JP2006098962A - Zoom lens and imaging apparatus having same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To obtain a zoom lens in which the whole lens system is compact while maintaining high image quality by properly performing lens configuration and lens group arrangement and an imaging apparatus having the same. <P>SOLUTION: The zoom lens has the first lens group B1 of negative refracting power, the second lens group B2 of positive or negative refracting power, the third lens group B3 of positive refracting power and the fourth lens group B4 of negative refracting power in order from the object side to the image side. The third lens group B3 and the fourth lens group B4 move to the object side and the second lens group B2 moves so that an interval between the second lens group B2 and the third lens group B3 at a telescopic end becomes small and an interval between the third lens group B3 and the fourth lens group B4 becomes small compared to a wide-angle end. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

  The present invention relates to a zoom lens, and more particularly to a zoom lens suitable as a photographing lens for a compact digital still camera.

  In recent years, in an imaging lens for a digital camera and an imaging lens for a video camera, the entire lens system is required to be more compact and have higher optical performance. In particular, in a digital camera, it is desired to have a thin form that places importance on the portability of a photographer.

  Conventionally, many lens barrels use a retractable structure that is efficient in storage to realize a thinner camera, and various optical and mechanical devices have been applied to the configuration related thereto. Yes.

  A retractable lens barrel tends to take a lot of time from retracted (stored) to ready to be photographed, and the mechanical mechanism tends to be complicated for efficient storage. is there.

  On the other hand, an optical system that achieves a thin camera without collapsing by suppressing the optical thickness in the object side direction by arranging a reflecting member in the optical system to compensate for such a defect and deflecting the optical axis by approximately 90 °. A system has been proposed (Patent Documents 1 and 2).

    A problem in the case of using a solid-state imaging device as an image forming unit of the imaging device is a structure in which a photoelectric conversion unit on the solid-state imaging device is present in a hole having a certain opening. For this reason, if the incident light beam deviates by more than the vertical angle, the light beam is vignetted at this opening, leading to a decrease in photoelectric conversion sensitivity. For this reason, a conventional photographing optical system using a fixed image sensor is desired to be a telecentric optical system so that the angle of light incident on the image sensor at the center and the periphery of the screen approaches as perpendicular as possible.

  However, an image pickup means has been proposed in which the hole structure of the image sensor is devised to make up for the drawback, and the light beam can be efficiently taken into the photoelectric conversion surface even when the light beam is obliquely incident or the incident angle fluctuates (patent). References 3, 4).

  Furthermore, instead of a glass filter such as an infrared light absorption filter or a quartz low-pass filter having a certain thickness placed on the front surface of a conventional solid-state imaging device, the same effect can be obtained by vapor deposition or a thin optical member. The technique which was made is proposed (patent document 5).

Further, a zoom lens optical system suitable when a solid-state image sensor is used as an imaging unit has been proposed (Patent Document 6).
JP 2004-37967 A JP 2004-69808 A JP 11-68074 A JP 2003-224249 A JP 2000-19457 A JP 2004-133058 A

  Many zoom lenses used in small digital camera photography systems have a negative component (negative refractive power) lens group closest to the object side, and a first positive component (positive refractive power) lens group on the image side. Further, the zoom lens is configured with a zoom lens having negative, positive, and positive component configurations in which the lens group closest to the imaging surface is the second positive component lens group.

  Then, the zooming operation is performed by moving the first positive component lens group, the image plane variation due to zooming is corrected by the negative component lens unit, and the image is incident on the imaging surface by the second positive component lens unit. The light beam is refracted so as to be close to telecentric, and a retrofocus optical system is formed as a whole.

  In such a retrofocus type optical system, the outer diameter (effective diameter) of the second positive component lens group closest to the imaging surface increases, and a constant zooming effect can be achieved with a small amount of lens movement. It is effective to give a strong positive refractive power to the first positive component lens group.

  However, in order to achieve a telecentric optical system, it is necessary to distribute the positive refractive power to the lens group of the second positive component and dispose it separately from the first positive component. For this reason, the refractive power of the lens unit of the first positive component decreases, and as a result, a large amount of movement of the lens unit of the first positive component during zooming must be ensured, and the overall length of the entire lens system increases. Resulting in.

  An object of the present invention is to provide a zoom lens in which the entire lens system is compact while maintaining high image quality and an imaging apparatus having the same by appropriately performing lens configuration and lens group arrangement.

  The zoom lens of the present invention includes, in order from the object side to the image side, a first lens group having a negative refractive power, a second lens group, a third lens group having a positive refractive power, and a fourth lens group having a negative refractive power. The third and fourth lens groups are objects so that the distance between the second lens group and the third lens group is small at the telephoto end relative to the wide-angle end, and the distance between the third lens group and the fourth lens group is small. It moves to the side and the 2nd lens group moves.

