KR101758622B1 - Zoom lens system - Google Patents

Abstract

The present invention relates to a fish-eye lens system and a photographing apparatus having the same, and includes a first lens having a negative refracting power, a second lens having a negative refracting power, and a third lens having a positive refracting power in this order from the object side to the image side A fourth lens having positive refractive power, a fourth lens having positive refractive power, a fifth lens having positive refractive power, a sixth lens having negative refractive power, a seventh lens having positive refractive power, and an eighth lens having positive refractive power And a second lens group having a positive refractive power as a whole, wherein the zoom lens system zooms by changing the interval between the first lens group and the second lens group.

Description

Zoom lens system

The present invention relates to a zoom lens system.

Storage devices such as digital cameras, video cameras, surveillance cameras, and mobile phones that implement images using CCD or CMOS are increasing in storage capacity as they are converted to digital. As the storage capacity increases, there is an increasing demand for miniaturization due to the demand for high optical performance for lens systems employed in digital imaging devices and for convenience.

The lens system must be well corrected to the aberrations occurring in the periphery of the screen in order to clearly record even the small information that the subject has. However, in order to achieve high performance, it is difficult to achieve miniaturization, and in order to achieve miniaturization, an increase in manufacturing cost is accompanied, which makes it difficult to satisfy high optical performance and manufacturing cost at the same time.

Embodiments of the present invention provide a zoom lens system composed of two lens groups.

According to an aspect of the present invention, there is provided a zoom lens comprising, in order from an object side to an image side, a first lens having a negative refractive power, a second lens having a negative refractive power and a third lens having a positive refractive power, 1 lens group; And a fourth lens having a positive refractive power, a fifth lens having a positive refractive power, a sixth lens having a negative refractive power, a seventh lens having a positive refractive power, and an eighth lens having a positive refractive power, And a second lens group, wherein zooming is performed by changing the interval between the first lens group and the second lens group.

According to an aspect of the present invention, the fifth lens can be expressed by the following equation.

<Expression>

vd5> 65

Here, vd5 represents the Abbe number of the d line of the fifth lens.

According to still another aspect of the present invention, the fourth lens can satisfy the following expression.

<Expression>

nd4 <1.55

Here, nd4 represents the refractive index of the d-line of the fourth lens

According to still another aspect of the present invention, the first lens unit may satisfy the following expression.

<Expression>

-3.0 < _fI / fw < -2.5

Here, f _I represents the focal length of the first lens unit, and fw represents the total focal length at the wide-angle end.

According to another aspect of the present invention, the second lens unit may satisfy the following expression.

<Expression>

v (G2 +) > 61

Here, v (G2 +) represents the Abbe number average of the lenses having positive refractive power in the second lens unit.

According to another aspect of the present invention, at least one of the first lens group and the second lens group may include an aspherical surface.

According to another aspect of the present invention, the third lens may include at least one aspherical surface.

According to another aspect of the present invention, at least one of the fourth lens and the eighth lens may include an aspherical surface.

According to another aspect of the present invention, the object side of the fourth lens may be aspherical.

According to still another aspect of the present invention, the image side surface of the eighth lens may be aspherical.

According to another aspect of the present invention, when zooming from the wide-angle end to the telephoto end, the first lens group moves toward the image side, and the second lens group moves toward the object side.

According to still another aspect of the present invention, the stop may be disposed between the first lens group and the second lens group.

According to another aspect of the present invention, the diaphragm may not move when zooming.

According to still another aspect of the present invention, there is provided a zoom lens comprising, in order from an object side to an image side, a first lens group having negative refractive power; And a second lens group having positive refractive power, wherein zooming is performed by changing the interval between the first lens group and the second lens group, and the second lens group can satisfy the following expression.

<Expression>

nd21 < 1.55

vd22> 65

Here, nd 24 represents the refractive index of the d line of the first lens from the object side of the second lens group, and vd 22 represents the Abbe number of the d line of the second lens from the object side of the second lens group.

According to the embodiment of the present invention as described above, a bright zoom lens system having high resolving power as well as a central portion as well as a peripheral portion can be provided.

