JP4677210B2 - Zoom lens and image pickup apparatus using the same - Google Patents

Description

  The present invention relates to a zoom lens, and in particular, by moving a part of a lens group constituting the zoom lens so as to have a component in a direction perpendicular to the optical axis, an image blur is optically corrected to obtain a still image. In addition, the present invention relates to a zoom lens that stabilizes a captured image.

  If an attempt is made to shoot from a moving object such as an ongoing car or aircraft, vibrations are transmitted to the photographic system, causing camera shake and blurring of the captured image. Conventionally, various anti-vibration optical systems have been proposed that have a function of preventing blurring of a photographed image at this time by decentering a part of a lens group of the photographing system in parallel.

  For example, in Patent Document 1, image stabilization is achieved by moving some optical members in a direction that cancels the vibrational displacement of an image due to vibration in accordance with an output signal from a detection unit that detects a vibration state in the optical device. I am trying. In Patent Document 2, in an imaging system in which a variable apex angle prism is arranged on the most object side, the apex angle of the variable apex angle prism is changed in accordance with vibrations of the imaging system to stabilize the image.

  In Patent Document 3 and Patent Document 4, vibration of the photographing system is detected using an acceleration sensor or the like, and a part of the lens group of the photographing system is vibrated in a direction perpendicular to the optical axis according to a signal obtained at this time. As a result, a still image is obtained.

  In Patent Document 5, a first lens group having a fixed positive refractive power, a second lens group having a negative refractive power having a variable power function, an aperture stop, and positive refraction in order from the object side upon zooming and focusing. A variable power optical system having four lens groups of a fourth lens group having a positive refractive power and both a correction function for correcting an image plane fluctuating due to zooming and a focusing function. The third lens group is composed of two lens groups, ie, a 31st group having a negative refractive power and a 32nd group having a positive refractive power. It corrects the blurring of the captured image when the double optical system vibrates.

  In Patent Document 6, the entire third lens unit of the variable magnification optical system having a four-group configuration including positive, negative, positive, and positive refractive power lens units is vibrated to prevent vibration.

  On the other hand, in Patent Document 7, the third lens group having a four-group structure including positive, negative, positive, and positive refractive power lens groups is used as a telephoto type of a positive lens and a meniscus negative lens to shorten the entire lens length. ing. Further, the present applicant has disclosed a zoom lens that performs vibration isolation by vibrating the entire third group in a four-group configuration including lens groups having positive, negative, positive, and positive refractive powers in Patent Document 8. . In this configuration, the first lens group has a three-lens configuration including a cemented lens including a negative lens and a positive lens in order from the object side, and a meniscus positive lens having a convex surface facing the object side.

  Further, in Patent Document 9, in a four-group configuration including positive, negative, positive, and positive refractive lens groups, the first lens unit is a cemented lens including a negative lens and a positive lens in order from the object side, and a convex surface on the object side. Discloses a zoom lens which has a four-lens structure composed of two positive meniscus lenses facing each other, and vibrates the entire third lens unit for vibration isolation.

Further, in Patent Document 10 and Patent Document 11, a part of the third lens group in the variable power optical system having a four-group structure including positive, negative, positive, and positive refractive power lens groups is vibrated. We have proposed a variable magnification optical system that simultaneously realizes miniaturization and high image quality of a CCD-compatible optical system.
JP 58-21133 A JP-A-61-223819 JP-A-1-116619 Japanese Patent Laid-Open No. 2-124521 Japanese Patent Laid-Open No. 7-128619 JP-A-7-199124 Japanese Patent Laid-Open No. 5-80974 JP 2001-42213 A JP 2002-169087 A JP 11-237550 A JP 2002-244037 A

  In general, in an optical system that performs image stabilization by decentering a part of a lens of a photographing system in a direction perpendicular to the optical axis, 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 to be moved is required, and the amount of decentration aberrations generated during vibration isolation increases.

  In recent years, a 3CCD system using three CCDs (Charge Coupled Devices) for each color as an image sensor has been adopted in some cameras in order to improve image quality in consumer video cameras. In a variable power optical system having a four-group structure including positive, negative, positive, and positive refractive power lenses compatible with 3CCD, a relatively small and lightweight lens group constituting a part of the variable power optical system is perpendicular to the optical axis. If it is configured to correct the image blur when the zooming optical system is vibrated (tilted) by moving in the direction, the overall size of the apparatus can be reduced, the mechanism can be simplified, and the load on the driving means can be reduced. The image stabilization function which corrects the decentration aberration when the lens unit is decentered and increases the sensitivity for the image stabilization of the decentering lens unit to reduce the size of the entire optical system. It is possible to provide a variable magnification optical system.

  On the other hand, a high resolution frequency is required for a photographing system as the density of a CCD increases. In general, when the required resolution frequency is increased, image degradation due to diffraction cannot be ignored when the aperture diameter is reduced or when the aperture diameter is in the aperture opening state far from the true circle.