  According to the present invention, by appropriately performing the lens configuration and the lens group arrangement, it is possible to obtain a zoom lens in which the entire lens system is compact while maintaining high image quality, 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 cross-sectional view of a zoom lens according to Embodiment 1 of the present invention, FIG. 2 is an optical path diagram when the optical path of the zoom lens according to Embodiment 1 of the present invention is bent, and FIGS. 3, 4, and 5 are respectively implemented. FIG. 6 is aberration diagrams of the zoom lens of Example 1 at a wide angle end, an intermediate zoom position, and a telephoto end (long focal length end).

  FIG. 6 is a lens cross-sectional view of a zoom lens according to Embodiment 2 of the present invention, FIG. 7 is an optical path diagram when the optical path of the zoom lens according to Embodiment 2 of the present invention is bent, and FIGS. FIG. 6 is aberration diagrams of the zoom lens of Example 2 at a wide angle end, an intermediate zoom position, and a telephoto end (long focal length end).

  FIG. 11 is a lens cross-sectional view of a zoom lens according to Embodiment 3 of the present invention, FIG. 12 is an optical path diagram when the optical path of the zoom lens according to Embodiment 3 of the present invention is bent, and FIGS. FIG. 12 is an aberration diagram for the zoom lens of Example 3 at a wide angle end, an intermediate zoom position, and a telephoto end (long focal length end).

  16 is a lens cross-sectional view of a zoom lens according to Example 4 of the present invention, FIG. 17 is an optical path diagram when the optical path of the zoom lens according to Example 4 of the present invention is bent, and FIGS. 18, 19, and 20 are respectively performed. FIG. 10 is aberration diagrams of the zoom lens of Example 4 at a wide angle end, an intermediate zoom position, and a telephoto end (long focal length end).

  21 is a lens cross-sectional view of a zoom lens according to Example 5 of the present invention, FIG. 22 is an optical path diagram when the optical path of the zoom lens according to Example 5 of the present invention is bent, and FIGS. 23, 24, and 25 are respectively performed. FIG. 10 is aberration diagrams of the zoom lens of Example 5 at a wide angle end, an intermediate zoom position, and a telephoto end (long focal length end).

  In the lens cross-sectional view, (A) represents the wide-angle end, (B) represents the intermediate zoom position, and (C) represents the telephoto end.

  FIG. 26 is a schematic diagram of a main part of a digital camera (imaging device) including the zoom lens of the present invention.

  The zoom lens of each embodiment is a photographing lens system used in an imaging apparatus. In the lens cross-sectional view, the left side is the subject side (front) and the right side is the image side (rear).

  In the lens cross-sectional view, B1 is a first lens group including a lens component having a negative refractive power (optical power = reciprocal of focal length), B2 is a second lens group having a positive or negative refractive power, and B3 is a positive refraction. The third lens unit for power, B4 is a fourth lens unit for negative refractive power, and SP is an aperture stop (iris stop), which is located on the object side of the third lens unit B3.

  P is a prism including a reflection surface for bending an optical path included in the first lens unit B1. OB is an object.

  LP is an optical block corresponding to an optical filter, a face plate, a quartz low-pass filter, an infrared cut filter, and the like. IP is an image plane. When used as an imaging optical system for a video camera or a digital still camera, the imaging optics of a silver salt film camera is applied to the imaging surface of a solid-state imaging device (photoelectric conversion device) such as a CCD sensor or a CMOS sensor. When used as a system, a photosensitive surface corresponding to the film surface is placed.

  In the aberration diagrams, d and g are d. C is a sine condition. ΔM and ΔS are meridional image surfaces, sagittal image surfaces, and lateral chromatic aberration is represented by g-line.

  In each of the following embodiments, the wide-angle end and the telephoto end are zoom positions when the zoom lens unit is positioned at both ends of the range in which the zoom lens unit can move on the optical axis.

  In each example, in order from the object side to the image side, the first lens unit B1 having a negative refractive power, the second lens unit B2 having a positive or negative refractive power, the third lens unit B3 having a positive refractive power, and a negative lens unit. The third lens unit B4 has a fourth lens unit B4 having a refractive power, the interval between the second lens unit B2 and the third lens unit B3 is small, and the interval between the third lens unit B3 and the fourth lens unit B4 is reduced. The fourth lens unit B3, B4 moves toward the object side, and the second lens unit B2 moves along a convex locus toward the object side or the image side.

