JP4829629B2 - Zoom lens and imaging apparatus having the same - Google Patents

Zoom lens and imaging apparatus having the same Download PDF

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Publication number
JP4829629B2
JP4829629B2 JP2006029724A JP2006029724A JP4829629B2 JP 4829629 B2 JP4829629 B2 JP 4829629B2 JP 2006029724 A JP2006029724 A JP 2006029724A JP 2006029724 A JP2006029724 A JP 2006029724A JP 4829629 B2 JP4829629 B2 JP 4829629B2
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lens
lt
zoom
lens group
wide
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JP2007212537A (en
JP2007212537A5 (en
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友紀 木村
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キヤノン株式会社
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    • GPHYSICS
    • G02OPTICS
    • G02BOPTICAL ELEMENTS, SYSTEMS, OR APPARATUS
    • G02B15/00Optical objectives with means for varying the magnification
    • G02B15/14Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
    • G02B15/16Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
    • G02B15/163Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group
    • G02B15/167Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group having an additional fixed front lens or group of lenses
    • G02B15/173Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group having an additional fixed front lens or group of lenses arranged +-+

Description

  The present invention relates to a zoom lens and an image pickup apparatus having the same, and is suitable for, for example, a video camera, a digital still camera, a silver salt photography camera, and the like.

  In recent years, imaging devices such as a video camera using a solid-state imaging device, a digital still camera, a broadcasting camera, and a camera using a silver salt film have become highly functional, and the entire device has been downsized. As a photographing optical system used therefor, there is a demand for a zoom lens having a short overall lens length, a compact size, and a high resolution.

As a zoom lens that meets these requirements, 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 refraction. Zoom lenses suitable for collapsible lens having four lens groups of the fourth lens group of power are known (Patent Documents 1 to 5).
JP-A-10-62687 JP 2001-194586 A JP 2003-315676 A JP 2004-94233 A JP 2000-347102 A

  In general, in order to reduce the size of the photographing optical system, it is only necessary to reduce the number of lenses while increasing the refractive power of each lens group constituting the photographing optical system. However, in such a photographic optical system, the lens thickness increases, the effect of shortening the lens system becomes insufficient, and correction of various aberrations becomes difficult.

  Further, when the lens groups are retracted and stored when the camera is not used, errors such as the tilting of the lenses and the lens groups inevitably increase due to the mechanical structure. At this time, if the sensitivity of the lens and the lens group is large, the optical performance is deteriorated and the image is shaken during zooming. For this reason, in the photographing optical system, it is desirable to reduce the sensitivity of the lens and the lens group as much as possible.

    The zoom lens disclosed in Patent Document 1 is suitable for a retractable structure because the sensitivity of the first lens group and the second lens group is relatively small.

  However, since the first lens group is fixed during zooming, it is difficult to shorten the total lens length at the wide-angle end or to reduce the front lens diameter.

  The zoom lens disclosed in Patent Document 2 achieves a small size, a large aperture, and high performance by moving the first lens group during zooming.

  In Patent Document 2, the amount of movement of the first lens group accompanying zooming from the wide-angle end to the telephoto end is small. For this reason, it is difficult to reduce the front lens diameter by sufficiently shortening the entrance pupil at the wide-angle end.

  The zoom lens disclosed in Patent Document 3 obtains a zoom ratio of about 5 times by appropriately setting the burden of zooming by the third lens group. In Patent Document 3, in order to realize a higher zoom ratio, it is necessary to share the magnification with the second lens group.

  In the zoom lens disclosed in Patent Document 4, the variation of the entrance pupil is reduced by defining the movement locus associated with the zooming of the fourth lens group, and the front lens diameter is reduced.

  However, when trying to achieve a high zoom ratio in Patent Document 4, the front lens diameter increases and the total lens length increases.

  In the zoom lens shown in Examples 4 to 6 of Patent Document 5, a high zoom of 6 times or more is obtained by appropriately determining the ratio of the combined magnification of the third lens group and the fourth lens group at the wide-angle end and the telephoto end. The ratio is aimed at.

  However, since the number of constituent lenses is large and the change in the distance between the third lens unit and the fourth lens unit is small during zooming, the total lens length tends to be long.