  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, consumer video cameras and the like have increased the number of photographing apparatuses capable of recording a still image, and therefore, a lens having a mechanical shutter function for the lens is required for controlling the amount of light to the CCD.

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, a zoom lens in which the second lens group and the fourth lens group hand moves during zooming, the first lens group comprises, in order from the object side to the image side, a negative lens and a positive lens Ri Do a cemented lens and two positive lenses, DF spacing on the optical axis from the most object side surface of the first lens group to the surface on the most image side, the focal length of the entire system at the wide angle end and fw When
4.472 ≦ DF / fw <5.0
It satisfies the following conditional expression.

Particularly in the first invention, the third lens group comprises, in order from the object side to the image side, the surface closest to the object side and the 3b lens unit having a negative refractive power. 3a lens group and positive refractive power of the concave shape The third lens group is moved so as to have a component perpendicular to the optical axis to change the position of the image formed by the zoom lens , and has a diaphragm unit on the object side of the third lens group. It is said.

In the zoom lens according to the second aspect of the invention, the third lens group includes, in order from the object side to the image side, a 3a lens group having a negative refractive power and a 3b lens group having a positive refractive power. When the distance on the optical axis between the group and the aperture stop is D, and the combined focal length at the wide angle end of the third lens group and the fourth lens group is f34,
0.1 × f34 <D <0.6 × f34
It is characterized by satisfying the following conditions.

In the third invention, the third lens group comprises, in order from the object side to the image side, and the most object side first 3a lens group faces the negative refractive power of the concave shape of the second 3b lens unit having a positive refractive power consists, 3b-th lens group includes, in order from the object side to the image side, one positive lens, meniscus lens having negative refractive power of the image side concave surface, is characterized in that it consists of one positive lens.

  According to the present invention, it is possible to achieve a zoom lens capable of maintaining high image quality while reducing the size of the entire optical system.

  Embodiments of a zoom lens and an imaging apparatus of the present invention will be described with reference to the drawings. The zoom lens disclosed in this embodiment has an anti-vibration function capable of correcting image blurring, but also includes an ND filter, iris diaphragm, mechanical shutter, and the like (aperture device) for controlling the amount of light in the optical path. The space for insertion should be secured, the mechanism can be simplified, and the appropriate power placement should ensure the proper exit pupil length while arranging the color separation prism, etc. Disclosed is a large-diameter, high-performance zoom lens that can secure a large amount of back focus.

  1 to 4 are lens cross-sectional views of zoom lenses according to Numerical Examples 1 to 4 described later.

  FIG. 5 is an aberration diagram at the wide-angle end, the intermediate zoom position, and the telephoto end when the zoom lens of Numerical Example 1 is focused on an object at infinity. FIG. 6 is an aberration diagram at the wide-angle end, the intermediate zoom position, and the telephoto end when the zoom lens of Numerical Example 2 is focused on an object at infinity. FIG. 7 is an aberration diagram at the wide-angle end, the intermediate zoom position, and the telephoto end when the zoom lens of Numerical Example 3 is focused on an object at infinity. FIG. 8 is an aberration diagram at the wide-angle end, the intermediate zoom position, and the telephoto end when the zoom lens of Numerical Example 4 is focused on an object at infinity.

  1-4, L1 is a first lens unit having a positive refractive power, L2 is a second lens unit having a negative refractive power, L3 is a third lens unit having a positive refractive power, and L4 is a positive lens unit. This is a fourth lens unit having a refractive power of. The third lens unit L3 includes a third lens unit L3a having a negative refractive power and a third lens unit L3b having a positive refractive power.

  In the present embodiment, the blur of the photographed image when the entire optical system vibrates (tilts) is corrected by moving the third lens group L3b so as to have a component perpendicular to the optical axis.

  SP is an aperture stop, and FP is a flare cut stop, which is located between the second lens unit L2 and the third lens unit L3. G is a glass block designed in correspondence with the face plate, filter, color separation means, and the like. IP is an image plane, on which an imaging plane of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor is arranged.

  During zooming from the wide-angle end to the telephoto end, the second lens unit L2 is moved to the image side as shown by the arrow in each lens cross-sectional view to perform zooming, and the image plane fluctuation accompanying zooming is changed to the fourth lens. The group L4 is moved and corrected while having a part of the convex locus on the object side.

  In addition, a rear focus method is employed in which the fourth lens unit L4 is moved on the optical axis for focusing. The solid curve 4a and the dashed curve 4b of the fourth lens unit L4 shown in the lens cross-sectional view are the image planes 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. It is a movement locus for correcting the fluctuation. Thus, by making the fourth lens unit L4 a locus 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 entire lens length can be shortened effectively. Has been achieved.