  According to the lens configuration of each embodiment, the total optical length can be shortened by the optical action of the telephoto system of the entire optical system, so that a compact zoom lens can be easily obtained.

  In addition, the entrance pupil position can be set to an appropriate position by disposing a lens component (optical member) G11 having a negative refractive power action in the first lens group B1. As a result, the lens outer diameter before and after the pupil position of the optical system can be balanced, and at the same time, the on-axis and off-axis optical paths can be set appropriately, so that aberration correction for obtaining good image quality can be performed satisfactorily. it can.

  The zoom action of the optical system is mainly caused by changing the relative positional relationship between the third lens group B3 and the fourth lens group B4.

  Specifically, an image obtained by the combined optical system of the first, second, and third lens groups B1 to B3 is further formed by the fourth lens group B4, and the fourth lens with respect to the third lens group B3. The magnification is changed by changing the lateral magnification due to the relative movement change of the group B4. At that time, the third and fourth lens groups B3 and B4 are simultaneously moved to correct (compensate) the change in the imaging position accompanying the zooming.

  Further, by further moving the optical axis of the second lens unit B2 at that time, it is possible to satisfactorily correct the field curvature aberration generated during zooming, and to obtain an image with good image quality even with a high zoom ratio. I can do it.

  Then, the lens thickness in the subject direction is reduced by disposing a reflecting member P having an action of deflecting the light beam (optical path) on the optical axis by approximately 90 ° in the first lens unit B1.

  In each embodiment, one or more of the following conditional expressions is satisfied in order to obtain a high-quality image with a small size.

The combined focal length at the wide-angle end zoom position of the first lens group B1 and the second lens group B2 is F12W, the focal lengths of the third lens group B3 and the fourth lens group B4 are F3 and F4, respectively, and the entire lens system at the wide-angle end. Is set to Fw, and the imaging magnification at the zoom position at the wide-angle end of the fourth lens unit B4 is β4w.
2 <| F12W / Fw | <6 (1)
(However, F12W <0)
0.8 <F3 / Fw <1.6 (2)
0.8 <| F4 / Fw | <1.5 (3)
1 <β4w <1.7 (4)
0.7 <| F3 / F4 | <1.5 (5)
Is satisfied.

  Conditional expression (1) is a condition for reducing the lens outer diameter and preventing the back focus from becoming too short, and obtaining good image quality.

  If the upper limit value of conditional expression (1) is exceeded, the negative combined refractive power of the first and second lens groups B1 and B2 becomes small (weak), so it is formed by the first and second lens groups B1 and B2. The virtual image position of the subject to be moved tends to move away from the object side. Then, in order to obtain a constant peripheral light amount because the back focus of the subject image formed by the third and fourth lens groups B3 and B4 described later becomes too short, the lens outer diameter of the fourth lens group B4 increases. .

  On the other hand, if the lower limit is exceeded, the negative combined refractive power of the first and second lens units B1 and B2 becomes too strong at the zoom position at the telephoto end, and a large amount of positive spherical aberration is generated. It becomes difficult to correct with the lens group.

  When the upper limit of conditional expression (2) is exceeded, the positive refractive power of the third lens unit B3 becomes too small, and in order to obtain a constant angle of view at an arbitrary image height at the zoom position at the wide angle end, The negative refractive power of the four lens unit B4 must also be reduced. As a result, in order to obtain a constant zooming effect, the amount of movement of the second and fourth lens groups B2 and B4 on the optical axis must be increased. As a result, the entire lens system becomes larger.

  On the other hand, if the positive refractive power of the third lens unit B3 exceeds the lower limit and becomes too strong, the back focus becomes too small, and the space for arranging the filter and the cover glass of the image sensor is reduced, which is not good.

  Conditional expression (3) relates to the negative refractive power of the fourth lens unit B4 at the zoom position at the wide-angle end.

  When the negative refractive power of the fourth lens unit B4 becomes weaker than the upper limit value, the zooming action by the fourth lens unit B4 is weakened during zooming (magnification), and thus a constant zooming ratio is obtained. Therefore, the movement amount of each lens group must be increased, and as a result, the total lens length becomes longer.

  On the other hand, if the lower limit is exceeded, the effect of the telephoto system increases as a whole lens, so that the back focus becomes too short, and at the same time, the lens outer diameter of the fourth lens unit B4 is increased in order to secure a constant peripheral light amount. Come on. At the same time, a lot of curvature of field and astigmatism occur, which is not good.

  If the upper limit value of conditional expression (4) is not satisfied, the back focus becomes too short, and if the lower limit value is exceeded, the total lens length increases.

  If the numerical value range of the conditional expression (5) is not satisfied, it becomes difficult to obtain a good image quality while reducing the size of the optical system.

