JP5907600B2 - Zoom lens and imaging apparatus having the same - Google Patents

Description

  The present invention relates to a zoom lens suitable for a still camera, a television camera, a video camera, a photographic camera, a digital camera, and the like. In particular, the present invention relates to a zoom lens using a focusing method capable of performing excellent aberration correction over the entire object distance from infinity to the closest distance.

  2. Description of the Related Art Conventionally, as a focusing method for a zoom lens, a so-called front lens focus method in which a first lens group located closest to the object side is moved in the optical axis direction is known. In addition, a so-called inner focus method or rear focus method is known in which the second lens unit and subsequent lens units are moved in the optical axis direction for focusing. In any of these focus methods, one lens group is moved in the optical axis direction during focusing. In the method of focusing by moving one lens unit, aberration variation is likely to occur during focusing, and it is difficult to obtain good optical performance over the entire object distance.

  In particular, when the object distance is as close as required for the macro lens system, the aberration variation becomes large, and it becomes difficult to maintain high optical performance. In recent years, there has been a demand for a zoom lens having good optical performance over a wide photographing distance range from infinity to a close range as required for a macro lens system. Conventionally, as a focusing method, zoom lenses using a floating method in which a plurality of lens groups are moved in the optical axis direction during focusing are known in order to improve aberration fluctuation during focusing (Patent Documents 1 to 4).

  When the floating method is used, the focusing stroke (movement amount) of the focusing lens group can be shortened when focusing to a close distance, and the entire lens system can be reduced in size and aberration variations can be easily reduced. Become. In particular, focusing is facilitated while reducing fluctuations in aberrations up to the close range as in macro photography.

  In Patent Document 1, in a zoom lens including a front group having a positive refractive power from the object side, a zooming group that moves during zooming, and a fixed relay lens group, two lens groups in the relay lens group are moved during focusing. Yes. In Patent Document 2, in a zoom lens including a front group having a negative refractive power from the object side, a zooming group that moves during zooming, and a fixed relay lens group, the two lens groups of the relay lens group are moved during focusing. .

  In the zoom lens disclosed in Patent Document 3, a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a lens group having a negative refractive power are included in the final lens group in order from the object side to the image side. doing. The first lens group and the last lens group are moved during focusing. In the zoom lens of Patent Document 4, 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 negative lens group. A fourth lens group having a refractive power and a fifth lens group having a positive refractive power are included. The first lens group and the second lens group are moved during focusing.

JP 61-236516 A Japanese Patent Laid-Open No. Sho 62-153914 Japanese Patent Application Laid-Open No. 08-015608 Japanese Patent Laid-Open No. 11-258506

  In a zoom lens, in order to obtain high optical performance over the entire zoom range and the entire object distance (full focus range), it is necessary to appropriately set the power and lens configuration of each lens group constituting the zoom lens. For example, it is important to appropriately set the zoom method and the focusing method.

  In general, when the object distance that can be photographed is shortened and the photographing magnification is increased, the aberration variation increases during focusing, and the optical performance is greatly deteriorated. The floating method described above is an effective method for reducing aberration fluctuations during focusing. However, it is difficult to reduce aberration fluctuations and maintain high optical performance even if focusing is performed by simply moving a plurality of lens groups among the lens groups constituting the zoom lens.

  For example, it is important to appropriately set the configuration of a lens group that is moved during zooming, the refractive power of the plurality of lens groups that are moved during focusing, the movement conditions such as the movement amount, and the focus sensitivity. If these configurations are inappropriate, it becomes difficult to obtain high optical performance over the entire object distance while ensuring a predetermined zoom ratio.

  An object of the present invention is to provide a zoom lens having a small aberration variation during focusing and having high optical performance over the entire object distance, and an image pickup apparatus having the same.

The zoom lens of the present invention includes, in order from the object side to the image side, a front group containing multiple lens groups, an aperture stop having a rear group that includes a plurality of lens groups move during focusing, adjacent zooming or focusing A zoom lens in which the distance between lens groups changes ,
Before SL rear group includes a lens group N of negative refractive power, a lens group P of positive refractive power disposed on the image side of the lens group N,
During focusing from infinity to the closest distance, the lens group N moves to the image side, the lens group P moves to the object side ,
When the respective F _N, F _P the focus sensitivity of the lens unit N and the lens group P when focusing on infinity in the telephoto end,
−10.0 <F _N ≦ −2.77
2.0 <F _P <10.0
It satisfies the following conditional expression .
In addition, the zoom lens of the present invention is arranged in order from the object side to the image side, from a front group including a plurality of lens groups that move during zooming, an aperture stop, and a rear group that includes a plurality of lens groups that move during focusing. A zoom lens configured to change the interval between adjacent lens groups during zooming or focusing,
The front group includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side. During zooming from the end to the telephoto end, the second lens group moves toward the image side, and the third lens group moves along a convex locus toward the image side,
The rear group includes a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a negative refractive power arranged in order from the object side to the image side. The fifth lens group is moved to the image side and the sixth lens group is moved to the object side during focusing from infinity to the closest distance.
Lenses arranged in order from the object side to the image side, including a front group including a plurality of lens groups that move during zooming, an aperture stop, and a rear group that includes a plurality of lens groups that move during focusing, and are adjacent to each other during zooming or focusing A zoom lens with variable group spacing,
The front group includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side. During zooming from the end to the telephoto end, the second lens group moves toward the image side, and the third lens group moves along a convex locus toward the image side,
The rear group includes a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, a sixth lens group having a negative refractive power, and a positive refractive power disposed in order from the object side to the image side. The seventh lens group and the eighth lens group having a negative refractive power, and when focusing from infinity to the closest distance, the fifth lens group moves to the image side, and the seventh lens group moves to the object side. It is characterized by moving.
Lenses arranged in order from the object side to the image side, including a front group including a plurality of lens groups that move during zooming, an aperture stop, and a rear group that includes a plurality of lens groups that move during focusing, and are adjacent to each other during zooming or focusing A zoom lens with variable group spacing,
The front group includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side. During zooming from the end to the telephoto end, the second lens group moves toward the image side, the third lens group moves along a locus that is convex toward the image side, and the fourth to eighth lenses. The group moves integrally to the object side,
The rear group includes a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a positive refractive power disposed in order from the object side to the image side. The seventh lens group and the eighth lens group having a negative refractive power, and when focusing from infinity to the closest distance, the fifth lens group moves to the image side, and the seventh lens group moves to the object side. It is characterized by moving.
Lenses arranged in order from the object side to the image side, including a front group including a plurality of lens groups that move during zooming, an aperture stop, and a rear group that includes a plurality of lens groups that move during focusing, and are adjacent to each other during zooming or focusing A zoom lens with variable group spacing,
The front group includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side. During zooming from the end to the telephoto end, the first lens group moves toward the object side, the second lens group moves along a convex locus toward the image side, and the third lens group moves toward the object side. The fourth lens group to the seventh lens group integrally move toward the object side,
The rear group includes a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a negative refractive power arranged in order from the object side to the image side. The fifth lens group is moved to the image side and the sixth lens group is moved to the object side during focusing from infinity to the closest distance.
Lenses arranged in order from the object side to the image side, including a front group including a plurality of lens groups that move during zooming, an aperture stop, and a rear group that includes a plurality of lens groups that move during focusing, and are adjacent to each other during zooming or focusing A zoom lens with variable group spacing,
The front group includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side. During zooming from the end to the telephoto end, the first lens group, the third lens group to the seventh lens group move to the object side along different paths, and the second lens group has a convex path toward the image side. Draw and move,
The rear group includes a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a negative refractive power arranged in order from the object side to the image side. The fifth lens group is moved to the image side and the sixth lens group is moved to the object side during focusing from infinity to the closest distance.

