JP2006058584A - Zoom lens and imaging apparatus having the same - Google Patents

Abstract

A zoom lens having an ultra-wide angle of view and high optical performance over the entire zoom range and an image pickup apparatus having the zoom lens are provided.
In order from the object side to the image side, first to fourth lens units L1 to L4 having negative, positive, and negative refractive powers are provided, and the first lens unit L1 and the second lens unit at the telephoto end are compared to the second lens unit at the telephoto end. The air gap between the lens group L2 is small, the air gap between the second lens group L2 and the third lens group L3 is large, and the air gap between the third lens group L3 and the fourth lens group L4 is small. A zoom lens in which the second to fourth lens units L2 to L4 move, and in order from the object side to the image side, the first lens unit L1 is a first lens having a negative refractive power with the widest air interval as a boundary. It consists of a group L1a and a first-b lens unit L1b having a negative refractive power, and satisfies a predetermined condition.
[Selection] Figure 1

Description

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

  Conventionally, a so-called negative lead type zoom lens preceded by a lens unit having negative refractive power (positioned closest to the object side) has a relatively short close-up shooting distance and a relatively wide shooting angle of view. Since it is easy and the back focus is relatively long, it is often used for a wide-angle shooting lens.

  As a negative lead type zoom lens, a four-group zoom lens including four lens groups having negative, positive, negative, and positive refractive powers in order from the object side to the image side is known (Patent Documents 1 to 3).

  In this four-group zoom lens, the first lens group and the second lens group as a whole have a positive refractive power, and the third lens group and the fourth lens group as a whole are negatively refracted at the zoom position at the telephoto end. Since the power lens group group can be configured so as to be a so-called telephoto type as the entire optical system, there is an advantage that the focal length at the telephoto end can be easily increased.

In the four-group zoom lens disclosed in Patent Documents 1 to 3, two or more lens groups are moved during zooming.
Japanese Patent Laid-Open No. 10-82594 Japanese Unexamined Patent Publication No. 2000-33897 JP 2002-287031 A

  In recent years, zoom lenses for digital single-lens reflex cameras have been strongly demanded to widen the angle of view and to improve the image quality of captured images.

  Generally, in a zoom lens, if the refractive power of each lens group is increased, the amount of movement of each lens group for obtaining a predetermined zoom ratio (magnification ratio) is reduced. A wide angle of view can be obtained.

  However, when the refractive power of each lens group is simply increased, aberration fluctuations accompanying zooming increase, and it becomes difficult to obtain good optical performance over the entire zoom range, especially when a wide angle of view is intended.

  In addition, when trying to make a wide angle of view, many distortions and astigmatism occur, and it becomes difficult to correct these aberrations.

  In addition, the entire photographing system becomes larger.

  The present invention provides a zoom lens having an ultra-wide angle of view and high optical performance over the entire zoom range by appropriately setting the refractive power of each lens group and the lens configuration of each lens group, and an image pickup having the same. The purpose is to provide a device.

The zoom lens of the present invention is
In order from the object side to the image side, there are a first lens unit having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power. The distance between the first lens group and the second lens group at the telephoto end is smaller than that at the wide-angle end, and the distance between the second lens group and the third lens group is large. The third lens group and the fourth lens A zoom lens in which the second to fourth lens groups move so that the distance between the first lens group and the second lens group becomes small. In order from the object side to the image side, the first lens group is negative at the widest distance. 1a lens group having a refractive power of 1b and 1b lens group having a negative refractive power, the air distance between the 1a lens group and the 1b lens group being Dab, the focal length of the entire system at the wide angle end being fw, When the focal lengths of the second lens group and the fourth lens group are f2 and f4, respectively.
0.8 <Dab / fw <2.0
2.0 <f2 / fw <3.5
3.0 <f4 / fw <4.5
It is characterized by satisfying the following conditions.

In order from the object side to the image side, there are a first lens unit having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power. The distance between the first lens group and the second lens group at the telephoto end is smaller than that at the wide-angle end, and the distance between the second lens group and the third lens group is large. The third lens group and the fourth lens A zoom lens in which the second to fourth lens groups move so that the distance between the first lens group and the second lens group becomes small. In order from the object side to the image side, the first lens group has a first The 1a lens group includes a negative lens G1a1 and a negative lens G1a2, and one or more aspherical surfaces. The first b lens group includes a negative lens G1b1 and a positive lens G1b1. The lens G1b2 and one or more aspherical surfaces, and the air between the first a lens group and the first b lens group When septum and the Dab, the focal length of the entire system at the wide angle end and fw,
0.8 <Dab / fw <2.0
It is characterized by satisfying the following conditions.

  According to the present invention, it is possible to obtain a zoom lens having an extremely wide angle of view and high optical performance over the entire zoom range, and an imaging apparatus having the same.

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

  1 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to Embodiment 1 of the present invention, and FIGS. 2, 3, and 4 are the wide-angle end and intermediate zoom position of the zoom lens according to Embodiment 1, respectively. FIG. 6 is an aberration diagram at the telephoto end (long focal length end).

  FIG. 5 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to Embodiment 2 of the present invention, and FIGS. 6, 7, and 8 are respectively the wide-angle end and intermediate zoom position of the zoom lens according to Embodiment 2. FIG. 6 is an aberration diagram at the telephoto end (long focal length end).

