JP4630578B2 - Zoom lens and imaging apparatus having the same - Google Patents

Description

  The present invention relates to a zoom lens, and is particularly suitable as a photographing optical system such as a video camera, a silver salt photographic camera, and a digital camera.

  When an object is photographed from a moving object such as a car or an aircraft that is in progress, vibrations are transmitted to the photographing system, resulting in camera shake and blurring of the photographed image. For this reason, various anti-vibration optical systems having an anti-vibration function for preventing blurring of captured images have been proposed.

  For example, a detection unit that detects a vibration state is provided in the optical device, and in accordance with an output signal from the detection unit, a part of the optical members of the optical system is moved in a direction that cancels the vibrational displacement of image blur due to vibration. This corrects image blur and stabilizes the image. In addition, in an imaging system in which a variable apex angle prism is arranged closest to the object side, image blur is corrected by changing the prism apex angle of the variable apex angle prism in response to the vibration of the imaging system, thereby stabilizing the image. ing. Further, the vibration of the photographing system is detected by using a detecting means such as an acceleration sensor, and a still image is obtained by vibrating a part of the lens group of the photographing system in a direction perpendicular to the optical axis in accordance with a signal obtained at this time. (Patent Documents 1 and 2).

  On the other hand, as a photographing system, many zoom lenses in which some lens groups are displaced to correct image blur are known.

  In a zoom lens having a four-group configuration including first, second, third, and fourth lens units having positive, negative, positive, and positive refractive powers in order from the object side to the image side, the entire third lens unit is defined as an optical axis. A zoom lens that obtains a still image by vibrating in the vertical direction is known (Patent Document 3).

  The present applicant consists of first, second, third, and fourth lens groups having positive, negative, positive, and positive refractive powers, and 4 having an aperture stop between the second lens group and the third lens group. In a zoom lens having a group configuration, the third lens unit is divided into a lens unit having a negative refractive power and a lens unit having a positive refractive power, and the lens unit having a positive refractive power is vibrated in a direction perpendicular to the optical axis to be stationary. The zoom lens which acquires an image is proposed (for example, patent documents 4-6).

In addition, the applicant of the present invention is a zoom lens having a four-group configuration including first, second, third, and fourth lens groups having positive, negative, positive, and positive refractive powers, and the third lens group is divided into two positive lenses. There has been proposed a zoom lens that is divided into groups and vibrates one of them in a direction perpendicular to the optical axis to obtain a still image (eg, Patent Document 7).
JP-A-1-116619 Japanese Patent Laid-Open No. 2-124521 JP-A-7-199124 Japanese Patent Laid-Open No. 7-128619 JP 11-237550 A JP 2002-244037 A JP 2001-66500 A

  In general, in an imaging system in which some lens groups of the imaging system are decentered in the direction perpendicular to the optical axis for image stabilization, there is an advantage that no extra optical system is required for image stabilization. However, there is a problem that a space for the lens group to be moved is required in the optical path, and decentration aberrations occur during image stabilization.

  In recent years, the 3CCD system has been adopted in some cameras to improve the image quality of consumer video cameras. As a zoom lens compatible with 3CCD, a zoom lens having a four-group structure including a lens group having positive, negative, positive, and positive refractive powers in order from the object side to the image side, a relatively small and light-weight lens that forms part of the zoom lens An image blur is corrected when the lens group is moved in the direction perpendicular to the optical axis to vibrate (tilt) the zoom lens.

  In this method, while reducing the size of the entire apparatus, simplifying the mechanism, and reducing the load on the driving means, it corrects decentration aberrations when the lens group is decentered, and prevents the decentered lens group. A zoom lens having an anti-vibration function can be easily obtained by increasing the sensitivity for vibration and reducing the size of the entire optical system.

  On the other hand, a high resolution frequency is required for an imaging system using the CCD with higher density. In general, when the required resolution frequency is increased, image degradation occurs due to the influence of diffraction when the aperture diameter is reduced or when the aperture diameter is in a shape that is far from a true circle, and this cannot be ignored. Come.

  As a method for solving this, a method of suppressing the influence of diffraction to a minimum by adopting an iris diaphragm or inserting an ND filter in the optical path is employed. In this case, a wide on-axis interval is required for inserting the aperture mechanism and the ND filter into the optical path. However, simply opening the aperture space tends to increase the size of the optical system.

  In recent years, there has been a demand for a photographing apparatus capable of recording a still image in a consumer video camera or the like. For this reason, a photographing system having a mechanical shutter function is required for controlling the amount of light to the CCD.

  The present invention secures sufficient space for inserting an ND filter, iris diaphragm, mechanical shutter, etc. in the optical path while reducing the size and weight of the lens group that adjusts the displacement of the image that occurs when the optical system vibrates. In addition, an object of the present invention is to provide a zoom lens and an imaging apparatus having the zoom lens that are simplified in terms of mechanism.