The chromatic aberration in the visible light band can be corrected well from the wide angle end to the telephoto end.

It is also possible to provide a small zoom lens system that provides a wide viewing angle and has a small number of lenses.

FIG. 1 schematically shows a configuration of a zoom lens system according to a first embodiment of the present invention.
2 shows aberration diagrams relating to longitudinal spherical aberration, astigmatism and distortion at the wide-angle end of the zoom lens system shown in Fig.
3 shows aberration diagrams relating to longitudinal spherical aberration, astigmatism and distortion at the telephoto end of the zoom lens system shown in Fig.
FIG. 4 schematically shows the configuration of a zoom lens system according to a second embodiment of the present invention.
5 shows aberration diagrams relating to longitudinal spherical aberration, astigmatism and distortion at the wide-angle end of the zoom lens system shown in Fig.
6 shows aberration diagrams relating to longitudinal spherical aberration, astigmatism and distortion at the telephoto end of the zoom lens system shown in Fig.
FIG. 7 schematically shows a configuration of a zoom lens system according to a third embodiment of the present invention.
8 shows aberration diagrams relating to longitudinal spherical aberration, astigmatism and distortion at the wide-angle end of the zoom lens system shown in Fig.
FIG. 9 is an aberration diagram relating to longitudinal spherical aberration, astigmatism and distortion at the telephoto end of the zoom lens system shown in FIG. 7; FIG.
10 schematically shows a configuration of a zoom lens system according to a fourth embodiment of the present invention.
11 shows aberration diagrams relating to longitudinal spherical aberration, astigmatism and distortion at the wide-angle end of the zoom lens system shown in Fig.
12 shows aberration diagrams relating to longitudinal spherical aberration, astigmatism and distortion at the telephoto end of the zoom lens system shown in Fig.

BRIEF DESCRIPTION OF THE DRAWINGS The advantages and features of the present invention and the manner of achieving them will become apparent with reference to the embodiments described in detail below with reference to the accompanying drawings. The present invention may, however, be embodied in many different forms and should not be construed as being limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Is provided to fully convey the scope of the invention to those skilled in the art, and the invention is only defined by the scope of the claims. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention. In the present specification, the singular form includes plural forms unless otherwise specified in the specification. It is noted that the terms "comprises" and / or "comprising" used in the specification are intended to be inclusive in a manner similar to the components, steps, operations, and / Or additions. Like reference numerals in the drawings denote like elements, and the sizes and thicknesses of the respective elements may be exaggerated for convenience of explanation. On the other hand, the embodiments described below are merely illustrative, and various modifications are possible from these embodiments.

1 shows a zoom lens system according to an embodiment of the present invention.

1, a zoom lens system according to an embodiment of the present invention includes a first lens group G1, a stop ST and a second lens group G2 in this order from the object side O to the image side I, . At least one of the first lens group G1 and the second lens group G2 may include at least one aspherical surface.

The first lens group G1 has a negative refractive power. The first lens group G1 may include three lenses consisting of a first lens 11, a second lens 12, and a third lens 13. [ The first lens 11 and the second lens 12 may have a negative refractive power and the third lens 13 may have a positive refractive power. The positive lens of the first lens group G1 may include an aspherical surface. For example, the surface of the third lens 13 facing the object side or the surface facing the image side may be aspherical. By configuring the third lens 13 to have an aspherical surface, generation of coma aberration can be effectively suppressed, and a high resolution can be obtained not only in the center portion but also in the peripheral portion.

The second lens group G2 has a positive refractive power. The second lens group G2 includes five lenses consisting of a fourth lens 21, a fifth lens 22, a sixth lens 23, a seventh lens 24, and an eighth lens 25 . &Lt; / RTI &gt; The fourth lens 21, the fifth lens 22, the seventh lens 24 and the eighth lens 25 may have a positive refractive power and the sixth lens 23 may have a negative refractive power. The second lens group G2 may include at least one aspherical surface. For example, the most image-side surface of the second lens group G2 may be an aspherical surface. Alternatively, the surface closest to the object side and the image-side surface of the second lens group G2 may be aspherical surfaces.

