CN108802981B - Zoom lens and image pickup apparatus - Google Patents
Zoom lens and image pickup apparatus Download PDFInfo
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- CN108802981B CN108802981B CN201711336321.9A CN201711336321A CN108802981B CN 108802981 B CN108802981 B CN 108802981B CN 201711336321 A CN201711336321 A CN 201711336321A CN 108802981 B CN108802981 B CN 108802981B
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- G02B15/00—Optical objectives with means for varying the magnification
- G02B15/14—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective
- G02B15/16—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group
- G02B15/163—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group
- G02B15/167—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group having an additional fixed front lens or group of lenses
- G02B15/173—Optical objectives with means for varying the magnification by axial movement of one or more lenses or groups of lenses relative to the image plane for continuously varying the equivalent focal length of the objective with interdependent non-linearly related movements between one lens or lens group, and another lens or lens group having a first movable lens or lens group and a second movable lens or lens group, both in front of a fixed lens or lens group having an additional fixed front lens or group of lenses arranged +-+
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Abstract
An object of the present invention is to provide a zoom lens capable of achieving high performance and low cost, and an image pickup apparatus including the zoom lens. To achieve this object, a zoom lens is formed which includes, in order from the object side, a positive first lens group G1, a negative second lens group G2, and a rear group including at least one lens group (i-th lens group), and performs zooming by changing the interval of each lens group, has an aperture stop S after the first lens group G1, and at least one of the first lens group G1 and the i-th lens group satisfies a predetermined conditional expression, respectively, and includes a negative lens Gni which satisfies the predetermined conditional expression.
Description
Technical Field
The present invention relates to a zoom lens suitable as an imaging optical system of a film camera, a video camera, a digital still camera, or the like, and an imaging apparatus having the zoom lens.
Background
Imaging devices using solid-state imaging elements, such as digital video cameras and video cameras, are becoming widespread. In recent years, with the miniaturization of an optical system in a lens-interchangeable system, the market for lens-interchangeable imaging apparatuses such as single-lens reflex cameras (hereinafter referred to as single-lens reflex cameras) and non-lens reflex cameras has been expanded significantly, and a wide range of users have started to use the lens-interchangeable imaging apparatuses. With such an expansion of the user group, there are demands for a lens switching system, such as high performance and downsizing of the optical system, and low cost.
In such a case, for example, patent document 1 proposes a zoom lens in which good optical performance is achieved by using a positive lens constituting the first lens group as a lens made of a glass material having positive anomalous dispersion.
Documents of the prior art
Patent document
[ patent document 1 ] Japanese patent No. 4687194
Disclosure of Invention
Problems to be solved by the invention
However, the above glass material having anomalous dispersion is not only expensive but also low in processability. In an optical system of the zoom lens, a lens constituting the first lens group is generally larger in outer diameter than lenses constituting other lens groups. Therefore, if the positive lens constituting the first lens group is made of a glass material having the above-described anomalous dispersion, as in the zoom lens described in patent document 1, it is difficult to reduce the cost of the zoom lens.
Therefore, an object of the present invention is to provide a zoom lens and an image pickup apparatus including the zoom lens, which can achieve high performance and low cost.
Means for solving the problems
In order to achieve the above object, a zoom lens according to the present invention includes, in order from an object side: the zoom lens includes a first lens group having positive refractive power, a second lens group having negative refractive power, and a rear group including at least one lens group, zooming is performed by changing an interval between the lens groups, an aperture stop is provided behind the first lens group, the first lens group satisfies the following conditional expression (1) and conditional expression (2), and when the lens group having positive refractive power included in the rear group is an i-th lens group (where i is a natural number of 3 or more), at least one of the i-th lens group satisfies the following conditional expression (3), and includes at least one negative lens Gni satisfying the following conditional expression (4) and conditional expression (5).