  According to the present invention, it is possible to obtain a zoom lens that has a small aberration variation during focusing and has high optical performance over the entire object distance.

(A), (B), (C) Lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end at an object distance of infinity according to Numerical Example 1 of the present invention. (A), (B), (C) Lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end near the object distance according to Numerical Example 1 of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end at an object distance of infinity according to Numerical Example 1 of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end near the object distance according to Numerical Example 1 of the present invention. (A), (B), (C) Lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end at infinite object distance according to Numerical Example 2 of the present invention. (A), (B), (C) Lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end near the object distance according to Numerical Example 2 of the present invention (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end at an object distance of infinity according to Numerical Example 2 of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end near the object distance according to Numerical Example 2 of the present invention. (A), (B), (C) Lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end at infinite object distance according to Numerical Example 3 of the present invention (A), (B), (C) Lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end close to the object distance according to Numerical Example 3 of the present invention (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end at an object distance of infinity according to Numerical Example 3 of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end near the object distance according to Numerical Example 3 of the present invention. (A), (B), (C) Cross-sectional views of lenses at the wide-angle end, the intermediate zoom position, and the telephoto end at an object distance of infinity according to Numerical Example 4 of the present invention. (A), (B), (C) Lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end close to the object distance according to Numerical Example 4 of the present invention (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end at an object distance of infinity according to Numerical Example 4 of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end near the object distance according to Numerical Example 4 of the present invention. (A), (B), (C) Lens sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end at an object distance of infinity according to Numerical Example 5 of the present invention. (A), (B), (C) Lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end near the object distance according to Numerical Example 5 of the present invention (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end at an object distance of infinity according to Numerical Example 5 of the present invention. (A), (B), (C) Aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end near the object distance according to Numerical Example 5 of the present invention. Paraxial conceptual diagram showing the basic principle of the zoom lens of the present invention Schematic diagram of main parts of an imaging apparatus of the present invention

Embodiments of a zoom lens of the present invention and an image pickup apparatus having the same will be described below with reference to the drawings. In the zoom lens of the present invention, a plurality of lens groups move during focusing. The zoom lens includes a lens group N having a negative refractive power and a lens group P having a positive refractive power disposed on the image side of the lens group N. During focusing from infinity to the closest distance, the lens unit N moves to the image side, and the lens unit P moves to the object side.

  The closest distance is the shortest shooting distance at each focal length, and corresponds to the end on the shorter shooting distance in the focusing range at each focal length. The shooting distance is a distance from a distance reference mark (for example, an image plane) provided on the camera body to the subject. In addition, the lens group in the present invention refers to a plurality of lenses or a single lens that moves together during zooming or focusing.

  In general, in order to perform quick AF (autofocus), it is desirable to perform focusing with a small and lightweight lens group disposed behind the stop. In order to suppress aberration fluctuations due to focusing, it is desirable to use a floating system in which a plurality of lens groups are independently moved. Furthermore, in order to reduce the size of the entire lens system, it is preferable that the amount of movement of each focus lens group when focusing to the closest distance is small.

In the zoom lens of the present invention, when focusing from infinity to the closest distance, the lens unit N having a negative refractive power located on the image side with respect to the stop is moved to the image side, adjacent to the image side, or other A lens unit P having a positive refractive power located across the lens unit is extended toward the object side. As a result, the maximum photographing magnification is increased, and aberration variation due to focusing is reduced.

The arrangement order of the focus lens groups is, in order from the object side to the image side, the lens group N 1 having a negative refractive power and the lens group P having a positive refractive power. If the refractive power is arranged in a positive or negative order, it is difficult to secure a required back focus length and to correct aberration fluctuations during focusing.

Next, a basic optical principle for obtaining a high photographing magnification in the zoom lens of the present invention will be described. In order from the object side to the image side, the zoom unit includes a movable lens group during zooming, and the imaging unit responsible for image formation. The light beam emitted from the zoom unit and incident on the image formation unit is parallel light. In this case, the zoom portion is called an afocal system. At this time, the following relational expression is established between the focal length f of the entire system and the focal length f ₀ of the imaging unit.

f = γ × f ₀
Γ in the equation is called angular magnification, and is defined by the ratio of the height of the light beam incident from the object side to the height of the light beam incident on the imaging unit from the optical axis. By changing the angular magnification γ, the focal length of the entire system changes, and a zoom lens is configured. FIG. 21 is an explanatory diagram of the characteristics of this optical system. Due to the coupling of the afocal system, the image side principal point position changes from H ′ ₀ to H ′ in the figure and the focal length changes, but the image side focal position F ′ does not change. In such an optical system, when focusing is performed in the imaging unit, the following relationship is established between the imaging magnification β _z of the optical system and the imaging magnification β _R of the imaging unit.

β _Z = β _R / γ
This relationship is derived by: Newton's formula (Source: Yoshiya Matsui Lens Design Method Kyoritsu Publishing)
x ・ x '= f ²
From the distance x ′ from the image-side focal point to the image plane and the focal length f of the optical system,
β _Z = -x '/ f = -x' / γ ・ f ₀ = β _R / γ
The relationship holds.

Since the focal length f is changed by the angular magnification γ without changing the distance x ′ by the connection of the afocal system, the photographing magnification of the optical system is determined by the lateral magnification β _R and the angular magnification γ of the imaging system. Using this principle, the shooting magnification of the entire zoom range can be determined. For example, in Numerical Example 1 to be described later of the present invention, the focal length of the lens group LR, which is an image forming unit, is 113 mm, and the angular magnification γ at the telephoto end is 1.7. Since the lateral magnification at the closest distance of the imaging unit is 0.85, the photographing magnification β _Z at the telephoto end is 0.85 / 1.7 = 0.5 times.

  In the zoom lens of the present invention, the maximum photographing magnification is the magnification at the closest distance at the telephoto end. When the lens group R is considered as one macro lens optical system, from the above-described principle, the present invention can be considered as an optical system in which the object point of the macro lens is changed by a zoom optical system located on the object side. In this case, the object point at the telephoto end is the longest in the entire zoom range, and this distance is the shortest shooting distance as a zoom lens that can change the focal length without changing the back focus.

  In the present invention, the photographing magnification in the wide-angle range can be made higher than the maximum photographing magnification as a zoom lens. In Numerical Example 1 to be described later of the present invention, the angular magnification at the wide-angle end is 0.63. Therefore, the photographing magnification is 0.85 / 0.63 = 1.3 with the same amount of focus lens group extended at the wide-angle end and the closest distance at the telephoto end. Doubled. By setting the angular magnification γ, the photographing magnification as the entire zoom system is increased more than the lateral magnification of the lens group LR, and photographing at a closer distance becomes easier.

  In the present invention, the closest distance can be arbitrarily set according to the amount of movement of the focus lens group. In this case, even if the maximum photographing magnification is small, a zoom lens that maintains good performance over the entire focus area can be obtained by floating.

  1A, 1B, and 1C show the wide-angle end (short focal length end), the intermediate zoom position, and the telephoto end (long focus) when focusing on infinity according to Numerical Example 1 of the present invention. It is lens sectional drawing of a distance end. 2A, 2B, and 2C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on the closest distance according to Numerical Example 1 of the present invention. FIGS. 3A, 3B, and 3C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on infinity according to Numerical Example 1 of the present invention. 4A, 4B, and 4C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on the closest distance according to Numerical Example 1 of the present invention.

  5A, 5B, and 5C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on infinity according to Numerical Example 2 of the present invention. 6A, 6B, and 6C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on the closest distance according to Numerical Example 2 of the present invention. FIGS. 7A, 7B, and 7C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on infinity according to Numerical Example 2 of the present invention. 8A, 8B, and 8C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on the closest distance according to Numerical Example 2 of the present invention.