The zoom lens according to the present invention includes, in order from the object side to the image side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive lens having a positive refractive power. is composed of the fourth lens group, the zoom lens to perform zooming by changing the distances between the lens groups, the third lens group includes, in order from the object side to the image side, the 3a lens unit having a negative refractive power, the aperture It consists of a 3b lens group having a positive aperture and a positive refractive power. The 3a lens group is composed of a negative lens having concave object-side and image-side surfaces and a positive lens having convex object-side and image-side surfaces. The 3b lens group includes, in order from the object side to the image side, a negative meniscus lens having a concave surface on the image side and two positive lenses, and the 3a lens group. spacing of the first 3b lens group, the most widely in the third lens group, before Moving the 3b-th lens group to have a direction perpendicular to the optical axis of the component can Rukoto displaces the image by, all the air space between the third 3b lens group and the third 3a lens group DL, at the wide angle end When the focal length of the system is fW and the total length of the third lens group is DT,
1.1 × fW <DL <2.5 × fW
0.34 <DL / DT <0.43
It is characterized by satisfying the following conditions .

  According to the present invention, a space for inserting an ND filter, an iris diaphragm, a mechanical shutter, and the like in the optical path is achieved while reducing the size and weight of the lens group that adjusts the displacement of an image generated when the optical system vibrates. It is possible to obtain a zoom lens sufficiently secured and simplified in terms of mechanism and an image pickup apparatus having the same.

  Embodiments of a zoom lens and an imaging apparatus according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a lens cross-sectional view at the wide-angle end of the zoom lens according to the first embodiment. FIGS. 2, 3, and 4 are zoom positions at the wide-angle end and the middle when the zoom lens according to the first embodiment is focused on an object at infinity. FIG. 6 is an aberration diagram at the telephoto end.

  5 is a lens cross-sectional view at the wide-angle end of the zoom lens according to the second embodiment. FIGS. 6, 7, and 8 are zoom positions at the wide-angle end and the middle when the zoom lens according to the second embodiment is focused on an infinite object. FIG. 6 is an aberration diagram at the telephoto end.

  FIG. 9 is a lens cross-sectional view at the wide-angle end of the zoom lens according to the third embodiment. FIGS. 10, 11, and 12 are zoom positions at the wide-angle end and the middle when the zoom lens according to the third embodiment is focused on an object at infinity. FIG. 6 is an aberration diagram at the telephoto end.

13 is a lens cross-sectional view at the wide-angle end of the zoom lens of Reference Example 1 of the present invention , and FIGS. 14, 15, and 16 are wide-angle end and intermediate when the zoom lens of Reference Example 1 is focused on an infinite object. FIG. 6 is an aberration diagram at a zoom position at a telephoto end.

FIG. 17 is a lens cross-sectional view at the wide-angle end of the zoom lens according to the fourth embodiment. FIGS. 18, 19, and 20 are zoom positions at the wide-angle end and the middle when the zoom lens according to the fourth embodiment focuses on an object at infinity. FIG. 6 is an aberration diagram at the telephoto end.

  FIG. 21 is a schematic diagram of a main part of a video camera (image pickup apparatus) including the zoom lens according to the present invention.

  In the lens cross-sectional views of FIGS. 1, 5, 9, 13, and 17, L1 is a first lens unit having a positive refractive power (optical power = reciprocal of focal length), and L2 is a first lens unit having a negative refractive power. 2 lens group, L3 is a third lens group having a positive refractive power, and L4 is a fourth lens group having a positive refractive power.

  The third lens unit L3 has a positive refracting power that moves to have a component in the direction perpendicular to the optical axis for anti-vibration (to adjust the displacement of the image). It has a 3b lens unit L3b. Note that the movement for anti-vibration may be rocking (rotational movement) with a certain point on the optical axis as the rotation center. That is, if the anti-vibration 3b lens unit L3b is moved so as to have a component perpendicular to the optical axis, the image can be moved in the plane.

  G is an optical block corresponding to an optical filter, a face plate, or the like. IP is an image plane, and when used as a photographing optical system for a video camera or a digital still camera, when the imaging surface of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor is a silver salt film camera Corresponds to the film surface. SP is an aperture stop, which is provided between the 3a lens unit L3a and the 3b lens unit L3b.

  In the aberration diagrams, d is a d-line, g is a g-line, M is a meridional image plane, S is a sagittal image plane, and lateral chromatic aberration is represented by a g-line.

  In each of the following embodiments, the zoom positions at the wide-angle end and the telephoto end are positioned at both ends of a range in which the lens unit for zooming (the second lens unit L2 in each embodiment) can move on the optical axis on the mechanism. This is the zoom position.

  In each embodiment, during zooming from the wide-angle end to the telephoto end zoom position, the second lens unit L2 is moved to the image side to perform zooming, and the image plane variation caused by zooming is changed to the fourth lens unit L4. The correction is performed by moving the object side while having a part of the convex locus.