  FIG. 9 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to Embodiment 3 of the present invention. FIGS. 10, 11 and 12 are the wide-angle end and intermediate zoom position of the zoom lens according to Embodiment 3, respectively. FIG. 6 is an aberration diagram at the telephoto end (long focal length end).

  13 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to Embodiment 4 of the present invention. FIGS. 14, 15, and 16 are the wide-angle end and intermediate zoom position of the zoom lens according to Embodiment 4, respectively. FIG. 6 is an aberration diagram at the telephoto end (long focal length end).

  FIG. 17 is a lens cross-sectional view at the wide-angle end (short focal length end) of the zoom lens according to Embodiment 5 of the present invention. FIGS. 18, 19, and 20 are the wide-angle end and intermediate zoom position of the zoom lens according to Embodiment 5, respectively. FIG. 6 is an aberration diagram at the telephoto end (long focal length 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.

  The zoom lens of each embodiment is a photographic lens system used in an imaging apparatus, and ZL is a zoom lens in the lens cross-sectional view.

  In the lens cross-sectional views shown in FIGS. 1, 5, 9, 13, 17, and 21, the left side is the object side and the right side is the image side.

  L1 is a first lens unit having negative refractive power (optical power = reciprocal of focal length), L2 is a second lens unit having positive refractive power, L3 is a third lens unit having negative refractive power, and L4 is positive. It is the 4th lens group of refractive power. As described above, the zoom lens of each embodiment has only four lens groups of the first to fourth lens groups as lens groups.

  In order from the object side to the image side, the first lens unit L1 includes a first-a lens unit L1a having a negative refractive power and a first-b lens unit L1b having a negative refractive power, with the widest air gap as a boundary.

  SP is an aperture stop for adjusting the amount of light, and is located on the object side of the third lens unit L3.

  SSP is a sub-aperture that restricts the F-number light flux in the wide-angle zoom region.

  FC is a flare cut stop, which is disposed on the image side of the fourth lens unit L4.

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

  In the aberration diagrams, d and g are the d-line and g-line, ΔM and ΔS are the d-line meridional image plane, the d-line sagittal image plane, ΔM ′ is the g-line meridional image plane, and ΔS ′ is the g-line. The sagittal image plane and lateral chromatic aberration are represented by the g-line. Fno is the F number, and Y is the image height.

  In each of the following embodiments, the wide-angle end and the telephoto end are located at both ends of a range in which the zooming lens groups (the second to fourth lens groups L2 to L4 in each embodiment) can move on the optical axis on the mechanism. The zoom position when it is positioned.

  In each embodiment, the zoom lens moves as indicated by an arrow during zooming from the wide-angle end to the telephoto end.

  Specifically, the air space between the first lens unit L1 and the second lens unit L2 at the telephoto end is smaller than the wide angle end, and the air space between the second lens unit L2 and the third lens unit L3 is large. The second to fourth lens groups L2 to L4 move to the object side so that the air gap between the third lens group L3 and the fourth lens group L4 becomes small.

  Note that the second lens unit L2 and the fourth lens unit L4 may be moved integrally or may be moved independently.

  1, 5, 9, and 13, the first lens unit L <b> 1 has a convex locus on the image side, and in Example 5 of FIG. 17, the first b lens unit L <b> 1 b has a convex locus on the image side. Moving to have.

  Note that Example 5 in FIG. 17 can also be handled as a zoom lens including five lens groups as a whole.

  Focusing is performed by moving the 1b lens unit L1b on the optical axis.

  Next, the basic configuration of the zoom lens of each embodiment will be described.

  In each example, the zoom lens includes, in order from the object side to the image side, a first lens unit L1 having a negative refractive power, a second lens unit L2 having a positive refractive power, a third lens unit L3 having a negative refractive power, and a positive lens unit. The fourth lens unit L4 has a refractive power of λ, and the air distance between the first lens unit L1 and the second lens unit L2 at the zoom position at the telephoto end is smaller than that at the wide-angle end, and the second lens unit L2 and the second lens unit L2 The basic configuration is that the fourth lens unit L4 moves from the second lens unit L2 so that the air interval between the third lens unit L3 is large and the air interval between the third lens unit L3 and the fourth lens unit L4 is small.

  In the zoom position at the wide-angle end where the back focus is the shortest, the refractive power is arranged such that the image side principal point is located closer to the image side so that the back focus becomes longer.

  That is, the entire lens system is made more retro-type at the zoom position at the wide-angle end. Specifically, in order from the object side to the image side, the negative and positive refractive power arrangement is desired. Therefore, at the zoom position at the wide angle end, the combined refractive power is positive and away from the first lens unit L1 having the negative refractive power. Second, third, and fourth lens groups are arranged. In the second, third, and fourth lens groups, the third lens unit L3 having negative refractive power is arranged closer to the object side so that the image-side principal point is arranged closer to the image side. To be long enough.

In the zoom position at the telephoto end, in order to shorten the total lens length of the entire system, the lens side is arranged with positive and negative refractive powers from the object side so that the image side principal point is located closer to the object side. Specifically, at the telephoto end zoom position, the first lens unit L1 having a negative refractive power and the second lens unit L2 having a positive refractive power are brought close to each other to form a lens unit having a positive combined refractive power. The three lens units L3 are brought close to the fourth lens unit L4 to form a lens unit having a negative combined refractive power. Thus, the telephoto type is formed to shorten the optical total length at the telephoto end.
The first-a lens unit L1a includes a negative lens G1a1, a negative lens G1a2, and one or more aspherical surfaces.