  9A, 9B, and 9C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on infinity according to Numerical Example 3 of the present invention. 10A, 10B, and 10C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on the closest distance according to Numerical Example 3 of the present invention. FIGS. 11A, 11B, and 11C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on infinity according to Numerical Example 3 of the present invention. 12A, 12B, and 12C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on the closest distance according to Numerical Example 3 of the present invention.

  13A, 13B, and 13C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on infinity according to Numerical Example 4 of the present invention. 14A, 14B, and 14C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on the closest distance according to Numerical Example 4 of the present invention. FIGS. 15A, 15B, and 15C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on infinity according to Numerical Example 4 of the present invention. 16A, 16B, and 16C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on the closest distance according to Numerical Example 4 of the present invention.

  17A, 17B, and 17C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on infinity according to Numerical Example 5 of the present invention. 18A, 18B, and 18C are lens cross-sectional views at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on the closest distance according to Numerical Example 5 of the present invention. FIGS. 19A, 19B, and 19C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on infinity according to Numerical Example 5 of the present invention. 20A, 20B, and 20C are aberration diagrams at the wide-angle end, the intermediate zoom position, and the telephoto end when focusing on the closest distance according to Numerical Example 5 of the present invention.

  FIG. 21 is an explanatory diagram of the zoom lens of the present invention. FIG. 22 is a schematic view of the main part of the imaging apparatus of the present invention. In the lens cross-sectional view, the left side is the object side (subject side) and the right side is the image side. In each lens cross-sectional view, Li is the i-th lens group, where i is the order when counted from the object side. LF is a front group having a plurality of lens groups, SP is an aperture stop, and LR is a rear group having a plurality of lens groups. FC is a flare-cut stop, and SP2 is an Fno stop. The aperture number is changed corresponding to zooming to change the F number of the entire system.

  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. The arrows related to zoom indicate the movement locus of each lens unit during zooming from the wide-angle end to the telephoto end zoom position. An arrow indicated by a dotted line related to the focus indicates a movement locus of each lens unit related to focusing from infinity to the closest distance.

  In the spherical aberration diagram, the solid line is the d-line. In the astigmatism diagram, the dotted line is the meridional image plane, and the solid line is the sagittal image plane. The distortion is shown for the d line. Fno is the F number, and ω is the half angle of view (degrees). In the following embodiments, the wide-angle end and the telephoto end refer to zoom positions when the zoom lens group is positioned at both ends of a range that can move on the optical axis due to the mechanism.

Next, features of the zoom lens of the present invention will be described. In each embodiment, the front unit LF includes a lens unit having a negative refractive power that moves during zooming and a lens unit having a positive refractive power that moves during zooming. The rear group LR includes a lens unit N having a negative refractive power that moves toward the image side and a lens group P having a positive refractive power that moves toward the object side during focusing from infinity to the closest distance. Each focus sensitivity of the lens unit N and the lens group P when focusing on infinity in the telephoto end F _N, and F _P. At this time,
−10.0 <F _N ≦ −2.77 (1)
2.0 <F _P <10.0 (2)
The following conditional expression is satisfied.

Conditional expressions (1) and (2) relate to the focus sensitivity of the lens group N and the lens group P that move during focusing. F _N in the formula, the focus sensitivity of the lens unit N for focusing having a negative refractive power, F _P is the focus sensitivity of the lens unit P for focusing having a positive refractive power.

  Here, the focus sensitivity is a value defined as “the amount of movement of the image point caused by moving the focus lens group by 1 mm (unit amount)”. Conditional expressions (1) and (2) indicate that the closest distance is shortened by the movement of the respective focus lens groups, and the optical performance at the closest distance and the efficient shortening of the closest distance are shown. It is a conditional expression for maintaining good.

Exceeds the upper limit of condition (1), the focus sensitivity F _N is a positive value, the closest distance becomes long by the lens group N of negative refractive power is moved to the image side, the entire system is large It will turn. If the refractive power of the lens unit N having a negative refractive power is so strong that the lower limit of the conditional expression (1) is exceeded, it becomes difficult to correct variations in various aberrations due to focusing.

If the refractive power of the lens unit P having a positive refractive power is so strong that the upper limit of the conditional expression (2) is exceeded, it becomes difficult to correct variations in various aberrations due to focusing. If the refractive power of the lens unit P having a positive refractive power is so weak that the lower limit of conditional expression (2) is exceeded, the entire system becomes large. Further, when the focus sensitivity F _P takes a negative value, the closest distance becomes longer by moving the lens unit P having a positive refractive power toward the object side, and the entire system becomes larger.

In each embodiment, it is more preferable to satisfy one or more of the following conditional expressions. The zoom lens includes, in order from the object side to the image side, a front group LF having a plurality of lens groups, an aperture stop SP, and a rear group LR having a plurality of lens groups. Let dfN and dfP be the movement amounts of the lens group N and the lens group P during focusing from infinity to the closest distance at the telephoto end, respectively. Let fR be the focal length of the rear lens group LR when focusing at infinity at the wide-angle end.

At the telephoto end, the lateral magnifications of the rear group LR when focusing on the infinity and the closest distance are β _Rtinf and β _Rtmod , respectively. The distance from the aperture stop SP to the front principal point position of the rear group LR when focusing on infinity at the wide angle end is defined as O1R. At this time, one or more of the following conditional expressions should be satisfied.

0.08 <| dfN / fR | <0.30 (3)
0.08 <| dfP / fR | <0.30 (4)
0.8 <| dfN / dfP | <1.5 (5)
0.2 <| β _Rtinf− β _Rtmod | <1.0 (6)
| O1R / fR | <0.5 (7)
Here, the sign of the amount of movement is positive when moving to the image side and negative when moving to the object side.

Conditional expressions (3) and (4) are for reducing the closest distance with respect to the moving amount of the lens group N and the lens group P that move by focusing.

If the movement amount of the lens group N and the lens group P increases beyond the upper limit of the conditional expressions (3) and (4), the entire system becomes larger. Condition (3), beyond the lower limit of (4), the moving amount of the focusing lens group is reduced, if not increasing the refractive power of the lens unit N N a lens group P P, focusing from infinity to the minimum object distance Can not be. Further, when the refractive power of the lens group N and the lens group P is increased, fluctuations in various aberrations due to focusing become large, and it becomes difficult to correct this.

Furthermore, conditional expression (5) represents the ratio of the moving amounts of the lens group N and the lens group P that move during focusing. When the lens unit N having a negative refractive power is moved to the image side, the spherical aberration moves in the over direction and the image plane moves in the under direction. When the lens unit P having a positive refractive power is moved to the object side, the spherical aberration moves in the under direction and the image plane moves in the over direction.

By moving the lens group N and the lens group P so as to satisfy the conditional expression (5), it becomes easy to cancel out these aberration changes and obtain good optical performance at the closest distance. If the upper and lower limits of conditional expression (5) are exceeded, there will be a lot of aberration fluctuations during focusing that the focus lens group with the larger movement amount will have, making it difficult to maintain good optical performance at the closest distance. Become.

  Conditional expression (6) relates to the imaging magnification at the closest distance of the zoom lens at the infinite distance and the closest distance at the telephoto end of the rear group LR located on the image side of the aperture stop SP. If the lateral magnification of the rear lens group LR is so large that the upper limit of conditional expression (6) is exceeded, correction of aberration fluctuations during zooming and focusing becomes difficult. If the lateral magnification of the rear group LR is so small that the lower limit of conditional expression (6) is exceeded, it becomes difficult to obtain a desired maximum photographing magnification.