  In addition, a rear focus method is employed in which focusing is performed by moving the fourth lens unit L4 on the optical axis. A solid line curve 4a and a dotted line curve 4b of the fourth lens unit L4 indicate image plane fluctuations during zooming from the wide-angle end to the telephoto end zoom position when focusing on an object at infinity and an object at close distance, respectively. This is a movement locus for correction.

  Thus, by making the fourth lens unit L4 convex toward the object side, the space between the third lens unit L3 and the fourth lens unit L4 can be effectively used, and the shortening of the total lens length can be effectively achieved. Has been achieved. The first lens unit L1 and the third lens unit L3 do not move for zooming and focusing.

  In each embodiment, for example, when focusing from an object at infinity to a close object at the zoom position at the telephoto end, the fourth lens unit L4 is moved forward as indicated by an arrow 4c. The first lens unit L1 and the third lens unit L3 do not move for zooming.

  In each embodiment, the third-b lens group (correction lens group) L3b is moved so as to have a component perpendicular to the optical axis so as to correct image blur when the entire optical system vibrates. 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 third lens group L3b is composed of a pair of cemented lenses in which a negative lens and a positive lens are cemented together and one positive lens, and the size of the correcting lens group is minimized so that the size of the correcting lens group can be reduced. And weight reduction. As a result, the actuator for driving the correction lens can be reduced in size, so that the entire apparatus can be reduced in size and power saving during driving can be achieved.

  The zoom lens in each embodiment uses a third lens unit L3 and a fourth lens unit L4 to convert a virtual image of an object formed by the combined system of the first lens unit L1 and the second lens unit L2 onto the photosensitive surface (on the imaging unit surface). ) A zoom method for forming an image on the IP is adopted.

  In each embodiment, as compared with the zoom lens in which the first lens unit is extended and focused, the above-described rear focus method is used to effectively prevent an increase in the effective lens diameter of the first lens unit L1. ing.

  Further, by arranging the aperture stop SP in the optical path with the widest air interval in the lens group of the third lens group L3, aberration variation due to the movable lens group (second and fourth lens groups) can be reduced, and the first lens. By shortening the distance between the group L1 and the aperture stop SP, the front lens diameter (effective system of the first lens group) can be easily reduced.

  In addition, when used as a photographing lens for a 3-CCD video camera, a space for arranging a color separation prism for color separation is required on the image plane side. A long back focus is required compared with a taking lens.

  For this reason, the positive refractive power of the third lens unit L3 is weak with respect to the fourth lens unit L4, and the decentration sensitivity in the direction perpendicular to the optical axis of the third lens unit L3 is reduced. Therefore, if the entire third lens unit L3 is moved in the direction perpendicular to the optical axis direction to perform image stabilization, the amount of movement of the third lens unit L3 becomes too large.

  Therefore, in each embodiment, the third lens unit L3 having a positive refractive power is divided into a third lens unit L3a having a negative refractive power and a third b lens unit L3b having a positive refractive power, and a third lens having a negative refractive power is used. The positive refractive power of the third b lens unit L3b is increased by the amount using the group L3a. As a result, the decentration sensitivity of the third lens group L3b is increased, and an anti-vibration optical system is achieved in which the entire optical system is compact even when used in a 3-CCD video camera.

  In general, in an imaging system aiming at high image quality, the use of an iris diaphragm having a large number of diaphragm blades can improve the blur. In addition, a shutter mechanism for temporarily cutting the amount of light incident on an image sensor such as a CCD is also required when capturing a still image.

Specifically, when the distance between the optical axes between the 3a lens unit L3a and the 3b lens unit Lb is DL, and the focal length of the entire system at the zoom position at the wide angle end is fW, 1.1 × fW <DL <2. .5xfW (1)
The following conditional expression is satisfied.

  By satisfying this conditional expression (1), each embodiment uses the space between the lenses of the third lens unit L3 (between the 3a lens unit L3a and the 3b lens unit L3b) as a space for that purpose. Further, the aperture SP, shutter, ND insertion / removal mechanism and the like are housed in the third lens unit L3, thereby simplifying the lens barrel structure.

More preferably, the numerical range of the conditional expression (1) is 1.4 × fW <DL <2.2 × fW (1a)
It is good to satisfy.

Further, when the air space between the third lens group and the third lens group is DL, and the total length of the third lens group is DT, 0.34 <DL / DT <0.43 (2)
To satisfy the following conditions.

  Accordingly, the lens configuration in the third lens unit L3 can be set appropriately, and the arrangement of optical members such as a diaphragm is facilitated.

More preferably, the numerical range of conditional expression (2) is 0.36 <DL / DT <0.41 (2a)
It is good to do.

  Then, in order to achieve a high optical performance while ensuring a sufficiently long distance before and after the stop SP, the third lens unit L3a includes a negative lens having a concave surface on the object side or a concave surface on the object side and the image side. The object side and image side surfaces are composed of a cemented lens in which convex positive lenses are cemented or two independent lenses, and the third b lens L3b group is arranged in order from the object side to the image side, and the image side surface is concave. It is composed of a meniscus negative lens and two positive lenses.