(1)1.45＜Ndp1ave＜1.65
(2)50.00＜Vdp1ave＜71.00
(3)0.50＜Hi_t/Hstop_t＜1.60
(4)1.79＜Ndni＜2.10
(5)26.00＜Vdni＜37.00
Wherein the content of the first and second substances,
ndp1 ave: an average value of refractive indexes of the positive lenses included in the first lens group to the d-line
Vdp1 ave: an average value of Abbe numbers of positive lenses included in the first lens group to d-line
Hi _ t: at the telephoto end of the zoom lens, the maximum height from the optical axis of the on-axis light beam passing through the surface of the i-th lens group closest to the object side
Hstop _ t: at the telephoto end of the zoom lens, the maximum height from the optical axis when the on-axis light beam passes through the aperture stop
Ndni: refractive index of the negative lens Gni included in the i-th lens group to d-line
Vdni: abbe number of the negative lens Gni to d-line included in the i-th lens group
In order to achieve the above object, an image pickup apparatus according to the present invention includes the zoom lens and an image pickup device which is provided on an image side of the zoom lens and converts an optical image formed by the zoom lens into an electric signal.
ADVANTAGEOUS EFFECTS OF INVENTION
According to the present invention, it is possible to provide a zoom lens capable of achieving high performance and low cost, and an image pickup apparatus including the zoom lens.
Drawings
Fig. 1 is a sectional view showing an example of a lens configuration in infinity focusing at the wide-angle end of a zoom lens system according to embodiment 1 of the present invention.
Fig. 2 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram at infinity focusing on the wide-angle end of the zoom lens of embodiment 1.
Fig. 3 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing at an intermediate focal length in the zoom lens of embodiment 1.
Fig. 4 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing at the telephoto end in the zoom lens of embodiment 1.
Fig. 5 is a sectional view showing an example of a lens configuration in infinity focusing at the wide-angle end of a zoom lens system according to embodiment 2 of the present invention.
Fig. 6 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram at infinity focusing on the wide-angle end of the zoom lens of embodiment 2.
Fig. 7 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing at an intermediate focal length in the zoom lens of embodiment 2.
Fig. 8 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing at the telephoto end in the zoom lens of embodiment 2.
Fig. 9 is a sectional view showing an example of a lens configuration in infinity focusing at the wide-angle end of a zoom lens system according to embodiment 3 of the present invention.
Fig. 10 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing on the wide-angle end of the zoom lens of embodiment 3.
Fig. 11 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing at an intermediate focal length in the zoom lens of embodiment 3.
Fig. 12 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing at the telephoto end in the zoom lens of embodiment 3.
Fig. 13 is a sectional view showing an example of a lens configuration in infinity focusing at the wide-angle end of a zoom lens system according to embodiment 4 of the present invention.
Fig. 14 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing on the wide-angle end of the zoom lens of embodiment 4.
Fig. 15 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing at an intermediate focal length in the zoom lens of embodiment 4.
Fig. 16 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing at the telephoto end in the zoom lens of embodiment 4.
Fig. 17 is a sectional view showing an example of a lens configuration in infinity focusing at the wide-angle end of a zoom lens system according to embodiment 5 of the present invention.
Fig. 18 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing on the wide-angle end of the zoom lens of embodiment 5.
Fig. 19 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing at an intermediate focal length in the zoom lens of embodiment 5.
Fig. 20 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing at the telephoto end in the zoom lens of embodiment 5.
Fig. 21 is a sectional view showing an example of a lens configuration in infinity focusing at the wide-angle end of a zoom lens system according to embodiment 6 of the present invention.
Fig. 22 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing on the wide-angle end of the zoom lens of embodiment 6.
Fig. 23 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing at an intermediate focal length in the zoom lens of embodiment 6.
Fig. 24 is a spherical aberration diagram, an astigmatism diagram, and a distortion aberration diagram in infinity focusing at the telephoto end in the zoom lens of embodiment 6.
Description of the elements by symbols
G1. first lens group
G2. second lens group
G3. third lens group
G4. fourth lens group
S.Aperture diaphragm
I. image plane
Detailed Description
Hereinafter, embodiments of a zoom lens and an imaging apparatus according to the present invention will be described. The zoom lens and the image pickup apparatus described below are examples of the zoom lens and the image pickup apparatus of the present invention, and the zoom lens and the image pickup apparatus of the present invention are not limited to the following embodiments.
