JP2018005165A - Zoom lens and imaging apparatus having the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a zoom lens small in size as a whole and having a wide angle of view, with which high optical performance can be easily obtained over the whole object distance.SOLUTION: The zoom lens has a first lens group having a negative refractive power, a second lens group having a positive refractive power, a first partial group having a positive refractive power, a second partial group having a negative refractive power and a third partial group having a positive refractive power, disposed successively from an object side to an image side, in which at a telephoto end, an interval between the first lens group and the second lens group decreases compared to a wide angle end, and upon zooming, intervals between adjoining lens groups vary. Upon focusing from an infinite distance to a closest distance, the first partial group moves to the object side, while the second partial group moves to the image side; and a moving amount M1 of the first lens group upon zooming from the wide angle end to the telephoto end, and a moving amount M2 of the second lens group upon zooming from the wide angle end to the telephoto end are each appropriately set.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a zoom lens and an image pickup apparatus having the same, and is suitable for an image pickup optical system used in an image pickup apparatus such as a digital camera, a video camera, a TV camera, a surveillance camera, and a silver salt film camera.

  An imaging optical system used in an imaging apparatus (camera) is required to include a wide imaging angle of view, and to be a small zoom lens with high resolution and the entire system. Further, there is a demand for having a high optical performance on the entire screen corresponding to a large-size (for example, full size or ASP size) image pickup device, and a zoom lens that can easily pick up an image of a close object point.

  2. Description of the Related Art Conventionally, a negative lead type zoom lens in which a lens group having a negative refractive power is disposed closest to the object side is known as a zoom lens having a wide angle of view and the entire system being small. As a negative lead type zoom lens, a zoom lens in which focusing is performed using a small and lightweight lens group is known (Patent Document 1).

  In Patent Document 1, in order from the object side to the image side, the lens unit includes first to fifth lens units having negative, positive, positive, negative, and positive refractive power, and zooming is performed by changing the interval between adjacent lens units. A 5-group zoom lens that performs focusing with the fourth lens group is disclosed. A negative lead type zoom lens using a floating system that moves a plurality of lens groups (partial groups) during focusing is known in order to reduce aberration fluctuations during focusing (Patent Documents 2 and 3).

  In Patent Document 2, the first lens unit to the fourth lens unit having negative, positive, negative, and positive refractive powers are arranged in order from the object side to the image side. In a zoom lens in which the distance between adjacent lens groups changes during zooming, a zoom lens using floating that moves the second lens group and the third lens group during focusing is disclosed.

  In Patent Document 3, the first lens unit to the third lens unit having negative, positive, and positive refractive powers are arranged in order from the object side to the image side. In a zoom lens in which an interval between adjacent lens groups changes during zooming, a zoom lens using a floating that moves a part of the second lens group and a third lens group during focusing is disclosed.

JP 2012-47813 A JP-A-2015-197593 JP2012-212123A

  The zoom lens used in the image pickup device has a wide angle of view and the entire lens system is small, the focus lens group is small and light, and it is easy to pick up images at close distances, and there is little aberration fluctuation during focusing. It is requested. In a negative lead type zoom lens, it is important to appropriately set the refractive power and lens configuration of each lens group in order to obtain a high optical performance over the entire zoom range and the entire object distance in a compact system. .

  For example, it is important to appropriately set the refractive power and movement conditions of the first lens group and the second lens group during zooming, the selection of the lens group to be moved and the refractive power and movement conditions when using floating. Come. In addition, when the incident angle of the light beam on the image sensor arranged on the image plane increases, the optical performance around the screen deteriorates when a large image sensor is used. For this reason, it is important to appropriately set the refractive power arrangement and the refractive power of each lens group. If these settings are not appropriate, it will be difficult to obtain a zoom lens having a small overall system, a wide angle of view, and high optical performance over the entire object distance.

  An object of the present invention is to provide a zoom lens that can easily obtain high optical performance over the entire object distance while being small in size and having a wide angle of view.

The zoom lens according to the present invention includes a first lens group having a negative refractive power, a second lens group having a positive refractive power, a first partial group having a positive refractive power, and a negative lens, which are arranged in order from the object side to the image side. A second sub-group having a refractive power and a third sub-group having a positive refractive power, and the distance between the first lens group and the second lens group is shorter at the telephoto end than at the wide-angle end, and adjacent to each other during zooming. In a zoom lens in which the distance between the matching lens groups changes,
During focusing from infinity to the closest distance, the first partial group moves toward the object side, the second partial group moves toward the image side, and the first lens group moves during zooming from the wide-angle end to the telephoto end. When the amount is M1, and the amount of movement of the second lens group in zooming from the wide-angle end to the telephoto end is M2,
0.00 <M1 / M2 <1.00
It satisfies the following conditional expression.

  According to the present invention, it is possible to obtain a zoom lens that can easily obtain high optical performance over the entire object distance while being small in size and having a wide angle of view.

Lens sectional view of Example 1 (A), (B), (C), (D) Aberration diagrams at the wide angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end when focusing on infinity according to the first embodiment. (A), (B), (C), (D) Aberration diagrams at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end when focusing on the closest distance according to the first embodiment. Lens sectional view of Example 2 (A), (B), (C), (D) Aberration diagrams at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end when focusing on infinity according to the second embodiment. (A), (B), (C), (D) Aberration diagrams at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end when focusing on the closest distance in Example 2. Lens sectional view of Example 3 (A), (B), (C), (D) Aberration diagrams at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end when focusing on infinity according to the third embodiment. (A), (B), (C), (D) Aberration diagrams at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end when focusing on the closest distance according to the third embodiment. Lens sectional view of Example 4 (A), (B), (C), (D) Aberration diagrams at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end when focusing on infinity according to the fourth embodiment. (A), (B), (C), (D) Aberration diagrams at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end when focusing on the closest distance according to the fourth embodiment. Lens sectional view of Example 5 (A), (B), (C), (D) Aberration diagrams at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end when focusing on infinity according to the fifth embodiment. (A), (B), (C), (D) Aberration diagrams at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end when focusing on the closest distance in Example 5. Lens sectional view of Example 6 (A), (B), (C), (D) Aberration diagrams at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end when focusing on infinity according to the sixth embodiment. (A), (B), (C), (D) Aberration diagrams at the wide-angle end, intermediate 1 zoom position, intermediate 2 zoom position, and telephoto end when focusing on the closest distance in Example 6 Schematic diagram of main parts of an imaging apparatus of the present invention

  Preferred embodiments of the present invention will be described below with reference to the accompanying drawings. 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 negative refractive power, a second lens group having a positive refractive power, and a first partial group having a positive refractive power (FP1). , A second partial group (FN) having a negative refractive power, and a third partial group (FP2) having a positive refractive power. The distance between the first lens group and the second lens group is narrower at the telephoto end than at the wide-angle end, and the distance between adjacent lens groups changes during zooming.

  During focusing from infinity to the closest distance, the first partial group moves toward the object side, and the second partial group moves toward the image side. Here, the lens group means a lens system composed of one or a plurality of lenses divided by a change in the lens interval in the optical axis direction accompanying zooming.

  FIG. 1 is a lens cross-sectional view of the first embodiment. 2 (A) to 2 (D) show a focus at infinity at the wide-angle end (short focal length end), intermediate 1 zoom position, intermediate 2 zoom position, and telephoto end (long focal length end) in the first embodiment. FIG. FIGS. 3A to 3D are aberration diagrams when focusing on the closest distance at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end of the first embodiment.

  Here, the closest distance represents the surface number 1 to the object point, and is 50 mm at the wide angle end, 80 mm at the intermediate zoom position, 80 mm at the intermediate zoom position, and 200 mm at the telephoto end. Example 1 is a zoom lens having a zoom ratio of 2.83 times and an aperture ratio of about 2.89 to 5.77.

  4 is a lens cross-sectional view of Example 2. FIG. FIGS. 5A to 5D are aberration diagrams when focusing to infinity at the wide angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end of the second embodiment. FIGS. 6A to 6D are aberration diagrams when focusing on the closest distance at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end according to the second embodiment.

  The closest distance represents the surface number 1 to the object point, and is 50 mm at the wide-angle end, 80 mm at the middle 1 zoom position, 80 mm at the middle 2 zoom position, and 200 mm at the telephoto end. The second embodiment is a zoom lens having a zoom ratio of 2.83 times and an aperture ratio of about 2.88 to 5.77.

  FIG. 7 is a lens cross-sectional view of Example 3. FIG. 8A to FIG. 8D are aberration diagrams when focusing to infinity at the wide angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end of the third embodiment. FIGS. 9A to 9D are aberration diagrams when focusing on the closest distance at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end according to the third embodiment.

  The closest distance represents the surface number 1 to the object point, and is 50 mm at the wide-angle end, 80 mm at the middle 1 zoom position, 80 mm at the middle 2 zoom position, and 200 mm at the telephoto end. Example 3 is a zoom lens having a zoom ratio of 2.85 times and an aperture ratio of about 2.06 to 5.78.

  FIG. 10 is a lens cross-sectional view of Example 4. FIGS. 11A to 11D are aberration diagrams when focusing on the wide angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end at infinity at the fourth embodiment. FIGS. 12A to 12D are aberration diagrams when focusing on the closest distance at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end according to the fourth embodiment.

  The closest distance represents the surface number 1 to the object point, and is 50 mm at the wide-angle end, 80 mm at the middle 1 zoom position, 80 mm at the middle 2 zoom position, and 200 mm at the telephoto end. Example 4 is a zoom lens having a zoom ratio of 2.83 times and an aperture ratio of about 2.06 to 5.05.