  Also, if the upper limit of conditional expression (5) is deviated and the refractive power of the fourth lens unit B4 is relatively increased with respect to the refractive power of the third lens unit B3, the telephoto system can be used to shorten the optical total length. However, it is difficult to correct high-order off-axis aberrations and lateral chromatic aberrations in the fourth lens unit.

  On the contrary, if the lower limit is exceeded, the total length of the optical system is increased and spherical aberration is greatly generated in the third lens group, which is not good.

  More preferably, the numerical ranges of the conditional expressions (1) to (5) are set as follows.

2.5 <| F12w / Fw | <5 (1a)
1.0 <| F3 / Fw | <1.4 (2a)
0.9 <| F4 / Fw | <1.4 (3a)
1.1 <β4w <1.5 (4a)
0.9 <| F3 / F4 | <1.4 (5a)
In order to achieve a compact and high-performance optical system while reducing the number of lenses, it is effective to dispose at least one aspherical surface in each of the third lens group B3 and the fourth lens group B4. .

  By introducing an aspherical surface to the third lens unit B3, a spherical aberration correction function is mainly provided, and by providing an aspherical surface in the fourth lens unit B4, various off-axis aberrations are balanced. Corrected well.

  In order to obtain good image quality over the entire zoom range while suppressing the outer diameter (moving diameter) of the first lens unit B1, an aperture stop SP is provided in the interval between the second lens unit B2 and the third lens unit B3. It is desirable to arrange.

  In order to further improve image quality and reduce costs, the following configuration is preferable.

  In each embodiment, a lens including an aspherical surface (aspherical lens) may be a composite aspherical lens (so-called replica aspherical lens) in order to expand the types of glass that can be used when considering productivity. It is valid.

  In view of manufacturability, the aspherical lens is preferably made of a plastic material.

  During zooming, the aperture stop SP can obtain an ideal entrance pupil position by moving the optical axis independent of each lens group. In order to simplify the mechanical mechanism, the optical axis may be fixed during zooming.

  A diffractive optical element or a refractive distribution type optical material may be introduced into the lens system, and according to this, the optical performance can be further improved.

To correct image blur due to camera shake that causes image quality degradation during shooting, the deflection angle or deflection direction can be changed by decentering the lens group or a part of the lens group, or by rotating or moving the reflecting member. It is preferable to correct the displacement of the image position for canceling the image blur at the time of shooting.
Focusing from an object at infinity to an object at a finite distance is preferably performed by moving the fourth lens unit B4 to the object side on the optical axis. However, the third lens unit B3 is moved or the third and fourth lens units B3 are moved. , B4 may be performed simultaneously by moving them to the object side on the optical axis.

  As the lens configuration of each lens group, the first lens group B1 is, in order from the object side to the image side, a first lens G11 having a negative refractive power having a larger absolute value of curvature on the image plane side than the object side, a prism or a reflecting mirror. It is good to comprise by deflection members P, such as. However, the negative lens G11 may be integrated with the prism P when a prism is used as the deflecting member, and the prism shape is made concave so that the exit surface has negative refractive power from the beginning. It may be processed. Further, in order to give negative refractive power to the incident surface of the prism P, the concave surface may be processed or joined to a concave lens.

  The second lens unit B2 is preferably a cemented lens in which a negative lens and a positive lens are cemented to satisfactorily correct chromatic aberration variation during zooming and spherical aberration.

  The third lens unit B3 is preferably configured to have a plurality of positive lenses and one or more negative lenses, and in order from the object side to the image side, becomes a positive lens component G31, a negative lens component G32, and a positive lens component G33. Such a lens configuration is desirable in order to perform good aberration correction.

  Here, the lens component refers to a group composed of one or two or more lenses.

  In order to reduce the size of the optical system, a positive lens component G32 having a positive refractive power as a whole and a positive lens component G33 on the image side are joined by sequentially joining a positive lens component, a positive lens, and a negative lens from the object side to the image side. Is preferably arranged.

  In the fifth embodiment, the third lens unit B3 is a cemented lens in which three lenses of a positive lens, a positive lens, and a negative lens are cemented, and a positive lens.

  Here, the two positive lenses on the object side constitute a positive lens component G31, and the negative lens constitutes a negative lens component G32. The positive lens on the image side constitutes the component G33.

  The fourth lens unit B4 is preferably composed of one or two negative lenses.

  When the fourth lens unit B4 is composed of a negative single lens, it is desirable that the fourth lens unit B4 has a lens shape in which the curvature of the lens surface on the image side is larger than that on the object side.