  SUMMARY OF THE INVENTION An object of the present invention is to provide a zoom lens and an image pickup apparatus having the zoom lens that have a good overall optical performance over the entire zoom range from the wide-angle end to the telephoto end while reducing the overall length of the lens.

In the present invention, 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 fourth lens having a positive refractive power The zoom lens is composed of a group, and each lens group moves to perform zooming. During zooming, the third lens group moves so as to be positioned closer to the object side at the telephoto end than at the wide-angle end. During zooming from the wide-angle end to the telephoto end, the first lens group moves along a convex locus on the image side, and the fourth lens group moves along a convex locus on the object side.

Here, at the zoom position Za where the first lens unit is located closest to the image side during zooming, the object side surface vertex of the lens disposed closest to the object side of the first lens unit is closest to the object side of the third lens unit. Let dm be the distance to the surface apex on the object side of the lens arranged at. Also, let fm be the focal length of the entire lens system at the zoom position Za. Further, the amount of movement on the optical axis in zooming from the wide-angle end to the telephoto end of the first lens group is assumed to be X1. Further, the focal lengths at the wide-angle end and the telephoto end of the entire lens system are fw and ft, respectively. The ratio of the imaging magnification at the telephoto end to the imaging magnification at the wide-angle end of the third lens group is β3z. At this time,
2.8 <dm / fm <4.0
1.5 <X1 / fw <3.5
0.3 <β3z / (ft / fw) <0.6
Is satisfied.

  According to the present invention, it is possible to obtain a zoom lens having a good optical performance over the entire zoom range from the wide-angle end to the telephoto end while reducing the overall length of the lens.

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

  The zoom lens of each embodiment 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 refractive power. The fourth lens group.

  Each lens group moves to perform zooming.

  During zooming, the third lens unit moves so as to be positioned closer to the object side at the telephoto end than at the wide-angle end. During zooming from the wide-angle end to the telephoto end, the first lens group moves along a convex locus on the image side, and the fourth lens group moves along a convex locus on the object side.

  Hereinafter, the zoom position where the first lens group is located closest to the image side during zooming is referred to as a first intermediate zoom position.

  The zoom position positioned between the first intermediate zoom position and the telephoto end is referred to as the second intermediate zoom position.

  FIG. 1 is a lens cross-sectional view at the wide-angle end (short focal length) of the zoom lens according to Embodiment 1 of the present invention. 2, 3, 4, and 5 are aberration diagrams of the zoom lens of Example 1 at the wide-angle end, the first intermediate zoom position, the second intermediate zoom position, and the telephoto end (long focal length), respectively.

  FIG. 6 is a lens cross-sectional view at the wide-angle end of the zoom lens according to Embodiment 2 of the present invention. 7, 8, 9, and 10 are aberration diagrams at the wide-angle end, the first intermediate zoom position, the second intermediate zoom position, and the telephoto end, respectively, of the zoom lens according to the second exemplary embodiment.

  FIG. 11 is a lens cross-sectional view at the wide-angle end of the zoom lens according to Embodiment 3 of the present invention. FIGS. 12, 13, 14, and 15 are aberration diagrams of the zoom lens of Example 3 at the wide-angle end, the first intermediate zoom position, the second intermediate zoom position, and the telephoto end, respectively.

  FIG. 16 is a lens cross-sectional view at the wide-angle end of the zoom lens according to Example 4 of the present invention. FIGS. 17, 18, 19, and 20 are aberration diagrams of the zoom lens of Example 4 at the wide-angle end, the first intermediate zoom position, the second intermediate zoom position, and the telephoto end, respectively.

  FIG. 21 is a schematic diagram of a main part of a camera (imaging device) including the zoom lens of the present invention. The zoom lens of each embodiment is a photographing lens system used for an imaging device such as a video camera or a digital camera. In the lens cross-sectional view, the left side is the subject 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.

  In the lens cross-sectional view, L1 is a first lens group having a positive refractive power (optical power = reciprocal of focal length), L2 is a second lens group having a negative refractive power, and L3 is a third lens group having a positive refractive power. , L4 is a fourth lens unit having a positive refractive power.