Condition (7) indicates the range up to the front principal point position when focusing on infinity in the wide-angle end of the rear unit LR that is located behind the aperture stop aperture from SP SP, compact zoom lens It is for aiming at. If the position of the front principal point of the rear group LR behind the aperture stop SP is closer to the image side than the upper limit of the conditional expression (7), it is positioned closer to the focus lens group, particularly the image side, depending on the height of off-axis rays. The effective diameter of the lens unit P having a positive refractive power increases, and the entire system increases in size. In addition, the weight of the focus lens group becomes heavy, and quick AF becomes difficult.

The rear group LR located on the image side from the aperture stop SP functions as a macro lens system that increases the photographing magnification at the closest distance. In order to satisfy the conditional expression (7), it is difficult to increase the refractive power of the lens unit N having negative refractive power and the lens unit P having positive refractive power on the image side. As a result, it is difficult to set the maximum photographing magnification as a macro lens system as large as a macro lens system with a single focal length.

  On the other hand, in the zoom lens according to the present invention, the angular magnification γ for obtaining a desired photographing magnification is set based on the principle described above. As a result, it is not necessary to ensure a large photographing magnification as in the macro lens system. This ensures high zoom magnification while ensuring a compact zoom lens. In each embodiment, even if a part of the lenses in the optical system is moved in a direction having a component perpendicular to the optical axis as an anti-vibration lens group, image blurring during vibration can be corrected. good.

  As described above, according to each embodiment, it is possible to provide a zoom lens having a maximum photographing magnification of about 0.5 and having good optical performance in the entire zoom range and the entire focus range. Next, features of the lens configuration of the zoom lens of each embodiment will be described. In the zoom lens of Example 1, the front lens group LF includes, in order from the object side to the image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, and a third lens having a positive refractive power. It consists of groups. The rear group LR includes a fourth lens unit L4 having a positive refractive power, a fifth lens unit L5 having a negative refractive power, a sixth lens unit L6 having a positive refractive power, and a seventh lens unit L7 having a negative refractive power. ing.

During zooming from the wide-angle end to the telephoto end, the second lens unit L2 moves toward the image side, and the third lens unit L3 moves along a locus that is convex toward the image side. During focusing from infinity to the closest distance, the fifth lens group ( lens group N ) L5 moves to the image side, and the sixth lens group ( lens group P ) L6 moves to the object side. During zooming from the wide-angle end to the telephoto end, the second lens unit L2 performs main zooming, and the image plane that moves due to zooming is corrected by the movement of the third lens unit L3. By moving the two lens groups, necessary zooming is obtained and fluctuations due to zooming of various aberrations are suppressed.

  In this embodiment, two lens groups are moved at the time of focusing. However, in order to reduce aberration fluctuation during further focusing, two or more lens groups may be moved. In Example 1, it is more preferable that conditional expressions (1) to (7) are in the following numerical ranges.

−5.0 <F _N ≦ −2.77 (1a)
2.0 < _FP <5.0 (2a)
0.10 <| dfN / fR | <0.30 (3a)
0.10 <| dfP / fR | <0.30 (4a)
1.1 <| dfN / dfP | <1.5 (5a)
0.7 <| β _Rtinf− β _Rtmod | <1.0 (6a)
| O1R / fR | <0.4 (7a)
In the zoom lens of Example 2, the front lens group LF includes, in order from the object side to the image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, and a third lens unit having a positive refractive power. L3. The rear group LR includes a fourth lens unit L4 having a positive refractive power, a fifth lens unit L5 having a negative refractive power, a sixth lens unit L6 having a negative refractive power, a seventh lens unit L7 having a positive refractive power, and a negative lens unit L7. It is composed of an eighth lens unit L8 having a refractive power.

During zooming from the wide-angle end to the telephoto end, the second lens unit L2 moves toward the image side, and the third lens unit L3 moves along a locus that is convex toward the image side. During focusing from infinity to the closest distance, the fifth lens group ( lens group N ) L5 moves to the image side, and the seventh lens group ( lens group P ) L7 moves to the object side. During zooming from the wide-angle end to the telephoto end, the second lens unit L2 performs main zooming, and the image plane that moves due to zooming is corrected by the movement of the third lens unit L3. By moving the two lens groups, necessary zooming is obtained and fluctuations due to zooming of various aberrations are suppressed.

  In this embodiment, two lens groups are moved at the time of focusing, but two or more lens groups may be moved in order to further reduce aberration fluctuations during focusing. In the second embodiment, the numerical ranges of the conditional expressions (1) to (7) are more preferably set as follows.

-10.0 <F _N <-5.0 (1b)
2.0 < _FP <9.0 (2b)
0.10 <| dfN / fR | <0.30 (3b)
0.10 <| dfP / fR | <0.30 (4b)
0.9 <| dfN / dfP | <1.2 (5b)
0.6 <| β _Rtinf− β _Rtmod | <1.0 (6b)
0.0 <| O1R / fR | <0.2 (7b)
In the zoom lens of Example 3, the front lens group LF includes, in order from the object side to the image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, and a third lens unit having a positive refractive power. L3. The rear group LR includes a fourth lens unit L4 having a positive refractive power, a fifth lens unit L5 having a negative refractive power, a sixth lens unit L6 having a positive refractive power, a seventh lens unit L7 having a positive refractive power, and a negative lens unit. It is composed of an eighth lens unit L8 having a refractive power.

During zooming from the wide-angle end to the telephoto end, the second lens unit L2 moves toward the image side, and the third lens unit L3 moves along a locus that is convex toward the image side. The fourth lens unit L4 to the eighth lens unit L8 move integrally to the object side. During focusing from infinity to the closest distance, the fifth lens unit L5 ( lens unit N ) L5 moves to the image side, and the seventh lens unit ( lens unit P ) L7 moves to the object side.

  During zooming from the wide-angle end to the telephoto end, the second lens unit L2 performs main zooming, and the image plane that moves due to zooming is corrected by the movement of the third lens unit L3. Two or more lens groups move during zooming, so that necessary zooming is obtained and fluctuations of various aberrations due to zooming are suppressed.

  In this embodiment, two lens groups are moved during focusing, but two or more lens groups may be moved in order to further reduce aberration fluctuations during focusing. In the third embodiment, it is more preferable to set the numerical ranges of the conditional expressions (1) to (7) as follows.

-10.0 <F _N <-2.0 (1c)
2.0 <F _P <5.0 (2c)
0.10 <| dfN / fR | <0.30 (3c)
0.10 <| dfP / fR | <0.30 (4c)
1.0 <| dfN / dfP | <1.5 (5c)
0.7 <| β _Rtinf− β _Rtmod | <1.0 (6c)
0.0 <| O1R / fR | <0.2 (7c)
In the zoom lens according to the fourth exemplary embodiment, the front lens group LF includes, in order from the object side to the image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, and a third lens having a positive refractive power. It consists of group L3. The rear group LR includes a fourth lens unit L4 having a positive refractive power, a fifth lens unit L5 having a negative refractive power, a sixth lens unit L6 having a positive refractive power, and a seventh lens unit L7 having a negative refractive power. ing.

During zooming from the wide-angle end to the telephoto end, the first lens unit L1 moves toward the object side, the second lens unit L2 moves along a locus that is convex toward the image side, and the third lens unit L3 moves toward the object side. Moving. The fourth lens unit L4 to the eighth lens unit L8 move integrally to the object side. During focusing from infinity to the closest distance, the fifth lens group ( lens group N ) L5 moves to the image side, and the sixth lens group ( lens group P ) L6 moves to the object side.