  In order to achieve high image quality, it is preferable to dispose a lens having a weak refractive power having an aspheric surface on the object side and a negative lens having a concave lens surface on the image side on the object side.

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

  In FIG. 26, 10 is a digital camera body, 11 is a photographing optical system constituted by the zoom lens of the present invention, 12 is a strobe built in the camera body, 13 is an external viewfinder, and 14 is a shutter button. Reference numeral 15 denotes a schematic arrangement of the optical system in the camera body of the optical system of the present invention.

  In this way, by applying the zoom lens of the present invention to an image pickup apparatus such as a digital camera, a small-size image pickup apparatus having high optical performance is realized, in particular, the camera body can be thinned.

  Further, in this example, the optical system is arranged so that the optical axis deflected by the reflecting member at the time of horizontal position photographing is in the vertical (vertical) direction, but the deflected optical axis is in the horizontal (horizontal) direction. You may arrange in.

  As described above, according to each embodiment, it is possible to obtain a zoom lens that is small and can maintain good optical performance.

  A lens group having a small refractive power may be added to the object side of the first lens group B1 and / or the image side of the fourth lens group B4.

  Next, numerical examples of the present invention will be shown. 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 distance between the i-th surface and the (i + 1) -th surface, and Ni and νi are d-lines, respectively. The refractive index and Abbe number are shown with reference to.

The two surfaces closest to the image are surfaces constituting the optical block LP. In addition, 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,
x = (h ² / R) / [1+ {1− (1 + k) (h / R) ² } ^1/2 ]
+ Ah ² + Bh ⁴ + Ch ⁶ + Dh ⁸ + Eh ¹⁰
It is represented by However, k is a conic constant, A, B, C, D, and E are aspherical coefficients, and R is a paraxial curvature radius.

“E-0X” means “× 10 ^−x ”. f indicates a focal length, Fno indicates an F number, and ω indicates a half angle of view. Table 1 shows the relationship between the above-described conditional expressions and numerical examples.
Numerical example 1
f = 5.82 to 15.50 Fno = 2.34 to 5.00 2ω = 54.6 to 21.9
R 1 = 17.420 D 1 = 0.80 N 1 = 1.696797 ν 1 = 55.5
R 2 = 9.165 D 2 = 2.50
R 3 = ∞ D 3 = 6.50 N 2 = 1.696797 ν 2 = 55.5
R 4 = ∞ D 4 = Variable
R 5 = -13.555 D 5 = 0.70 N 3 = 1.696797 ν 3 = 55.5
R 6 = 50.746 D 6 = 1.30 N 4 = 1.834000 ν 4 = 37.2
R 7 = -22.278 D 7 = variable
R 8 = Aperture D 8 = 0.70
R 9 = 5.953 D 9 = 1.70 N 5 = 1.733997 ν 5 = 51.5
R10 = 20.439 D10 = 0.25
R11 = -13.273 D11 = 1.70 N 6 = 1.719995 ν 6 = 50.2
R12 = -3.864 D12 = 0.60 N 7 = 1.800999 ν 7 = 35.0
R13 = -38.096 D13 = 0.20
* R14 = 13.106 D14 = 1.70 N 8 = 1.487490 ν 8 = 70.2
* R15 = -4.634 D15 = variable
* R16 = 159.392 D16 = 1.50 N 9 = 1.491710 ν 9 = 57.4
* R17 = 112.510 D17 = 0.60
R18 = -3.771 D18 = 0.70 N10 = 1.729157 ν10 = 54.7
R19 = -18.062 D19 = variable
R20 = ∞ D20 = 0.60 N11 = 1.516330 ν11 = 64.1
R21 = ∞

\ Focal length 5.82 10.46 15.50
Variable interval \
D 4 2.51 0.73 1.19
D 7 7.30 5.16 0.80
D15 2.68 0.97 0.49
D19 1.00 6.62 11.01

Aspheric coefficient
14th: k = -2.39711e + 01 A = 0 B = -2.63697e-03 C = -3.10017e-04 D = -2.70261e-06 E = -6.08507e-06
15th: k = 3.75824e-01 A = 0 B = 3.45097e-04 C = -1.78596e-04 D = 1.09833e-05 E = -4.36814e-06
16 sides: k = -4.70761e + 06 A = 0 B = 6.47376e-03 C = -2.44585e-04 D = 1.35856e-04 E = -1.02447e-05
17th: k = -3.93361e + 06 A = 0 B = 5.70058e-03 C = 2.84537e-04 D = -2.77559e-05 E = 2.99998e-05