  If the first-a lens unit L1a is composed of one negative lens, it is difficult to satisfactorily correct distortion and coma. Therefore, by configuring the first-a lens unit L1a as described above, aberration correction is shared by the two negative lenses, and distortion and coma particularly at the zoom position at the wide-angle end are corrected well.

  Further, in order to satisfactorily correct distortion and coma at the zoom position at the wide-angle end, at least one aspheric surface having a negative refractive power that weakens from the center to the periphery of the optical axis is provided. This aspherical surface is sufficient because the off-axis light beam that passes through the first-a lens unit L1a is relatively far from the optical axis, so that aberration can be corrected effectively.

  In particular, it is desirable that the most object side negative lens G1a1 has an aspherical shape.

  In view of processing of the aspherical lens, the surface of the second negative lens G1a2 having a small outer diameter counted from the object side may be aspherical.

  The 1b lens group L1b has a negative lens G1b1, a positive lens G1b2, and one or more aspherical surfaces.

  The first-b lens unit L1b includes a negative lens G1b1 and a positive lens G1b2 in order from the object side to the image side. Thus, the first-b lens unit L1b mainly corrects chromatic aberration favorably, and at the same time the image-side main of the first-b lens unit L1b. The point is arranged on the object side, and the image side principal point of the entire first lens unit L1 is arranged on the object side. As a result, the overall lens length and front lens diameter of the entire system are reduced.

  The 1b lens unit L1b is also provided with at least one aspherical surface. Thereby, the distortion aberration at the zoom position at the wide-angle end and the spherical aberration at the zoom position at the telephoto end are corrected well.

  Further, focusing is performed by the 1b lens unit L1b having a smaller lens outer diameter than that of the 1a lens unit L1a, thereby reducing variations in spherical aberration due to variations in object distance.

  In each embodiment, one or more of the following conditions are satisfied, thereby obtaining an effect corresponding to each condition.

The air distance between the 1a lens unit L1a and the 1b lens unit L1b is Dab, the focal length of the entire system at the zoom position at the wide-angle end is fw, the focal length of the i-th lens group is fi, and the entire system at the zoom position at the wide-angle end The back focus is bfw, the air distance between the negative lens G1a1 and the negative lens G1a2 is d1a, and the first-a lens unit L1a has one or more negative lenses, of which the material of the negative lens G1a1 disposed closest to the object side When the Abbe number of νg1 is
0.8 <Dab / fw <2.0 (1)
2.0 <f2 / fw <3.5 (2)
3.0 <f4 / fw <4.5 (3)
0.25 <fw / bfw <0.5 (4)
0.1 <d1a / fw <0.7 (5)
−0.8 <f1 / f2 <−0.4 (6)
-6.0 <f3 / fw <-3.4 (7)
42 <νg1 <71 (8)
Is satisfied.

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

  Conditional expression (1) defines an air space Dab between the most image-side lens surface of the 1a lens unit L1a and the most object-side lens surface of the 1b lens unit L1b.

  If the lower limit of conditional expression (1) is exceeded, the air gap between the first lens unit L1a and the first b lens unit L1b becomes too narrow and the refractive power of the first lens unit L1 tends to become weak, so an ultra wide angle of view. In order to maintain this, it is necessary to increase the refractive power of the first-a lens unit L1a and the first-b lens unit L1b, and it becomes difficult to correct distortion particularly at the zoom position at the wide-angle end.

  If the upper limit is exceeded, the air distance between the 1a lens unit L1a and the 1b lens unit L1b becomes too large, and the 1a lens unit L1a is located closer to the object side, which is not good because the lens diameter increases.

  Furthermore, in order to maintain a balance between high performance and downsizing, it is desirable to set the lower limit of conditional expression (1) to 1.0.

  Conditional expression (2) is for achieving both high performance and miniaturization by appropriately setting the focal length of the second lens unit L2.

  If the lower limit of conditional expression (2) is exceeded, it will be difficult to correct spherical aberration, especially at the zoom position at the telephoto end, and the fourth lens group L4 will cancel spherical aberration generated in the second lens group L2. The sensitivity to parallel decentering of the second lens unit L2 with respect to the four lens unit L4 becomes too high, which makes manufacturing difficult.

  If the upper limit is exceeded, the effect of shortening the total length by the telephoto type is weakened, especially at the zoom position at the telephoto end, which is not good because the total optical length increases and the lens diameter of the second lens unit L2 increases.

Furthermore, in order to maintain a balance between higher performance and smaller size, it is desirable to set the upper limit of conditional expression (2) to 3.0.
Conditional expression (3) is to achieve both high performance and small size by appropriately setting the focal length of the fourth lens unit L4.

  When the lower limit value of conditional expression (3) is exceeded, the refractive power of the fourth lens unit L4 becomes too strong, and it becomes difficult to correct astigmatism fluctuations particularly during zooming, and particularly at the zoom position at the wide-angle end. It is not good because it becomes difficult to correct distortion and lateral chromatic aberration. If the upper limit is exceeded, the effect of extending the back focus by the retro type becomes weak and it becomes difficult to lengthen the back focus. If the refractive power is arranged to increase the back focus, the refractive power of the first lens unit L1 is increased. It is not good because it tends to weaken and the front lens diameter tends to increase.

  In order to maintain a balance between higher performance and smaller size, it is desirable to set the lower limit of conditional expression (3) to 3.1. Further, it is desirable that the upper limit value is 3.5.