  During zooming from the wide-angle end to the telephoto end, the first, third, and fourth to eighth lens groups perform zooming, and the image plane that moves due to zooming is corrected by the movement of the second lens group L2. ing. By moving a plurality of lens groups during zooming, necessary zooming is obtained and fluctuations of various aberrations due to zooming are suppressed. In this embodiment, two lens groups are moved at the time of focusing, but two or more lens groups may be moved in order to further reduce aberration fluctuations during focusing. In the fourth embodiment, it is more preferable to set the numerical ranges of the conditional expressions (1) to (7) as follows.

-2.0 <F _N <0.0 (1d)
3.0 <F _P <8.0 (2d)
0.10 <| dfN / fR | <0.30 (3d)
0.09 <| dfP / fR | <0.30 (4d)
0.9 <| dfN / dfP | <1.5 (5d)
0.4 <| β _Rtinf− β _Rtmod | <0.8 (6d)
0.1 <| O1R / fR | <0.3 (7d)
In the zoom lens of Embodiment 5, the front lens group LF includes, in order from the object side to the image side, a first lens unit L1 having a positive refractive power, a second lens unit L2 having a negative refractive power, and a third lens having a positive refractive power. It consists of group L3. The rear group LR includes a fourth lens unit L4 having a positive refractive power, a fifth lens unit L5 having a negative refractive power, a sixth lens unit L6 having a positive refractive power, and a seventh lens unit L7 having a negative refractive power. ing.

During zooming from the wide-angle end to the telephoto end, the first lens unit L1, the third lens unit L3 to the seventh lens unit L7 move to the object side along different paths, and the second lens unit L2 is convex toward the image side. Move along a trail. During focusing from infinity to the closest distance, the fifth lens group ( lens group N ) L5 moves to the image side, and the sixth lens group ( lens group P ) L6 moves to the object side.

  During zooming from the wide-angle end to the telephoto end, the first, third, and fourth to seventh lens units perform zooming, and the image plane that moves due to zooming is corrected by the movement of the second lens unit L2. ing. All the lens groups move independently during zooming, so that necessary zooming is obtained and fluctuations of various aberrations due to zooming are suppressed.

  In this embodiment, two lens groups are moved during focusing, but two or more lens groups may be moved in order to further reduce aberration fluctuations during focusing. In the fifth embodiment, it is more preferable to set the numerical ranges of the conditional expressions (1) to (8) as follows.

-2.0 <F _N <0.0 (1e)
4.0 <F _P <8.0 (2e)
0.08 <| dfN / fR | <0.25 (3e)
0.08 <| dfP / fR | <0.25 (4e)
1.0 <| dfN / dfP | <1.5 (5e)
0.3 <| β _Rtinf− β _Rtmod | <0.6 (6e)
0.1 <| O1R / fR | <0.2 (7e)
Next, numerical examples 1 to 5 corresponding to the first to fifth embodiments of the present invention are shown.

  In the numerical examples, i indicates the order of the surfaces from the object side. ri is the radius of curvature of the i-th surface, and di is the distance between the i-th and i + 1-th surfaces. ndi and νdi are values of the refractive index and Abbe number of the lens material with respect to the d-line (λ = 587.6 nm), respectively. A4, A6, A8, and A10 are aspheric coefficients, and the shape of the aspheric surface is the position X in the optical axis direction when the intersection of the lens surface and the optical axis is the origin, and the light traveling direction is positive. From the position Y in the direction perpendicular to the optical axis, it is expressed by the following formula.

Where R is the paraxial radius of curvature. “E-0X” means “× 10 ^−x ”. BF is a back focus. Table 1 shows the relationship between the above-described conditional expressions and numerical examples.

[Numerical Example 1]
Unit mm

Surface data
Surface number rd nd νd Effective diameter
1 100.925 2.1 1.69895 30.1 61.79
2 65.156 0.31 60
3 66.709 8.35 1.43387 95.1 60.01
4 1206.703 0.15 59.58
5 71.044 7.34 1.497 81.5 57.44
6 1793.281 (variable) 56.64
7 157.425 1.2 1.804 46.6 32.52
8 31.727 6.84 29.82
9 -134.64 1.25 1.497 81.5 28.97
10 33.05 4.77 1.80518 25.4 28.1
11 493.419 3.61 27.57
12 -47.186 1.25 1.801 35 26.84
13 -172.301 (variable) 27.24
14 190.401 4.9 1.6968 55.5 27.89
15 -29.377 1.4 1.83481 42.7 28
16 -68.103 (variable) 28.67
17 (Aperture) ∞ 1.4 28.69
18 62.76 3.57 1.6727 32.1 28.69
19 -98.523 0.2 28.53
20 42.855 3.8 1.6968 55.5 26.73
21 80.685 2.44 25.18
22 -91.944 1.6 1.80518 25.4 24.7
23 28.001 5.04 1.59282 68.6 23.32
24 -77.381 0.71 22.99
25 1629.791 1.37 1.84666 23.9 22.17
26 36.519 3.14 21.36
27 -64.404 2.05 1.6223 53.2 21.36
28 31.211 4.32 1.80809 22.8 21.99
29 -119.497 38.39 22.05
30 357.537 5.04 1.72 50.2 35.22
31 -53.635 0.5 35.53
32 62.636 7.26 1.6223 53.2 34.52
33 -43.07 1.5 1.883 40.8 34.09
34 645.292 2.78 33.32
35 -131.214 1.5 1.834 37.2 32.96
36 45.5 3.29 32.9
37 43.514 3.54 1.883 40.8 35.8
38 96.86 50.12 35.67

Image plane ∞
Various data
Zoom ratio 2.68
Wide angle Medium telephoto focal length 72.11 131.37 193.4
F number 4 4 4
Half angle of view (degrees) 16.7 9.35 6.38
Image height 21.64 21.64 21.64
Total lens length 234.52 234.52 234.52
BF 50.12 50.12 50.12

d6 2.37 31.13 42.35
d13 28.82 15.21 0.95
d16 16.3 1.16 4.19






Entrance pupil position 59.23 131.61 171.53
Exit pupil position -97.31 -97.31 -97.31
Front principal point position 96.07 145.92 111.23
Rear principal point position -21.99 -81.25 -143.27


Zoom lens group data
Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 111.53 18.25 4.86 -7.69
2 7 -32.51 18.92 5.2 -8.85
3 14 89.69 6.3 2.81 -0.88
4 17 55.87 18.05 0.36 -12.1
5 25 -54.26 10.89 -1.54 -9.53
6 30 53.49 14.29 0.86 -7.59
7 35 -78.84 8.33 -1.22 -7.24


Single lens data
Lens Start surface Focal length
1 1 -269.54
2 3 162.39
3 5 148.63
4 7 -49.63
5 9 -53.26
6 10 43.79
7 12 -81.49
8 14 36.86
9 15 -62.92
10 18 57.5
11 20 125.98
12 22 -26.5
13 23 35.31
14 25 -44.14
15 27 -33.51
16 28 31.02
17 30 65.11
18 32 42.12
19 33 -45.68
20 35 -40.35
21 37 86.78