Numerical example 2
f = 5.81 to 17.40 Fno = 2.17 to 5.00 2ω = 54.6 to 19.6
R 1 = 22.207 D 1 = 0.80 N 1 = 1.696797 ν 1 = 55.5
R 2 = 10.567 D 2 = 2.50
R 3 = ∞ D 3 = 6.50 N 2 = 1.696797 ν 2 = 55.5
R 4 = ∞ D 4 = Variable
R 5 = -17.860 D 5 = 0.70 N 3 = 1.696797 ν 3 = 55.5
R 6 = 22.922 D 6 = 1.40 N 4 = 1.834000 ν 4 = 37.2
R 7 = -37.907 D 7 = Variable
R 8 = Aperture D 8 = 0.70
R 9 = 5.861 D 9 = 1.70 N 5 = 1.733997 ν 5 = 51.5
R10 = 16.392 D10 = 0.40
R11 = -13.982 D11 = 1.70 N 6 = 1.719995 ν 6 = 50.2
R12 = -3.927 D12 = 0.60 N 7 = 1.800999 ν 7 = 35.0
R13 = -33.158 D13 = 0.20
* R14 = 14.057 D14 = 2.00 N 8 = 1.487490 ν 8 = 70.2
* R15 = -4.784 D15 = variable
* R16 = 1044.095 D16 = 1.20 N 9 = 1.491710 ν 9 = 57.4
* R17 = -2467.527 D17 = 0.70
R18 = -3.634 D18 = 0.70 N10 = 1.729157 ν10 = 54.7
R19 = -13.932 D19 = variable
R20 = ∞ D20 = 0.60 N11 = 1.516330 ν11 = 64.1
R21 = ∞

\ Focal length 5.81 11.23 17.40
Variable interval \
D 4 4.02 1.66 1.69
D 7 7.98 5.58 0.80
D15 2.96 1.01 0.55
D19 1.00 7.71 12.93

Aspheric coefficient
14th: k = 1.21465e + 01 A = 0 B = -3.99646e-03 C = -2.24782e-04 D = 9.20299e-06 E = -3.28205e-06
15th: k = 3.31649e-01 A = 0 B = 4.71148e-04 C = -9.90586e-05 D = 9.47969e-06 E = -1.90976e-06
16 sides: k = -4.70761e + 06 A = 0 B = 7.60243e-03 C = -1.59383e-04 D = 1.36597e-04 E = -6.94020e-06
17th: k = -3.93361e + 06 A = 0 B = 5.98738e-03 C = 5.26927e-04 D = -8.13470e-05 E = 4.19792e-05

Numerical Example 3
f = 5.64 to 16.80 Fno = 2.13 to 5.00 2ω = 56.0 to 20.2
R 1 = 26.248 D 1 = 0.80 N 1 = 1.696797 ν 1 = 55.5
R 2 = 11.139 D 2 = 2.50
R 3 = ∞ D 3 = 10.00 N 2 = 1.696797 ν 2 = 55.5
R 4 = ∞ D 4 = Variable
R 5 = -34.597 D 5 = 0.70 N 3 = 1.603112 ν 3 = 60.6
R 6 = 43.046 D 6 = 1.40 N 4 = 1.805181 ν 4 = 25.4
R 7 = -140.373 D 7 = Variable
R 8 = Aperture D 8 = 0.70
R 9 = 5.194 D 9 = 2.00 N 5 = 1.487490 ν 5 = 70.2
R10 = -164.837 D10 = 0.25
R11 = -14.903 D11 = 1.70 N 6 = 1.666718 ν 6 = 48.3
R12 = -4.462 D12 = 0.60 N 7 = 1.834000 ν 7 = 37.2
R13 = -64.758 D13 = 0.20
* R14 = 13.569 D14 = 2.00 N 8 = 1.487490 ν 8 = 70.2
* R15 = -5.014 D15 = variable
* R16 = 88.288 D16 = 1.20 N 9 = 1.491710 ν 9 = 57.4
* R17 = 67.332 D17 = 1.00
R18 = -3.408 D18 = 0.70 N10 = 1.729157 ν10 = 54.7
R19 = -12.646 D19 = variable
R20 = ∞ D20 = 0.60 N11 = 1.516330 ν11 = 64.1
R21 = ∞

\ Focal length 5.64 11.15 16.80
Variable interval \
D 4 1.50 6.60 4.01
D 7 12.31 2.71 0.80
D15 3.17 1.40 0.88
D19 0.70 6.97 12.00