  As a result, when the divergent light beam from the third-a lens unit L3a is made approximately afocal, good optical performance is maintained while widening the aperture SP space, and fluctuations in decentration aberrations during image stabilization are also well corrected. .

  One or more surfaces of each of the third-a lens unit L3a and the third-b lens unit L3b are aspherical.

  According to this, it becomes easy to reduce various aberrations occurring in each lens group and to suppress deterioration of optical performance during image stabilization.

  In particular, the most image-side lens surface of the 3a lens unit L3a and the convex lens surface of the 3b lens unit L3b are preferably aspherical. According to this, spherical aberration and coma generated in each lens unit are improved. Aberrations are reduced, and it becomes easy to satisfactorily correct decentration aberrations, particularly decentration coma aberration, that occur during image stabilization.

  The position of the non-spherical surface may be different from the position described above.

  The third-b lens unit L3b having a positive refractive power, which is an anti-vibration lens unit, may include one or more negative lenses.

  In order to correct the lateral chromatic aberration when the third lens unit L3b is decentered for image stabilization and the curvature of field due to the decentering, the third lens unit L3b alone corrects chromatic aberration as much as possible. In addition, it is desirable that the Petzval sum is small. Therefore, it is effective for correcting the chromatic aberration and reducing the Petzval sum to include at least one negative lens in the third lens group L3b. Further, in order to reduce the Petzval sum, it is preferable that the refractive index of the material of the negative lens is 1.8 or more.

  At this time, in order to maintain good chromatic aberration of the entire system, it is preferable to have at least one positive lens in the third a lens unit L3a other than the third b lens unit L3b.

  The second lens unit L2, in order from the object side to the image side, is a negative meniscus lens having a concave image side surface, a negative lens having a concave surface on the object side, and a positive lens having convex surfaces on the object side and the image side. It is preferable that the lens and the object-side and image-side surfaces are concave lenses.

  According to this, it becomes easy to satisfactorily correct lateral chromatic aberration over the entire zooming range.

  The fourth lens unit L4 is preferably composed of one or more negative lenses and two positive lenses, and one or more surfaces are preferably aspherical.

  According to this, when applied to a 3CCD camera, when the back focus is extended, the refractive power of the fourth lens unit L4 increases and the height of the axial ray passing through the fourth lens unit L4 increases. Thus, it is easy to satisfactorily correct the occurrence of spherical aberration.

  The fourth lens unit L4 includes a positive lens having a convex surface on the object side and the image side, a negative lens having a convex meniscus shape on the object side, and a positive lens having a convex surface on the object side and the image side. Is good for aberration correction.

  In each embodiment, as described above, by setting each element, the relatively small and light lens group L3b constituting a part of the zoom lens is moved so as to have a component perpendicular to the optical axis. In order to insert an ND filter, iris diaphragm, mechanical shutter, etc. for light quantity control into the optical path while having an image stabilization function that can correct (adjust) image blur when the zoom lens vibrates A sufficient amount of space is secured and the mechanism is simplified. Further, by setting the third lens unit L3 to an appropriate power arrangement, the exit pupil position can be secured at a length of 100 mm or more, and a zoom lens that can sufficiently cope with an imaging device using a CCD is achieved.

Next, numerical data of Numerical Examples 1 to 5 respectively corresponding to Examples 1 to 3, Reference Example 1, and Example 4 are shown. 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), and Di is between the i-th surface and the (i + 1) -th surface. , Ni and νi respectively indicate the refractive index and Abbe number of the i-th optical member with respect to the d-line. f is a focal length, Fno is an F number, and ω is a half angle of view.

  In each of Numerical Examples 1 and 5, seven surfaces closest to the image side, five surfaces closest to the image side in Numerical Example 2, and six surfaces closest to the image side in Numerical Examples 3 and 4 are color separation prisms. This is a surface constituting a glass block G corresponding to a face plate, various filters and the like.

Further, when k is a conic constant, B, C, D, and E are aspherical coefficients, respectively, and the displacement in the optical axis direction at the position of the height H from the optical axis is X with respect to the surface vertex, the aspherical shape Is

Is displayed. Where R is the paraxial radius of curvature. For example, “e-Z” means “10 ^−Z ”. Table 1 shows the correspondence with the above-described conditional expressions in each numerical example.