  In each embodiment, for example, focusing from an infinitely distant object to a close object at the telephoto end is performed by extending the fourth lens unit L4 forward as indicated by a straight line 4c in the lens cross-sectional view.

  In the zoom lens in this embodiment, a virtual image formed by the combined system of the first lens unit L1 and the second lens unit L2 is formed on the photosensitive surface (on the imaging unit surface) by the third lens unit L3 and the fourth lens unit L4. The zoom method is used to form an image.

  In this embodiment, compared with a conventional so-called four-group zoom lens in which the first lens unit L1 is extended and focusing is performed, the rear focus method as described above is employed, so that the effective lens diameter of the first lens unit L1 is increased. The increase is effectively prevented.

  Further, by arranging the aperture stop SP on the object side of the third lens unit L3, the entrance pupil position can be set short, and the front lens diameter (effective system of the first lens unit) can be easily reduced. is doing.

  In the numerical example of the zoom lens according to the present invention, the third lens unit L3 is composed of a third lens unit L3a having a negative refractive power and a third lens unit L3b having a positive refractive power, of which the third lens unit L3b is composed. For image stabilization, image blur is corrected when the entire optical system is vibrated by moving it so as to have a component perpendicular to the optical axis. As a result, image stabilization is performed without adding an optical member such as a variable apex angle prism or a lens group for image stabilization.

  In particular, a photographing lens for a video camera compatible with 3CCD requires a space for arranging a color separation prism for color separation on the image plane side, and therefore requires a longer back focus than an ordinary single-plate photographing lens. . For this reason, the refractive power of the third lens unit L3 is weaker than that of 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 vibration is to be prevented by moving the entire third lens unit L3 in a direction perpendicular to the optical axis direction, the amount of movement of the third lens unit L3 increases, and a lens having a large effective diameter is required.

  Therefore, in the present invention, 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 lens unit having a negative refractive power is used. The amount of movement in the direction perpendicular to the optical axis for anti-vibration is reduced by increasing the positive refractive power of the shift lens unit (the 3b lens unit L3b) and increasing its decentration sensitivity. As a result, the entire optical system including the third lens unit L3 is made compact.

  In a photographing system aiming at high image quality, such as the zoom type of the present invention, it is possible to improve the blur by adopting an iris diaphragm having a large number of diaphragm blades. In addition, a shutter mechanism for temporarily cutting the amount of light incident on a solid-state imaging device such as a CCD is also required when capturing a still image. Therefore, in the present invention, the space between the second lens unit L2 and the third lens unit L3 is used as a space for that purpose, and an aperture device such as an aperture stop, a shutter, and an ND insertion / removal mechanism is disposed in front of the third lens unit L3. I made it.

Therefore, when the distance on the optical axis between the third lens unit L3 and the aperture stop SP is D, and the combined focal length at the wide-angle end of the third lens unit and the fourth lens unit is f34,
0.1 × f34 <D <0.6 × f34 (1)
It is important to satisfy the following conditions.

  The above equation is a condition for maintaining the optimization of the entire lens length while keeping the exit pupil position that fluctuates with the movement of the fourth lens unit L4 away during zooming.

  If the space up to the aperture stop SP exceeds the upper limit value, the entrance pupil position enters the inside of the lens, the front lens diameter increases, and compactness cannot be achieved. When the interval is shortened, the exit pupil position is shortened by plus, and therefore, the variation in the incident angle of off-axis rays to the color separation dichroic mirror for 3CCD becomes large, and the color unevenness of the entire screen becomes large, which is not preferable. Furthermore, there arises a problem that it becomes impossible to secure a space for disposing an iris device such as an iris diaphragm, a mechanical shutter, and an ND filter insertion / removal mechanism for adjusting the amount of light.

Furthermore,
0.2 × f34 <D <0.47 × f34 (1a)
It is preferable that it exists in the range.

  In the present invention, in order to achieve a high optical performance while ensuring a sufficient distance before and after the aperture stop SP, the third-a lens unit L3a is composed of a concave lens and a positive lens with a concave surface facing the object side. is there.

  According to this, when making the divergent light beam from the second lens unit L2 substantially afocal, it is possible to maintain good optical performance without generating higher-order spherical aberration, and fluctuations in decentration aberrations during image stabilization It becomes possible to correct well.

  Furthermore, an aspherical lens is provided on at least one surface of each of the third-a lens unit L3a and the third-b lens unit L3b.

  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, it is preferable to introduce an aspherical surface into the most image side lens surface of the 3a lens unit L3a and the convex lens surface of the 3b lens unit L3b. According to this, spherical aberration generated in each lens unit, The coma aberration is reduced, and it is easy to satisfactorily correct the decentration aberration generated during the image stabilization, particularly the decentration coma aberration.

  The position of the aspheric surface may be a different lens surface of each lens group.