  FIG. 13 is a lens cross-sectional view of Example 5. FIGS. 14A to 14D are aberration diagrams when the zoom lens of Example 5 is focused to infinity at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end. FIGS. 15A to 15D are aberration diagrams when focusing on the closest distance at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end according to the fifth embodiment.

  The closest distance represents the surface number 1 to the object point, and is 50 mm at the wide-angle end, 80 mm at the middle 1 zoom position, 80 mm at the middle 2 zoom position, and 200 mm at the telephoto end. Example 5 is a zoom lens having a zoom ratio of 2.83 times and an aperture ratio of about 2.88 to 5.77.

  FIG. 16 is a lens cross-sectional view of Example 6. FIGS. 17A to 17D are aberration diagrams when focusing to infinity at the wide angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end of the sixth embodiment. FIGS. 18A to 18D are aberration diagrams when focusing on the closest distance at the wide-angle end, the intermediate 1 zoom position, the intermediate 2 zoom position, and the telephoto end according to the sixth embodiment.

  The closest distance represents the surface number 1 to the object point, and is 50 mm at the wide-angle end, 80 mm at the middle 1 zoom position, 80 mm at the middle 2 zoom position, and 200 mm at the telephoto end. The sixth embodiment is a zoom lens having a zoom ratio of 2.83 times and an aperture ratio of about 2.88 to 5.77. FIG. 19 is a schematic view of the main part of the imaging apparatus of the present invention.

  The zoom lens of each embodiment is an imaging optical system used in an imaging apparatus such as a video camera, a digital camera, or a silver salt film camera. In the lens cross-sectional view, the left side is the object side (front), and the right side is the image side (rear). The zoom lens of each embodiment may be used for a projector. In this case, the left side is the screen side and the right side is the projected image side.

  In the lens cross-sectional view, OL is a zoom lens. i indicates the order of the lens groups from the object side, and Li is the i-th lens group. FP1 represents a first partial group having a positive refractive power, FN represents a second partial group having a negative refractive power, and FP2 represents a third partial group having a positive refractive power. SP1 is an aperture stop. SP2 is a flare cut stop. G is an optical block corresponding to an optical filter, a face plate, an infrared cut filter, or the like.

  IP is an image plane. When used as an imaging optical system for a video camera or a digital still camera, the imaging surface of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor is used for a silver salt film camera. Corresponds to the film surface.

  In the lens cross-sectional view, solid arrows indicate the movement trajectory of each lens unit during zooming from the wide-angle end to the telephoto end when focused at infinity. A dotted arrow indicates a movement locus of each lens unit during zooming from the wide-angle end to the telephoto end when the closest distance is in focus. The arrow related to the focus indicates the moving direction of the first partial group FP1 and the second partial group FN during focusing from infinity to the closest distance.

  In the longitudinal aberration diagram, d is the d-line (wavelength 587.6 nm), and g is the g-line (wavelength 435.8 nm). M is a meridional image plane of d line, and S is a sagittal image plane of d line. Lateral chromatic aberration is represented by the g-line. ω is a half angle of view (degree), 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 intermediate zoom position is a zoom position where the first lens unit L1 is positioned closest to the image side during zooming.

  The lens configurations of the zoom lenses of Examples 1, 2, and 6 are as follows in order from the object side to the image side. First lens unit L1 having negative refractive power, aperture stop SP1, second lens unit L2 having positive refractive power, first partial group FP1 having positive refractive power, second partial group FN having negative refractive power, positive It is composed of a third partial group FP2 having a refractive power. The first partial group FP1 having a positive refractive power and the second partial group FN having a negative refractive power constitute a third lens group L3. The third partial group FP2 having positive refractive power constitutes the fourth lens group L4.

  The distance between adjacent lens units changes during zooming. In order to reduce the size of the entire system at a zoom ratio of about three times, the zoom configuration includes a first lens unit L1 having a negative refractive power and a second lens unit L2 having a positive refractive power in order from the object side to the image side. It has a negative lead lens configuration.

  A positive lead zoom configuration in which the first lens unit has a positive refractive power is advantageous for achieving a high zoom ratio, but the front lens effective diameter increases when a wide angle of view is aimed at the wide angle end. Therefore, at a zoom magnification of about 3 times, a negative lead zoom configuration in which the first lens unit has a negative refractive power is more advantageous for downsizing the entire system.

  During zooming from the wide-angle end to the telephoto end, the first lens unit L1 moves to the object side along a locus convex to the image side, and the aperture stop SP1 moves to the object side. Further, the second lens group L2 moves to the object, the first partial group FP1 and the second partial group FN move integrally to the object side, and the third partial group FP2 moves to the image side.

  When zooming from the wide-angle end to the telephoto end, the total lens length at the wide-angle end is shortened by moving the first lens unit L1 to the object side, and the aperture stop SP1 and the first lens unit L1 are brought closer to each other. The effective diameter of the front ball is reduced. Further, during zooming, the moving surface of the first lens unit L1 is moved in a convex locus toward the image side, so that the image plane characteristics in zooming are corrected well.

  Further, during zooming, the aperture stop SP1 is moved independently of each lens unit L1 (with a different locus). Specifically, it moves away from the second lens unit L2 toward the object side at the intermediate focal length zoom position, and moves along a locus convex toward the object side with respect to the second lens unit L2. Or it is set as the locus | trajectory which the space | interval of aperture stop SP1 and the 2nd lens group L2 narrows from a wide angle end to a telephoto end. Accordingly, the underline flare of the off-axis light beam at the zoom position from the wide angle end to the intermediate focal length is cut, and the optical performance at the zoom position from the wide angle end to the intermediate focal position is improved.

  In addition, the first partial group FP1 and the second partial group FN are set as separate movement loci for the second lens unit L2 having a positive refractive power in zooming, so that the image plane is at the zoom position of the intermediate focal length in zooming. The characteristic is corrected well. In zooming, the third partial group FP2 having a positive refractive power is moved to the image side to provide a zooming effect. As a result, the amount of movement of the second lens group L2, the first partial group FP1, and the second partial group FN is reduced, and the total lens length at the telephoto end is shortened. The final third partial group FP2 is composed of one positive lens.

  By making the third partial group FP2 have a positive refractive power, the exit pupil at the wide-angle end is moved away from the object side, and the telecentricity is improved. That is, the incident height of the light beam on the image plane is reduced.

  The third partial group FP2 is disposed at a position close to the image formation point (image plane), and the effective lens diameter is large. Therefore, if the third partial group FP2 is composed of a plurality of lenses, the thickness of the lens increases, The system becomes larger. For this reason, it is composed of one lens. A second partial group FN having a negative refractive power is disposed on the object side of the third partial group FP2 having a positive refractive power. By making the third partial group FP2 have a positive refractive power, the effective diameter of the second partial group FN on the object side of the third partial group FP2 is reduced, while reducing the total lens length by using a negative refractive power. doing.

  The first partial group FP1 having a positive refractive power is disposed on the object side of the second partial group FN having a negative refractive power. The first partial group FP1 having positive refractive power is arranged on the object side of the second partial group FN. Accordingly, of the first partial group FP1, the second partial group FN, and the third partial group FP2 (fourth lens group L4), the positive refractive power is positively refracted by the first partial group FP1 and the third partial group FP2. The power is distributed.

  Since the third sub-group FP2 arranged in front of the image plane has a large effective diameter, if the refractive power is strong, the lens thickness increases, which affects the camera thickness when retracted. Therefore, by giving positive refractive power to the first partial group FP1 having a small effective diameter, the positive refractive power of the third partial group FP2 is weakened and the lens thickness is reduced.

  Further, the first partial group FP1 having a positive refractive power and a sign different from that of the second partial group FN having a negative refractive power is arranged on the object side. Thus, the position sensitivity of the first partial group FP1 and the second partial group FN is increased. Further, the first subgroup FP1 is arranged on the object side of the second subgroup FN and on the image side of the aperture stop SP1, thereby making the effective diameter smaller than that of the second subgroup FN. For this reason, the first partial group FP1 and the second partial group FN are used as focusing lens groups to reduce the amount of movement during focusing from infinity to the closest distance and to facilitate rapid focusing.

  The first partial group FP1 having a positive refractive power is configured to move toward the object side during focusing from infinity to the closest distance. The second sub-group FN having a negative refractive power is configured to move to the image side during focusing from infinity to the closest distance. By adopting a structure in which the first partial group FP1 and the second partial group FN are moved simultaneously at the time of focusing from infinity to the closest distance, for example, the second partial group FN is moved closer to the closest distance than when focusing alone. Easy to focus on.

  In the lens cross-sectional view, a solid line curve FP1a and a dotted line curve FP1b relating to the first subgroup FP1 are moving loci for correcting image plane fluctuations caused by zooming when focusing at infinity and closest distance, respectively. It is. Further, when focusing from infinity to a short-distance object point, the first partial group FP1 is extended to the object side as indicated by an arrow FP1c.

  A solid line curve FNa and a dotted line curve FNb relating to the second subgroup FN are movement trajectories for correcting image plane fluctuations caused by zooming when focusing at infinity and the closest distance, respectively. Further, when focusing from infinity to the closest distance at the telephoto end, the second subgroup FN is moved toward the image side as indicated by an arrow FNc.