  Conditional expression (4) defines the ratio of the focal length of the entire system to the length of the back focus at the zoom position at the wide-angle end, and is intended to reduce the size of the entire system.

  If the back focus is too long compared to the focal length beyond the lower limit of conditional expression (4), the total optical length at the zoom position at the wide-angle end increases, which is not good. In addition, if the back focus is too short compared to the focal length beyond the upper limit value, the rear lens diameter increases, which is not good.

  Conditional expression (5) defines the axial air space between the two negative lenses G1a1 and G1a2 arranged on the most object side of the first-a lens unit L1a, and particularly improves performance at the zoom position at the wide-angle end. This is to maintain a balance between miniaturization.

  When the lower limit of conditional expression (5) is exceeded, the difference in curvature between the lens surface on the image plane side of the negative lens G1a1 and the lens surface on the object side of the negative lens G1a2 decreases, and in particular, correction of distortion aberration at the zoom position at the wide-angle end. It becomes difficult.

  On the other hand, if the upper limit value is exceeded, the negative lens G1a1 is located closer to the object side and the lens diameter increases, which is not good.

  Conditional expression (6) defines the ratio of the focal lengths of the first lens unit L1 and the second lens unit L2, and maintains the balance between high performance and miniaturization.

  If the lower limit of conditional expression (6) is exceeded and the refractive power of the first lens unit L1 relative to the second lens unit L2 becomes too strong, distortion aberrations particularly at the zoom position at the wide-angle end and spherical aberrations at the zoom position at the telephoto end will occur. This is not good because the correction is insufficient and it is difficult to set the Petzval sum to an appropriate value. On the other hand, if the upper limit is exceeded, the refractive power of the first lens unit L1 with respect to the second lens unit L2 becomes too weak and the lens diameter of the first lens unit L1 increases, which is not good.

  Conditional expression (7) defines the focal length of the third lens unit L3 and is mainly for maintaining a balance between high performance and miniaturization.

  If the refractive power of the third lens unit L3 becomes too weak beyond the lower limit of conditional expression (7), the total length of the telephoto type at the zoom position at the telephoto end is ensured while ensuring the back focus at the zoom position at the wide-angle end. It becomes difficult to set the refractive power arrangement for obtaining the shortening effect.

  When the upper limit is exceeded, the refractive power of the third lens unit L3 becomes too strong, and it becomes difficult to correct field curvature in the entire zoom range.

  Furthermore, in order to maintain a balance between higher performance and smaller size, it is desirable to set the lower limit value of conditional expression (7) to −5.0. Moreover, it is desirable that the upper limit value be −2.5.

  Conditional expression (8) defines the Abbe number of the material of the negative lens G1a1 located closest to the object side in the first-a lens unit L1a, and is for correcting lateral chromatic aberration particularly at the zoom position at the wide-angle end. .

  The negative lens G1a1 greatly affects the chromatic aberration of magnification because the off-axis light beam passes through the portion farthest from the center as compared with other lenses.

  If the lower limit value of conditional expression (8) is exceeded, the lateral chromatic aberration particularly at the zoom position at the wide-angle end becomes worse and difficult to correct. On the other hand, if the upper limit is exceeded, the chromatic aberration of magnification at the zoom position at the wide-angle end will be greatly bent, which makes it difficult to correct the entire range from the center to the periphery.

  In each embodiment, it is more preferable to set the numerical ranges of the conditional expressions (1) to (8) as follows.

1.05 <Dab <fw <1.8 (1a)
2.05 <f2 / fw <2.8 (2a)
3.15 <f4 / fw <4.0 (3a)
0.3 <fw / bfw <0.4 (4a)
0.15 <d1a / fw <0.6 (5a)
−0.7 <f1 / f2 <−0.45 (6a)
-4.9 <f3 / fw <-2.8 (7a)
45 <νg1 <65 (8a)
Next, an embodiment of a single-lens reflex camera system using the zoom lens of the present invention will be described with reference to FIG. In FIG. 21, 10 is a single-lens reflex camera body, 11 is an interchangeable lens equipped with a zoom lens according to the present invention, 12 is a recording means such as a film or an image sensor for recording a subject image obtained through the interchangeable lens 11, and 13 is an interchangeable lens. A finder optical system for observing the subject image from 11, and a rotating quick return mirror 14 for switching and transmitting the subject image from the interchangeable lens 11 to the recording means 12 and the finder optical system 13. When observing the subject image with the finder, the subject image formed on the focusing plate 15 via the quick return mirror 14 is made into an erect image with the pentaprism 16 and then magnified and observed with the eyepiece optical system 17. At the time of shooting, the quick return mirror 14 rotates in the direction of the arrow, and the subject image is formed and recorded on the recording means 12. Reference numeral 18 denotes a submirror, and 19 denotes a focus detection device.

  Thus, by applying the zoom lens of the present invention to an optical device such as a single lens reflex camera interchangeable lens, an optical device having high optical performance can be realized.

  The present invention can be similarly applied to an SLR (Single Lens Reflex) camera without a quick return mirror.

  As described above, according to each embodiment, it is possible to obtain a compact zoom lens having excellent optical performance and an imaging apparatus having the same, which are suitable for an imaging system using a solid-state imaging device.