1. Zoom lens
1-1. zoom lens constitution
First, an embodiment of a zoom lens of the present invention is explained. The zoom lens according to the present embodiment is characterized by comprising, in order from an object side: the zoom lens includes a first lens group having positive refractive power, a second lens group having negative refractive power, and a rear group including at least one lens group, wherein zooming is performed by changing an interval between the lens groups, an aperture stop is provided behind the first lens group, the first lens group satisfies conditional expression (1) and conditional expression (2) described later, and when the lens group having positive refractive power included in the rear group is an i-th lens group (where i is a natural number of 3 or more), at least one of the i-th lens group satisfies conditional expression (3) described later, and includes at least one negative lens Gni of conditional expression (4) and conditional expression (5) described later. In the following, first, the matters related to the configuration of the zoom lens will be described, and then, the matters related to the conditional expressions will be described.
(1) Lens group constitution
The zoom lens has no particular limitation on the specific lens group configuration as long as it satisfies the above-described configuration and the like. For example, the number of lens groups included in the rear group may be one, or two or more. The larger the number of lens groups constituting the zoom lens, the more advantageous in achieving a high zoom ratio and high optical performance. However, if the number of lens groups constituting the zoom lens increases, it is difficult to achieve downsizing, weight saving, and cost reduction of the zoom lens. In addition, a moving mechanism for moving the lens group along the optical axis during zooming becomes complicated. Therefore, by simplifying the configuration of the zoom lens, the number of lens groups included in the rear group is preferably two or less, and more preferably one, from the viewpoint of downsizing and cost reduction. By setting the number of lens groups included in the rear group to two or less, more preferably to one, it is possible to achieve downsizing and weight reduction of the zoom lens while maintaining sufficient optical performance, to simplify a moving mechanism for moving the lens groups, and the like, and to further more easily achieve cost reduction. Here, the rear group may have positive refractive power as a whole or negative refractive power, but preferably has positive refractive power. In the telephoto zoom lens as in the present embodiment, the combined focal length of the first lens group and the second lens group is a negative value at the wide-angle end. In order to form a subject image on the image plane, it is necessary to arrange positive refractive power in the rear group. Therefore, in the telephoto zoom lens as in the present embodiment, the rear group preferably has positive refractive power as a whole.
(2) Group of lens
In the present invention, the rear group includes the i-th lens group. As described above, the i-th lens group is a lens group having positive refractive power included in the rear group. The third lens group disposed on the object side of the second lens group is preferably a lens group having positive refractive power, and is preferably the i-th lens group described in the present invention. However, the i-th lens group is not necessarily the third lens group. That is, the i-th lens group having the negative lens Gni satisfying the conditional expressions (4) and (5) may be disposed in the rear group, and the effect of the present invention can be obtained similarly when the third lens group is a lens group having a negative refractive power and the lens group having a positive refractive power (i-th lens group) is disposed on the image side of the third lens group. When the rear group includes two or more i-th lens groups, at least one of the i-th lens groups may satisfy the conditional expression (3) and may include the negative lens Gni satisfying the conditional expressions (4) and (5), and a plurality of the i-th lens groups may satisfy the conditional expressions. Further, for the same reason as described above, the number of i-th lens groups included in the rear group is preferably two or less, and more preferably one.
In the i-th lens group, the lens group satisfying the conditional expression (3) described later includes at least one negative lens Gni, and the object side of the negative lens Gni preferably includes a positive lens Gpi satisfying the conditional expressions (9) and (10) described later. Note that the negative lens Gni and the positive lens Gpi will be described later together with the matters related to the conditional expressions.
(3) Aperture diaphragm
The zoom lens has an aperture stop behind the first lens group. Here, the term "having an aperture stop after the first lens group" means that the aperture stop is disposed in the first lens group, or the aperture stop is disposed on the image side of the first lens group. The position of the aperture stop in the optical system of the zoom lens is not particularly limited as long as the relationship between the aperture stop and the i-th lens group satisfies conditional expression (3) described later. For example, in the embodiments described below, an example is given in which the aperture stop is disposed on the object side of the i-th lens group or within the i-th lens group, but in the zoom lens of the present invention, the aperture stop may be disposed at an appropriate and appropriate position such as on the image side of the first lens group or on the image side of the second lens group depending on the size of the image pickup element, the angle range of view of the zoom lens, and the like.
1-2. conditional formula
The following describes conditions that the zoom lens needs to satisfy or preferably satisfy.
In the zoom lens, as described above, the first lens group satisfies the following conditional expression (1) and conditional expression (2), and at least one group among the i-th lens groups satisfies the following conditional expression (3), and the i-th lens group includes at least one negative lens Gni satisfying the following conditional expression (4) and conditional expression (5).