  The third-b lens unit L3b having positive refractive power, which is the anti-vibration lens unit, has 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 chromatic aberration is corrected as much as possible by the image stabilizing lens unit alone. 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 anti-vibration lens group (the third b lens group L3b).

  Further, in order to reduce the Petzval sum satisfactorily, when the refractive index of the negative lens included in the third lens group L3b is N3b, N3b is preferably 1.8 or more.

  In order to keep the chromatic aberration of the entire system favorable, it is preferable to have at least one positive lens in the 3a lens unit L3a.

When the focal lengths of the 3a lens unit L3a and the 3b lens unit L3b are f3a and f3b, respectively.
1.0 <| f3a / f3b | <2.0 (2)
It is preferable to satisfy the following conditional expression:

  When the upper limit of the above formula is exceeded, the refractive power of the third lens unit L3b becomes too strong, and the refractive power of the third lens unit L3 becomes relatively strong, making it difficult to ensure an appropriate back focus. It becomes. If the lower limit is exceeded, the anti-vibration sensitivity of the third lens unit L3b as the anti-vibration lens unit becomes small, and the movement amount for correcting camera shake increases, which is not preferable.

Furthermore, the conditional expression is
1.25 <| f3a / f3b | <1.8 (2a)
It is preferable that it exists in the range.

  The second lens unit L2 includes, in order from the object side, a negative meniscus lens having a concave surface on the image side, a negative lens having a concave surface on the object side, a positive lens having both convex surfaces, and a negative lens having both concave surfaces. Is good. According to this, it becomes easy to satisfactorily correct lateral chromatic aberration over the entire zoom range.

The positive lens and the respective average refractive index of the negative lens Np constituting the first lens unit L1, Nn, the average Abbe numbers respectively vp, .nu.n, most refractive index of the positive lens constituting the first lens unit L1 is low When the refractive index of the lens is Np1,
1.7 <Np <1.8 (3)
0.1 <Nn-Np <0.2 (4)
νP-νn> 28 (5)
Nn-Np1> 0.3 (6)
It is preferable to satisfy the following conditional expression:

  By satisfying the equation (3), the curvature of the positive lens can be reduced by setting the average refractive index of the positive lens to 1.7 or more, contributing to the reduction of the front lens diameter by reducing the thickness of the positive lens. To do. In addition, the refractive index difference with the negative lens is 0.1 or more so as to satisfy the expression (4), and the Abbe number difference is 28 or more so as to satisfy the expression (5), and the expression (6) is satisfied. As described above, by ensuring a refractive index difference of 0.3 or more with respect to at least one positive lens, it is possible to effectively eliminate chromatic aberration generated in the first lens unit L1.

  If either of these limits is exceeded, the chromatic aberration will be overcorrected or undercorrected, leaving the longitudinal chromatic aberration at the telephoto end and the residual chromatic aberration at the wide angle end.

In the zoom lens of each numerical example, the thickness of the first lens unit L1 (the distance on the optical axis from the most object-side surface to the most image-side surface of the first lens unit L1) is DF, and the wide-angle end. Where fw is the focal length of the entire system at
3.0 <DF / fw <5.0 (7)
The following conditional expression is satisfied .

  This conditional expression is obtained by normalizing DF, which is the combined thickness of the first lens unit L1, with respect to the total focal length. If the upper limit of the expression (7) is exceeded and the first lens unit L1 is thick, the front lens diameter increases, and the front lens weight, which has the largest weight ratio to the entire lens, increases. Further, it is not preferable to make the first lens unit L1 thin beyond the lower limit value because the outer peripheral thickness of the positive lens becomes small and processing becomes difficult.

  The fourth lens unit L4 is preferably composed of at least one negative lens and two positive lenses, and has at least one aspherical surface.

  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, resulting in spherical aberration. It is easy to properly correct the occurrence of the above.

  The fourth lens unit L4 is composed of a positive lens having at least one aspheric surface and convex both surfaces, a negative meniscus lens having a convex surface facing the object side, and a positive lens having both surfaces convex. In order to obtain a long back focus according to the present proposal, the on-axis light beam emitted from the third lens unit L3 enters the fourth lens unit L4 at a high position. Therefore, the spherical aberration can be corrected more effectively by arranging a positive lens having an aspheric surface at the beginning of the fourth lens unit L4. By disposing a negative lens in the fourth lens unit L4, it is possible to reduce variation in chromatic aberration when moving in the optical axis direction and maintain high optical performance.

When the focal length of the fourth lens unit L4 is f4,
4.5 <f4 / fw <8.0 (8)
Satisfying the following conditional expression makes it easier to secure the back focus.

  When the focal length of the fourth lens unit L4 is reduced beyond the lower limit of the equation (8), it is difficult to obtain an appropriate back focus when designing an ultra wide-angle zoom lens. If the focal length of the fourth lens unit L4 is increased beyond the upper limit of the expression (8), a space more than necessary for maintaining the color separation prism and the like is maintained, and it becomes difficult to increase the diameter. .