Numerical example 1

f = 4.51 to 50.48 Fno = 1.65 to 1.95 2ω = 70.7 ° to 7.2 °
R 1 = 822.890 D 1 = 3.00 N 1 = 1.65844 ν 1 = 50.9
R 2 = 57.792 D 2 = 20.35
R 3 = 93.476 D 3 = 8.18 N 2 = 1.51633 ν 2 = 64.1
R 4 = -139.363 D 4 = 1.50
R 5 = 69.540 D 5 = 1.76 N 3 = 1.84666 ν 3 = 23.9
R 6 = 39.272 D 6 = 10.02 N 4 = 1.48749 ν 4 = 70.2
R 7 = -438.344 D 7 = 0.25
R 8 = 37.114 D 8 = 7.22 N 5 = 1.69680 ν 5 = 55.5
R 9 = 209.209 D 9 = Variable
R10 = 200.560 D10 = 1.00 N 6 = 1.88300 ν 6 = 40.8
R11 = 8.991 D11 = 3.63
R12 = -42.912 D12 = 0.90 N 7 = 1.88300 ν 7 = 40.8
R13 = 67.644 D13 = 0.44
R14 = 16.001 D14 = 3.90 N 8 = 1.84666 ν 8 = 23.9
R15 = -41.123 D15 = 0.90 N 9 = 1.77250 ν 9 = 49.6
R16 = 28.679 D16 = variable
R17 = -14.783 D17 = 0.90 N10 = 1.77250 ν10 = 49.6
R18 = 30.123 D18 = 4.50 N11 = 1.69895 ν11 = 30.1
R19 = -21.243 D19 = 7.00
R20 = Aperture D20 = 1.50
R21 = 110.389 D21 = 1.20 N12 = 1.80518 ν12 = 25.4
R22 = 37.919 D22 = 3.75 N13 = 1.58313 ν13 = 59.4
* R23 = -44.470 D23 = 0.15
R24 = 103.541 D24 = 2.40 N14 = 1.48749 ν14 = 70.2
R25 = -113.482 D25 = variable
* R26 = 27.502 D26 = 3.80 N15 = 1.58313 ν15 = 59.4
R27 = -59.571 D27 = 0.20
R28 = 83.356 D28 = 0.90 N16 = 1.84666 ν16 = 23.9
R29 = 21.414 D29 = 4.70 N17 = 1.48749 ν17 = 70.2
R30 = -57.843 D30 = 4.14
R31 = ∞ D31 = 1.00 N18 = 1.52000 ν18 = 64.0
R32 = ∞ D32 = 0.00
R33 = ∞ D33 = 1.36 N19 = 1.55000 ν19 = 64.0
R34 = ∞ D34 = 0.50
R35 = ∞ D35 = 21.00 N20 = 1.52000 ν20 = 64.0
R36 = ∞ D36 = 0.70 N21 = 1.55000 ν21 = 60.0
R37 = ∞

\ Focal length 4.51 13.12 50.48
Variable interval \
D 9 1.22 18.44 29.92
D16 33.60 16.38 4.90
D25 12.14 9.85 12.75

* Indicates an aspheric surface, and the aspheric coefficient is
R23 k = -4.9040 B = -5.44038e-04 C = 3.71831e-05 D = 0.0 E = 0.0
R26 k = -2.9022 B = 2.34392e-04 C = -2.04772e-05 D = 2.25500e-06 E = -1.16811e-07

Numerical example 2
f = 5.07 to 100.98 Fno = 1.65 to 1.97 2ω = 64.5 ° to 3.6 °
R 1 = 88.779 D 1 = 2.80 N 1 = 1.84666 ν 1 = 23.9
R 2 = 54.271 D 2 = 2.80
R 3 = 81.181 D 3 = 9.50 N 2 = 1.43387 ν 2 = 95.1
R 4 = -175.805 D 4 = 0.25
R 5 = 41.749 D 5 = 8.80 N 3 = 1.60311 ν 3 = 60.6
R 6 = 255.887 D 6 = variable
R 7 = 71.606 D 7 = 1.10 N 4 = 1.88300 ν 4 = 40.8
R 8 = 9.706 D 8 = 4.80
R 9 = -33.980 D 9 = 1.00 N 5 = 1.88300 ν 5 = 40.8
R10 = 108.117 D10 = 0.70
R11 = 20.608 D11 = 4.20 N 6 = 1.84666 ν 6 = 23.9
R12 = -52.272 D12 = 0.90 N 7 = 1.77250 ν 7 = 49.6
R13 = 50.374 D13 = variable
R14 = -27.907 D14 = 0.90 N 8 = 1.77250 ν 8 = 49.6
R15 = 29.634 D15 = 4.00 N 9 = 1.69895 ν 9 = 30.1
R16 = -41.906 D16 = 7.00
R17 = Aperture D17 = 1.98
R18 = 81.781 D18 = 1.20 N10 = 1.80518 ν10 = 25.4
R19 = 27.378 D19 = 5.50 N11 = 1.58313 ν11 = 59.4
* R20 = -68.445 D20 = 0.15
R21 = 66.065 D21 = 3.50 N12 = 1.48749 ν12 = 70.2
R22 = -81.266 D22 = variable
* R23 = 35.362 D23 = 3.70 N13 = 1.58313 ν13 = 59.4
R24 = -87.646 D24 = 1.35
R25 = 56.308 D25 = 1.10 N14 = 1.84666 ν14 = 23.9
R26 = 24.220 D26 = 4.50 N15 = 1.51633 ν15 = 64.1
R27 = -187.715 D27 = 4.00
R28 = ∞ D28 = 1.30 N16 = 1.55000 ν16 = 60.0
R29 = ∞ D29 = 2.00 N17 = 1.52000 ν17 = 69.0
R30 = ∞ D30 = 20.00 N18 = 1.58913 ν18 = 61.0
R31 = ∞ D31 = 1.00 N19 = 1.52000 ν19 = 64.0
R32 = ∞