  SP is an aperture stop, which is disposed on the object side of the third lens unit L3. FP is a flare stop, which is disposed on the image side of the third lens unit L3 and shields unnecessary light.

  G is an optical block corresponding to an optical filter, a face plate, a quartz low-pass filter, an infrared cut filter, or 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. When zooming from the wide-angle end to the telephoto end, each lens group specifically moves as follows.

  The lens unit L1 moves along a locus that is convex on the image side.

  At this time, the first lens unit L1 moves so as to be positioned closer to the object side at the telephoto end than at the wide-angle end.

  The second lens unit L2 moves along a convex locus toward the image side and corrects image plane fluctuations accompanying zooming. The third lens unit L3 moves so as to be located on the object side at the telephoto end compared to the wide-angle end. The fourth lens unit L4 moves along a locus convex toward the object side.

  During zooming, the first lens unit L1 is moved closer to the object side at the telephoto end than at the wide-angle end, so that a large zoom ratio can be obtained while keeping the entire lens length at the wide-angle end small. .

  During zooming, the third lens unit L3 has a large zooming effect by moving the third lens unit L3 so that it is positioned closer to the object side at the telephoto end than at the wide-angle end.

  Further, by moving the first lens unit L1 having a positive refractive power toward the object side, the second lens unit L2 is also provided with a zooming effect. Thereby, a high zoom ratio of 5 times or more is obtained without increasing the refractive power of the first lens unit L1 and the second lens unit L2.

  A rear focus type is employed in which focusing is performed by moving the fourth lens unit L4 on the optical axis.

  When focusing from an infinitely distant object to a close object at the telephoto end, as shown by an arrow 4c in the figure, the fourth lens unit L4 is extended forward. A solid line curve 4a and a dotted line curve 4b of the fourth lens unit L4 are for correcting image plane fluctuations during zooming from the wide-angle end to the telephoto end when focusing on an object at infinity and an object at close distance, respectively. The movement trajectory is shown.

  By moving the lightweight fourth lens unit L4 for focusing, quick focusing, for example, automatic focusing detection is facilitated.

  Image blurring when the entire optical system vibrates is corrected by moving all or part of the third lens unit L3 so as to have a component perpendicular to the optical axis.

  That is, vibration isolation is performed.

  As a result, image stabilization is performed without newly adding an optical member such as a variable apex angle prism or a lens group for image stabilization, and the entire optical system is prevented from being enlarged.

  The aperture stop SP moves together with the third lens unit L3 during zooming, but may move separately or be fixed. When moved together, the number of groups divided by movement / movability is reduced, and the mechanical structure is easily simplified.

  Further, when the lens is moved separately from the third lens unit L3, it is advantageous for reducing the front lens diameter.

  In addition, when the aperture stop SP is fixed, it is not necessary to move the aperture unit, which is advantageous in terms of power saving in that the driving torque of the actuator to be driven can be set small during zooming.

  Since the effective lens diameter of the first lens unit L1 is large, it is preferable that the first lens unit L1 has a small number of lenses.

In each embodiment, the chromatic aberration generated in the first lens unit L1 with a small number of lenses can be obtained by arranging each of the positive lens and the negative lens individually as one cemented lens component (joint lens) or independently. Suppressed.

  The second lens unit L2 is composed of three independent lenses: a negative meniscus lens having a convex object side surface, a negative lens having both concave lens surfaces, and a positive lens having a convex object side surface. Yes.

  This reduces aberration fluctuations during zooming, and particularly corrects distortion aberrations at the wide-angle end and spherical aberrations at the telephoto end.

  The third lens unit L3 is composed of two positive lenses from the object side to the image side, and a negative lens having a concave surface on the image side, and the principal point interval between the second lens unit L2 and the third lens unit L3 is set as follows. It is small. This shortens the lens length after the second lens unit L2.

  The third lens unit L3 has one or more aspherical surfaces. As a result, aberration fluctuations accompanying zooming are corrected satisfactorily.

  The fourth lens unit L4 includes a single positive lens having a convex object-side surface.

  In each embodiment, a lens group including only one lens is also handled.