Aspheric coefficient
14th: k = 1.49021e + 01 A = 0 B = -3.74979e-03 C = -2.23417e-04 D = 1.27559e-05 E = -3.03564e-06
15th: k = 2.94165e-01 A = 0 B = 4.67205e-04 C = -1.33565e-04 D = 1.28139e-05 E = -1.54544e-06
16 sides: k = -4.70761e + 06 A = 0 B = 6.90793e-03 C = -3.09883e-04 D = 9.86846e-05 E = -1.24701e-06
17th: k = -3.93361e + 06 A = 0 B = 5.49110e-03 C = -1.23267e-04 D = -1.25373e-06 E = 2.46770e-05

Numerical Example 4
f = 5.63 to 16.80 Fno = 2.08 to 5.00 2ω = 56.1 to 20.2
R 1 = 48.153 D 1 = 0.80 N 1 = 1.603112 ν 1 = 60.6
R 2 = 11.083 D 2 = 2.30
R 3 = ∞ D 3 = 10.00 N 2 = 1.772499 ν 2 = 49.6
R 4 = ∞ D 4 = Variable
R 5 = 199.961 D 5 = 0.70 N 3 = 1.772499 ν 3 = 49.6
R 6 = 22.845 D 6 = 1.40 N 4 = 1.805181 ν 4 = 25.4
R 7 = 242.865 D 7 = variable
R 8 = Aperture D 8 = 0.70
R 9 = 5.245 D 9 = 2.00 N 5 = 1.487490 ν 5 = 70.2
R10 = -35.017 D10 = 0.25
R11 = -12.568 D11 = 1.70 N 6 = 1.719995 ν 6 = 50.2
R12 = -3.940 D12 = 0.60 N 7 = 1.834000 ν 7 = 37.2
R13 = -109.961 D13 = 0.50
* R14 = 18.634 D14 = 2.00 N 8 = 1.583126 ν 8 = 59.4
* R15 = -5.135 D15 = variable
* R16 = 151.895 D16 = 1.20 N 9 = 1.749497 ν 9 = 35.3
* R17 = 121.189 D17 = 1.00
R18 = -3.555 D18 = 0.70 N10 = 1.729157 ν10 = 54.7
R19 = -20.295 D19 = variable
R20 = ∞ D20 = 0.60 N11 = 1.516330 ν11 = 64.1
R21 = ∞

\ Focal length 5.63 11.07 16.80
Variable interval \
D 4 0.95 2.52 1.84
D 7 10.69 4.61 0.80
D15 2.77 0.98 0.51
D19 0.70 6.99 11.96

Aspheric coefficient
14th: k = 1.66335e + 01 A = 0 B = -3.21818e-03 C = -1.86168e-04 D = 5.40611e-06 E = -2.02531e-06
15th: k = 2.53718e-01 A = 0 B = 3.69525e-04 C = -1.49964e-04 D = 1.18370e-05 E = -1.34525e-06
16 sides: k = -5.25720e + 06 A = 0 B = 5.24497e-03 C = -1.79913e-04 D = 7.42054e-05 E = -3.94180e-06
17th: k = -3.87782e + 06 A = 0 B = 4.24203e-03 C = 4.38752e-05 D = 2.06324e-05 E = 5.70011e-06

Numerical Example 5
f = 5.44 to 10.80 Fno = 2.33 to 4.50 2ω = 57.8 to 31.1
R 1 = 28.789 D 1 = 0.80 N 1 = 1.603112 ν 1 = 60.6
R 2 = 8.451 D 2 = 1.80
R 3 = ∞ D 3 = 8.00 N 2 = 1.772499 ν 2 = 49.6
R 4 = ∞ D 4 = Variable
R 5 = -106.294 D 5 = 0.60 N 3 = 1.772499 ν 3 = 49.6
R 6 = 13.391 D 6 = 1.30 N 4 = 1.805181 ν 4 = 25.4
R 7 = 196.529 D 7 = Variable
R 8 = Aperture D 8 = Variable
R 9 = 5.241 D 9 = 2.10 N 5 = 1.487490 ν 5 = 70.2
R10 = -12.689 D10 = 2.00 N 6 = 1.719995 ν 6 = 50.2
R11 = -3.116 D11 = 0.60 N 7 = 1.834000 ν 7 = 37.2
R12 = 76.863 D12 = 0.50
* R13 = 16.133 D13 = 2.20 N 8 = 1.583126 ν 8 = 59.4
* R14 = -4.841 D14 = variable
* R15 = 724.667 D15 = 1.20 N 9 = 1.749497 ν 9 = 35.3
* R16 = 515.103 D16 = 1.20
R17 = -3.899 D17 = 0.70 N10 = 1.729157 ν10 = 54.7
R18 = -23.118 D18 = variable
R19 = ∞ D19 = 0.60 N11 = 1.516330 ν11 = 64.1
R20 = ∞