\ Focal length 5.07 17.09 100.98
Variable interval \
D 6 1.14 29.70 48.74
D13 52.88 24.32 5.28
D22 19.03 15.41 19.84

* Indicates an aspheric surface, and the aspheric coefficient is
R20 k = 1.3831 B = 1.85431e-04 C = -1.22227e-05 D = 0.0 E = 0.0
R23 k = -1.7894 B = -8.81701e-05 C = -8.32135e-06 D = 0.0 E = 0.0

Numerical example 3
f = 4.15-47.99 Fno = 1.65-1.95 2ω = 75.3 °-7.6 °
R 1 = 822.890 D 1 = 3.00 N 1 = 1.65844 ν 1 = 50.9
R 2 = 59.873 D 2 = 23.23
R 3 = 98.566 D 3 = 8.07 N 2 = 1.51633 ν 2 = 64.1
R 4 = -152.955 D 4 = 1.50
R 5 = 61.578 D 5 = 1.76 N 3 = 1.84666 ν 3 = 23.9
R 6 = 36.004 D 6 = 9.25 N 4 = 1.48749 ν 4 = 70.2
R 7 = -903.961 D 7 = 0.25
R 8 = 35.597 D 8 = 6.20 N 5 = 1.69680 ν 5 = 55.5
R 9 = 188.576 D 9 = variable
R10 = 128.267 D10 = 1.00 N 6 = 1.88300 ν 6 = 40.8
R11 = 8.759 D11 = 4.09
R12 = -33.581 D12 = 0.90 N 7 = 1.88300 ν 7 = 40.8
R13 = 74.512 D13 = 0.44
R14 = 18.309 D14 = 3.90 N 8 = 1.84666 ν 8 = 23.9
R15 = -27.722 D15 = 0.90 N 9 = 1.77250 ν 9 = 49.6
R16 = 47.644 D16 = variable
R17 = -18.306 D17 = 0.90 N10 = 1.77250 ν10 = 49.6
R18 = 22.108 D18 = 4.50 N11 = 1.69895 ν11 = 30.1
R19 = -26.555 D19 = 1.00
R20 = Aperture D20 = 7.20
R21 = 102.153 D21 = 1.20 N12 = 1.80518 ν12 = 25.4
R22 = 32.290 D22 = 4.50 N13 = 1.58313 ν13 = 59.4
* R23 = -53.663 D23 = 0.15
R24 = 82.507 D24 = 3.00 N14 = 1.48749 ν14 = 70.2
R25 = -82.507 D25 = variable
* R26 = 25.947 D26 = 3.50 N15 = 1.58313 ν15 = 59.4
R27 = -110.664 D27 = 0.20
R28 = 35.366 D28 = 0.90 N16 = 1.84666 ν16 = 23.9
R29 = 16.126 D29 = 4.70 N17 = 1.48749 ν17 = 70.2
R30 = -78.072 D30 = 3.95
R31 = ∞ D31 = 0.43 N18 = 1.52000 ν18 = 64.0
R32 = ∞ D32 = 1.86 N19 = 1.55000 ν19 = 63.0
R33 = ∞ D33 = 1.00
R34 = ∞ D34 = 21.00 N20 = 1.52000 ν20 = 64.0
R35 = ∞ D35 = 0.70 N21 = 1.55000 ν21 = 59.0
R36 = ∞

\ Focal length 4.15 12.24 47.99
Variable interval \
D 9 1.06 18.32 29.82
D16 32.55 15.29 3.78
D25 11.91 10.04 13.15

* Indicates an aspheric surface, and the aspheric coefficient is
R23 k = -3.5400 B = -9.76098e-05 C = 8.21658e-07 D = 0.0 E = 0.0
R26 k = -0.1069 B = -6.07681e-04 C = -2.06091e-05 D = 2.27537e-06 E = -1.18169e-07