  With the configuration described above, the zoom lens of each embodiment achieves a compact optical system with a high zoom ratio. Furthermore, the effect corresponding to each conditional expression is obtained so as to satisfy one or more of the following conditional expressions.

  At the first intermediate zoom position (zoom position Za), the object of the lens disposed on the most object side of the third lens unit L3 from the surface apex of the lens disposed on the most object side of the first lens unit L1. Let dm be the distance to the side surface apex.

  Let fm be the focal length of the entire lens system at the first intermediate zoom position.

  The amounts of movement on the optical axis in zooming from the wide-angle end to the telephoto end of the first lens unit L1, the second lens unit L2, and the third lens unit L3 are X1, X2, and X3 in this order.

  However, the moving amount is the maximum moving amount in the optical axis direction when the lens group reciprocates. Let the focal length of the first lens unit L1 be f1.

  The focal lengths at the wide-angle end and the telephoto end of the entire lens system are fw and ft, respectively.

  The ratios of the imaging positions β2t and β3t at the telephoto end with respect to the imaging magnifications (lateral magnifications) β2w and β3w at the wide-angle end of the second lens unit L2 and the third lens unit L3 are β2z and β3z, respectively.

That is,
β2z = β2t / β2w
β3z = β3t / β3w
And

At this time,
2.8 <dm / fm <4.0 (1)
1.5 <X1 / fw <3.5 (2)
0.3 <β3z / (ft / fw) <0.6 (3)
2.0 <X1 / X2 <6.0 (4)
6.0 <f1 / fw <10.0 (5)
2.0 <X3 / fw <2.8 (6)
0.3 <β2z / (ft / fw) <0.4 (7)
One or more of the following conditions are satisfied.

  In each embodiment, by satisfying each conditional expression, an effect corresponding to the conditional expression is obtained.

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

  Conditional expression (1) defines the distance between the first lens unit L1 and the third lens unit L3 at the first intermediate zoom position where the first lens unit L1 is located closest to the image side during zooming. This is related to the downsizing of the front lens diameter.

  In a four-unit zoom lens composed of positive, negative, positive, and positive refractive power lenses from the object side, the front lens effective diameter is generally the maximum at the intermediate zoom position where zooming is performed slightly from the wide-angle end to the telephoto side. Often determined by the luminous flux around the angle of view. For this reason, the first lens unit L1 is once moved to the image side during zooming from the wide-angle end to the telephoto end. This reduces the distance between the front lens (first lens unit) and the aperture stop SP at the first intermediate zoom position and shortens the entrance pupil distance, thereby reducing the front lens diameter.

  If the lower limit of conditional expression (1) is exceeded and the amount of movement of the first lens unit L1 toward the image side becomes too large, it becomes difficult to obtain good optical performance at the first intermediate zoom position.

  In particular, it is difficult to suppress coma aberration at the peripheral angle of view.

  Conversely, when the amount of movement of the first lens unit L1 toward the image side becomes smaller than the upper limit, the entrance pupil distance at the first intermediate zoom position that determines the front lens effective diameter becomes longer and the front lens diameter increases. Not good.

  Conditional expression (2) sets the amount of movement of the first lens unit L1 during zooming. If the amount of movement of the first lens unit L1 becomes too small beyond the lower limit, the distance from the second lens unit L2 cannot be made sufficiently long at the telephoto end, and a sufficient zooming effect is achieved by the second lens unit L2. Harder to get.

  Conversely, if the upper limit is exceeded and the amount of movement during zooming becomes too large, it is difficult to reduce the total lens length.

  Conditional expression (3) relates to the ratio (magnification ratio) of the imaging magnification at the wide-angle end and the telephoto end of the third lens unit L3.

  If the zoom ratio of the third lens unit L3 becomes too small exceeding the lower limit of the conditional expression (3), the zooming burden of the second lens unit L2 becomes large. As a result, it is necessary to increase the amount of movement during zooming of the first lens unit L1 and the second lens unit L2, and the entire length of the lens barrel is increased.

On the other hand, if the upper limit is exceeded, it becomes necessary to increase the refractive power of the third lens unit L3, so that it becomes difficult to correct spherical aberration and coma particularly at the telephoto end.