  In the following, numerical examples 1 to 5 corresponding to the first to fifth examples will be described. In each numerical example, i indicates the order of the surfaces from the object side, Ri is the radius of curvature of each surface, Di is the member thickness or air space between the i-th surface and the i-th surface + 1 surface, Ni, νi represents the refractive index and Abbe number for the d-line, respectively. When the aspherical shape is X with the displacement in the optical axis direction at the position of the height h from the optical axis as the reference to the surface vertex,

It is represented by Where R is the paraxial radius of curvature, and A, B, C, D, E, and F are aspheric coefficients.
“E-X” means “× 10 ^−X ”. f represents a focal length, Fno represents an F number, and ω represents a half angle of view. Table 1 shows the relationship between the above-described conditional expressions and numerical values in the numerical examples.
Numerical example 1
f = 14.36-27.31 Fno = 2.9-2.9 2ω = 112.9-76.8

* R 1 = 223.581 D 1 = 4.00 N 1 = 1.696797 ν 1 = 55.5
R 2 = 33.100 D 2 = 6.60
R 3 = 56.307 D 3 = 3.50 N 2 = 1.772499 ν 2 = 49.6
R 4 = 25.380 D 4 = Variable
* R 5 = -467.418 D 5 = 0.15 N 3 = 1.524210 ν 3 = 51.4
R 6 = -442.388 D 6 = 1.20 N 4 = 1.834807 ν 4 = 42.7
R 7 = 33.164 D 7 = 0.40
R 8 = 32.328 D 8 = 6.00 N 5 = 1.846660 ν 5 = 23.9
R 9 = 126.348 D 9 = variable
R10 = 68.672 D10 = 1.30 N 6 = 1.805181 ν 6 = 25.4
R11 = 20.889 D11 = 10.63 N 7 = 1.517417 ν 7 = 52.4
R12 = -138.404 D12 = 0.15
R13 = 37.519 D13 = 4.59 N 8 = 1.603420 ν 8 = 38.0
R14 = -60.492 D14 = variable
R15 = Aperture D15 = 1.75
R16 = -485.237 D16 = 1.45 N 9 = 1.834000 ν 9 = 37.2
R17 = 95.437 D17 = 2.88
R18 = -33.132 D18 = 1.00 N10 = 1.688212 ν10 = 36.9
R19 = 25.299 D19 = 5.67 N11 = 1.846660 ν11 = 23.9
R20 = -86.941 D20 = 2.24
R21 = ∞ D21 = variable
R22 = 29.168 D22 = 8.20 N12 = 1.496999 ν12 = 81.5
R23 = -24.286 D23 = 1.20 N13 = 1.846660 ν13 = 23.9
R24 = -39.969 D24 = 0.20
R25 = 369.930 D25 = 1.20 N14 = 1.834000 ν14 = 37.2
R26 = 22.018 D26 = 5.76 N15 = 1.496999 ν15 = 81.5
R27 = 351.539 D27 = 0.80
R28 = 84.207 D28 = 3.40 N16 = 1.516330 ν16 = 64.1
* R29 = -83.342 D29 = variable
R30 = ∞

\ Focal length 14.36 20.13 27.31
Variable interval \
D 4 18.67 18.67 18.67
D 9 22.36 9.11 0.91
D14 0.46 5.72 11.03
D21 10.87 5.60 0.29
D29 0.00 7.57 17.79

Aspheric coefficient

1st: A = 0.00000e + 00 B = 5.73935e-06 C = -4.36016e-09 D = 3.35180e-12
E = -1.54311e-15 F = 3.20074e-19

5th: A = 0.00000e + 00 B = -1.49548e-06 C = 4.13178e-09 D = 2.87900e-11
E = -8.95658e-14 F = 9.04275e-17

29 planes: A = 0.00000e + 00 B = 1.48459e-05 C = 6.48731e-09 D = 6.90394e-11
E = -2.39156e-15 F = -3.89575e-16



Numerical example 2
f = 14.49 to 27.38 Fno = 2.9 to 2.9 2ω = 112.4 to 76.6

R 1 = 76.231 D 1 = 3.00 N 1 = 1.799969 ν 1 = 47.2
R 2 = 30.750 D 2 = 2.74
* R 3 = 59.728 D 3 = 2.52 N 2 = 1.738454 ν 2 = 53.2
R 4 = 22.492 D 4 = Variable
* R 5 = -221.065 D 5 = 0.15 N 3 = 1.491710 ν 3 = 57.4
R 6 = -168.893 D 6 = 1.20 N 4 = 1.834807 ν 4 = 42.7
R 7 = 31.608 D 7 = 0.39
R 8 = 31.406 D 8 = 5.50 N 5 = 1.846660 ν 5 = 23.9
R 9 = 171.995 D 9 = variable
R10 = 41.855 D10 = 1.30 N 6 = 1.755199 ν 6 = 27.5
R11 = 21.672 D11 = 14.21 N 7 = 1.516330 ν 7 = 64.1
R12 = -62.366 D12 = 0.15
R13 = 35.949 D13 = 3.56 N 8 = 1.603112 ν 8 = 60.6
R14 = -200.256 D14 = variable
R15 = Aperture D15 = 1.75
R16 = -101.225 D16 = 1.45 N 9 = 1.834807 ν 9 = 42.7
R17 = 74.496 D17 = 2.08
R18 = -45.350 D18 = 1.00 N10 = 1.723420 ν10 = 38.0
R19 = 21.767 D19 = 4.84 N11 = 1.846660 ν11 = 23.9
R20 = -93.123 D20 = 2.24
R21 = ∞ D21 = variable
R22 = 27.559 D22 = 6.96 N12 = 1.496999 ν12 = 81.5
R23 = -25.293 D23 = 1.20 N13 = 1.846660 ν13 = 23.9
R24 = -35.046 D24 = 0.20
R25 = -64.663 D25 = 1.20 N14 = 1.834000 ν14 = 37.2
R26 = 24.342 D26 = 5.70 N15 = 1.496999 ν15 = 81.5
R27 = -108.988 D27 = 0.15
R28 = 91.872 D28 = 3.50 N16 = 1.516330 ν16 = 64.1
* R29 = -54.675 D29 = variable
R30 = ∞