Furthermore, equation (8) is
5.0 <f4 / fw <6. (8a)
It is preferable that it exists in the range.

  Next, numerical data of numerical examples 1 to 4 will be shown. In the numerical examples, f is a focal length, Fno is an F number, and ω is a half angle of view. i indicates the order counted from the object side, ri is the radius of curvature of the i-th surface, di is the axial distance between the i-th surface and the (i + 1) -th surface, and ni and νi are i-th The refractive index and the Abbe number based on the d-line of the second material.

  R31 to R37 in Numerical Example 1; R28 to R32 in Numerical Example 2; R31 to R36 in Numerical Example 3; R31 to R36 in Numerical Example 4; and R29 to R35 in Numerical Example 5 are low-pass filters. It corresponds to an infrared cut filter, a three-color separation prism, a CCD cover glass, and the like.

  The aspherical shape is such that the traveling direction of light is positive, X is the amount of displacement from the surface vertex in the optical axis direction, h is the height from the optical axis in the direction perpendicular to the optical axis, R is the paraxial radius of curvature, K Is a conic constant, and B to E are aspherical coefficients, respectively.

It is expressed by the following formula. “E ± Z” means “× 10 ^{± Z} ”.

  Table 1 shows the relationship between the above-described conditional expressions and numerical examples.

(Numerical example 1)
f = 10-116.6 Fno = 1.66-1.95 2ω = 58.5 ° -5.5 °
R 1 = 2432.438 D 1 = 5.83 N 1 = 1.84666 ν 1 = 23.8
R 2 = 121.734 D 2 = 17.07 N 2 = 1.48749 ν 2 = 70.2
R 3 = -818.931 D 3 = 0.54
R 4 = 167.005 D 4 = 10.15 N 3 = 1.83480 ν 3 = 42.7
R 5 = 2351.013 D 5 = 0.54
R 6 = 92.340 D 6 = 10.59 N 4 = 1.80 400 ν 4 = 46.6
R 7 = 261.296 D 7 = variable
R 8 = 161.055 D 8 = 2.27 N 5 = 1.80609 ν 5 = 40.9
R 9 = 19.845 D 9 = 10.31
R10 = -89.388 D10 = 2.38 N 6 = 1.77249 ν 6 = 49.6
R11 = 68.384 D11 = 2.92
R12 = 39.816 D12 = 9.72 N 7 = 1.84666 ν 7 = 23.8
R13 = -53.929 D13 = 1.94 N 8 = 1.83400 ν 8 = 37.2
R14 = 86.612 D14 = variable
R15 = flare aperture D15 = 6.48
R16 = iris diaphragm D16 = 12.96
r17 = -55.284 D17 = 1.94 N 9 = 1.69680 ν 9 = 55.5
R18 = 35.267 D18 = 6.91 N10 = 1.68329 ν10 = 31.4
R19 * = -131.198 D19 = 1.94
R20 * = 44.978 D20 = 4.75 N11 = 1.58913 ν11 = 61.3
R21 = 132.008 D21 = 2.16 N12 = 1.80518 ν12 = 25.4
R22 = 57.994 D22 = 1.78
R23 = 174.373 D23 = 5.83 N13 = 1.48749 ν13 = 70.2
R24 = -75.386 D24 = variable
R25 * = 53.816 D25 = 7.13 N14 = 1.583130 ν14 = 59.4
R26 = -236.538 D26 = 0.43
R27 = 64.274 D27 = 1.94 N15 = 1.846660 ν15 = 23.8
R28 = 29.798 D28 = 10.59 N16 = 1.487490 ν16 = 70.2
R29 = -86.155 D29 = variable
R30 = ∞ D30 = 3.89 N17 = 1.516330 ν17 = 64.1
R31 = ∞ D31 = 2.16
R32 = ∞ D32 = 46.98 N18 = 1.516330 ν18 = 64.1
R33 = ∞ D33 = 6.30
R34 = ∞

\ Focal length 10.0 30.2 116.6
Variable interval \
D 7 2.118 45.738 74.818
D14 78.713 35.093 6.013
D24 21.593 16.133 18.979
D29 6.162 11.621 8.776

* Indicates an aspheric surface, and the aspheric coefficient is
R19 k = -124.820 B = -6.42746e-06 C = 1.99763e-08 D = -2.97435e-11 E = 0.0
R20 k = -0.19830 B = -1.63530e-06 C = 3.01342e-09 D = -6.90812e-12 E = 0.0
R25 k = -0.68858 B = -8.53526e-07 C = 5.45737e-10 D = -1.72620e-13 E = 0.0