  Conditional expression (4) relates to the amount of movement of the first and second lens units L1 and L2 during zooming.

  If the lower limit of conditional expression (4) is exceeded and the amount of movement of the first lens unit L1 during zooming becomes too small, it becomes impossible to provide a sufficient distance from the second lens unit L2 at the telephoto end. For this reason, a sufficient zooming effect cannot be obtained with the second lens unit L2.

  Conversely, when the amount of movement of the first lens unit L1 exceeds the upper limit, only the stroke of the first lens unit L1 becomes too large compared to the other lens units. For this reason, in order to shorten the collapsible length, it is inevitable that the collapsible structure is multi-staged, and the lens barrel diameter increases.

  Conditional expression (5) relates to the refractive power of the first lens unit L1.

  If the lower limit of conditional expression (5) is exceeded and the refractive power of the first lens unit L1 becomes too large, it will be difficult to correct spherical aberration and coma particularly at the wide-angle end.

  Further, the curvature of the lens surface of the positive lens of the first lens unit L1 becomes tight, and it is necessary to increase the thickness in order to secure the lens edge thickness, which is not preferable because the front lens becomes large.

  On the contrary, if the refractive power of the first lens unit L1 becomes too small beyond the upper limit, a sufficient zooming effect cannot be obtained in the second lens unit L2, which is not good.

If the amount of movement of the third lens unit L3 during zooming is too small beyond the lower limit of conditional expression (6), it is necessary to increase the refractive power of the third lens unit L3 in order to obtain a sufficient zoom ratio. Come. This makes it difficult to correct spherical aberration and coma particularly at the telephoto end.

  On the contrary, if the upper limit is exceeded, if the amount of movement of the third lens unit L3 becomes too large, the total lens length at the wide-angle end becomes long, so it becomes difficult to shorten the total lens length.

  Conditional expression (7) relates to the ratio (magnification ratio) of the imaging magnification at the wide-angle end and the telephoto end of the second lens unit L2.

  If the zoom ratio of the second lens unit L2 becomes too small beyond the lower limit of the conditional expression (7), the zooming burden of the third lens unit L3 increases. As a result, it is necessary to increase the amount of movement of the third lens unit L3 during zooming, and the entire length of the lens barrel increases. Conversely, when the upper limit is exceeded, it is necessary to increase the amount of movement of the first lens unit L1 and the second lens unit L2, which makes it difficult to reduce the overall length of the lens.

  In order to further reduce the size of the entire lens system while further reducing aberration variations during aberration correction and zooming, it is preferable to set the numerical ranges of conditional expressions (1) to (7) as follows.

3.0 <dm / fm <3.9 (1a)
1.7 <X1 / fw <3.3 (2a)
0.4 <β3z / (ft / fw) <0.6 (3a)
2.0 <X1 / X2 <5.0 (4a)
6.3 <f1 / fw <9.6 (5a)
2.1 <X3 / fw <2.7 (6a)
0.32 <β2z / (ft / fw) <0.38 (7a)
More preferably, if the numerical ranges of the conditional expressions (1a) and (2a) are set as follows, the lens system can be further reduced in size.

3.1 <dm / fm <3.8 (1b)
1.8 <X1 / fw <3.2 (2b)
As described above, according to each embodiment, by appropriately setting the amount of movement of each lens unit and the refractive power of each lens unit during zooming, the total lens length is achieved despite a high zoom ratio of 5 times or more. Downsizing can be achieved.

  In particular, it is possible to obtain a zoom lens having good optical performance over the entire zoom range from the wide-angle end to the telephoto end.

  In each embodiment, another lens unit such as a converter lens may be disposed on the object side of the first lens unit L1, the image side of the fourth lens unit L4, or both.

  Next, numerical examples 1 to 4 corresponding to the first to fourth embodiments of the present invention will be described. In each numerical example, i indicates the order of the optical surfaces from the object side, Ri is the radius of curvature of the i-th optical surface (i-th surface), Di is the distance between the i-th surface and the i + 1-th surface, Ni and νi indicate the refractive index and Abbe number of the material of the i-th optical member with respect to the d-line, respectively.