\ Focal length 14.49 20.06 27.38
Variable interval \
D 4 18.95 18.95 18.95
D 9 26.17 12.46 3.53
D14 0.43 4.31 8.98
D21 10.68 6.80 2.13
D29 0.00 6.65 15.63

Aspheric coefficient

3rd: A = 0.00000e + 00 B = 1.28079e-05 C = -1.06919e-08 D = 3.07241e-11
E = -4.34149e-14 F = 3.74659e-17

5th: A = 0.00000e + 00 B = -6.04627e-06 C = 2.07633e-08 D = -1.45843e-11
E = -6.27917e-14 F = 1.21729e-16

29th: A = 0.00000e + 00 B = 1.50293e-05 C = 1.04202e-08 D = 3.71158e-11
E = 1.04329e-13 F = -5.36305e-16



Numerical example 3
f = 14.37-27.36 Fno = 2.9-2.9 2ω = 112.8-76.7

* R 1 = 306.359 D 1 = 4.00 N 1 = 1.677900 ν 1 = 55.3
R 2 = 35.974 D 2 = 6.13
R 3 = 59.209 D 3 = 3.50 N 2 = 1.696797 ν 2 = 55.5
R 4 = 24.750 D 4 = variable
R 5 = -129.125 D 5 = 1.35 N 3 = 1.696797 ν 3 = 55.5
R 6 = 32.486 D 6 = 0.40
* R 7 = 32.136 D 7 = 6.20 N 4 = 1.688931 ν 4 = 31.1
R 8 = 263.907 D 8 = variable
R 9 = 69.014 D 9 = 1.30 N 5 = 1.805181 ν 5 = 25.4
R10 = 21.060 D10 = 9.70 N 6 = 1.517417 ν 6 = 52.4
R11 = -113.992 D11 = 0.15
R12 = 37.795 D12 = 4.59 N 7 = 1.603420 ν 7 = 38.0
R13 = -58.146 D13 = Variable
R14 = Aperture D14 = 1.75
R15 = -451.470 D15 = 1.45 N 8 = 1.834000 ν 8 = 37.2
R16 = 88.632 D16 = 2.95
R17 = -32.844 D17 = 1.00 N 9 = 1.700443 ν 9 = 37.9
R18 = 24.500 D18 = 5.73 N10 = 1.846660 ν10 = 23.9
R19 = -87.765 D19 = 2.24
R20 = ∞ D20 = variable
R21 = 29.125 D21 = 8.20 N11 = 1.496999 ν11 = 81.5
R22 = -24.226 D22 = 1.20 N12 = 1.846660 ν12 = 23.9
R23 = -39.281 D23 = 0.20
R24 = 473.553 D24 = 1.20 N13 = 1.834000 ν13 = 37.2
R25 = 20.831 D25 = 5.76 N14 = 1.496999 ν14 = 81.5
R26 = 285.653 D26 = 0.80
R27 = 81.409 D27 = 3.40 N15 = 1.516330 ν15 = 64.1
* R28 = -69.791 D28 = variable
R29 = ∞

\ Focal length 14.37 20.10 27.36
Variable interval \
D 4 20.69 20.69 20.69
D 8 23.08 9.23 0.59
D13 0.69 5.49 10.68
D20 10.82 6.03 0.84
D28 0.00 7.15 16.80

Aspheric coefficient

Side 1: A = 0.00000e + 00 B = 5.87978e-06 C = -4.73949e-09 D = 3.60568e-12
E = -1.54917e-15 F = 2.95596e-19

7th: A = 0.00000e + 00 B = -6.01199e-07 C = 2.91369e-09 D = 2.22624e-11
E = -8.02839e-14 F = 8.51770e-17

28th surface: A = 0.00000e + 00 B = 1.35926e-05 C = 1.35713e-09 D = 9.20909e-11
E = -1.75129e-13 F = 1.94189e-18