  The lens configurations of the zoom lenses of Examples 3 and 4 are as follows in order from the object side to the image side. First lens unit L1 having negative refractive power, flare-cut stop SP2, second lens unit L2 having positive refractive power, aperture stop SP1, first partial group FP1 having positive refractive power, and second portion having negative refractive power It is composed of a group FN and a third partial group FP2 having a positive refractive power.

  The lens configuration of the zoom lens of Example 5 is as follows in order from the object side to the image side. First lens unit L1 having negative refractive power, aperture stop SP1, second lens unit L2 having positive refractive power, flare-cut stop SP2, first partial group FP1 having positive refractive power, and second portion having negative refractive power It is composed of a group FN and a third partial group FP2 having a positive refractive power.

  In Examples 3, 4, and 5, the first partial group FP1 having a positive refractive power constitutes the third lens group L3, and the second partial group FN having a negative refractive power constitutes the fourth lens group L4. The third partial group FP2 having the refracting power constitutes the fifth lens unit L5. The distance between adjacent lens units changes during zooming. The flare cut stop SP2 has a constant aperture diameter.

  In order to reduce the size of the entire system at a zoom ratio of about three times, the zoom configuration includes a first lens unit L1 having a negative refractive power and a second lens unit L2 having a positive refractive power in order from the object side to the image side. It has a negative lead lens configuration. A positive lead zoom configuration in which the first lens unit has a positive refractive power is advantageous for achieving a high zoom, but has a large front lens diameter. Therefore, at a zoom magnification of about 3 times, a negative lead zoom configuration in which the first lens unit L1 has a negative refractive power is more advantageous for downsizing the entire system.

  During zooming from the wide-angle end to the telephoto end, the first lens unit L1 moves to the object side along a locus convex to the image side, and the flare cut stop SP2 moves to the object side. Further, the second lens group L2 moves to the object, the first partial group FP1 moves to the object side, the second partial group FN moves to the object side, and the third partial group FP2 moves to the image side. The aperture stop SP moves along the same locus as the second lens unit L2.

  When zooming from the wide-angle end to the telephoto end, the total lens length at the wide-angle end is shortened by moving the first lens unit L1 to the object side, and the aperture stop SP1 and the first lens unit L1 are brought closer to each other. The effective diameter of the front ball is reduced. In zooming, in Examples 3 and 4, the flare-cut stop SP2 is made a different locus from each lens group, and at the intermediate focal length zoom position, the object moves away from the second lens group L2 toward the object side. Move along a locus that protrudes to the side.

  Or it is set as the locus | trajectory which the space | interval of aperture stop SP1 and the 2nd lens group L2 narrows from a wide angle end to a telephoto end. As a result, the underline flare of the off-axis light beam at the zoom position from the wide angle end to the intermediate focal length is cut, and the optical performance at the zoom position from the wide angle end to the intermediate focal position is improved. Further, by setting the first partial group FP1 and the second partial group FN having positive refractive power as separate movement loci with respect to the second lens group L2 having positive refractive power in zooming, the intermediate focal length in zooming can be reduced. The image plane characteristic is satisfactorily corrected at the zoom position.

  In zooming, the third partial group FP2 having a positive refractive power is moved to the image side to provide a zooming effect. As a result, the movement amounts of the second lens group L2, the first partial group FP1, and the second partial group FN are reduced, and the total lens length at the telephoto end is shortened. The final third partial group FP2 is composed of one positive lens. By making the third partial group FP2 have a positive refractive power, the exit pupil at the wide-angle end is moved away from the object side, and the telecentricity is improved.

  The third partial group FP2 is disposed at a position close to the image formation point (image plane), and the effective lens diameter is large. Therefore, if the third partial group FP2 is composed of a plurality of lenses, the thickness of the lens increases, The system becomes larger. For this reason, it is composed of one lens. A second partial group FN having a negative refractive power is disposed on the object side of the third partial group FP2 having a positive refractive power. By making the third partial group FP2 have positive refractive power, the effective diameter of the second partial group FN on the object side of the third partial group FP2 is reduced, and by making it negative refractive power, the total lens length is shortened. ing. A first partial group FP1 having a positive refractive power is arranged on the object side of the second partial group FN having a negative refractive power.

  The first partial group FP1 having positive refractive power is arranged on the object side of the second partial group FN. This disperses the positive refractive powers of the first partial group FP1 and the third partial group FP2 out of the first partial group FP1, the second partial group FN, and the third partial group FP2 arranged on the image side. doing.

  Since the third sub-group FP2 arranged in front of the image plane has a large effective diameter, if the refractive power is strong, the lens thickness increases, which affects the camera thickness when retracted. Therefore, by giving positive refractive power to the first partial group FP1 having a small effective diameter, the positive refractive power of the third partial group FP2 is weakened and the lens thickness is reduced. Further, the first partial group FP1 having a positive refractive power having a different sign from the second partial group FN having a negative refractive power is arranged on the object side, so that the position sensitivity of the first partial group FP1 and the second partial group FN is sensitive. The degree is high.

  Further, the first subgroup FP1 is arranged on the object side of the second subgroup FN and on the image side of the aperture stop SP1, thereby making the effective diameter smaller than that of the second subgroup FN. For this reason, the first partial group FP1 and the second partial group FN are used as focusing lens groups to reduce the amount of movement during focusing from infinity to the closest distance and to facilitate rapid focusing.

  The first partial group FP1 having a positive refractive power is configured to move toward the object side during focusing from infinity to the closest distance. The second sub-group FN having a negative refractive power is configured to move to the image side during focusing from infinity to the closest distance. By adopting a structure in which the first partial group FP1 and the second partial group FN are moved simultaneously at the time of focusing from infinity to the closest distance, for example, the second partial group FN is moved closer to the closest distance than when focusing alone. Easy to focus on.

  In the lens cross-sectional view, a solid line curve FP1a and a dotted line curve FP1b relating to the first subgroup FP1 are moving loci for correcting image plane fluctuations caused by zooming when focusing at infinity and closest distance, respectively. It is.

  Further, when focusing from infinity to a short-distance object point, the first partial group FP1 is extended to the object side as indicated by an arrow FP1c. A solid line curve FNa and a dotted line curve FNb relating to the second subgroup FN are movement trajectories for correcting image plane fluctuations caused by zooming when focusing at infinity and the closest distance, respectively. Further, when focusing from infinity to the closest distance at the telephoto end, the second subgroup FN is moved toward the image side as indicated by an arrow FNc.

In each embodiment, the movement amount of the first lens unit L1 during zooming from the wide-angle end to the telephoto end is M1, and the movement amount of the second lens unit L2 is M2. At this time,
0.00 <M1 / M2 <1.00 (1)
The following conditional expression is satisfied.

  Here, the sign of the amount of movement is negative when the lens group is located on the object side at the telephoto end, and positive when it is located on the image side, compared to the wide-angle end.

  Conditional expression (1) defines the ratio of the movement amount of the first lens unit L1 and the movement amount of the second lens unit L2 during zooming from the wide-angle end to the telephoto end. If the amount of movement of the first lens unit L1 increases beyond the upper limit value of conditional expression (1), the total lens length at the wide-angle end decreases. By shortening the total lens length at the wide angle end, the distance between the first lens unit L1 and the aperture stop SP1 is narrowed, and the effective diameter of the first lens unit L1 is reduced.

  Therefore, although it is advantageous for reducing the size of the first lens unit L1, the amount of movement in zooming between the first lens unit L1 and the second lens unit L2 becomes large. This increases the total lens length at the telephoto end, increases the number of lens barrel members for retracting, and increases the radial direction, which is not preferable.

When the first lens unit L1 moves so as to exceed the lower limit value of the conditional expression (1), the first lens unit L1 moves from the object side to the image side during zooming. This increases the overall lens length. At the wide angle end, the aperture stop SP1 and the first lens unit L1 are in the expanding direction. Therefore, the effective diameter of the first lens unit L1 is increased, the optical axis direction of the first lens unit L1 is increased, and the radial direction is increased. It will become larger. Preferably, the numerical range of conditional expression (1) should be as follows.
0.10 <M1 / M2 <0.80 (1a)

More preferably, if the numerical range of the conditional expression (1a) is set as follows, the effect implied by the conditional expression described above can be obtained to the maximum.
0.20 <M1 / M2 <0.60 (1b)

  In each embodiment, by configuring as described above, it is possible to obtain a zoom lens in which the entire system is small and has high performance and can be easily focused to the closest distance.

  In each embodiment, it is more preferable that at least one of the following conditional expressions is satisfied. The amount of movement of the second subgroup FN in focusing from infinity to the closest distance is MfFN, and the amount of movement of the first subgroup FP1 is MfFP1. The focal length of the first partial group FP1 is fP1, and the focal length of the second partial group FN is fN. Let the focal length of the third subgroup FP2 be fP2.

  When focusing at infinity, the distance between the second partial group FN and the third partial group FP2 at the wide-angle end is DW4, and the focal length of the entire system at the wide-angle end is fW. The distance between the second lens unit L2 and the first partial unit FP1 at the wide-angle end when focusing on infinity is DW2. The focal length of the first lens unit L1 is f1, and the focal length of the second lens unit L2 is f2. The moving amount of the first partial group FP1 during zooming from the wide-angle end to the telephoto end is assumed to be MFP1. The amount of movement of the second partial group FN during zooming from the wide-angle end to the telephoto end is MFN, and the amount of movement of the third partial group FP2 during zooming from the wide-angle end to the telephoto end is MFP2.