By configuring the most image side surface of the second lens group G2 as an aspheric surface, astigmatism and surface curvature can be corrected effectively.

A diaphragm ST may be disposed between the first lens group G1 and the second lens group G2, and reference numeral 30 denotes an optical filter.

In the zoom lens system according to the embodiment of the present invention, the first lens group G1 and the second lens group G2 can move when zooming. When zooming from the wide-angle end to the telephoto end, the first lens group G1 moves toward the image side, and the second lens group G2 moves toward the object side. For example, the first lens group G1 can move along the parabolic trajectory toward the image side (or the second lens group G2), and the second lens group G2 can move toward the object side (or the first lens group G1) in a straight line. At the time of zooming, the stop ST can be kept fixed without moving.

The zoom lens system having such a configuration can reduce the chromatic aberration of magnification, suppress the occurrence of coma aberration and astigmatism, and realize high resolution resolution as a whole. Meanwhile, the zoom lens system according to the embodiment of the present invention may have an F number of 1.25 or less.

 The zoom lens system according to the embodiment of the present invention may satisfy the following conditions.

First, the second lens group G2 according to the embodiment of the present invention can satisfy the following expression (1).

vd22> 65 ... ... ... (Equation 1)

Here, vd22 is the Abbe number of the d line of the second lens arranged from the object side of the second lens group G2, for example, Abbe number of the fifth lens 22 of the second lens group G2.

Equation 1 defines the Abbe number of the d line of the second lens arranged from the object side in the second lens group G2. When this value is smaller than 65, chromatic aberration occurs.

The second lens group G2 according to the embodiment of the present invention can satisfy the following expression (2).

v (G2 +) > 61 ... ... ... (Equation 2)

Here, v (G2 +) represents the Abbe number average of the lenses having positive refractive power in the second lens group G2.

Equation 2 defines the average value of the Abbe number of the lenses having the positive refractive power among the lenses included in the second lens group G2. When this value is smaller than 61, chromatic aberration occurs.

The second lens group G2 according to the embodiment of the present invention can satisfy the following expression (3).

nd21 < 1.55 ... ... ... (Equation 3)

Here, nd21 represents the refractive index of the d-line of the lens disposed closest to the object side among the second lens group G2, and represents, for example, the refractive index of the fourth lens 21 in the second lens group G2.

Equation 3 defines the refractive index of the d-line of the lens disposed closest to the object side among the second lens group G2. When this value is larger than 1.55, chromatic aberration occurs.

The zoom lens system according to the present invention can minimize the axial chromatic aberration according to the conditions of Equations 1 and 3.

Meanwhile, the first lens group G1 according to the embodiment of the present invention can satisfy the following expression (4).

-3.0 < _fI / fw < -2.5 ... ... ... (Equation 4)

Here, f _I represents the focal length of the first lens unit, and fw represents the total focal length at the wide-angle end.

Equation 4 defines the ratio of the focal length of the first lens group G1 to the focal length of the wide-angle end. When this value exceeds the upper limit value, the magnification becomes large, but aberration occurs in the first lens group G1 The resolving power of the zoom lens system is lowered. When the value of Equation 4 exceeds the lower limit value, the angle of view of the zoom lens system becomes smaller and the magnification becomes smaller. In addition, the overall length of the zoom lens system becomes long, so that the miniaturization of the lens system can not be achieved.

The definitions of the aspheric surface in the embodiment of the present invention are as follows.

The aspheric surface shape of the zoom lens according to the embodiment of the present invention can be expressed by the following expression with the direction of the light ray as a positive when the direction of the optical axis is the x axis and the direction perpendicular to the optical axis direction is the y axis have. Where x is the distance from the vertex of the lens to the optical axis direction, y is the distance in the direction perpendicular to the optical axis, k is a conic constant, A, B, C and D are aspheric coefficients, and c represents the inverse number (1 / R) of the radius of curvature at the apex of the lens.

The following is a design data of a lens system according to an embodiment of the present invention.

Hereinafter, EFL denotes a focal distance, Fno denotes an F number, FOV denotes a field angle, and D6, D7 and D17 denote variable distances. D is the lens center thickness or distance between the lens and the lens, nd is the refractive index of the material, vd is the Abbe number of the material, and ASP is the aspherical surface.