Further, when k is a conic constant, B, C, D, and E 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 ,
x = (h 2 / R) / [1+ [1− (1 + k) (h / R) 2 ] 1/2 ] + Bh 4 + Ch 6 + Dh 8 + Eh 10
Is displayed. Where R is the radius of curvature.

Also for example, a display of the "E-Z" means "10 -Z". f represents a focal length, Fno represents an F number, and ω represents a half angle of view.

  In the numerical example, the last two surfaces are surfaces constituting the optical block G.

  Table 1 shows the correspondence with the above-described conditional expressions in each numerical example.

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

  In FIG. 21, reference numeral 20 denotes a camera body, and reference numeral 21 denotes a photographing optical system constituted by any of the zoom lenses described in the first to fourth embodiments. 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.

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

Lens cross-sectional view at the wide-angle end of the zoom lens of Example 1 Aberration diagram at the wide-angle end of the zoom lens of Example 1 Aberration diagram at the first intermediate zoom position of the zoom lens of Example 1 Aberration diagram at the second intermediate zoom position of the zoom lens of Example 1 Aberration diagram at the telephoto end of the zoom lens of Example 1 Lens sectional view at the wide-angle end of the zoom lens according to Embodiment 2 Aberration diagram at the wide-angle end of the zoom lens of Example 2 Aberration diagram at the first intermediate zoom position of the zoom lens of Example 2 Aberration diagram at the second intermediate zoom position of the zoom lens of Example 2 Aberration diagram at the telephoto end of the zoom lens of Example 2 Lens sectional view at the wide-angle end of the zoom lens according to Embodiment 3 Aberration diagram at the wide-angle end of the zoom lens of Example 3 Aberration diagram at the first intermediate zoom position of the zoom lens of Example 3 Aberration diagram at the second intermediate zoom position of the zoom lens of Example 3 Aberration diagram at the telephoto end of the zoom lens of Example 3 Lens sectional view at the wide-angle end of the zoom lens according to Embodiment 4 Aberration diagram at the wide-angle end of the zoom lens of Example 4 Aberration diagram at the first intermediate zoom position of the zoom lens of Example 4 Aberration diagram at the second intermediate zoom position of the zoom lens of Example 4 Aberration diagram at the telephoto end of the zoom lens of Example 4 Schematic diagram of imaging device

Explanation of symbols

L1 First lens group L2 Second lens group L3 Third lens group L4 Fourth lens group d d line g g line ΔM meridional image plane ΔS sagittal image plane SP stop FP flare cut stop G CCD force plate, low pass filter, etc. Glass block ω Half angle of view Fno F number

Claims (10)