Numerical example 4
f = 14.35-27.31 Fno = 2.9-2.9 2ω = 112.9-76.8

* R 1 = 448.399 D 1 = 4.00 N 1 = 1.677900 ν 1 = 55.3
R 2 = 36.035 D 2 = 5.09
R 3 = 51.191 D 3 = 3.50 N 2 = 1.718546 ν 2 = 54.3
R 4 = 24.461 D 4 = variable
* R 5 = -349.842 D 5 = 0.15 N 3 = 1.524210 ν 3 = 51.4
R 6 = -442.388 D 6 = 1.20 N 4 = 1.834807 ν 4 = 42.7
R 7 = 34.450 D 7 = 0.37
R 8 = 31.788 D 8 = 6.00 N 5 = 1.805181 ν 5 = 25.4
R 9 = 129.390 D 9 = variable
R10 = 84.734 D10 = 1.30 N 6 = 1.805181 ν 6 = 25.4
R11 = 20.181 D11 = 9.53 N 7 = 1.517417 ν 7 = 52.4
R12 = -192.015 D12 = 0.15
R13 = 38.193 D13 = 4.59 N 8 = 1.634142 ν 8 = 34.5
R14 = -53.659 D14 = variable
R15 = Aperture D15 = 1.75
R16 = -2156.794 D16 = 1.45 N 9 = 1.783540 ν 9 = 36.3
R17 = 85.166 D17 = 3.00
R18 = -30.783 D18 = 1.00 N10 = 1.676500 ν10 = 37.6
R19 = 25.297 D19 = 4.96 N11 = 1.846660 ν11 = 23.9
R20 = -89.288 D20 = 2.24
R21 = ∞ D21 = variable
R22 = 30.342 D22 = 8.20 N12 = 1.496999 ν12 = 81.5
R23 = -23.249 D23 = 1.20 N13 = 1.846660 ν13 = 23.9
R24 = -38.401 D24 = 0.20
R25 = 223.295 D25 = 1.20 N14 = 1.834000 ν14 = 37.2
R26 = 21.167 D26 = 5.76 N15 = 1.496999 ν15 = 81.5
R27 = 281.425 D27 = 0.80
R28 = 81.072 D28 = 3.40 N16 = 1.516330 ν16 = 64.1
* R29 = -77.752 D29 = variable
R30 = ∞

\ Focal length 14.35 20.07 27.31
Variable interval \
D 4 20.18 20.18 20.18
D 9 23.57 9.41 0.48
D14 0.70 5.23 10.05
D21 10.66 6.13 1.32
D29 0.00 7.48 17.58

Aspheric coefficient

1 side: A = 0.00000e + 00 B = 6.20731e-06 C = -4.72921e-09 D = 3.34323e-12
E = -1.35101e-15 F = 2.51467e-19

5th: A = 0.00000e + 00 B = -3.46981e-06 C = 6.61213e-09 D = 3.25391e-12
E = -3.02309e-14 F = 3.03195e-17

29th: A = 0.00000e + 00 B = 1.29914e-05 C = 6.66495e-09 D = 6.58619e-12
E = 2.39061e-13 F = -7.51612e-16


Numerical example 5
f = 14.66-26.72 Fno = 2.9-2.9 2ω = 111.8-78.0

* R 1 = 175.589 D 1 = 4.00 N 1 = 1.696797 ν 1 = 55.5
R 2 = 33.982 D 2 = 7.76
R 3 = 66.593 D 3 = 3.50 N 2 = 1.719995 ν 2 = 50.2
R 4 = 28.174 D 4 = variable
* R 5 = -261.392 D 5 = 0.15 N 3 = 1.834807 ν 3 = 42.7
R 6 = -300.691 D 6 = 1.20 N 4 = 1.834807 ν 4 = 42.7
R 7 = 29.557 D 7 = 0.39
R 8 = 29.676 D 8 = 5.50 N 5 = 1.846660 ν 5 = 23.9
R 9 = 95.118 D 9 = variable
R10 = 72.697 D10 = 1.30 N 6 = 1.846660 ν 6 = 23.9
R11 = 21.355 D11 = 10.23 N 7 = 1.515574 ν 7 = 51.6
R12 = -89.175 D12 = 0.15
R13 = 37.817 D13 = 4.79 N 8 = 1.624022 ν 8 = 35.9
R14 = -54.604 D14 = variable
R15 = Aperture D15 = 1.75
R16 = -620.483 D16 = 1.45 N 9 = 1.855247 ν 9 = 40.1
R17 = 74.971 D17 = 3.89
R18 = -29.335 D18 = 1.00 N10 = 1.665285 ν10 = 37.3
R19 = 24.316 D19 = 4.82 N11 = 1.846660 ν11 = 23.9
R20 = -80.794 D20 = 2.24
R21 = ∞ D21 = variable
R22 = 28.351 D22 = 8.60 N12 = 1.496999 ν12 = 81.5
R23 = -23.368 D23 = 1.20 N13 = 1.846660 ν13 = 23.9
R24 = -40.483 D24 = 0.20
R25 = 220.197 D25 = 1.20 N14 = 1.834000 ν14 = 37.2
R26 = 20.390 D26 = 5.74 N15 = 1.496999 ν15 = 81.5
R27 = 187.907 D27 = 0.80
R28 = 72.203 D28 = 3.40 N16 = 1.516330 ν16 = 64.1
* R29 = -74.229 D29 = variable
R30 = ∞

\ Focal length 14.66 19.53 26.72
Variable interval \
D 4 17.23 23.97 19.43
D 9 21.82 7.64 2.14
D14 1.35 6.66 10.89
D21 10.33 5.02 0.78
D29 0.00 7.44 17.48

Aspheric coefficient

1 side: A = 0.00000e + 00 B = 4.55515e-06 C = -3.44502e-09 D = 3.21538e-12
E = -1.72122e-15 F = 4.06512e-19

5th: A = 0.00000e + 00 B = 7.28597e-07 C = -5.39086e-09 D = 5.66902e-12
E = 4.65407e-14 F = -1.06317e-16

29th: A = 0.00000e + 00 B = 1.50137e-05 C = 1.29734e-08 D = -2.98943e-11
E = 3.97281e-13 F = -1.08994e-15