(1)1.45＜Ndp1ave＜1.65
(2)50.00＜Vdp1ave＜71.00
(3)0.50＜Hi_t/Hstop_t＜1.60
(4)1.79＜Ndni＜2.10
(5)26.00＜Vdni＜37.00
Wherein the content of the first and second substances,
ndp1 ave: average value of refractive index of positive lens included in first lens group to d line
Vdp1 ave: average value of Abbe number of positive lens included in first lens group to d-line
Hi _ t: at the telephoto end of the zoom lens, the maximum height from the optical axis of the on-axis light beam passing through the surface of the i-th lens group closest to the object side
Hstop _ t: at the telephoto end of the zoom lens, the maximum height from the optical axis when the on-axis light beam passes through the aperture stop
Ndni: refractive index of negative lens Gni included in the i-th lens group to d-line
Vdni: abbe number of negative lens Gni included in the i-th lens group to d-line
1-2-1. conditional expression (1)
The conditional expression (1) specifies an average value of refractive indexes of the positive lenses included in the first lens group with respect to the d-line. The first lens group includes at least 1 positive lens because of having positive refractive power. Ndp1ave in conditional expression (1) is a value obtained by dividing the total number of positive lenses included in the first lens group by the sum of the refractive indices of the positive lenses included in the first lens group with respect to the d-line. By satisfying the conditional expression (1), the average value of the refractive index of the positive lens included in the first lens group to the d-line falls within an appropriate range. That is, the positive refractive power arranged in the first lens group is within an appropriate range, so that the aberration generated in the first lens group can be reduced, and the aberration can be corrected satisfactorily with a small number of lens sheets. Therefore, aberration correction can be performed well over the entire zoom range, and a high-performance zoom lens can be realized in a small size.
On the other hand, if the numerical value of the conditional expression (1) is equal to or greater than the upper limit value, the average value of the refractive indexes of the positive lenses included in the first lens group is larger than the appropriate range, and the positive refractive power arranged in the first lens group becomes strong. Therefore, in order to cancel out spherical aberration or coma generated by the first lens group, it is necessary to increase negative refractive power arranged after the second lens group. In this case, in order to ensure good optical performance over the entire zoom range, the number of lens pieces required for aberration correction is increased, and it is difficult to configure the zoom lens with a small number of lens pieces, and therefore, it is difficult to reduce the cost of the zoom lens. Further, if the number of lenses constituting each lens group is increased, each lens group becomes heavy, and a load on a driving mechanism for moving each lens group during zooming also becomes large, and the driving mechanism itself becomes large. Therefore, it is difficult to reduce the size and cost of the entire zoom lens unit, which is not preferable.
On the other hand, if the numerical value of conditional expression (1) is the lower limit or less, the average value of the refractive indices of the positive lenses included in the first lens group is smaller than the appropriate range, and the positive refractive power arranged in the first lens group becomes small. Therefore, if a prescribed zoom ratio is to be achieved, the amount of movement of each lens group increases, making it difficult to achieve miniaturization of the zoom lens at the telephoto end. In addition, the zoom lens generally houses one or more inner cylinders inside a lens barrel (outermost cylinder) in a box-like manner. The inner cylinder expands and contracts on the object side according to the zoom ratio. If the difference between the optical total lengths at the wide-angle end and the telephoto end becomes large, a plurality of inner tubes are housed in the outermost tube in order to shorten the total length of the lens barrel when housing the inner tubes. In this case, the outer diameter of the lens barrel becomes large only by the thickness of the inner cylinder, and a cam mechanism for extending and retracting the inner cylinder becomes complicated. For these reasons, it is difficult to reduce the size and cost of the entire zoom lens unit, which is not preferable.
From the viewpoint of obtaining these effects, the lower limit value in conditional formula (1) is preferably 1.46. The upper limit of conditional expression (1) is preferably 1.60, more preferably 1.56, and still more preferably 1.52. In addition, regarding these preferable numerical values, the inequality numbers described in the conditional expression (1) may be replaced with inequality numbers with equal numbers. The same applies to other conditional expressions described later.