Numerical example 4
f = 4.15-48.89 Fno = 1.67-1.95 2ω = 75.3 °-7.5 °
R 1 = 633.105 D 1 = 3.00 N 1 = 1.65844 ν 1 = 50.9
R 2 = 58.632 D 2 = 19.90
R 3 = 118.507 D 3 = 6.80 N 2 = 1.51633 ν 2 = 64.1
R 4 = -130.457 D 4 = 1.50
R 5 = 55.362 D 5 = 1.76 N 3 = 1.84666 ν 3 = 23.9
R 6 = 33.744 D 6 = 8.50 N 4 = 1.48749 ν 4 = 70.2
R 7 = 1148.002 D 7 = 0.25
R 8 = 35.332 D 8 = 6.30 N 5 = 1.69680 ν 5 = 55.5
R 9 = 237.585 D 9 = variable
R10 = 70.424 D10 = 1.00 N 6 = 1.88300 ν 6 = 40.8
R11 = 7.870 D11 = 3.90
R12 = -25.097 D12 = 0.90 N 7 = 1.88300 ν 7 = 40.8
R13 = 63.711 D13 = 0.44
R14 = 18.279 D14 = 3.90 N 8 = 1.84666 ν 8 = 23.9
R15 = -27.134 D15 = 0.90 N 9 = 1.77250 ν 9 = 49.6
R16 = 148.026 D16 = variable
R17 = -26.420 D17 = 0.90 N10 = 1.69680 ν10 = 55.5
R18 = 16.735 D18 = 3.10 N11 = 1.68893 ν11 = 31.1
* R19 = -43.070 D19 = 1.00
R20 = Aperture D20 = 7.20
* R21 = 20.090 D21 = 3.50 N12 = 1.58913 ν12 = 61.3
R22 = 105.342 D22 = 1.00 N13 = 1.80518 ν13 = 25.4
R23 = 25.853 D23 = 2.00
R24 = -78.674 D24 = 3.50 N14 = 1.48749 ν14 = 70.2
R25 = -28.185 D25 = variable
* R26 = 23.688 D26 = 3.50 N15 = 1.58313 ν15 = 59.4
R27 = -66.288 D27 = 0.20
R28 = 28.300 D28 = 0.90 N16 = 1.84666 ν16 = 23.9
R29 = 15.107 D29 = 4.70 N17 = 1.48749 ν17 = 70.2
R30 = -78.353 D30 = 3.95
R31 = ∞ D31 = 0.43 N18 = 1.51633 ν18 = 64.2
R32 = ∞ D32 = 1.36 N19 = 1.55232 ν19 = 63.4
R33 = ∞ D33 = 1.00
R34 = ∞ D34 = 21.00 N20 = 1.51633 ν20 = 64.2
R35 = ∞ D35 = 0.70 N21 = 1.55671 ν21 = 58.6
R36 = ∞

\ Focal length 4.15 12.54 48.89
Variable interval \
D 9 1.06 18.32 29.82
D16 32.27 15.01 3.50
D25 7.61 5.62 8.93

* Indicates an aspheric surface, and the aspheric coefficient is
R19 k = -83.0533 B = -9.29815e-03 C = 3.10399e-03 D = -4.86106e-04 E = 0.0
R21 k = -0.9806 B = -4.84116e-04 C = 3.81514e-04 D = -4.94727e-05 E = 0.0
R26 k = -0.4882 B = -6.57830e-04 C = -4.80325e-05 D = 7.43907e-06 E = -5.41951e-07


Numerical example 5
f = 4.43 to 48.49 Fno = 1.65 to 1.95 2ω = 71.7 ° to 7.5 °
R 1 = -1074.538 D 1 = 2.00 N 1 = 1.84666 ν 1 = 23.9
R 2 = 76.294 D 2 = 14.37 N 2 = 1.63854 ν 2 = 55.4
R 3 = -157.324 D 3 = 0.30
R 4 = 97.509 D 4 = 5.67 N 3 = 1.63854 ν 3 = 55.4
R 5 = 484.397 D 5 = 0.20
R 6 = 46.928 D 6 = 7.64 N 4 = 1.77250 ν 4 = 49.6
R 7 = 124.924 D 7 = Variable
R 8 = 119.991 D 8 = 1.00 N 5 = 1.88300 ν 5 = 40.8
R 9 = 10.524 D 9 = 6.48
R10 = -27.999 D10 = 0.90 N 6 = 1.88300 ν 6 = 40.8
R11 = -158.469 D11 = 0.44
R12 = 20.700 D12 = 6.60 N 7 = 1.84666 ν 7 = 23.9
R13 = -18.931 D13 = 0.90 N 8 = 1.77250 ν 8 = 49.6
R14 = 25.201 D14 = variable
R15 = -15.072 D15 = 0.90 N 9 = 1.77250 ν 9 = 49.6
R16 = 20.781 D16 = 4.50 N10 = 1.69895 ν10 = 30.1
R17 = -21.216 D17 = 7.00
R18 = Aperture D18 = 1.50
R19 = 291.276 D19 = 1.20 N11 = 1.80518 ν11 = 25.4
R20 = 29.390 D20 = 3.75 N12 = 1.58313 ν12 = 59.4
* R21 = -48.998 D21 = 0.15
R22 = 93.796 D22 = 2.40 N13 = 1.48749 ν13 = 70.2
R23 = -60.653 D23 = variable
* R24 = 31.483 D24 = 3.80 N14 = 1.58313 ν14 = 59.4
R25 = -56.156 D25 = 0.20
R26 = 72.538 D26 = 0.90 N15 = 1.84666 ν15 = 23.9
R27 = 24.839 D27 = 4.70 N16 = 1.48749 ν16 = 70.2
R28 = -62.010 D28 = 3.70
R29 = ∞ D29 = 1.00 N17 = 1.52000 ν17 = 64.0
R30 = ∞ D30 = 1.00
R31 = ∞ D31 = 1.36 N18 = 1.55000 ν18 = 63.0
R32 = ∞ D32 = 0.50
R33 = ∞ D33 = 21.00 N19 = 1.52000 ν19 = 64.0
R34 = ∞ D34 = 0.70 N20 = 1.55000 ν20 = 58.0
R35 = ∞