  The radius of curvature of the lens surface closest to the object side in the second partial group FN is FNR1, and the radius of curvature of the lens surface closest to the image side in the second partial group FN is FNR2. Let FP1R1 be the radius of curvature of the lens surface closest to the object side of the first partial group FP1, and FP1R2 be the radius of curvature of the lens surface closest to the image side of the first partial group FP1. The radius of curvature of the lens surface closest to the object side of the third partial group FP2 is FP2R1, and the radius of curvature of the lens surface closest to the image side of the third partial group FP2 is FP2R2.

  The zoom lens has an aperture stop SP1, the length from the aperture stop SP1 at the wide-angle end to the image plane is DSIP, and on the optical axis from the aperture stop SP1 at the wide-angle end to the object-side lens surface of the first subgroup FP1. The length is DSP1. The length on the optical axis from the aperture stop SP1 at the wide angle end to the lens surface on the object side of the second partial group FN is defined as DSN.

  During zooming from the wide-angle end to the telephoto end, the first lens unit L1 moves along a convex locus toward the image side. During zooming, the zoom position at which the first lens unit L1 is closest to the image side is defined as the intermediate zoom position. To do. At this time, the movement amount of the first lens unit L1 from the wide-angle end to the intermediate 1 zoom position is M1a, and the movement amount of the first lens unit L1 from the intermediate 1 zoom position to the telephoto end is M1b.

  The refractive index of the material of the lens closest to the object side of the first lens unit L1 is G1Nd. Here, the sign of the amount of movement in focusing from infinity to the closest distance is negative when moving to the object side and positive when moving to the image side. At this time, one or more of the following conditional expressions should be satisfied.

-1.00 <MfFP1 / MfFN <0.00 (2)
−1.80 <fP1 / fN <−0.30 (3)
−2.00 <fP2 / fN <−0.50 (4)
0.40 <fP2 / fP1 <1.20 (5)
0.10 <DW4 / fW <1.00 (6)
0.10 <DW2 / fW <1.00 (7)
−1.50 <f1 / f2 <−0.60 (8)
−1.50 <M1 / fW <−0.20 (9)
1.00 <M2 / MFP1 <1.50 (10)
-12.00 <MFN / MFP2 <-2.00 (11)
1.00 <(FNR2 + FNR1) / (FNR2-FNR1) <15.00
(12)
0.20 <(FP1R2 + FP1R1) / (FP1R2-FP1R1) <5.00
... (13)
0.20 <(FP2R2 + FP2R1) / (FP2R2-FP2R1) <3.00
(14)
0.05 <DSP1 / DSIP <0.60 (15)
0.20 <DSN / DSIP <0.70 (16)
-0.50 <M1a / M1b <0.00 (17)
1.920 <G1Nd <2.060 (18)

  Next, the technical meaning of each conditional expression described above will be described. Conditional expression (2) limits the ratio of the movement amounts of the first subgroup FP1 and the second subgroup FN in focusing from infinity to the closest distance. When the movement amount of the first partial group FP1 increases with respect to the second partial group FN beyond the upper limit value of the conditional expression (2), the first partial group FP1 is more sensitive than the second partial group FN in terms of position sensitivity. Therefore, the amount of movement during focusing can be reduced. However, in addition to the fluctuation of spherical aberration, the fluctuation of coma becomes large, which is not preferable.

  If the amount of movement of the second partial group FN with respect to the first partial group FP1 exceeds the lower limit value of the conditional expression (2), the second partial group FN and the third partial group FP2 tend to physically interfere with each other. This is not preferable because focusing on a desired macro region becomes difficult.

  Conditional expression (3) defines the ratio of the refractive power of the first partial group FP1 to the refractive power of the second partial group FN. When the negative refracting power of the second subgroup FN becomes weaker than the upper limit value of the conditional expression (3) (the absolute value of the negative refracting power becomes small), focusing to the closeness of the second subgroup FN at the wide angle end. The amount of movement at that time increases. Then, the second partial group FN and the third partial group FP2 are liable to interfere with each other, which makes it difficult to focus on a desired macro region.

  When the negative refracting power of the second subgroup FN is increased beyond the lower limit value of the conditional expression (3) (the absolute value of the negative refracting power is increased), the amount of movement in focusing can be shortened. It is advantageous for conversion. However, it is not preferable because the sensitivity to eccentricity becomes high and assembly manufacture becomes difficult.

  Conditional expression (4) defines the ratio of the refractive power of the third partial group FP2 to the refractive power of the second partial group FN. When the positive refractive power of the third partial group FP2 with respect to the second partial group FN is increased beyond the upper limit value of the conditional expression (4), the incident angle at the wide angle end is improved, but the positive refraction of the third partial group FP2 is improved. Strength becomes stronger. Therefore, the thickness of the third partial group FP2 in the optical axis direction is increased, and the entire system is increased in size, which is not preferable. The third partial group FP2 is disposed in the vicinity of the image plane and is a lens having a large effective diameter. However, as the effective diameter increases, the center thickness increases as the refractive power increases.

  If the refractive power of the third partial group FP2 with respect to the second partial group FN becomes weaker than the lower limit value of the conditional expression (4), the incident angle of the light beam at the wide angle end becomes unfavorable.

  Conditional expression (5) defines the ratio of the refractive powers of the first partial group FP1 and the third partial group FP2. If the positive refractive power of the third partial group FP2 with respect to the first partial group FP1 becomes weaker than the upper limit value of the conditional expression (5), the incident angle of the light beam at the wide angle end becomes undesired. Further, since the refractive power of the first partial group FP1 is increased, the eccentric sensitivity of the first partial group FP1 is increased, which makes it difficult to manufacture and assemble.

  When the positive refractive power of the third partial group FP2 with respect to the first partial group FP1 is increased beyond the lower limit value of the conditional expression (5), the incident angle of the light beam at the wide angle end is improved (smaller), but the third part As the refractive power of the group FP2 increases, the thickness of the third partial group FP2 in the optical axis direction increases. And since the whole system enlarges, it is not preferable.

  Conditional expression (6) defines the distance DW4 between the second partial group FN and the third partial group FP2 at the wide-angle end when focusing on infinity. When DW4 increases beyond the upper limit value of conditional expression (6), the second subgroup FN has a sufficient amount of movement in focusing from infinity to the closest distance, but the third subgroup FP2 is arranged on the image side. Will be in the direction. For this reason, the amount of movement of the third partial group FP2 during zooming is reduced, and the image plane characteristics are deteriorated over the entire zoom range.

  In addition, the zoom ratio in zooming of the third partial group FP2 is decreased, the movement amount of the second lens group L2 for increasing the zoom ratio is increased, and the total lens length at the telephoto end is increased.

  When the distance DW4 becomes smaller than the lower limit value of the conditional expression (6), interference with the third subgroup FP2 occurs in focusing from the infinity to the closest distance of the second subgroup FN, which is not preferable. In order to realize focusing to the nearest distance, it is necessary to increase the refractive power of the second partial group FN, which increases the sensitivity of eccentricity of the second partial group FN and affects the assembly, which is not preferable.

  Conditional expression (7) defines the distance DW2 between the second lens unit L2 and the first partial unit FP1 at the wide-angle end when focusing on infinity. When the distance DW2 increases beyond the upper limit value of the conditional expression (7), a sufficient amount of movement between the second lens group and the first subgroup FP1 can be secured during focusing to the closest distance, but the second subgroup FN and the second subgroup FN The distance from the third subgroup FP2 becomes narrower. As a result, the second partial group FN and the third partial group FP2 are liable to interfere during focusing, which is not preferable.

  Further, the second partial group FN having a negative refractive power at the wide-angle end is disposed on the image side, which is not preferable because the incident angle of the light beam on the image plane becomes tight. In order to reduce the incident angle, it is necessary to move the second subgroup FN to the object side, which is not preferable because the total lens length at the wide angle end becomes long.

  When DW2 becomes smaller than the lower limit value of conditional expression (7), it becomes difficult to ensure a sufficient amount of movement of the first subgroup FP1 during focusing from infinity to the closest distance. As a result, it is difficult to perform focusing on an object located at a short distance, which is not preferable.

  Conditional expression (8) defines the ratio of the refractive powers of the first lens unit L1 and the second lens unit L2. If the negative refractive power of the first lens unit L1 with respect to the second lens unit L2 exceeds the upper limit value of the conditional expression (8), the amount of movement of the second lens unit L2 during zooming increases, and the total lens length at the telephoto end increases. Increase. Further, the Petzval sum becomes small, and the field curvature tends to be under, which is not preferable.

  If the negative refractive power of the first lens unit L1 with respect to the second lens unit L2 becomes weaker than the lower limit value of the conditional expression (8), the total lens length is reduced, but the first lens unit L1 is in the radial direction. It is not preferable because the entire system is enlarged due to enlargement. Further, the Petzval sum is increased, and the curvature of field tends to be over.

  Conditional expression (9) defines the amount of movement of the first lens unit L1 during zooming. If the amount of movement of the first lens unit L1 exceeds the upper limit value of conditional expression (9), the total lens length at the telephoto end increases and the entire system becomes large, which is not preferable. Further, if the upper limit is exceeded while keeping the total lens length at the telephoto end constant, the total lens length at the wide-angle end becomes shorter and the effective diameter of the front lens becomes smaller, but the refractive power of the first lens unit L1 becomes stronger. The curve becomes under, which is not preferable.