[Numerical Example 2]
Unit mm

Surface data
Surface number rd nd νd Effective diameter
1 142.116 2.1 1.72047 34.7 61.09
2 75.448 0.5 59.57
3 75.024 10 1.43387 95.1 59.61
4 -258.928 0.15 59.17
5 59.745 7.3 1.43387 95.1 55.63
6 350.491 (variable) 54.74
7 494.288 1.2 1.804 46.6 31.2
8 32.35 4 28.67
9 1145.599 1.25 1.497 81.5 28.46
10 28.377 4.77 1.80518 25.4 27.52
11 222.399 2.5 26.96
12 -49.976 1.25 1.801 35 26.82
13 -366.162 (variable) 26.74
14 155.236 4.9 1.6968 55.5 27.22
15 -28.249 1.4 1.83481 42.7 27.32
16 -65.951 (variable) 27.96
17 (Aperture) ∞ 1.4 27.69
18 127.375 3.57 1.6727 32.1 27.65
19 -76.515 0.2 27.5
20 31.655 3.8 1.6968 55.5 25.73
21 85.018 2.24 24.53
22 -111.684 1.6 1.80518 25.4 23.93
23 26.296 5.04 1.59282 68.6 22.34
24 -75.11 0.81 21.89
25 467.939 1.37 1.84666 23.9 20.81
26 29.607 2.86 19.78
27 -61.646 1.08 1.6223 53.2 19.76
28 24.917 4.32 1.80809 22.8 20.14
29 -100.428 16.61 20.12
30 160.401 2.5 1.76182 26.5 24.23
31 106.675 15.28 24.63
32 -142.61 3.08 1.80518 25.4 30.72
33 -42.788 0.5 31.06
34 59.299 6.42 1.51742 52.4 31.06
35 -37.718 1.5 2.00069 25.5 30.86
36 -114.687 1.44 31.16
37 -83.271 1.5 1.834 37.2 31.04
38 56.799 3.29 31.62
39 43.514 3.54 1.883 40.8 35.33
40 96.86 39.96 35.24

Image plane ∞
Various data
Zoom ratio 2.68
Wide angle Medium telephoto focal length 72.14 130.58 193.38
F number 4 4 4
Half angle of view (degrees) 16.69 9.41 6.38
Image height 21.64 21.64 21.64
Total lens length 213.85 213.85 213.85
BF 39.96 39.96 39.96

d6 3.97 32.75 43.98
d13 28.89 15.38 1.07
d16 15.74 0.48 3.56






Entrance pupil position 60.46 130.39 166.94
Exit pupil position -77.06 -77.06 -77.06
Front principal point position 88.13 115.26 40.77
Rear principal point position -32.19 -90.63 -153.42


Zoom lens group data
Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 111.14 20.05 6.72 -7.28
2 7 -32.25 14.97 4.11 -6.42
3 14 82.21 6.3 2.65 -1.04
4 17 46.22 17.85 1.95 -10.45
5 25 -50.05 9.64 -1.46 -8.54
6 30 -426.64 2.5 4.32 2.88
7 32 54.59 11.5 1.78 -5.37
8 37 -78.82 8.33 -1.45 -7.48

Single lens data
Lens Start surface Focal length
1 1 -226.22
2 3 135.3
3 5 164.75
4 7 -43.1
5 9 -58.57
6 10 39.96
7 12 -72.38
8 14 34.68
9 15 -60.21
10 18 71.56
11 20 70.32
12 22 -26.3
13 23 33.47
14 25 -37.38
15 27 -28.38
16 28 25.09
17 30 -426.64
18 32 74.89
19 34 45.58
20 35 -56.72
21 37 -40.29
22 39 86.78

[Numerical Example 3]
Unit mm

Surface data
Surface number rd nd νd Effective diameter
1 101.942 2.1 1.72047 34.7 61.45
2 64.514 0.46 59.63
3 67.415 8.51 1.43387 95.1 59.63
4 7799.242 0.15 59.23
5 64.986 8.2 1.43875 94.9 56.89
6 -4511.65 (variable) 56.04
7 136.575 1.2 1.804 46.6 32.4
8 32.132 7.99 29.77
9 -67.699 1.25 1.497 81.5 28.65
10 38.466 4.77 1.80518 25.4 27.95
11 -331.876 2.89 27.5
12 -49.886 1.25 1.801 35 26.73
13 -302.862 (variable) 27.36
14 190.408 5.9 1.6968 55.5 28.03
15 -28.467 1.4 1.8348 42.7 28.12
16 -65.753 (variable) 28.86
17 (Aperture) ∞ 1.4 28.9
18 63.068 3.57 1.6727 32.1 28.93
19 -101.907 0.2 28.77
20 41.704 3.8 1.6968 55.5 27
21 85.528 2.6 25.53
22 -100.149 1.6 1.80518 25.4 24.6
23 26.371 5.04 1.59282 68.6 23.12
24 -77.054 0.58 22.81
25 -1700.67 1.37 1.84666 23.9 22.02
26 36.486 2.96 21.21
27 -67.657 2.05 1.6223 53.2 21.21
28 30.006 4.32 1.80809 22.8 21.83
29 -124.655 18.13 21.89
30 ∞ 3.6 26.64
31 -10636.7 3 1.6223 53.2 28.14
32 -355.643 12.99 28.84
33 -232.907 4.14 1.72047 34.7 33.52
34 -46.764 0.5 33.93
35 54.282 7.21 1.59282 68.6 33.38
36 -43.153 1.5 1.883 40.8 32.98
37 -1721.54 2.63 32.43
38 -110.459 1.5 1.834 37.2 32.03
39 45.45 3.29 32
40 43.514 3.54 1.883 40.8 34.85
41 96.86 (variable) 34.73


Image plane ∞
Various data
Zoom ratio 2.68
Wide angle Medium telephoto focal length 72.11 132.09 193.4
F number 4.0 4.0 4.0
Half angle of view (degrees) 16.7 9.3 6.38
Image height 21.64 21.64 21.64
Total lens length 233.51 233.51 233.51
BF 49.05 49.77 50.05

d6 2.03 30.58 41.73
d13 26.8 14.1 1.28
d16 18.03 1.46 2.85
d41 49.05 49.77 50.05





Entrance pupil position 59.91 132.19 171.75
Exit pupil position -85.83 -85.83 -85.83
Front principal point position 93.46 135.61 89.89
Rear principal point position -23.05 -82.31 -143.34


Zoom lens group data
Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 110.72 19.43 5.62 -8
2 7 -31.26 19.35 5.46 -8.97
3 14 87.58 7.3 3.25 -1.04
4 17 53.26 18.21 0.57 -12.06
5 25 -52.53 10.71 -1.5 -9.29
6 30 591.2 6.6 5.51 0.06
7 33 56.2 13.35 1.4 -6.65
8 38 -72.05 8.33 -1.11 -7.13


Single lens data
Lens Start surface Focal length
1 1 -249.76
2 3 156.68
3 5 146.09
4 7 -52.53
5 9 -49.16
6 10 43.06
7 12 -74.73
8 14 35.94
9 15 -61.18
10 18 58.42
11 20 112.79
12 22 -25.78
13 23 33.75
14 25 -42.17
15 27 -33.14
16 28 30.31
17 31 591.2
18 33 80.46
19 35 41.7
20 36 -50.15
21 38 -38.44
22 40 86.78

[Numerical Example 4]
Unit mm

Surface data
Surface number rd nd νd Effective diameter
1 1618.788 1.8 1.85026 32.3 68.51
2 53.723 9 1.7495 35.3 60.45
3 336.311 0.15 59.87
4 62.893 8 1.51742 52.4 55.2
5 8285.464 (variable) 53.67
6 * 47.754 1.3 1.72903 54 36.12
7 15.087 11.35 26.71
8 -40.19 1 1.6968 55.5 25.56
9 42.175 0.15 24.56
10 31.019 6.1 1.71736 29.5 24.62
11 -46.487 1.5 24.01
12 -27.605 1.2 1.80809 22.8 23.51
13 -37.805 (variable) 23.42
14 ∞ 1.5 16.28
15 -181.794 2 1.43875 94.9 16.66
16 -29.039 0.48 16.88
17 (Aperture) ∞ 0.5 17.01
18 -66.842 1.35 1.84666 23.9 17
19 28.128 0.84 17.52
20 49.584 3 1.90366 31.3 17.77
21 -52.34 0.15 18.18
22 25.212 2.5 1.497 81.5 18.84
23 113.336 2.24 18.72
24 -33.255 1.23 1.64 60.1 18.67
25 300.546 2.13 19.14
26 -65.277 1.5 1.59282 68.6 19.55
27 44.277 6 1.6398 34.5 20.66
28 -28.176 7.79 21.45
29 ∞ 6.06 21.12
30 286.846 3.6 1.497 81.5 23.03
31 -28.198 0.07 23.3
32 54.81 5.81 1.497 81.5 23.4
33 -25.109 1.14 2.00069 25.5 23.19
34 -72.291 2.0 23.69
35 112.921 5.5 1.7495 35.3 23.7
36 -28.384 1.5 1.804 46.6 23.49
37 31.949 (variable) 23.13