FIG. 3 is a lens cross-sectional view at the zoom position at the wide angle end according to the first embodiment of the present invention. Aberration diagram at the zoom position at the wide angle end according to the first embodiment of the present invention. Aberration diagram at the intermediate zoom position in Example 1 of the present invention Aberration diagram at the zoom position at the telephoto end according to the first embodiment of the present invention. Sectional drawing of the lens at the zoom position at the wide angle end according to the second embodiment of the present invention Aberration diagram at the zoom position at the wide angle end according to the second embodiment of the present invention. Aberration diagram at the intermediate zoom position in Embodiment 2 of the present invention Aberration diagram at the zoom position at the telephoto end according to the second embodiment of the present invention. FIG. 6 is a lens cross-sectional view at the zoom position at the wide angle end according to the third embodiment of the present invention. Aberration diagram at the zoom position at the wide angle end according to the third embodiment of the present invention. Aberration diagram at the intermediate zoom position in Embodiment 3 of the present invention Aberration diagram at the zoom position at the telephoto end according to the third embodiment of the present invention. Cross-sectional view of a lens at a zoom position at the wide-angle end according to Embodiment 4 of the present invention Aberration diagrams at the zoom position at the wide-angle end according to Embodiment 4 of the present invention. Aberration diagram at the intermediate zoom position in Embodiment 4 of the present invention Aberration diagram at the zoom position at the telephoto end according to the fourth embodiment of the present invention. Cross-sectional view of a lens at a zoom position at the wide-angle end according to Embodiment 5 of the present invention Aberration diagram at zoom position at wide-angle end according to Embodiment 5 of the present invention Aberration diagrams at the intermediate zoom position in Example 5 of the present invention Aberration diagrams at the zoom position at the telephoto end according to the fifth embodiment of the present invention. Schematic diagram of the main part of the imaging apparatus of the present invention

Explanation of symbols

L1: First lens unit L2: Second lens unit L3: Third lens unit L4: Fourth lens unit L1a: First a lens unit L1b: First b lens unit SP: Aperture IP: Image plane d: d-line g: g Line ΔS: Sagittal image plane ΔM: Meridional image plane

Claims (10)

In order from the object side to the image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power are provided. The distance between the first lens group and the second lens group at the telephoto end is smaller than that at the wide-angle end, and the distance between the second lens group and the third lens group is large. The third lens group and the fourth lens group Zoom lens in which the second to fourth lens groups move so that the distance between the first lens group and the first lens group becomes negative at the widest distance in order from the object side to the image side. It consists of a 1a lens group having a refractive power and a 1b lens group having a negative refractive power. The air distance between the 1a lens group and the 1b lens group is Dab, the focal length of the entire system at the wide angle end is fw, When the focal lengths of the second lens group and the fourth lens group are f2 and f4, respectively.
0.8 <Dab / fw <2.0
2.0 <f2 / fw <3.5
3.0 <f4 / fw <4.5
A zoom lens characterized by satisfying the following conditions: In order from the object side to the image side, a first lens group having a negative refractive power, a second lens group having a positive refractive power, a third lens group having a negative refractive power, and a fourth lens group having a positive refractive power are provided. The distance between the first lens group and the second lens group at the telephoto end is smaller than that at the wide-angle end, and the distance between the second lens group and the third lens group is large. The third lens group and the fourth lens group Zoom lens in which the second to fourth lens groups move so that the distance between the first lens group and the first lens group increases in order from the object side to the image side. The lens group includes a lens group and a 1b lens group. The 1a lens group includes a negative lens G1a1 and a negative lens G1a2 and one or more aspherical surfaces. The 1b lens group includes a negative lens G1b1 and a positive lens. G1b2 and one or more aspherical surfaces, and the distance between the 1a lens group and the 1b lens group is When ab, the focal length of the entire system at the wide angle end fw,
0.8 <Dab / fw <2.0
A zoom lens characterized by satisfying the following conditions: When the back focus of the entire system at the wide angle end is bfw and the focal length of the entire system at the wide angle end is fw,
0.25 <fw / bfw <0.5
The zoom lens according to claim 1 or 2, wherein the following condition is satisfied. In order from the object side to the image side, the first-a lens group includes a negative lens G1a1 and a negative lens G1a2. The distance between the negative lens G1a1 and the negative lens G1a2 is d1a, and the focal length of the entire system at the wide-angle end is fw. And when
0.1 <d1a / fw <0.7
The zoom lens according to claim 1, 2 or 3, wherein the following condition is satisfied. When the focal lengths of the first lens group and the second lens group are f1 and f2, respectively.
−0.8 <f1 / f2 <−0.4
The zoom lens according to claim 1, wherein the following condition is satisfied. When the focal length of the third lens group is f3 and the focal length of the entire system at the wide angle end is fw,
−6.0 <f3 / fw <−3.4
The zoom lens according to claim 1, wherein the following condition is satisfied.   The zoom lens according to claim 1, wherein the first b lens group is a lens group for focusing. The 1a lens group has one or more negative lenses, and when the Abbe number of the material of the negative lens arranged closest to the object is νg1,
42 <νg1 <71
The zoom lens according to claim 1, wherein the following condition is satisfied.   The zoom lens according to claim 1, wherein an image is formed on a solid-state imaging device.   An image pickup apparatus comprising: the zoom lens according to claim 1; and a solid-state image pickup device that receives an image formed by the zoom lens.