  When the amount of movement of the first lens unit L1 becomes smaller than the lower limit value of the conditional expression (9), the total lens length at the telephoto end decreases, but the total lens length at the wide angle end increases, and the first lens unit L1 and the aperture stop Since the distance from SP1 increases, the effective diameter of the front lens increases, which is not preferable.

  Conditional expression (10) defines the ratio of the movement amounts of the second lens unit L2 and the first partial unit FP1 during zooming. If the amount of movement of the second lens unit L2 exceeds the upper limit value of conditional expression (10), the total lens length becomes longer at the telephoto end, which is not preferable. If the amount of movement of the second lens unit L2 becomes smaller than the lower limit value of the conditional expression (10), it is easy to downsize the entire system, but the second lens unit L2 and the first subgroup FP1 are at the telephoto end. Since it tends to interfere, it is not preferable. Further, in focusing from the infinity to the closest distance at the telephoto end, it is not preferable because the second lens unit L2 and the first partial unit FP1 easily interfere with each other.

  Conditional expression (11) defines the ratio of the movement amount of the second partial group FN and the movement amount of the third partial group FP2 during zooming. If the amount of movement of the second subgroup FN increases beyond the lower limit of conditional expression (11), the total lens length becomes longer at the telephoto end, which is not preferable. When the movement amount of the third partial group FP2 increases beyond the upper limit value of the conditional expression (11), the variable magnification share increases in the third partial group FP2, and the lens group on the object side of the third partial group FP2 increases. The amount of movement during zooming can be reduced.

  However, since the third partial group FP2 is located on the object side at the wide-angle end, it is easy to interfere with the second partial group FN, which is not preferable. In order to avoid interference, it is necessary to lengthen the entire lens length at the wide-angle end, which is not preferable because the entire system becomes large.

  Conditional expression (12) defines the lens shape of the second subgroup FN. Conditional expression (12) means that the second subgroup FN is formed of a meniscus lens having a convex surface facing the image side. The second subgroup FN is a meniscus lens having a convex surface facing the image side, thereby providing a concentric arrangement with off-axis rays. As a result, when focusing from infinity to the closest distance, the concentric state with the off-axis light does not change even after moving to the image side, thereby reducing image plane fluctuations due to focusing.

  When the lens shape changes beyond the upper limit value of conditional expression (12), the lens shape with the first lens unit L1 becomes a shape in which the difference between the curvature of the object-side lens surface and the curvature of the image-side lens surface is eliminated. This is not preferable because the symmetry of the lens is broken and a lot of coma occurs. When the lens shape changes beyond the lower limit of conditional expression (12), the difference between the curvature of the object-side lens surface and the curvature of the image-side lens surface increases, and the symmetry of the lens shape with the first lens unit L1. Becomes better, and coma aberration is reduced. However, the negative refractive power becomes strong, the Petzval sum increases in the positive direction, and the field curvature is over, which is not preferable.

  Conditional expression (13) defines the lens shape of the first subgroup FP1. Conditional expression (13) means that the first subgroup FP1 has a meniscus shape or a biconvex shape with a convex surface facing the image side. If the first partial group FP1 has a meniscus shape with the convex surface facing the image side, the second partial group FN has a lens shape with the concave surface facing the image side, so the second partial group FN and the first partial group are retracted. The air interval of the FP 1 can be reduced, which is effective for downsizing the entire system.

  When the lens shape changes beyond the upper limit value of conditional expression (13), the positive refractive power of the first subgroup FP1 becomes weak. When the refractive power of the first partial group FP1 is weakened, the positive refractive power of the third partial group FP2, which is a lens group having the same positive refractive power as that of the first partial group FP1, is increased. This is not preferable because the thickness is increased and the collapsed thickness is increased.

  When the lens shape changes beyond the lower limit value of conditional expression (13), the lens surface on the object side of the second subgroup FN has a biconvex shape with a strong curvature on the object side or a meniscus shape with the convex surface facing the object side. Become. A lens shape in which the convex shape does not face the image side of the second partial group FN is not preferable because a wasteful space is formed in the interval between the first partial group FP1 and the second partial group FN during the retracting operation, and the retracting thickness is increased.

  Conditional expression (14) defines the lens shape of the third subgroup FP2. Conditional expression (14) means a meniscus shape having a convex surface facing the image side or a biconvex shape. If the curvature of the lens surface on the object side of the third partial group FP2 becomes tight beyond the upper limit of conditional expression (14), the field curvature will be good at the telephoto end, but the field curvature will increase at the wide angle end. It is not preferable. Specifically, at the wide-angle end, the field curvature is under at a low image height, and the field curvature is over at a high image height.

  If the curvature of the lens surface on the object side of the third partial group FP2 becomes tighter toward the object side beyond the lower limit value of the conditional expression (14), the curvature of field is improved at the wide angle end, but the image at the telephoto end is improved. The surface curvature is over, which is not preferable. In addition, if the lens shape of the third partial group FP2 having a large effective diameter is a meniscus shape having a tight curvature, a space is required in the peripheral portion because of the structure, and the entire system is enlarged, which is not preferable.

  Conditional expression (15) defines the ratio of the length from the aperture stop SP1 at the wide-angle end to the object-side lens surface of the first partial group FP1 and the length from the aperture stop SP1 to the image forming point at the wide-angle end. Here, when the length from the aperture stop SP1 to the image formation point is obtained and there is a filter or the like having no refractive power between the final lens surface and the image surface, the length is an air-converted length. .

  When the first partial group FP1 approaches the imaging point (image plane) beyond the upper limit value of the conditional expression (15), the interval between the second lens group L2 and the first partial group FP1 is increased. For this reason, there is no interference in focusing from infinity to the closest distance, but the distance between the second partial group FN and the third partial group FP2 is narrowed, so that the amount of movement of the second partial group FN during focusing is limited. Avoiding this limitation is not preferable because the total lens length at the wide-angle end becomes long.

  If the first partial group FP1 moves away from the imaging point beyond the lower limit value of the conditional expression (15), the second lens group L2 and the first partial group FP1 are likely to interfere with each other during focusing from infinity to the closest distance. It is not preferable.

  Conditional expression (16) defines the ratio of the length from the aperture stop SP1 at the wide-angle end to the object-side lens surface of the second subgroup FN and the length from the aperture stop SP1 to the imaging point at the wide-angle end. If the second subgroup FN approaches the imaging point beyond the upper limit value of conditional expression (16), it is not preferable because the amount of space that moves during focusing decreases. In addition, in order to reduce the size of the entire system, it is necessary to increase the refractive power of the second subgroup FN. As a result, the incident angle of the light beam on the image plane becomes tight or the final incident angle is relaxed. This is not preferable because the refractive power of the lens group (third partial group FP2) is increased and the thickness of the lens group is increased.

  If the second subgroup FN approaches the aperture stop SP1 beyond the lower limit value of the conditional expression (16), a space for movement during focusing can be secured, but the symmetry between the first lens group L1 and the aperture stop SP1 is lost. This is not preferable because much coma occurs.

  Conditional expression (17) defines the amount of movement when moving along the locus convex to the image side of the first lens unit L1 during zooming. If the amount of movement of the first lens unit L1 toward the object side exceeds the upper limit value of conditional expression (17), the total lens length at the telephoto end becomes longer, which is not preferable. If the lower limit of conditional expression (17) is exceeded and the amount of movement of the first lens unit L1 toward the image side increases, the total lens length becomes longer at the wide-angle end, and the effective diameter of the front lens increases.

  Conditional Expression (18) Defines the refractive index of the material of the lens closest to the object side in the first lens unit L1. When the refractive index increases beyond the upper limit of conditional expression (18), the existing glass material becomes a glass material with a small Abbe number, and the glass material of the positive lens in the first lens unit L1 for achromaticity decreases. It is not preferable because achromatic color becomes difficult. If the refractive index decreases beyond the lower limit of conditional expression (18), there are many glass materials for achromatization, but since the refractive index decreases, the effective diameter of the front lens increases, which is not preferable.

  In each embodiment, it is preferable to set the numerical ranges of conditional expressions (2) to (18) as follows.

−0.85 <MfFP1 / MfFN <−0.05 (2a)
−1.50 <fP1 / fN <−0.40 (3a)
-1.90 <fP2 / fN <−0.55 (4a)
0.50 <fP2 / fP1 <1.00 (5a)
0.15 <DW4 / fW <0.90 (6a)
0.20 <DW2 / fW <0.80 (7a)
−1.30 <f1 / f2 <−0.65 (8a)
−1.30 <M1 / fW <−0.30 (9a)
1.01 <M2 / MFP1 <1.40 (10a)
-11.00 <MFN / MFP2 <-2.50 (11a)
1.005 <(FNR2 + FNR1) / (FNR2-FNR1) <12.000
... (12a)
0.50 <(FP1R2 + FP1R1) / (FP1R2-FP1R1) <4.50
... (13a)
0.25 <(FP2R2 + FP2R1) / (FP2R2-FP2R1) <2.00
... (14a)
0.08 <DSP1 / DSIP <0.50 (15a)
0.25 <DSN / DSIP <0.65 (16a)
−0.40 <M1a / M1b <0.00 (17a)
1.930 <G1Nd <2.030 (18a)

  More preferably, if the numerical ranges of the conditional expressions (2a) to (18a) are set as follows, the effects implied by the conditional expressions described above can be obtained to the maximum.