&Lt; Embodiment 1 >

Table 1 shows design data of the zoom lens system according to the embodiment shown in FIG. In Table 1, an optical filter 30 may be further disposed between the eighth lens 25 and the image plane, and S18 and S19 represent two surfaces of the optical filter 30. [

# R Dn nd vd One 23.3885 0.8500 1.34810 42.72 2 7.2253 7.0356 3 -13.7945 0.8000 1.696802 55.46 4 21.1667 0.3436 5 21.4887 2.3235 1.821150 24.10 6 (ASP) -54.0572 12.7147 7 (ST) infinity 6.3395 8 (ASP) 10.4349 2.0776 1.515410 63.20 9 (ASP) infinity 0.1000 10 9.6076 4.5481 1.496997 81.61 11 -18.6696 0.5027 12 25.9447 0.7000 1.805182 25.43 13 5.3260 0.0836 14 5.5400 1.3229 1.589129 61.25 15 6.2563 0.4848 16 6.8136 2.0013 1.693500 53.20 17 (ASP) 54.6741 4.5644 18 infinity 1.7000 1.516800 64.17 19 infinity 0.2637

Table 2 shows the aspherical surface coefficients in the zoom lens system shown in Fig. 1, Table 3 shows the focal length (EFL), the F number (Fno), the view angle (FOV), and the variable distance at the wide angle end and at the telephoto end, respectively. The variable distance D6 is a distance from the most image side surface R6 of the third lens 13 to the stop ST and D7 is a distance from the stop ST to the most object side surface R8 of the fourth lens 21 And D17 is the distance from the most image side surface R17 of the eighth lens 25 to the most image side surface S18 of the filter 30. [

# A B C D k 6 5.26E-05 -9.17E-07 0.00E + 00 0.00E + 00 0.00E + 00 8 -0.000131204 -3.58E-06 -3.63E-08 0.00E + 00 0.00E + 00 9 0.000180157 -2.89E-06 0.00E + 00 0.00E + 00 0.00E + 00 17 0.000419533 3.65E-06 2.27E-07 0.00E + 00 0.00E + 00

EFL FOV Fno D6 D7 D17 Wide angle stage 3.01 68 1.23 12.7147 6.3395 4.5644 Telescope 8.35 23.6 2.01 2.1225 0.5 8.7938

FIGS. 2 and 3 illustrate aberration diagrams at the wide-angle end and the telephoto end of the zoom lens system shown in FIG. 1. FIG. Figs. 2A to 2C show longitudinal spherical aberration, astigmatism and distortion at the wide-angle end, respectively. 3A to 3C show longitudinal spherical aberration, astigmatism, and distortion at the telephoto end, respectively. The longitudinal spherical aberration is shown for light having a wavelength of about 656.2725 nm (c line), 587.5600 nm (d line), 546.0700 nm (e line), 486.1300 nm (f line), 435.8400 nm (g line) The astigmatism and distortion are shown for light having a wavelength of about 546.07 nm (e line). Referring to FIGS. 2B and 3B, in the astigmatic field curve, the dotted line indicates tangential astigmatism and the solid line indicates sagittal astigmatism.

&Lt; Embodiment 2 >

Table 4 shows design data of the zoom lens system according to the embodiment shown in FIG. In Table 4, an optical filter 30 may be further disposed between the eighth lens 25 and the image plane, and S18 and S19 represent two surfaces of the optical filter 30. [

# R Dn nd vd One 19.7859 0.8500 1.834810 42.72 2 6.8497 6.9865 3 -13.7693 0.8000 1.696802 55.46 4 21.6275 0.2505 5 (ASP) 21.5542 2.3949 1.821000 24.10 6 (ASP) -54.4283 12.6691 7 (ST) infinity 6.2695 8 (ASP) 11.0143 2.1137 1.514670 62.90 9 (ASP) infinity 0.1000 10 9.7455 4.8147 1.484150 84.90 11 -17.8038 0.2343 12 28.6844 0.7000 1.805182 25.43 13 5.3973 0.0918 14 5.6477 1.2686 1.589129 61.25 15 6.3587 0.8419 16 6.9892 2.0567 1.689970 53.00 17 (ASP) 63.1229 4.5577 18 infinity 1.7000 1.516800 64.17 19 infinity 0.0850

Table 5 shows the aspherical surface coefficients in the zoom lens system shown in Fig. 4, Table 6 shows the focal length EFL, F number Fno, FOV and variable distances D6, D7 and D17 at the wide- Respectively.

