48749 70.2
13 * -23.455 1.30
14 (Aperture) ∞ 2.20
15 479.434 0.60 1.80518 25.4
16 14.443 0.30
17 39.539 1.60 1.69680 55.5
18 -18.726 (variable)
19 18.925 1.20 1.48749 70.2
20 24.426 (variable)
21 14.604 2.00 1.69680 55.5
22 -12.287 0.55 1.84666 23.9
23 -36.037 (variable)
24 ∞ 3.00 1.51633 64.1
25 ∞ 0.78
Image plane ∞

Aspheric data 12th surface
K = -1.06924e + 000 A 4 = 1.83141e-005 A 6 = 9.64183e-007 A 8 = -1.79063e-008
Side 13
K = -1.28413e + 000 A 4 = 1.34906e-004

Various data Zoom ratio 15.62
Wide angle Medium Telephoto focal length 4.10 15.76 64.00
F number 1.85 2.70 3.00
Angle of view 33.19 9.65 2.40
Image height 2.68 2.68 2.68
Total lens length 62.36 61.64 64.30
BF 6.02 11.56 4.60

d 5 0.70 12.89 20.08
d11 19.80 4.83 0.71
d18 0.89 2.96 2.55
d20 7.57 2.03 8.98
d23 3.26 8.80 1.85

Zoom lens group data group Start surface Focal length
1 1 31.23
2 6 -5.59
3 12 16.12
4 19 160.87
5 21 17.21

[Numerical Example 8]
Surface data surface number rd nd νd
1 34.506 1.10 1.84666 23.9
2 20.951 4.50 1.48749 70.2
3 -564.191 0.18
4 20.521 3.05 1.69680 55.5
5 69.656 (variable)
6 55.663 0.70 1.88300 40.8
7 5.235 2.40
8 -15.762 0.60 1.71300 53.9
9 14.766 0.60
10 11.570 1.40 1.94595 18.0
11 55.212 (variable)
12 * 10.149 2.90 1.48749 70.2
13 * -23.214 1.30
14 (Aperture) ∞ 2.20
15 512.617 0.60 1.80518 25.4
16 13.042 0.30
17 38.054 1.60 1.69680 55.5
18 -19.816 (variable)
19 20.525 1.20 1.48749 70.2
20 37.884 (variable)
21 14.513 2.10 1.69680 55.5
22 -14.530 0.55 1.84666 23.9
23 -42.350 (variable)
24 ∞ 2.50 1.51633 64.1
25 ∞ 1.22
Image plane ∞

Aspheric data 12th surface
K = -2.94904e-001 A 4 = -6.73498e-005 A 6 = 5.89193e-007 A 8 = -1.03967e-008
Side 13
K = -2.99197e + 000 A 4 = 1.15822e-004

Various data Zoom ratio 15.61
Wide angle Medium Telephoto focal length 4.10 15.42 64.00
F number 1.85 2.70 3.00
Angle of view 33.18 9.86 2.40
Image height 2.68 2.68 2.68
Total lens length 62.35 62.34 65.33
BF 5.50 11.42 4.81

d 5 0.70 12.68 19.87
d11 20.12 5.03 0.70
d18 1.00 4.10 4.22
d20 7.75 1.83 8.44
d23 2.63 8.56 1.95

Zoom lens group data group Start surface Focal length
1 1 31.03
2 6 -5.53
3 12 16.40
4 19 89.85
5 21 17.58

  As described above, in each embodiment, high zoom ratio, compact, high performance capable of handling high-pixel digital cameras, video cameras, etc. with excellent correction of spherical aberration, coma, curvature of field, axial chromatic aberration, and lateral chromatic aberration. Has achieved a zoom lens.

  Next, an embodiment of a digital still camera using the zoom lens of the present invention as a photographing optical system will be described with reference to FIG.

  In FIG. 33, reference numeral 20 denotes a camera body, 21 denotes a photographing optical system constituted by any of the zoom lenses described in Reference Examples 1 to 6 and Examples 1 and 2.

  Reference numeral 22 denotes a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor that receives a subject image formed by the photographing optical system 21 and is built in the camera body. A memory 23 records information corresponding to a subject image photoelectrically converted by the solid-state imaging device 22.

  Reference numeral 24 denotes a finder for observing a subject image formed on the solid-state image sensor 22, which includes a liquid crystal display panel or the like.

  Next, an embodiment of a video camera (optical apparatus) using the zoom lens of the present invention as a photographing optical system will be described with reference to FIG.

  In FIG. 34, reference numeral 10 denotes a video camera body, 11 denotes a photographing optical system constituted by any of the zoom lenses described in Reference Examples 1 to 6 and Examples 1 and 2.