Image plane ∞
Aspheric data
6th page
K = 0.000000E + 00 A 4 = 5.812450E-06 A 6 = -1.114980E-09
A 8 = 1.148370E-12 A10 = 1.237750E-14
Various data
Zoom ratio 2.04
Wide angle Medium Telephoto focal length 24.7 35.15 50.48
F number 4.12 4.12 4.12
Half angle of view (degrees) 41.22 31.61 23.2
Image height 21.64 21.64 21.64
Total lens length 162.21 172.02 187.21
BF 37.48 45.52 56.09

d5 1.21 15.76 30.36
d13 23.07 10.29 0.31
d37 37.48 45.52 56.09






Entrance pupil position 33.93 50.28 68.61
Exit pupil position -38.76 -38.76 -38.76
Front principal point position 50.63 70.77 92.22
Rear principal point position 12.78 10.37 5.6


Zoom lens group data
Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 215.95 18.95 7.66 -3.84
2 6 -29.37 22.6 0.53 -19.01
3 14 78.46 3.5 3.15 0.26
4 17 87.37 8.34 9.73 5
5 24 -375.96 10.86 -55.95 -74.66
6 29 ∞ 0 0 0
7 30 44.02 10.62 1.55 -5.35
8 35 -50.55 7 5.37 1.25
Single lens data
Lens Start surface Focal length
1 1 -65.39
2 2 84.16
3 4 122.44
4 6 -30.77
5 8 -29.39
6 10 26.82
7 12 -133.64
8 15 78.46
9 18 -23.23
10 20 28.58
11 22 64.63
12 24 -46.72
13 26 -44.28
14 27 27.81
15 30 51.86
16 32 35.51
17 33 -38.91
18 35 30.78
19 36 -18.49

[Numerical Example 5]
Unit mm

Surface data
Surface number rd nd νd Effective diameter
1 6701.597 1.8 1.85026 32.3 69.02
2 58.356 9 1.7495 35.3 60.86
3 333.062 0.15 59.49
4 54.018 8 1.51742 52.4 52.32
5 404.569 (variable) 50.54
6 * 52.391 1.3 1.72903 54 37.56
7 15.176 12.83 27.46
8 -34.144 1 1.6968 55.5 26.11
9 44.099 0.15 25.58
10 34.239 6.1 1.71736 29.5 25.78
11 -37.536 1.5 25.53
12 -25.658 1.2 1.80809 22.8 25.04
13 -35.12 (variable) 25.18
14 ∞ 1 20.78
15 143.496 3 1.43875 94.9 21.31
16 -44.691 (variable) 21.58
17 (Aperture) ∞ 0.5 21.79
18 243.24 1.35 2.00069 25.5 21.86
19 25.817 0.71 21.86
20 31.104 3.96 1.72047 34.7 22.31
21 -72.399 0.15 22.55
22 27.381 2.5 1.497 81.5 23.26
23 58.874 (variable) 23.07
24 -70.714 1.23 1.62041 60.3 22.92
25 310.123 1.56 23.11
26 -57.828 1.5 1.883 40.8 23.14
27 69.622 4.53 1.72825 28.5 24.2
28 -35.007 (variable) 24.62
29 91.609 5 1.497 81.5 25.47
30 -32.703 0.5 25.38
31 55.515 5.8 1.59282 68.6 23.16
32 -27.961 1.14 1.80518 25.4 22.86
33 -1453.64 (variable) 22.79
34 66.8 5.38 1.76182 26.5 22.68
35 -22.815 1.5 1.834 37.2 22.42
36 * 25.96 (variable) 21.6

Image plane ∞
Aspheric data
6th page
K = 0 A 4 = 7.59711E-06 A 6 = -5.83894E-10
A 8 = 1.29909E-12 A10 = 1.54230E-14
36th page
K = 0 A 4 = 1.43261E-06 A 6 =-2.41409E-08
A 8 = 2.48719E-10 A10 = -1.00577E-12
Various data
Zoom ratio 2.43
Wide angle Medium Telephoto focal length 24.7 39.95 60.07
F number 4.12 4.12 4.12
Half angle of view (degrees) 41.22 28.44 19.81
Image height 21.64 21.64 21.64
Total lens length 173.65 183.45 198.65
BF 38.28 48.44 62.68

d5 1.21 18.54 31.16
d13 30.35 10.99 0.46
d16 0.5 2.19 0.98
d23 3.35 4.02 4.06
d28 14.34 12.17 11.52


d33 1.28 2.78 3.45
d36 38.28 48.44 62.68

Entrance pupil position 34.81 55.2 70.97
Exit pupil position -34.42 -32.99 -32.43
Front principal point position 51.12 75.55 93.1
Rear principal point position 13.58 8.49 2.61


Zoom lens group data
Group Start surface Focal length Lens construction length Front principal point position Rear principal point position
1 1 220.13 18.95 6.65 -4.81
2 6 -27.57 24.08 0.62 -20.7
3 14 78.05 4 2.6 -0.5
4 17 100.35 9.17 7.29 1.58
5 24 - 183.83 8.82 -14.42 -22.04
6 29 40.55 12.44 1.69 -6.3
7 34 -44.57 6.88 5.98 1.86

Single lens data
Lens Start surface Focal length
1 1 -69.24
2 2 93.09
3 4 119.56
4 6 -29.74
5 8 -27.47
6 10 25.88
7 12 -124.94
8 15 78.05
9 18 -28.95
10 20 30.69
11 22 100.34
12 24 -92.7
13 26 -35.58
14 27 32.58
15 29 49.15
16 31 32.2
17 32 -35.42
18 34 22.92
19 35 -14.36

  Next, an embodiment of a single lens reflex camera system (imaging device) using the zoom lens of the present invention will be described with reference to FIG. In FIG. 22, 10 is a single-lens reflex camera body, and 11 is an interchangeable lens equipped with a zoom lens according to the present invention. Reference numeral 12 denotes a recording means such as a film or an image sensor for recording (receiving) a subject image formed through the interchangeable lens 11. Reference numeral 13 denotes a finder optical system for observing a subject image from the interchangeable lens 11, and reference numeral 14 denotes a rotating quick return mirror 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 imaging apparatus such as a single-lens reflex camera interchangeable lens, an imaging apparatus having high optical performance can be realized.

  The present invention can be similarly applied to a mirrorless single-lens reflex camera without a quick return mirror.