# A B C D k 5 5.92E-05 2.58E-06 -1.82E-08 0.00E + 00 0.00E + 00 6 2.33E-05 2.06E-06 0.00E + 00 0.00E + 00 0.00E + 00 8 -0.000100251 -1.99E-06 -4.26E-08 0.00E + 00 0.00E + 00 9 0.000180025 -2.01E-06 0.00E + 00 0.00E + 00 0.00E + 00 17 0.000390482 3.48E-06 1.18E-07 0.00E + 00 0.00E + 00

EFL FOV Fno D6 D7 D17 Wide angle stage 3.09 68 1.23 12.6691 6.2695 4.5577 Telescope 8.25 23 2.09 1.6 0.5 8.7938

Figs. 5 and 6 show aberration diagrams at the wide-angle end and the telephoto end of the zoom lens system shown in Fig. 5A to 5C show longitudinal spherical aberration, astigmatism and distortion at the wide-angle end, respectively. 6A to 6C show longitudinal spherical aberration, astigmatism and distortion at the telephoto end, respectively. The longitudinal spherical aberration is shown for light having wavelengths of about 656.28 nm, 587.56 nm, 546.07 nm, 486.13 nm, 435.84 nm, and the astigmatism and distortion are shown for light having a wavelength of about 546.07 nm. Referring to FIGS. 5B and 6B, in the astigmatic field curve, the dotted line indicates tangential astigmatism and the solid line indicates sagittal astigmatism.

&Lt; Third Embodiment >

Table 7 shows design data of the zoom lens system according to the embodiment shown in FIG. In Table 7, an optical filter 30 may be further disposed between the eighth lens 25 and the image plane, and S18 and S19 represent two surfaces of the optical filter 30. [

# R Dn nd vd One 27.6032 0.8500 1.834810 42.72 2 6.7332 6.2877 3 -17.1476 0.8000 1.696802 55.46 4 23.1478 0.1001 5 (ASP) 20.5752 2.1829 1.922860 20.88 6 (ASP) -59.1171 13.5995 7 (ST) infinity 6.4321 8 (ASP) 10.1491 2.3627 1.487489 70.44 9 (ASP) 173.6014 0.1000 10 9.3248 3.8477 1.496997 81.61 11 -23.0646 0.9817 12 -380.8872 0.7000 1.784701 26.08 13 5.9080 0.1997 14 6.4239 1.3016 1.589129 61.25 15 8.1251 0.8671 16 7.5466 2.0979 1.689970 52.90 17 (ASP) -97.3397 4.8913 18 infinity 1.1000 1.516800 64.17 19 infinity 0.0980

Table 8 shows the aspherical surface coefficients in the zoom lens system shown in Fig. 7, Table 9 shows the focal length EFL, F number Fno, FOV and variable distances D6, D7 and D17 at the wide- Respectively.

# A B C D k 5 2.01E-05 2.72E-06 -2.61E-09 0.00E + 00 0.00E + 00 6 -1.60E-05 2.28E-06 0.00E + 00 0.00E + 00 0.00E + 00 8 -5.76E-05 -1.12E-06 -2.89E-08 0.00E + 00 0.00E + 00 9 1.88E-04 -1.15E-06 0.00E + 00 0.00E + 00 0.00E + 00 17 0.000546397 6.11E-06 -4.91E-09 0.00E + 00 0.00E + 00

f FOV F / # D6 D7 D17 Wide angle stage 3 68 1.25 13.5 6.4 4.8913 Telescope 8.6 22 2.07 1.6 0.5 9.1292