(Numerical example 2)
f = 10 to 116.8 Fno = 1.66 to 1.95 2ω = 58.5 ° to 5.5 °
R 1 = 697.890 D 1 = 5.44 N 1 = 1.846660 ν 1 = 23.8
R 2 = 107.693 D 2 = 16.71 N 2 = 1.496999 ν 2 = 81.5
R 3 = 1560.073 D 3 = 0.37
R 4 = 154.122 D 4 = 10.77 N 3 = 1.804000 ν 3 = 46.6
R 5 = -254618.720 D 5 = 0.48
R 6 = 95.557 D 6 = 11.46 N 4 = 1.834000 ν 4 = 37.2
R 7 = 260.308 D 7 = Variable
R 8 = 177.036 D 8 = 2.16 N 5 = 1.806098 ν 5 = 40.9
R 9 = 21.017 D 9 = 10.96
R10 = -61.404 D10 = 2.91 N 6 = 1.772499 ν 6 = 49.6
R11 = 56.089 D11 = 2.92
R12 = 46.422 D12 = 7.76 N 7 = 1.846660 ν 7 = 23.8
R13 = -82.547 D13 = 2.14 N 8 = 1.834000 ν 8 = 37.2
R14 = 280.162 D14 = variable
R15 = Aperture D15 = 19.43
R16 = -51.178 D16 = 1.94 N 9 = 1.696797 ν 9 = 55.5
R17 = 41.435 D17 = 6.69 N10 = 1.688931 ν10 = 31.1
R18 * = -105.058 D18 = 1.94
R19 * = 36.414 D19 = 6.91 N11 = 1.589130 ν11 = 61.3
R20 = 189.839 D20 = 2.16 N12 = 1.805181 ν12 = 25.4
R21 = 54.043 D21 = 2.66
R22 = 1625.338 D22 = 6.91 N13 = 1.487490 ν13 = 70.2
R23 = -64.107 D23 = variable
R24 * = 58.424 D24 = 7.56 N14 = 1.583126 ν14 = 59.4
R25 = -196.169 D25 = 0.43
R26 = 59.587 D26 = 1.94 N15 = 1.846660 ν15 = 23.9
R27 = 30.636 D27 = 10.15 N16 = 1.487490 ν16 = 70.2
R28 = -116.012 D28 = variable
R29 = ∞ D29 = 3.89 N17 = 1.516330 ν17 = 64.1
R30 = ∞ D30 = 2.16
R31 = ∞ D31 = 46.84 N18 = 1.516330 ν18 = 64.2
R32 = ∞

\ Focal length 10.0 29.6 116.8
Variable interval \
D 7 2.116 45.106 73.766
D14 78.660 35.670 7.010
D23 23.207 18.281 21.502
D28 6.158 11.083 7.863

* Indicates an aspheric surface, and the aspheric coefficient is
R18 k = -96.7046 B = -1.04102e-05 C = 3.06287e-08 D = -4.39663e-11 E = 0.0
R19 k = -1.09924 B = -1.25161e-06 C = 6.10487e-09 D = -9.86198e-12 E = 0.0
R24 k = 1.31001 B = -2.05391e-06 C = -1.11659e-09 D = 2.05162e-12 E = -2.01940e-15

(Numerical Example 3)
f = 10 ~ 117.2 Fno = 1.66 ~ 1.95 2ω = 58.5 ° ~ 5.5 °
R 1 = 1718.915 D 1 = 5.39 N 1 = 1.846660 ν 1 = 23.8
R 2 = 111.669 D 2 = 16.60 N 2 = 1.496999 ν 2 = 81.5
R 3 = -6364.569 D 3 = 0.54
R 4 = 157.475 D 4 = 11.64 N 3 = 1.804000 ν 3 = 46.6
R 5 = -2753.019 D 5 = 0.54
R 6 = 93.097 D 6 = 10.57 N 4 = 1.834000 ν 4 = 37.2
R 7 = 237.557 D 7 = variable
R 8 = 147.493 D 8 = 2.16 N 5 = 1.806098 ν 5 = 40.9
R 9 = 19.642 D 9 = 10.33
R10 = -75.204 D10 = 2.91 N 6 = 1.772499 ν 6 = 49.6
R11 = 87.050 D11 = 2.92
R12 = 41.118 D12 = 8.30 N 7 = 1.846660 ν 7 = 23.8
R13 = -54.014 D13 = 1.94 N 8 = 1.834000 ν 8 = 37.2
R14 = 83.927 D14 = variable
R15 = iris diaphragm D15 = 4.31
R16 = flare aperture D16 = 15.09
R17 = -59.736 D17 = 1.94 N 9 = 1.696797 ν 9 = 55.5
R18 = 36.801 D18 = 7.98 N10 = 1.688931 ν10 = 31.1
R19 * = -124.316 D19 = 1.94
R20 * = 41.822 D20 = 6.90 N11 = 1.589130 ν11 = 61.3
R21 = 149.700 D21 = 2.16 N12 = 1.805181 ν12 = 25.4
R22 = 55.160 D22 = 2.66
R23 = 257.115 D23 = 6.90 N13 = 1.487490 ν13 = 70.2
R24 = -68.575 D24 = variable
R25 * = 52.975 D25 = 7.55 N14 = 1.583126 ν14 = 59.4
R26 = -285.863 D26 = 0.43
R27 = 60.981 D27 = 1.94 N15 = 1.846660 ν15 = 23.9
R28 = 29.058 D28 = 10.57 N16 = 1.487490 ν16 = 70.2
R29 = -100.378 D29 = variable
R30 = ∞ D30 = 3.88 N17 = 1.516330 ν17 = 64.1
R31 = ∞ D31 = 2.16
R32 = ∞ D32 = 46.79 N18 = 1.516330 ν18 = 64.1
R33 = ∞