−0.70 <MfFP1 / MfFN <−0.10 (2b)
−1.30 <fP1 / fN <−0.45 (3b)
−1.85 <fP2 / fN <−0.60 (4b)
0.60 <fP2 / fP1 <0.90 (5b)
0.20 <DW4 / fW <0.80 (6b)
0.25 <DW2 / fW <0.60 (7b)
−1.20 <f1 / f2 <−0.70 (8b)
-1.25 <M1 / fW <-0.33 (9b)
1.02 <M2 / MFP1 <1.30 (10b)
-10.30 <MFN / MFP2 <−3.00 (11b)
1.01 <(FNR2 + FNR1) / (FNR2-FNR1) <9.50
... (12b)
0.70 <(FP1R2 + FP1R1) / (FP1R2-FP1R1) <4.00
... (13b)
0.30 <(FP2R2 + FP2R1) / (FP2R2-FP2R1) <1.65
... (14b)
0.10 <DSP1 / DSIP <0.45 (15b)
0.30 <DSN / DSIP <0.60 (16b)
-0.385 <M1a / M1b <0.00 (17b)
1.950 <G1Nd <2.010 (18b)

  In each embodiment, by configuring each element as described above, a zoom lens that is easy to focus to the closest distance is obtained while the entire system is small and has high optical performance. When aiming to reduce the effective diameter of the first lens unit in a negative lead zoom lens, the refractive power of the first lens unit L1 having a negative refractive power is increased, so the first lens unit has a three-lens configuration. Is good.

  In order to reduce the size, a two-lens configuration of a negative lens and a positive lens with a reduced number of lenses can be considered. However, if the refractive power of the first lens unit is increased for compactness, the curvature of the negative lens becomes tight. In addition, since the distance between the two lenses is also necessary in order to improve the spherical aberration and the image surface characteristics, the thickness of the first lens group is required to some extent even in the two-lens configuration. Therefore, by dividing the refractive power of the negative lens in the first lens group and using two negative lenses, it is easy to reduce the size in the radial direction while maintaining good optical performance.

  In order to satisfactorily correct various aberrations, it is preferable that the first lens unit L1 includes three lenses of a negative lens 11, a negative lens 12, and a positive lens 13 in order from the object side to the image side. In addition, the negative lens 11 closest to the object employs a high refractive index material, and the lens surface of the negative lens 12 having a smaller lens diameter than the negative lens 11 is made aspherical. High optical performance can be obtained while downsizing the entire system.

  Further, the first lens 11 is preferably a meniscus shape having a concave surface on the image side. By making the second subgroup FN having a negative refractive power into a single meniscus lens having a convex surface facing the image side, a symmetrical shape with respect to the first lens L1 having a negative refractive power and the aperture stop SP1 is obtained. Coma is corrected well.

  It is desirable for the second lens unit L2 to have a positive refractive power. At the wide angle end, the axial light beam becomes a divergent light beam when passing through the first lens unit L1 having a negative refractive power. As described above, the converging action is given to the luminous flux, and the effective lens diameter of the rear group is reduced.

  The second lens unit L1 preferably includes a positive lens 21, a positive lens 22, and a negative lens 23 in order from the object side to the image side, and the positive lens 21 preferably has an aspheric lens surface. The positive lens 21 on the most object side having the largest effective diameter has an aspherical lens surface, so that it is easy to satisfactorily correct spherical aberration and coma aberration in the entire zoom region. The third lens group is preferably composed of one positive lens.

  During zooming from the wide-angle end to the telephoto end, the second lens unit L2, the first partial unit FP1, and the second partial unit FN all move toward the object side. Further, during zooming from the wide-angle end to the telephoto end, the third subgroup FP2 moves to the image side. According to this, a high zoom ratio can be obtained effectively.

  Next, an embodiment of a digital camera (optical apparatus) using the zoom lens of the present invention as an imaging optical system will be described with reference to FIG. In FIG. 19, 20 is a digital camera body, 21 is an imaging optical system constituted by the zoom lens of each of the above-described embodiments, 22 is an imaging element such as a CCD that receives a subject image by the imaging optical system 21, and 23 is an imaging element. Reference numeral 22 denotes recording means for recording the received subject image. Reference numeral 24 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 22 is displayed. Reference numeral 24 denotes a liquid crystal display panel having a function equivalent to that of the viewfinder.

  Thus, by applying the zoom lens of the present invention to an imaging apparatus such as a digital camera, an imaging apparatus having a small size and high optical performance is realized.

  Next, numerical data 1 to 6 corresponding to the first to sixth embodiments of the present invention are shown. In each numerical data, i indicates the order of the surfaces from the object side, ndi, ri is the radius of curvature of the lens surface, di is the lens thickness and air spacing between the i-th surface and the i + 1-th surface, ndi, νdi Indicates the refractive index and Abbe number for the d-line, respectively. In the numerical data 3 and 4, the interval value is given a “−” sign because it is counted from the object surface in order of the aperture stop and the lens.

The two surfaces closest to the image side are glass materials such as face plates. K is a conic constant, and A4, A6, A8, and A10 are aspherical coefficients. When the aspherical shape is x with the displacement in the optical axis direction at the position of the height h from the optical axis as x based on the surface vertex,
x = (h ² / R) / [1+ {1− (1 + k) (h / R) ² } ^1/2 ] + A4h ⁴ + A6h ⁶ + A8h ⁸ + A10h ¹⁰
It is represented by Where R is the paraxial radius of curvature.

The numerical value “E ± XX” means “× 10 ^{± XX} ”. Further, the portion where the interval d between the optical surfaces is (variable) changes during zooming, and the surface interval corresponding to the focal length is shown in the separate table. Tables 1A and 1B show the calculation results of the conditional expressions based on the lens data of numerical data 1 to 6 described below.

[Numeric data 1]
Unit mm

Surface data surface number rd nd νd
1 76.577 0.85 1.95375 32.3
2 15.499 4.26
3 * 65.924 1.40 1.53160 55.8
4 * 28.208 0.15
5 21.601 2.24 1.95906 17.5
6 43.976 (variable)
7 (Aperture) (SP1) ∞ (Variable)
8 * 13.639 2.21 1.69350 53.2
9 * -182.217 1.11
10 20.617 3.08 2.00 100 29.1
11 -11.603 0.60 1.85478 24.8
12 8.846 2.00
13 (SP2) ∞ (variable)
14 328.008 2.08 1.74330 49.3
15 * -26.016 2.70
16 -25.700 0.70 1.83400 37.2
17 -77.285 (variable)
18 -340.267 3.60 1.53160 55.8
19 * -24.859 (variable)
20 ∞ 1.30 1.51633 64.1
21 ∞ 0.50
Image plane ∞

Aspheric data 3rd surface
K = 0.00000e + 000 A 4 = -1.01756e-005 A 6 = -2.37078e-007 A 8 = 9.83465e-010

4th page
K = 0.00000e + 000 A 4 = -2.29560e-005 A 6 = -2.67140e-007 A 8 = 1.06706e-009 A10 = -1.01510e-013

8th page
K = 0.00000e + 000 A 4 = -6.93027e-005 A 6 = -3.22498e-007 A 8 = -5.41392e-009

9th page
K = 0.00000e + 000 A 4 = 2.49446e-005

15th page
K = 0.00000e + 000 A 4 = 4.40364e-007 A 6 = -3.52863e-008 A 8 = -3.87550e-010

19th page
K = 0.00000e + 000 A 4 = 5.62098e-005 A 6 = -1.45256e-007 A 8 = 2.55362e-010

Various data Zoom ratio 2.83
Wide-angle end Medium 1 Medium 2 Telephoto end focal length 15.45 22.75 26.04 43.70
F number 2.89 3.60 4.00 5.77
Half angle of view (degrees) 38.02 30.56 27.29 17.09
Total lens length 69.79 66.41 66.81 75.34
BF 8.65 7.97 7.57 4.69

d 6 20.96 10.52 7.89 2.02
d 7 1.99 1.93 1.79 0.10
d13 5.48 6.63 7.18 10.31
d17 5.72 12.38 15.40 31.23
d19 7.30 6.61 6.21 3.33

At close focus (distance from surface number 1 to object point)
50mm 80mm 80mm 200mm
d 6 20.96 10.52 7.89 2.02
d 7 1.99 1.93 1.79 0.10
d13 3.87 5.85 6.23 9.10
d15 7.70 9.03 10.13 7.20
d17 2.33 6.83 8.92 27.94
d19 7.30 6.61 6.21 3.33
d21 0.50 0.50 0.50 0.50

Group Start surface Focal length
1 1 -29.09
2 8 25.47
3 14 91.30
4 18 50.25

[Numeric data 2]
Unit mm

Surface data surface number rd nd νd
1 74.111 0.85 2.00 100 29.1
2 15.977 4.79
3 * 61.391 1.20 1.58573 59.7
4 * 25.653 0.56
5 23.402 2.60 1.95906 17.5
6 58.274 (variable)
7 (Aperture) (SP1) ∞ (Variable)
8 * 15.590 3.00 1.76802 49.2
9 * -144.212 1.79
10 21.549 2.60 1.95375 32.3
11 -17.690 0.60 1.85478 24.8
12 10.031 2.74
13 (SP2) ∞ (variable)
14 -59.298 1.20 1.95375 32.3
15 -21.585 3.65
16 -20.917 1.55 1.67300 38.1
17 -13.219 0.50 1.72825 28.5
18 -49.907 (variable)
19 1551.093 4.00 1.77250 49.5
20 * -32.506 (variable)
21 ∞ 1.30 1.51633 64.1
22 ∞ 0.50
Image plane ∞