Figs. 8 and 9 show aberration diagrams at the wide-angle end and the telephoto end of the zoom lens system shown in Fig. 8A to 8C show longitudinal spherical aberration, astigmatism and distortion at the wide-angle end, respectively. 9A to 9C show longitudinal spherical aberration, astigmatism and distortion at the telephoto end, respectively. The longitudinal spherical aberration is shown for light having wavelengths of about 656.28 nm, 587.56 nm, 546.07 nm, 486.13 nm, 435.84 nm, and the astigmatism and distortion are shown for light having a wavelength of about 546.07 nm. 8B and 9B, in the astigmatic field curve, the dotted line indicates the tangential astigmatism, and the solid line indicates the sagittal astigmatism.

<Fourth Embodiment>

Table 10 shows design data of the zoom lens system according to the embodiment shown in FIG. In Table 10, an optical filter 30 may be further disposed between the eighth lens 25 and the image plane, and S18 and S19 represent two surfaces of the optical filter 30. [

# R Dn nd vd One 44.5722 0.8500 1.834810 42.72 2 7.1731 5.9106 3 -17.6935 0.8000 1.696802 55.46 4 26.8437 0.1225 5 20.4093 2.4000 1.922860 20.88 6 -306.5610 12.8118 7 (ST) infinity 6.8552 8 (ASP) 8.8808 2.7067 1.514240 63.90 9 (ASP) 273.0589 0.1000 10 11.4918 3.3630 1.496997 81.61 11 -20.0051 0.6907 12 -51.8224 0.7000 1.755200 27.53 13 6.1922 0.0694 14 6.3608 2.5103 1.589129 61.25 15 8.2575 0.8255 16 (ASP) 7.1286 1.9986 1.693501 53.23 17 (ASP) -438.812 2.5856 18 infinity 3.4000 1.516800 64.17 19 infinity 0.0000

Table 11 shows the aspherical surface coefficients in the zoom lens system shown in Fig. 10, Table 12 shows the focal length EFL, F number Fno, FOV and variable distances D6, D7 and D17 at the wide- Respectively.

# A B C D k 8 -1.04E-04 4.63E-07 -2.88E-08 0.00E + 00 0.00E + 00 9 1.84E-04 1.09E-06 0.00E + 00 0.00E + 00 0.00E + 00 16 0.00E + 00 7.36E-06 0.00E + 00 0.00E + 00 0.00E + 00 17 0.00064017 1.83E-05 0.00E + 00 0.00E + 00 0.00E + 00

EFL FOV F / # D6 D7 D17 Wide angle stage 2.9 69 1.25 12.8 6.85 2.59 Telescope 8.5 22.5 2.07 1.8 0.5 6.8

Figs. 11 and 12 show aberration diagrams at the wide-angle end and the telephoto end of the zoom lens system shown in Fig. 11A to 11C show longitudinal spherical aberration, astigmatism and distortion at the wide-angle end, respectively. 12A to 12C show longitudinal spherical aberration, astigmatism and distortion at the telephoto end, respectively. The longitudinal spherical aberration is shown for light having wavelengths of about 656.28 nm, 587.56 nm, 546.07 nm, 486.13 nm, 435.84 nm, and the astigmatism and distortion are shown for light having a wavelength of about 546.07 nm. Referring to FIGS. 11B and 12B, in the astigmatic field curve, the dotted line indicates the tangential astigmatism and the solid line indicates the sagittal astigmatism.

The following shows that the first to fourth embodiments satisfy the conditions of the above-mentioned equations (1) and (4), respectively.

First Embodiment Second Embodiment Third Embodiment Fourth Embodiment Equation 1 81.61 84.90 81.61 81.61 Equation 2 64.815 65.5125 66.55 65.00 Equation 3 1.51541 1.514670 1.487489 1.514240 Equation 4 -2.81 -2.79 -2.92 -2.83

The zoom lens system according to the embodiment of the present invention has a high zoom magnification and can realize miniaturization and low cost. The zoom lens system according to the embodiment of the present invention is a surveillance camera or a digital still camera using solid-state image pickup devices such as CCD or CMOS. And can be suitably used for photographing apparatuses such as a single-lens reflex camera, a video camera, and a portable terminal.