  1. In order from the object side to an image side, a first lens unit having a positive refractive power, second lens unit having a negative refractive power, a third lens unit having a positive refractive power and a fourth lens unit having a positive refractive power The zoom lens performs zooming by moving each lens group, and the third lens group is moved so as to be positioned closer to the object side at the telephoto end than at the wide-angle end during zooming, and from the wide-angle end to the telephoto end. During zooming, the first lens group moves along a locus that is convex on the image side, and the fourth lens group moves along a locus that is convex on the object side. At the zoom position Za where the lens group is positioned closest to the image side, the lens disposed on the most object side of the third lens group from the surface apex on the object side of the lens disposed closest to the object side of the first lens group. The distance to the surface vertex on the object side is dm, at the zoom position Za The focal length of the entire lens system is fm, the amount of movement on the optical axis in zooming from the wide-angle end to the telephoto end of the first lens group is X1, and the focal lengths at the wide-angle end and the telephoto end of the entire lens system are fw, When the ratio of the imaging magnification at the telephoto end to the imaging magnification at the wide-angle end of the third lens group is β3z,
    2.8 <dm / fm <4.0
    1.5 <X1 / fw <3.5
    0.3 <β3z / (ft / fw) <0.6
    A zoom lens characterized by satisfying the following conditions:
  2. When the movement amounts on the optical axis in zooming from the wide-angle end to the telephoto end of the first and second lens groups are X1 and X2, respectively.
    2.0 <X1 / X2 <6.0
    The zoom lens according to claim 1, wherein the following condition is satisfied.
  3. When the focal length of the first lens group is f1,
    6.0 <f1 / fw <10.0
    The zoom lens according to claim 1 or 2, wherein the following condition is satisfied.
  4. When the amount of movement on the optical axis in zooming from the wide-angle end to the telephoto end of the third lens group is X3,
    2.0 <X3 / fw <2.8
    The zoom lens according to claim 1, wherein the following condition is satisfied.
  5. When the ratio of the imaging magnification at the telephoto end to the imaging magnification at the wide-angle end of the second lens group is β2z,
    0.3 <β2z / (ft / fw) <0.4
    The zoom lens according to claim 1, wherein the following condition is satisfied.
  6.   The zoom lens according to claim 1, wherein the first lens group includes one lens component.
  7.   The zoom lens according to any one of claims 1 to 6, wherein the first lens group includes a cemented lens in which one negative lens and one positive lens are bonded to each other.
  8.   The zoom lens according to any one of claims 1 to 7, wherein the second lens group includes two negative lenses and one positive lens in order from the object side to the image side. .
  9. The zoom lens according to any one of claims 1 8, characterized by forming an image on a solid-state image element.
  10.   An image pickup apparatus comprising: the zoom lens according to claim 1; and a solid-state image pickup device that receives an image formed by the zoom lens.
JP2006029724A 2006-02-07 2006-02-07 Zoom lens and imaging apparatus having the same Expired - Fee Related JP4829629B2 (en)

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JP5349844B2 (en) 2008-06-03 2013-11-20 キヤノン株式会社 Zoom lens and imaging apparatus having the same
JP5344549B2 (en) 2008-08-08 2013-11-20 キヤノン株式会社 Zoom lens and imaging apparatus having the same
JP5328324B2 (en) 2008-12-03 2013-10-30 キヤノン株式会社 Zoom lens and imaging apparatus having the same
US8014079B2 (en) 2009-07-03 2011-09-06 Panasonic Corporation Zoom lens system, imaging device and camera
JP5527577B2 (en) * 2009-08-03 2014-06-18 株式会社ニコン Zoom lens and optical apparatus including the zoom lens
CN102472885B (en) 2009-10-19 2014-06-25 松下电器产业株式会社 Zoom lens system, image-capturing device, and camera
JP2012048033A (en) 2010-08-27 2012-03-08 Hoya Corp High zoom-ratio zoom lens system
JP5935390B2 (en) * 2012-02-29 2016-06-15 株式会社ニコン Variable magnification optical system, optical device
WO2013129487A1 (en) 2012-02-29 2013-09-06 株式会社ニコン Variable-power optical system, optical device, and method for producing variable-power optical system

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JP2001194586A (en) * 2000-01-07 2001-07-19 Canon Inc Zoom lens and photographing device using the same
JP3542552B2 (en) * 2000-09-29 2004-07-14 キヤノン株式会社 Zoom lens and optical device using the same
JP4323796B2 (en) * 2002-12-27 2009-09-02 キヤノン株式会社 Zoom lens and imaging apparatus having the same
CN100368859C (en) * 2003-06-13 2008-02-13 松下电器产业株式会社 Zoom lens, imaging device, and camera having imaging device
JP4624730B2 (en) * 2004-04-30 2011-02-02 オリンパス株式会社 Zoom lens and image pickup apparatus equipped with the same
JP4601328B2 (en) * 2004-05-19 2010-12-22 オリンパス株式会社 Zoom optical system and imaging apparatus using the same
JP4601327B2 (en) * 2004-05-19 2010-12-22 オリンパス株式会社 Zoom optical system and imaging apparatus using the same
JP4605699B2 (en) * 2004-07-08 2011-01-05 オリンパス株式会社 Zoom lens and image pickup apparatus equipped with the same
JP2006023530A (en) * 2004-07-08 2006-01-26 Olympus Corp Zoom lens and imaging apparatus incorporating it
JP4605698B2 (en) * 2004-07-08 2011-01-05 オリンパス株式会社 Zoom lens and image pickup apparatus equipped with the same

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