L1 1st lens group L2 2nd lens group L3 3rd lens group L3 3rd lens group L4 4th lens group L5 5th lens group L6 6th lens group L7 7th lens group L8 8th lens group SP Aperture stop

Claims (17)

In order from the object side to the image side, a front group that includes a lens group of multiple, aperture stop has a rear group that includes a plurality of lens groups which move during focusing, the distance between lens adjacent zooming or focusing is changed A zoom lens ,
Before SL rear group includes a lens group N of negative refractive power, a lens group P of positive refractive power disposed on the image side of the lens group N,
During focusing from infinity to the closest distance, the lens group N moves to the image side, the lens group P moves to the object side ,
When the respective F _N, F _P the focus sensitivity of the lens unit N and the lens group P when focusing on infinity in the telephoto end,
−10.0 <F _N ≦ −2.77
2.0 <F _P <10.0
A zoom lens satisfying the following conditional expression: The zoom lens according to claim 1, wherein the front group includes a lens unit having a negative refractive power that moves during zooming and a lens group having a positive refractive power that moves during zooming . The focal lengths of the rear group when focusing the lens group N and the lens group P when focusing from infinity to the closest distance at the telephoto end is set to dfN and dfP, respectively, and at infinity at the wide angle end. When the distance is fR,
0.08 <| dfN / fR | <0.30
0.08 <| dfP / fR | <0.30
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the movement amounts of the lens group N and the lens group P when performing focusing from infinity to the closest distance at the telephoto end are dfN and dfP, respectively,
0.8 <| dfN / dfP | <1.5
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the lateral magnifications of the rear group when focusing at infinity and the closest distance at the telephoto end are β _Rtinf and β _Rtmod , respectively,
0.2 <| β _Rtinf− β _Rtmod | <1.0
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. When the distance on the optical axis from the aperture stop to the front principal point position of the rear group is O1R, and the focal length of the rear group when focusing at infinity at the wide angle end is fR,
| O1R / fR | <0.5
The zoom lens according to claim 1, wherein the following conditional expression is satisfied. The zoom lens is arranged in order from the object side to the image side, and includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive refractive power. A fourth lens group, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a seventh lens group having a negative refractive power,
During zooming from the wide-angle end to the telephoto end, the second lens group moves toward the image side, and the third lens group moves along a convex locus toward the image side, and during focusing from infinity to the closest distance The zoom lens according to claim 1, wherein the fifth lens group moves to the image side and the sixth lens group moves to the object side. The zoom lens includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive refractive power arranged in order from the object side to the image side. A fourth lens group, a fifth lens group having a negative refractive power, a sixth lens group having a negative refractive power, a seventh lens group having a positive refractive power, and an eighth lens group having a negative refractive power,
During zooming from the wide-angle end to the telephoto end, the second lens group moves toward the image side, and the third lens group moves along a convex locus toward the image side, and during focusing from infinity to the closest distance The zoom lens according to claim 1, wherein the fifth lens group moves to the image side, and the seventh lens group moves to the object side. The zoom lens includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive refractive power arranged in order from the object side to the image side. A fourth lens group, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, a seventh lens group having a positive refractive power, and an eighth lens group having a negative refractive power,
During zooming from the wide-angle end to the telephoto end, the second lens group moves toward the image side, the third lens group moves along a locus that is convex toward the image side, and the fourth lens group through the eighth lens group. The lens group moves integrally to the object side,
The focusing lens from infinity to the closest distance, the fifth lens group moves to the image side, and the seventh lens group moves to the object side. Zoom lens. The zoom lens includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive refractive power arranged in order from the object side to the image side. A fourth lens group, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a seventh lens group having a negative refractive power,
During zooming from the wide-angle end to the telephoto end, the first lens group moves toward the object side, the second lens group moves along a locus that is convex toward the image side, and the third lens group moves toward the object side. The fourth lens group to the seventh lens group integrally move toward the object side,
The focusing lens from infinity to the closest distance, the fifth lens group moves to the image side, and the sixth lens group moves to the object side. Zoom lens. The zoom lens includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a positive refractive power, and a positive refractive power arranged in order from the object side to the image side. A fourth lens group, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a seventh lens group having a negative refractive power,
During zooming from the wide-angle end to the telephoto end, the first lens group, the third lens group to the seventh lens group move to the object side along different paths, and the second lens group has a convex path toward the image side. Draw and move
The focusing lens from infinity to the closest distance, the fifth lens group moves to the image side, and the sixth lens group moves to the object side. Zoom lens. Lenses arranged in order from the object side to the image side, including a front group including a plurality of lens groups that move during zooming, an aperture stop, and a rear group that includes a plurality of lens groups that move during focusing, and are adjacent to each other during zooming or focusing A zoom lens with variable group spacing,
  The front group includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side. During zooming from the end to the telephoto end, the second lens group moves toward the image side, and the third lens group moves along a convex locus toward the image side,
  The rear group includes a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a negative refractive power arranged in order from the object side to the image side. Zoom lens, wherein the fifth lens group moves to the image side and the sixth lens group moves to the object side during focusing from infinity to the closest distance. Lenses arranged in order from the object side to the image side, including a front group including a plurality of lens groups that move during zooming, an aperture stop, and a rear group that includes a plurality of lens groups that move during focusing, and are adjacent to each other during zooming or focusing A zoom lens with variable group spacing,
  The front group includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side. During zooming from the end to the telephoto end, the second lens group moves toward the image side, and the third lens group moves along a convex locus toward the image side,
  The rear group includes a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, a sixth lens group having a negative refractive power, and a positive refractive power disposed in order from the object side to the image side. The seventh lens group and the eighth lens group having a negative refractive power, and when focusing from infinity to the closest distance, the fifth lens group moves to the image side, and the seventh lens group moves to the object side. A zoom lens characterized by moving. Lenses arranged in order from the object side to the image side, including a front group including a plurality of lens groups that move during zooming, an aperture stop, and a rear group that includes a plurality of lens groups that move during focusing, and are adjacent to each other during zooming or focusing A zoom lens with variable group spacing,
  The front group includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side. During zooming from the end to the telephoto end, the second lens group moves toward the image side, the third lens group moves along a locus that is convex toward the image side, and the fourth to eighth lenses. The group moves integrally to the object side,
  The rear group includes a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a positive refractive power disposed in order from the object side to the image side. The seventh lens group and the eighth lens group having a negative refractive power, and when focusing from infinity to the closest distance, the fifth lens group moves to the image side, and the seventh lens group moves to the object side. A zoom lens characterized by moving. Lenses arranged in order from the object side to the image side, including a front group including a plurality of lens groups that move during zooming, an aperture stop, and a rear group that includes a plurality of lens groups that move during focusing, and are adjacent to each other during zooming or focusing A zoom lens with variable group spacing,
  The front group includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side. During zooming from the end to the telephoto end, the first lens group moves toward the object side, the second lens group moves along a convex locus toward the image side, and the third lens group moves toward the object side. The fourth lens group to the seventh lens group integrally move toward the object side,
  The rear group includes a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a negative refractive power arranged in order from the object side to the image side. Zoom lens, wherein the fifth lens group moves to the image side and the sixth lens group moves to the object side during focusing from infinity to the closest distance. Lenses arranged in order from the object side to the image side, including a front group including a plurality of lens groups that move during zooming, an aperture stop, and a rear group that includes a plurality of lens groups that move during focusing, and are adjacent to each other during zooming or focusing A zoom lens with variable group spacing,
  The front group includes a first lens group having a positive refractive power, a second lens group having a negative refractive power, and a third lens group having a positive refractive power, which are arranged in order from the object side to the image side. During zooming from the end to the telephoto end, the first lens group, the third lens group to the seventh lens group move to the object side along different paths, and the second lens group has a convex path toward the image side. Draw and move,
  The rear group includes a fourth lens group having a positive refractive power, a fifth lens group having a negative refractive power, a sixth lens group having a positive refractive power, and a negative refractive power arranged in order from the object side to the image side. Zoom lens, wherein the fifth lens group moves to the image side and the sixth lens group moves to the object side during focusing from infinity to the closest distance. A zoom lens according to any one of claims 1 to 16, an imaging apparatus characterized by comprising an imaging element for receiving an image formed by the zoom lens.