\ Focal length 10.00 30.0 117.2
Variable interval \
D 7 2.114 45.554 74.514
D14 78.575 35.135 6.175
D24 19.973 14.705 17.678
D29 6.151 11.420 8.447

* Indicates an aspheric surface, and the aspheric coefficient is
R19 k = -102.330 B = -6.40087e-06 C = 2.01455e-08 D = -3.13331e-11 E = 0.00
R20 k = -0.69845 B = -1.22524e-06 C = 4.96336e-09 D = -9.93644e-12 E = 0.00
R25 k = -0.03891 B = -9.17462e-07 C = -5.10062e-10 D = 1.79248e-12 E = -1.69755e-15

(Numerical example 4)
f = 10-116.1 Fno = 1.66-1.95 2ω = 58.5 ° -5.5 °
R 1 = 10584.097 D 1 = 5.82 N 1 = 1.846660 ν 1 = 23.9
R 2 = 124.113 D 2 = 17.25 N 2 = 1.487490 ν 2 = 70.2
R 3 = -632.187 D 3 = 0.54
R 4 = 163.602 D 4 = 10.13 N 3 = 1.834807 ν 3 = 42.7
R 5 = 2439.838 D 5 = 0.54
R 6 = 91.838 D 6 = 10.56 N 4 = 1.804000 ν 4 = 46.6
R 7 = 249.308 D 7 = variable
R 8 = 153.472 D 8 = 2.26 N 5 = 1.806098 ν 5 = 40.9
R 9 = 19.556 D 9 = 10.29
R10 = -93.040 D10 = 2.37 N 6 = 1.772499 ν 6 = 49.6
R11 = 65.428 D11 = 2.91
R12 = 38.665 D12 = 9.70 N 7 = 1.846660 ν 7 = 23.8
R13 = -57.519 D13 = 1.94 N 8 = 1.834000 ν 8 = 37.2
R14 = 84.333 D14 = variable
R15 = flare aperture D15 = 4.31
R16 = iris diaphragm D16 = 15.09
R17 = -53.227 D17 = 1.94 N 9 = 1.696797 ν 9 = 55.5
R18 = 35.905 D18 = 7.65 N10 = 1.683290 ν10 = 31.4
R19 * = -128.190 D19 = 1.94
R20 * = 45.679 D20 = 6.47 N11 = 1.589130 ν11 = 61.3
R21 = 121.490 D21 = 2.16 N12 = 1.805181 ν12 = 25.4
R22 = 57.309 D22 = 1.75
R23 = 153.556 D23 = 5.82 N13 = 1.487490 ν13 = 70.2
R24 = -77.312 D24 = variable
R25 * = 52.359 D25 = 7.11 N14 = 1.583126 ν14 = 59.4
R26 = -229.097 D26 = 0.43
R27 = 70.837 D27 = 1.94 N15 = 1.846660 ν15 = 23.9
R28 = 31.363 D28 = 10.76 N16 = 1.487490 ν16 = 70.2
R29 = -84.181 D29 = variable
R30 = ∞ D30 = 3.88 N17 = 1.516330 ν17 = 64.1
R31 = ∞ D31 = 2.16
R32 = ∞ D32 = 46.89 N18 = 1.516330 ν18 = 64.2
R33 = ∞

\ Focal length 10.000 30.2 116.1
Variable interval \
D 7 2.114 45.626 74.634
D14 78.555 35.043 6.035
D24 20.462 14.961 17.779
D29 10.366 15.867 13.049

* Indicates an aspheric surface, and the aspheric coefficient is
R19 k = -102.123 B = -5.87959e-06 C = 1.84834e-08 D = -3.36183e-11 E = 1.81092e-14
R20 k = -0.13863 B = -1.50799e-06 C = 2.90309e-09 D = -9.46585e-12 E = 7.48131e-15
R25 k = -1.03360 B = -8.21071e-07 C = 9.59867e-10 D = -1.14958e-12 E = 9.35384e-16

  Next, an embodiment of an optical apparatus using the zoom lenses of Numerical Examples 1 to 4 as a photographing optical system will be described with reference to FIG.