1-2-2. conditional expression (2)
Conditional expression (2) specifies an average value of abbe numbers of the positive lenses included in the first lens group with respect to the d-line. The Vdp1ave in the conditional expression (2) is a value obtained by dividing the total number of positive lenses included in the first lens group by the sum of the abbe numbers of the positive lenses with respect to the d-line included in the first lens group. By satisfying the conditional expression (2), the average value of the abbe number of the positive lens included in the first lens group with respect to the d-line falls within an appropriate range. Therefore, axial chromatic aberration and chromatic aberration of magnification can be corrected satisfactorily with a small number of lens sheets, and a compact zoom lens with satisfactory chromatic aberration can be realized over the entire zoom range.
On the other hand, if the numerical value of the conditional expression (2) is equal to or greater than the upper limit value, the average value of the abbe numbers of the positive lenses included in the first lens group is larger than the appropriate range, and the positive lenses included in the first lens group need to include positive lenses made of a glass material having low dispersion or positive lenses made of a glass material having anomalous dispersion, as compared with the case where the conditional expression (2) is satisfied. Low dispersion glass materials, glass materials with anomalous dispersion, are generally more expensive than other glass materials. In addition, the glass material having anomalous dispersion has low processability. Therefore, it is difficult to reduce the cost of the zoom lens from the viewpoint of the required glass material cost and the required processing cost.
On the other hand, if the numerical value of the conditional expression (2) is less than or equal to the lower limit, the average value of the abbe numbers of the positive lenses included in the first lens group is less than the appropriate range, and the positive lenses included in the first lens group need to include positive lenses made of a glass material having high dispersion, as compared with the case where the conditional expression (2) is satisfied. At this time, it is difficult to correct the chromatic aberration of magnification and the chromatic aberration of axis generated by the first lens group, and it is difficult to realize a zoom lens with good chromatic aberration in the entire zoom range.
From the viewpoint of obtaining these effects, the lower limit value in conditional formula (2) is preferably 55.00, and more preferably 60.00.
1-2-3. conditional expression (3)
Conditional expression (3) specifies a ratio of a maximum height from the optical axis when the on-axis light beam passes through the surface of the i-th lens group closest to the object side to a maximum height from the optical axis when the on-axis light beam passes through the aperture stop, at the telephoto end of the zoom lens. By satisfying conditional expression (3), when the surface of the i-th lens group closest to the object side is transmitted, the height of the outermost ray of the on-axis light beam from the optical axis falls within an appropriate range, and generation of spherical aberration or coma aberration in the i-th lens group can be suppressed. Therefore, a high-performance zoom lens can be easily realized with a small number of lenses, and the size and cost of the zoom lens can be reduced.
On the other hand, if the numerical value of conditional expression (3) is equal to or greater than the upper limit, the height of the outermost ray of the on-axis light flux is larger than the appropriate range when the light passes through the surface of the i-th lens group closest to the object side. In this case, spherical aberration and coma aberration generated in the i-th lens group become large, and the number of lens pieces required for aberration correction becomes large, so that it is difficult to achieve downsizing and cost reduction of the zoom lens.
On the other hand, if the value of conditional expression (3) is less than or equal to the lower limit, the height of the highest ray of the on-axis light flux is smaller than the appropriate range when passing through the surface of the i-th lens group closest to the object side. At this time, the height of the outermost ray of the on-axis light flux passing through the negative lens Gni included in the i-th lens group from the optical axis becomes small, and the effect of correcting chromatic aberration by the negative lens Gni becomes weak, and therefore, the correction of chromatic aberration is insufficient from the viewpoint of the entire zoom lens system. Thus, it is difficult to achieve high optical performance in the entire zoom range.
From the viewpoint of obtaining these effects, the lower limit value in conditional expression (3) is preferably 0.75, and more preferably 0.85. The upper limit value is preferably 1.40, more preferably 1.30, and still more preferably 1.20.
1-2-4. conditional expression (4)
The conditional expression (4) specifies the refractive index of the negative lens Gni included in the i-th lens group with respect to the d-line. When the conditional expression (4) is satisfied, spherical aberration and coma aberration generated by the negative lens Gni can be suppressed, and these aberrations can be easily corrected with a small number of lenses. Therefore, a high-performance, small zoom lens can be realized at low cost over the entire zoom range.