\ Focal length 4.43 12.87 48.49
Variable interval \
D 7 1.17 22.17 36.17
D14 42.67 22.67 7.67
D23 12.72 10.63 11.07

* Indicates an aspheric surface, and the aspheric coefficient is
R21 k = -5.0131 B = -5.77223e-04 C = 6.07070e-06 D = 0.0 E = 0.0
R24 k = -2.9167 B = -2.87701e-05 C = -1.07167e-05 D = 9.10871e-07 E = -3.64174e-08

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

  In FIG. 21, 10 is a video camera body, 11 is a photographing optical system constituted by the zoom lens of the present invention, 12 is a solid-state imaging device (photoelectric conversion) such as a CCD sensor or a CMOS sensor that receives a subject image by the photographing optical system 11. (Elements) and 13 are memories for recording a subject image received by the image sensor 12, and 14 is a viewfinder for observing the subject image displayed on a display element (not shown). The display element is constituted by a liquid crystal panel or the like, and a subject image formed on the image sensor 12 is displayed.

  In this way, by applying the zoom lens of the present invention to an imaging apparatus such as a video camera, it is possible to realize a small and high optical performance optical device with little ghost and flare.

Cross-sectional view of the zoom lens of Embodiment 1 at the wide-angle end Aberration diagram at the wide-angle end of the zoom lens according to Embodiment 1 Aberration diagram at the intermediate zoom position of the zoom lens of Embodiment 1 Aberration diagram at the telephoto end of the zoom lens according to Embodiment 1 Cross-sectional view of the zoom lens of Embodiment 2 at the wide-angle end Aberration diagram at the wide-angle end of the zoom lens according to Embodiment 2 Aberration diagram at the intermediate zoom position of the zoom lens according to Embodiment 2 Aberration diagram at the telephoto end of the zoom lens according to Embodiment 2 Cross-sectional view of the zoom lens of Embodiment 3 at the wide-angle end Aberration diagram at the wide-angle end of the zoom lens according to Embodiment 3 Aberration diagram at the intermediate zoom position of the zoom lens according to Embodiment 3 Aberration diagrams at the telephoto end of the zoom lens according to Embodiment 3 Cross-sectional view of the wide-angle end of the zoom lens of Reference Example 1 Aberration diagram at the wide-angle end of the zoom lens of Reference Example 1 Aberration diagram at the intermediate zoom position of the zoom lens of Reference Example 1 Aberration diagram at the telephoto end of the zoom lens of Reference Example 1 Cross-sectional view of the zoom lens of Embodiment 4 at the wide-angle end Aberration diagrams at the wide-angle end of the zoom lens according to Embodiment 4 Aberration diagram at the intermediate zoom position of the zoom lens according to Embodiment 4 Aberration diagrams at the telephoto end of the zoom lens according to Embodiment 4 Schematic diagram of main parts of video camera

Explanation of symbols

L1 1st lens group L2 2nd lens group L3 3rd lens group L3a 3a lens group L3b 3b lens group L4 4th lens group d d line g g line M meridional image plane S sagittal image plane SP aperture IP imaging plane G Glass block ω Half angle of view fno F number

Claims (3)

In order from the object side to the image side, the lens unit includes a first lens unit having a positive refractive power, a second lens unit having a negative refractive power, a third lens unit having a positive refractive power, and a fourth lens group having a positive refractive power. in the zoom lens to perform zooming by changing the distances between the lens groups, the third lens group includes, in order from the object side to the image side, the 3a lens unit having a negative refractive power, an aperture stop, a positive refractive power The third lens group is composed of a cemented lens obtained by cementing a negative lens having a concave surface on the object side and the image side and a positive lens having a convex surface on the object side and the image side. the 3b-th lens group includes, in order from the object side to the image side, the image side surface is composed of a negative lens and two positive lenses of meniscus shape concave shape, wherein the first 3a lens group 3b-th lens group spacing is the most widely in the third lens group, and the optical axis of the second 3b lens group Is moved to have a perpendicular direction component can Rukoto displaces the image by the air gap DL between the first 3a lens group and the third 3b lens group, the focal length of the entire system at the wide-angle end fW, the When the total length of the third lens group is DT,
1.1 × fW <DL <2.5 × fW
0.34 <DL / DT <0.43
A zoom lens characterized by satisfying the following conditions: The zoom lens according to claim 1 , wherein an image is formed on a solid-state image sensor. Imaging apparatus characterized by comprising: a claim 1 or 2 of the zoom lens, and a solid-state imaging device for receiving an image formed by the zoom lens.

Images