  FIG. 9 shows an example in which the zoom lens of the present invention is used in a video camera. In FIG. 9, 10 is a camera body, 11 is a photographing optical system constituted by the zoom lenses of Numerical Examples 1 to 4, 12 is a CCD sensor, a CMOS sensor, or the like that receives a subject image formed by the photographing optical system 11. A solid-state image sensor (photoelectric conversion element), 13 is a memory for recording a subject image received by the solid-state image sensor 12, and 14 is a viewfinder for observing the subject image. As the finder 14, a finder of a type that observes a subject image displayed on a display element such as an optical finder or a liquid crystal panel can be considered.

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

2 is a lens cross-sectional view of a zoom lens according to Numerical Example 1. FIG. 6 is a lens cross-sectional view of a zoom lens according to Numerical Example 2. FIG. 10 is a lens cross-sectional view of a zoom lens according to Numerical Example 3. FIG. 6 is a lens cross-sectional view of a zoom lens according to Numerical Example 4. FIG. FIG. 6 is an aberration diagram of the zoom lens according to Numerical Example 1. FIG. 6 is an aberration diagram of the zoom lens according to Numerical Example 2. FIG. 10 is an aberration diagram of the zoom lens according to Numerical example 3; FIG. 10 is an aberration diagram of the zoom lens according to Numerical example 4; It is a principal part schematic diagram of a video camera.

Explanation of symbols

L1 1st lens group L2 2nd lens group L3 3rd lens group L4 4th lens group SP Aperture stop IP Image surface G Glass block L3a 3a lens group L3b 3b lens group

Claims (8)

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. , a zoom lens, wherein the hand the second lens group the fourth lens group moves during zooming, the first lens group comprises, in order from the object side to the image side, a cemented lens consisting of a negative lens and a positive lens and 2 The third lens group includes, in order from the object side to the image side, the third lens group having a negative refractive power and a 3a lens group having a negative refractive power, and a 3b lens having a positive refractive power. made from the group, the 3b-th lens group is moved so as to have an optical axis vertical component, together with changing the position of the image where the zoom lens is formed, the first 3a lens aperture unit on the object side of the group It has a most image from the most object side surface of the first lens group When the distance on the optical axis to the surface DF, the focal length of the entire system at the wide angle end fw,
4.472 ≦ DF / fw <5.0
A zoom lens satisfying the following conditional expression: 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. , a zoom lens, wherein the hand the second lens group the fourth lens group moves during zooming, the first lens group comprises, in order from the object side to the image side, a cemented lens consisting of a negative lens and a positive lens and 2 The third lens group is composed of , in order from the object side to the image side, the third lens group having a negative refractive power and the third lens group having a positive refractive power. and a distance on the optical axis between the aperture stop D, the third combined lens group at the wide angle end of the fourth lens group focal distance f34, the most image side from the most object side surface of the first lens group The distance on the optical axis to the surface is DF, and the focal length of the entire system at the wide angle end is f. When w
0.1 × f34 <D <0.6 × f34
4.472 ≦ DF / fw <5.0
A zoom lens satisfying the following conditional expression: 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. , a zoom lens, wherein the hand the second lens group the fourth lens group moves during zooming, the first lens group comprises, in order from the object side to the image side, a cemented lens consisting of a negative lens and a positive lens and 2 The third lens group includes, in order from the object side to the image side, the third lens group having a negative refractive power and a third lens group having a positive refractive power. made, the 3b-th lens group includes, in order from the object side to the image side, one positive lens, meniscus lens having negative refractive power of the image side concave surface, Ri Do one positive lens, the first lens group The distance on the optical axis from the most object-side surface to the most image-side surface of The focal length of the entire system when the fw that,
4.472 ≦ DF / fw <5.0
A zoom lens satisfying the following conditional expression: When the focal lengths of the 3a lens group and the 3b lens group are f3a and f3b, respectively.
1.0 <| f3a / f3b | <2.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. Lenses having the lowest refractive index among the positive lenses constituting the first lens group, the average refractive index of the positive lens and the negative lens being Np, Nn, the average Abbe number being νp, νn, respectively. When the refractive index of Np1 is Np1,
1.7 <Np <1.8
0.1 <Nn-Np <0.2
νP-νn> 28
Nn-Np1> 0.3
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the focal length of the fourth lens group is f4,
4.5 <f4 / fw <8.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. The zoom lens according to claim 1 , wherein an image is formed on the photoelectric conversion element. An imaging apparatus comprising: the zoom lens according to claim 1 ; and a photoelectric conversion element that receives an image formed by the zoom lens.

Images