Aspheric data 3rd surface
K = 0.00000e + 000 A 4 = -2.29628e-005 A 6 = 2.45167e-008 A 8 = -3.64727e-010 A10 = 1.13474e-012

4th page
K = 0.00000e + 000 A 4 = -3.90911e-005 A 6 = 2.88273e-008 A 8 = -7.44512e-010 A10 = 2.53874e-012

8th page
K = -1.41037e-002 A 4 = -3.75568e-005 A 6 = -1.22940e-007 A 8 = 1.34745e-010

9th page
K = 0.00000e + 000 A 4 = 1.58555e-005

20th page
K = 0.00000e + 000 A 4 = 2.25597e-005 A 6 = -3.57346e-008 A 8 = 3.62029e-011

Various data Zoom ratio 2.83
Wide angle end Medium 1 Medium 2 Telephoto end focal length 15.45 21.71 26.07 43.70
F number 2.88 3.50 4.00 5.77
Half angle of view (degrees) 38.01 31.75 27.26 17.09
Total lens length 73.53 70.70 71.46 81.81
BF 9.53 9.28 9.04 6.94

d 6 22.91 11.98 7.61 2.09
d 7 0.00 1.42 1.92 0.10
d13 4.02 4.37 4.71 6.70
d18 5.44 12.01 16.55 34.35
d20 8.18 7.93 7.68 5.58

At close focus (distance from surface number 1 to object point)
50mm 80mm 80mm 200mm
d 6 22.91 11.98 7.61 2.09
d 7 0.00 1.42 1.92 0.10
d13 2.28 3.59 3.69 5.45
d15 8.75 9.53 10.96 8.09
d18 2.09 6.91 10.26 31.16
d20 8.18 7.93 7.68 5.58
d22 0.50 0.50 0.50 0.50

Group Start surface Focal length
1 1 -29.13
2 8 26.77
3 14 112.97
4 19 41.26

[Numeric data 3]
Unit mm

Surface data surface number rd nd νd
1 115.898 1.00 1.95375 32.3
2 16.600 5.00
3 * 282.648 1.20 1.58573 59.7
4 * 24.916 0.30
5 22.736 2.70 1.95906 17.5
6 53.461 (variable)
7 (SP2) ∞ (variable)
8 * 19.620 3.65 1.85135 40.1
9 * -102.233 2.00
10 26.476 3.60 1.88300 40.8
11 -29.098 0.60 1.85478 24.8
12 12.091 3.47
13 (Aperture) (SP1) ∞ (Variable)
14 -86.525 0.70 1.68893 31.1
15 16.587 3.20 1.88300 40.8
16 -27.502 (variable)
17 * -34.234 1.00 1.69350 53.2
18 -295.311 (variable)
19 58.601 4.90 1.53160 55.8
20 * -31.375 (variable)
21 ∞ 1.30 1.51633 64.1
22 ∞ 0.50
Image plane ∞

Aspheric data 3rd surface
K = 0.00000e + 000 A 4 = 1.63022e-005 A 6 = -1.86018e-008 A 8 = -1.33443e-010

4th page
K = 0.00000e + 000 A 4 = 6.64320e-006 A 6 = -4.89576e-008 A 8 = -1.46214e-010

8th page
K = -1.41037e-002 A 4 = -2.21133e-005 A 6 = -2.45947e-008

9th page
K = 0.00000e + 000 A 4 = 5.90844e-006

17th page
K = 0.00000e + 000 A 4 = -2.18571e-005 A 6 = 7.39569e-008 A 8 = -2.84554e-009

20th page
K = 0.00000e + 000 A 4 = 3.00769e-005 A 6 = -2.40015e-008 A 8 = 2.87542e-011

Various data Zoom ratio 2.85
Wide angle end Medium 1 Medium 2 Telephoto end focal length 15.45 16.16 26.00 44.00
F number 2.06 2.20 3.50 5.78
Half angle of view (degrees) 38.01 39.73 27.33 16.98
Total lens length 76.88 76.85 81.58 95.60
BF 9.44 9.38 7.95 4.70

d 6 16.71 15.80 8.48 2.45
d 7 1.25 1.07 -0.58 -0.93
d13 3.89 4.03 5.72 7.60
d16 4.54 4.71 6.89 10.00
d18 7.72 8.53 19.80 38.45
d20 8.09 8.02 6.59 3.34

At close focus (distance from surface number 1 to object point)
50mm 80mm 80mm 200mm
d 6 16.71 15.80 8.48 2.45
d 7 1.25 1.07 -0.58 -0.93
d13 2.17 3.54 4.65 5.99
d16 10.24 9.42 15.29 15.32
d18 3.74 4.31 12.47 34.74
d20 8.09 8.02 6.59 3.34
d22 0.50 0.50 0.50 0.50

Group Start surface Focal length
1 1 -22.00
2 8 29.70
3 14 27.95
4 17 -55.92
5 19 39.18

[Numeric data 4]
Unit mm

Surface data surface number rd nd νd
1 117.391 1.00 2.00 100 29.1
2 19.846 5.00
3 * 332.714 1.20 1.58573 59.7
4 * 40.910 0.30
5 28.763 2.80 1.95906 17.5
6 76.299 (variable)
7 (SP2) ∞ (variable)
8 * 19.647 4.09 1.85 135 40.1
9 * -150.119 1.58
10 23.758 3.36 1.88300 40.8
11 -41.943 0.90 1.85478 24.8
12 11.832 3.47
13 (Aperture) (SP1) ∞ (Variable)
14 -80.896 1.00 1.69895 30.1
15 22.724 3.42 1.88300 40.8
16 -30.315 (variable)
17 * -23.402 1.00 1.69350 53.2
18 * -91.963 (variable)
19 232.943 5.20 1.59201 67.0
20 * -28.000 (variable)
21 ∞ 1.30 1.51633 64.1
22 ∞ 0.50
Image plane ∞

Aspheric data 3rd surface
K = 0.00000e + 000 A 4 = -2.76034e-008 A 6 = 4.26310e-008 A 8 = -5.96223e-011

4th page
K = 0.00000e + 000 A 4 = -2.80012e-006 A 6 = 4.34912e-008 A 8 = -1.02259e-010

8th page
K = -1.41037e-002 A 4 = -1.78164e-005 A 6 = -2.62673e-008

9th page
K = 0.00000e + 000 A 4 = 3.57156e-006

17th page
K = 0.00000e + 000 A 4 = 3.78072e-005 A 6 = 3.12691e-007 A 8 = -2.44431e-009

18th page
K = 0.00000e + 000 A 4 = 4.87963e-005 A 6 = 1.83684e-007 A 8 = -1.36312e-009

20th page
K = 0.00000e + 000 A 4 = 2.07848e-005 A 6 = -4.32159e-008 A 8 = 5.20787e-011

Various data Zoom ratio 2.83
Wide angle end Medium 1 Medium 2 Telephoto end focal length 17.90 25.26 30.07 50.67
F number 2.06 2.52 3.00 5.05
Half angle of view (degrees) 34.01 28.00 24.07 14.85
Total lens length 84.12 81.28 81.95 90.36
BF 11.77 10.85 10.11 6.43

d 6 23.02 13.73 10.20 2.00
d 7 1.98 0.57 -0.08 -0.99
d13 3.61 5.55 6.65 9.99
d16 2.70 4.62 5.80 10.00
d18 6.72 11.63 14.94 28.61
d20 10.41 9.49 8.76 5.08

At close focus (distance from surface number 1 to object point)
50mm 80mm 80mm 200mm
d 6 23.02 13.73 10.20 2.00
d 7 1.98 0.57 -0.08 -0.99
d13 1.56 4.56 5.34 8.20
d16 8.52 12.22 15.68 16.72
d18 2.96 5.03 6.36 23.68
d20 10.41 9.49 8.76 5.08
d22 0.50 0.50 0.50 0.50

Group Start surface Focal length
1 1 -31.71
2 8 30.40
3 14 34.72
4 17 -45.53
5 19 42.54

[Numeric data 5]
Unit mm

Surface data surface number rd nd νd
1 72.579 0.70 2.00 100 29.1
2 20.326 4.50
3 * -74.405 1.20 1.58313 59.4
4 * 49.343 0.88
5 23.291 2.10 1.95906 17.5
6 44.181 (variable)
7 (Aperture) (SP1) ∞ (Variable)
8 * 18.232 3.00 1.77250 49.5
9 * -85.005 1.60
10 25.246 2.80 1.95375 32.3
11 -17.363 0.60 1.85478 24.8
12 12.242 2.74
13 (SP2) ∞ (variable)
14 148.748 2.10 1.88300 40.8
15 -25.477 (variable)
16 -16.543 0.70 1.83400 37.2
17 -2056.249 (variable)
18 * 417.602 5.40 1.59201 67.0
19 * -22.351 (variable)
20 ∞ 1.30 1.51633 64.1
21 ∞ 0.50
Image plane ∞

Aspheric data 3rd surface
K = 0.00000e + 000 A 4 = 6.84946e-005 A 6 = -9.84114e-007 A 8 = 7.17643e-009 A10 = -1.96317e-011

4th page
K = 0.00000e + 000 A 4 = 8.36427e-005 A 6 = -1.00679e-006 A 8 = 7.93824e-009 A10 = -2.23888e-011

8th page
K = -1.41037e-002 A 4 = -3.34581e-005 A 6 = -1.03774e-007 A 8 = 1.69118e-010