Although the present invention has been described in connection with the above-mentioned preferred embodiments, it is possible to make various modifications and variations without departing from the spirit and scope of the invention. Accordingly, it is intended that the appended claims cover all such modifications and variations as fall within the true spirit of the invention.

G1: first lens group G2: second lens group
11: first lens 12: second lens
13: third lens 21: fourth lens
22: fifth lens 23: sixth lens
24: seventh lens 25: eighth lens
30: Filter ST: Aperture

Claims (14)

In order from the object side to the image side,
A first lens group having a negative refractive power, a first lens having a negative refractive power, a second lens having a negative refractive power, and a third lens having a positive refractive power, the refractive power being entirely negative; And
A fourth lens having a positive refractive power, a fifth lens having a positive refractive power, a sixth lens having a negative refractive power, a seventh lens having a positive refractive power, and an eighth lens having a positive refractive power, Lens group,
Wherein zooming is performed by changing an interval between the first lens group and the second lens group,
Wherein the fifth lens satisfies the following expression.
<Expression>
vd5> 65
Here, vd5 represents the Abbe number of the d line of the fifth lens. delete In order from the object side to the image side,
A first lens group having a negative refractive power, a first lens having a negative refractive power, a second lens having a negative refractive power, and a third lens having a positive refractive power, the refractive power being entirely negative; And
A fourth lens having a positive refractive power, a fifth lens having a positive refractive power, a sixth lens having a negative refractive power, a seventh lens having a positive refractive power, and an eighth lens having a positive refractive power, Lens group,
Wherein zooming is performed by changing an interval between the first lens group and the second lens group,
And the fourth lens satisfies the following expression.
<Expression>
nd4 <1.55
Here, nd4 represents the refractive index of the d-line of the fourth lens. [Claim 4 is abandoned upon payment of the registration fee.] The method according to claim 1,
Wherein the first lens group satisfies the following expression.
<Expression>
-3.0 < _fI / fw < -2.5
Here, f _I represents the focal length of the first lens unit, and fw represents the total focal length at the wide-angle end. [Claim 5 is abandoned upon payment of registration fee.] In order from the object side to the image side,
A first lens group having a negative refractive power, a first lens having a negative refractive power, a second lens having a negative refractive power, and a third lens having a positive refractive power, the refractive power being entirely negative; And
A fourth lens having a positive refractive power, a fifth lens having a positive refractive power, a sixth lens having a negative refractive power, a seventh lens having a positive refractive power, and an eighth lens having a positive refractive power, Lens group,
Wherein zooming is performed by changing an interval between the first lens group and the second lens group,
And the second lens group satisfies the following expression.
<Expression>
v (G2 +) > 61
Here, v (G2 +) represents the Abbe number average of the lenses having positive refractive power in the second lens unit. [Claim 6 is abandoned due to the registration fee.] 6. The method according to any one of claims 1 to 5,
Wherein at least one of the first lens group and the second lens group includes an aspherical surface. [7] has been abandoned due to the registration fee. 6. The method according to any one of claims 1 to 5,
Wherein the third lens includes at least one aspherical surface. [8] has been abandoned due to the registration fee. 6. The method according to any one of claims 1 to 5,
And at least one of the fourth lens and the eighth lens includes an aspherical surface. [Claim 9 is abandoned upon payment of registration fee.] 6. The method according to any one of claims 1 to 5,
And the object side surface of the fourth lens is an aspherical surface. [Claim 10 is abandoned upon payment of the registration fee.] 6. The method according to any one of claims 1 to 5,
And the image side surface of the eighth lens is an aspherical surface. [Claim 11 is abandoned upon payment of the registration fee.] 6. The method according to any one of claims 1 to 5,
Wherein the first lens group moves toward the image side when zooming from the wide-angle end to the telephoto end, and the second lens group moves toward the object side. [12] has been abandoned due to the registration fee. 6. The method according to any one of claims 1 to 5,
And a diaphragm disposed between the first lens group and the second lens group. [13] has been abandoned due to the registration fee. 13. The method of claim 12,
Wherein the diaphragm does not move when zooming. delete

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