  Reference numeral 12 denotes a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor that receives a subject image formed by the photographing optical system 11 and is built in the camera body. Reference numeral 13 denotes recording means for recording information corresponding to the subject image photoelectrically converted by the solid-state imaging device 12.

  Reference numeral 14 denotes a finder for observing a subject image displayed on a display element (not shown).

  The display element is constituted by a liquid crystal panel or the like, and a subject image formed on the image sensor 12 is displayed.

  In this way, by applying the zoom lens of the present invention to an imaging apparatus such as a digital still camera or a video camera, an imaging apparatus having a small size and high optical performance can be realized.

L1 1st lens group L2 2nd lens group L3 3rd lens group L4 4th lens group L5 5th lens group L3a 3a lens group L3b 3b lens group Lr Rear group d d line g g line ΔM meridional image surface ΔS sagittal Image plane SP Aperture IP Imaging plane G Glass block such as CCD face plate and low-pass filter ω Half angle of view Fno F number

Claims (14)

In order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, a fourth lens group having a positive refractive power, and a positive lens The fifth lens unit has a refractive power, and when zooming from the wide-angle end to the telephoto end, the second lens unit moves to the image plane side, and the distance between the lens units changes, so that the third lens unit is made to emit light. A zoom lens that moves in a direction having a component perpendicular to the axis to change an image formation position, and the third lens group includes, in order from the object side to the image side, a third a lens group L3a having a positive refractive power, An aperture stop and a third lens unit L3b, the third lens unit L3a includes a lens component having one positive refractive power, the third lens unit L3b includes a negative lens, and the third lens unit L3a, The focal length of the third lens group L3b is f3a, When you and 3b,
-0.1 <f3a / f3b <0.1
A zoom lens satisfying the following conditional expression: The zoom lens according to claim 1, wherein the fifth lens group moves along a locus convex toward the object side during zooming from the wide-angle end to the telephoto end. When the combined focal length of the fourth lens group and the fifth lens group at the wide angle end is fr, and the focal length at the wide angle end of the entire lens system is fw,
3.2 <fr / fw <6.4
The zoom lens according to claim 1, wherein the following condition is satisfied. When the Abbe number of the material of one negative lens G3bn of the third b lens unit L3b is νd3bn,
20 <νd3bn <33
The zoom lens according to claim 1, wherein the following condition is satisfied. The third-a lens unit L3a is composed of one positive lens G3ap, and when the Abbe number of the material of the positive lens G3ap is νd3ap,
55 <νd3ap
The zoom lens according to claim 1, wherein the following condition is satisfied. When the third lens group L3b has a positive lens G3bp and the focal length of the positive lens G3bp is f3bp,
0.7 <f3a / f3bp <1.3
The zoom lens according to claim 1, wherein the following condition is satisfied. When the imaging magnifications at the wide-angle end and the telephoto end of the third b lens unit L3b are β3bw and β3bt,
0.8 <β3bt / β3bw <1.2
The zoom lens according to claim 1, wherein the following condition is satisfied. When the distance between the third-a lens unit L3a and the third-b lens unit L3b is dab and the maximum effective diameter of the aperture stop at the wide-angle end is Dsp,
0.1 <dab / Dsp <1.6
The zoom lens according to claim 1, wherein the following condition is satisfied. When the focal length of the first lens group is f1, and the focal lengths at the wide-angle end and the telephoto end of the entire lens system are fw and ft, respectively.
1.2 <f1 / (fw · ft) ^1/2 <3.0
The zoom lens according to claim 1, wherein the following condition is satisfied. When the imaging magnifications at the wide-angle end and the telephoto end of the second lens group are β2w and β2t, respectively, and the focal lengths at the wide-angle end and the telephoto end of the entire lens system are fw and ft, respectively.
0.6 <(β2t / β2w) / (ft / fw) <1.6
The zoom lens according to claim 1, wherein the following condition is satisfied. The said 3a lens group L3a is comprised from one positive lens G3ap, and this positive lens G3ap has an aspherical shape at least 1 surface, The any one of Claim 1 thru | or 10 characterized by the above-mentioned. Zoom lens. The second lens group includes, in order from the object side to the image side, a negative lens having a convex meniscus shape on the object side, a negative lens having a concave surface on the image side, and a positive lens having a convex surface on the object side The zoom lens according to claim 1, comprising: The zoom lens according to claim 1, wherein an image is formed on a solid-state imaging device. An image pickup apparatus comprising: the zoom lens according to claim 1; and a solid-state image sensor that receives an image formed by the zoom lens.