9th page
K = 0.00000e + 000 A 4 = 9.20213e-006

18th page
K = 0.00000e + 000 A 4 = -8.59285e-006

19th page
K = 0.00000e + 000 A 4 = 3.27888e-005 A 6 = -6.39636e-008 A 8 = 1.13443e-010

Various data Zoom ratio 2.83
Wide angle end Medium 1 Medium 2 Telephoto end focal length 17.92 24.54 30.03 50.67
F number 2.88 3.50 4.00 5.77
Half angle of view (degrees) 33.98 28.70 24.10 14.85
Total lens length 73.73 71.59 72.47 82.15
BF 7.74 7.70 7.56 5.19

d 6 21.54 12.59 8.20 2.14
d 7 0.00 0.87 1.30 0.86
d13 7.83 8.38 8.90 11.09
d15 4.51 4.90 5.18 5.78
d17 3.78 8.81 13.01 28.77
d19 6.38 6.34 6.20 3.83

At close focus (distance from surface number 1 to object point)
50mm 80mm 80mm 200mm
d 6 21.54 12.59 8.20 2.14
d 7 0.00 0.87 1.30 0.86
d13 6.62 7.90 8.30 10.41
d15 7.63 8.01 8.94 8.00
d17 1.87 6.19 9.85 27.23
d19 6.38 6.34 6.20 3.83
d21 0.50 0.50 0.50 0.50

Group Start surface Focal length
1 1 -29.12
2 8 26.27
3 14 24.77
4 16 -20.00
5 18 36.00

[Numeric data 6]
Unit mm

Surface data surface number rd nd νd
1 230.579 0.70 1.95375 32.3
2 18.261 4.50
3 -316.966 1.20 1.58313 59.4
4 * 100.965 1.20
5 28.470 1.90 1.98738 16.4
6 58.052 (variable)
7 (Aperture) (SP1) ∞ (Variable)
8 * 15.913 3.20 1.76802 49.2
9 * -154.619 1.90
10 19.458 2.30 1.91082 35.3
11 -61.067 0.60 1.85478 24.8
12 10.431 2.74
13 (SP2) ∞ (variable)
14 -32.868 1.00 1.80 400 46.6
15 -19.220 3.04
16 -14.129 0.70 1.68893 31.1
17 -17.542 (variable)
18 -122.530 2.80 1.53160 55.8
19 * -28.770 (variable)
20 ∞ 1.30 1.51633 64.1
21 ∞ 0.50
Image plane ∞

Aspheric data 4th surface
K = 0.00000e + 000 A 4 = -3.58677e-006 A 6 = 4.41917e-008 A 8 = -4.79957e-010 A10 = 1.60314e-012

8th page
K = -1.41037e-002 A 4 = -2.53994e-005 A 6 = -2.06589e-008 A 8 = -2.25174e-010

9th page
K = 0.00000e + 000 A 4 = 1.51133e-005

19th page
K = 0.00000e + 000 A 4 = 3.59260e-005 A 6 = -4.01298e-008 A 8 = -1.00406e-011

Various data Zoom ratio 2.83
Wide angle end Medium 1 Medium 2 Telephoto end focal length 17.92 25.27 30.36 50.67
F number 2.88 3.53 4.00 5.77
Half angle of view (degrees) 33.98 27.99 23.87 14.85
Total lens length 76.23 73.86 74.60 84.25
BF 9.18 7.65 6.94 4.70

d 6 23.63 12.63 8.14 1.83
d 7 0.00 1.47 1.94 0.00
d13 2.50 3.09 3.35 3.43
d17 13.14 21.24 26.45 46.50
d19 7.82 6.29 5.58 3.34

At close focus (distance from surface number 1 to object point)
100mm 120mm 120mm 250mm
d 6 23.63 12.63 8.14 1.83
d 7 0.00 1.47 1.94 0.00
d13 1.34 2.10 2.05 2.37
d15 9.53 12.62 15.32 13.09
d17 7.80 12.64 15.47 37.51
d19 7.82 6.29 5.58 3.34
d21 0.50 0.50 0.50 0.50

Group Start surface Focal length
1 1 -29.14
2 8 27.56
3 14 107.46
4 18 70.00

L0 Zoom lens L1 First lens group L2 Second lens group FP1 First part group FN Second part group FP2 Third part group

Claims (25)

A first lens group having a negative refractive power, a second lens group having a positive refractive power, a first partial group having a positive refractive power, and a second partial group having a negative refractive power, which are arranged in order from the object side to the image side. The third lens unit has a positive refractive power and the distance between the first lens group and the second lens group is shorter at the telephoto end than at the wide-angle end, and the distance between adjacent lens groups changes during zooming. Zoom lens
During focusing from infinity to the closest distance, the first partial group moves toward the object side, the second partial group moves toward the image side, and the first lens group moves during zooming from the wide-angle end to the telephoto end. When the amount is M1, and the amount of movement of the second lens group in zooming from the wide-angle end to the telephoto end is M2,
0.00 <M1 / M2 <1.00
A zoom lens satisfying the following conditional expression: When the amount of movement of the second partial group in focusing from infinity to the closest distance is MfFN, and the amount of movement of the first partial group in focusing from infinity to the closest distance is MfFP1,
-1.00 <MfFP1 / MfFN <0.00
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the first partial group is fP1, and the focal length of the second partial group is fN,
−1.80 <fP1 / fN <−0.30
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the second partial group is fN and the focal length of the third partial group is fP2,
−2.00 <fP2 / fN <−0.50
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the first partial group is fP1, and the focal length of the third partial group is fP2, 0.40 <fP2 / fP1 <1.20.
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the distance on the optical axis between the second partial group and the third partial group at the wide-angle end when focusing at infinity is DW4, and the focal length of the entire system at the wide-angle end is fW,
0.10 <DW4 / fW <1.00
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the distance between the second lens group and the first partial group at the wide-angle end on the optical axis when focusing at infinity is DW2, and the focal length of the entire system at the wide-angle end is fW,
0.10 <DW2 / fW <1.00
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the first lens group is f1 and the focal length of the second lens group is f2, −1.50 <f1 / f2 <−0.60.
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the entire system at the wide angle end is fW,
−1.50 <M1 / fW <−0.20
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the movement amount of the first subgroup in zooming from the wide-angle end to the telephoto end is MFP1, 1.00 <M2 / MFP1 <1.50
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the movement amount of the second partial group in zooming from the wide-angle end to the telephoto end is MFN, and the movement amount of the third partial group in zooming from the wide-angle end to the telephoto end is MFP2,
-12.00 <MFN / MFP2 <-2.00
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the radius of curvature of the lens surface closest to the object side of the second partial group is FNR1, and the radius of curvature of the lens surface closest to the image side of the second partial group is FNR2,
1.00 <(FNR2 + FNR1) / (FNR2-FNR1) <15.00
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the radius of curvature of the lens surface closest to the object side of the first partial group is FP1R1, and the radius of curvature of the lens surface closest to the image side of the first partial group is FP1R2,
0.20 <(FP1R2 + FP1R1) / (FP1R2-FP1R1) <5.00
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the curvature radius of the lens surface closest to the object side of the third partial group is FP2R1, and the curvature radius of the lens surface closest to the image side of the third partial group is FP2R2,
0.20 <(FP2R2 + FP2R1) / (FP2R2-FP2R1) <3.00
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. The zoom lens further includes an aperture stop, the distance on the optical axis from the aperture stop to the image plane at the wide-angle end is DSIP, and the distance from the aperture stop at the wide-angle end to the object-side lens surface of the first subgroup When the distance on the optical axis is DSP1,
0.05 <DSP1 / DSIP <0.60
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. The zoom lens further includes an aperture stop, the distance on the optical axis from the aperture stop to the image plane at the wide-angle end is DSIP, and the distance from the aperture stop at the wide-angle end to the object-side lens surface of the second subgroup When the distance on the optical axis is DSN,
0.20 <DSN / DSIP <0.70
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.   The zoom lens according to any one of claims 1 to 16, wherein the first lens unit moves along a locus convex toward the image side during zooming from the wide-angle end to the telephoto end. When the zoom position at which the first lens group is closest to the image side during zooming is the intermediate zoom position, the amount of movement of the first lens group from the wide-angle end to the intermediate zoom position is M1a, and the telephoto from the intermediate zoom position. When the movement amount of the first lens group at the end is M1b,
-0.50 <M1a / M1b <0.00
The zoom lens according to claim 17, wherein the following conditional expression is satisfied.   The zoom lens according to any one of claims 1 to 18, wherein the first lens group includes three lenses. When the refractive index of the material of the lens arranged closest to the object side in the first lens group is G1Nd,
1.920 <G1Nd <2.060
The zoom lens according to claim 1, wherein the following conditional expression is satisfied.   The zoom lens according to any one of claims 1 to 20, wherein the first lens group includes a negative lens, a negative lens, and a positive lens arranged in order from the object side to the image side.   The zoom lens according to any one of claims 1 to 21, wherein the second lens group includes a positive lens, a positive lens, and a negative lens arranged in order from the object side to the image side.   The zoom lens from the wide angle end to the telephoto end, the second lens group, the first partial group, and the second partial group move to the object side. The described zoom lens.   The zoom lens according to any one of claims 1 to 23, wherein the third partial group moves toward the image side during zooming from the wide-angle end to the telephoto end.   An image pickup apparatus comprising: the zoom lens according to claim 1; and an image pickup element that receives an image formed by the zoom lens.