\ Focal length 5.44 8.80 10.80
Variable interval \
D 4 0.79 2.60 2.49
D 7 2.61 0.80 0.91
D14 2.76 1.49 1.19
D18 0.70 4.57 6.43


Aspheric coefficient
13th: k = 7.45902e + 00 A = 0 B = -3.86276e-03C = -7.97946e-05 D = -5.25583e-06 E = -1.40582e-06
14th: k = 2.62115e-01 A = 0 B = 1.24566e-04 C = -1.22168e-04 D = 1.28930e-05 E = -1.31993e-06
15th: k = -5.25720e + 06 A = 0 B = 5.58683e-03 C = -3.26978e-04 D = 7.10164e-05 E = -2.09598e-06
16th plane: k = -3.87782e + 06 A = 0 B = 5.30136e-03 C = -1.60201e-04 D = 1.71346e-5
E = 1.02599e-05

Optical cross-sectional view of the zoom lens of Example 1 Optical path diagram when the optical path of the zoom lens of Example 1 is bent 90 degrees Aberration diagram at the wide-angle end of the zoom lens of Example 1 Aberration diagram at the middle zoom position of the zoom lens of Example 1 Aberration diagram at the telephoto end of the zoom lens of Example 1 Optical sectional view of the zoom lens of Example 2 Optical path diagram when the optical path of the zoom lens of Example 2 is bent 90 degrees Aberration diagram at the wide-angle end of the zoom lens of Example 2 Aberration diagram at the intermediate zoom position of the zoom lens of Example 2 Aberration diagram at the telephoto end of the zoom lens of Example 2 Optical sectional view of the zoom lens of Example 3 Optical path diagram when the optical path of the zoom lens of Example 3 is bent 90 degrees Aberration diagram at the wide-angle end of the zoom lens of Example 3 Aberration diagram at the intermediate zoom position of the zoom lens of Example 3 Aberration diagram at the telephoto end of the zoom lens of Example 3 Optical sectional view of the zoom lens of Example 4 Optical path diagram when the optical path of the zoom lens of Example 4 is bent 90 degrees Aberration diagram at the wide-angle end of the zoom lens in Example 4 Aberration diagram at the intermediate zoom position of the zoom lens of Example 4 Aberration diagram at the telephoto end of the zoom lens of Example 4 Optical sectional view of the zoom lens of Example 5 Optical path diagram when the optical path of the zoom lens of Example 5 is bent 90 degrees Aberration diagram at the wide-angle end of the zoom lens in Example 5 Aberration diagram at the intermediate zoom position of the zoom lens of Example 5 Aberration diagram at the telephoto end of the zoom lens of Example 5 Schematic diagram of main parts of an imaging apparatus of the present invention

Explanation of symbols

B1 1st lens group B2 2nd lens group B3 3rd lens group B4 4th lens group SP Aperture IP Image surface G Glass block d d line ΔS Sagittal image surface ΔM Meridional image surface

Claims (9)

  In order from the object side to the image side, there are a first lens group having a negative refractive power, a second lens group, a third lens group having a positive refractive power, and a fourth lens group having a negative refractive power. The third and fourth lens groups move toward the object side so that the distance between the second lens group and the third lens group is small at the telephoto end, and the distance between the third lens group and the fourth lens group is small. A zoom lens, wherein the second lens group moves.   2. The zoom lens according to claim 1, wherein a reflecting member for deflecting a light beam on the optical axis by 90 degrees is provided in the first lens group. When the combined focal length of the first lens group and the second lens group at the wide-angle end is F12w, the focal length of the i-th lens group is Fi, and the focal length of the entire system at the wide-angle end is Fw.
2 <| F12W / Fw | <6
0.8 <F3 / Fw <1.6
0.8 <| F4 / Fw | <1.5
The zoom lens according to claim 1, wherein the following condition is satisfied. When the lateral magnification at the wide angle end of the fourth lens group is β4w,
1 <β4w <1.7
The zoom lens according to claim 1, 2 or 3, wherein the following condition is satisfied. When the focal lengths of the third lens group and the fourth lens group are F3 and F4, respectively.
0.7 <| F3 / F4 | <1.5
The zoom lens according to claim 1, wherein the following condition is satisfied.   6. The zoom lens according to claim 1, wherein each of the third lens and the fourth lens group has one or more aspherical surfaces.   The zoom lens according to any one of claims 1 to 6, further comprising an aperture stop in an interval between the second lens group and the third lens group.   The zoom lens according to claim 1, wherein the zoom lens is an optical system for forming an image on a solid-state imaging device.   An image pickup apparatus comprising: the zoom lens according to claim 1; and a solid-state image sensor that receives an image formed by the zoom lens.