On the other hand, if the numerical value of the conditional expression (4) is equal to or greater than the upper limit, the refractive index of the negative lens Gni with respect to the d-line is larger than the appropriate range, and spherical aberration and coma aberration generated by the negative lens Gni become large. Therefore, it is difficult to correct these aberrations with a small number of lenses, and it is difficult to realize a high-performance, small zoom lens with low cost over the entire zoom range.
On the other hand, if the numerical value of conditional expression (4) is equal to or less than the lower limit, the refractive index of the negative lens Gni with respect to the d-line is smaller than the appropriate range, and it becomes difficult to cancel out spherical aberration or coma aberration generated by the positive lens included in the i-th lens group with the negative lens Gni, resulting in insufficient correction. Therefore, it is difficult to realize a high-performance, small zoom lens with a small number of lenses in the entire zoom range at low cost.
From the viewpoint of obtaining these effects, the lower limit value in conditional expression (4) is preferably 1.82, and more preferably 1.86. The upper limit value is preferably 1.99, and more preferably 1.95.
1-2-5 conditional expression (5)
Conditional expression (5) specifies the abbe number of the negative lens Gni included in the i-th lens group with respect to the d-line. When the conditional expression (5) is satisfied, axial chromatic aberration and magnification chromatic aberration generated in the positive lens included in the i-th lens group can be corrected well, and a compact zoom lens with good chromatic aberration can be realized in the entire zoom range.
On the other hand, if the numerical value of the conditional expression (5) is equal to or greater than the upper limit value, the abbe number of the negative lens Gni is larger than the appropriate range, which means that the negative lens Gni is made of a glass material with low dispersion as compared with the case where the conditional expression (5) is satisfied. In this case, the correction of axial chromatic aberration and chromatic aberration of magnification by the positive lens included in the i-th lens group is insufficient, and it is difficult to realize a zoom lens having good chromatic aberration over the entire zoom range.
On the other hand, if the value of the conditional expression (5) is equal to or less than the lower limit value, the abbe number of the negative lens Gni is smaller than the appropriate range, meaning that the negative lens Gni is made of a glass material having high dispersion as compared with the case where the conditional expression (5) is satisfied. At this time, excessive correction of chromatic aberration on axis and chromatic aberration of magnification generated by the first lens group is caused, and it is difficult to realize a zoom lens having good chromatic aberration over the entire zoom range.
From the viewpoint of obtaining these effects, the lower limit value in conditional expression (5) is preferably 28.00, and more preferably 30.00. The upper limit value is more preferably 35.00.
In the zoom lens, the i-th lens group includes at least 1 negative lens Gni satisfying the above conditional expression (4) and conditional expression (5). The i-th lens group may include a plurality of negative lenses Gni, but from the viewpoint of downsizing and cost reduction of the zoom lens, 1 negative lens Gni is sufficient.
1-2-6 conditional expressions (6) and (7)
In the zoom lens, the first lens group preferably includes at least 1 negative lens satisfying the following conditional expression (6) and conditional expression (7).
(6)1.70＜Ndn1＜2.10
(7)15.00＜Vdn1＜37.00
Wherein the content of the first and second substances,
ndn 1: refractive index of negative lens included in first lens group to d line
Vdn 1: abbe number of negative lens included in first lens group to d-line
Conditional expression (6) specifies the refractive index of the negative lens included in the first lens group with respect to the d-line. Since the first lens group includes the negative lens satisfying the conditional expression (6), spherical aberration or coma aberration generated by the positive lens included in the first lens group can be corrected well by the negative lens. Therefore, a high-performance, small zoom lens can be realized at low cost over the entire zoom range.
On the other hand, if the numerical value of conditional expression (6) is equal to or greater than the upper limit, the refractive index of the negative lens is larger than the appropriate range, and spherical aberration or coma aberration generated in the negative lens becomes large. Therefore, the negative lens corrects spherical aberration or coma aberration generated in the positive lens included in the first lens group to excessive correction. On the other hand, if the numerical value of conditional expression (6) is equal to or less than the lower limit, the refractive index of the negative lens is smaller than the appropriate range, and spherical aberration or coma aberration generated by the negative lens becomes small. Therefore, the negative lens becomes insufficient in correction of spherical aberration or coma aberration generated in the positive lens included in the first lens group. For these reasons, if the numerical value of conditional expression (6) falls outside the range, it is difficult to achieve good optical performance in the entire zoom range, and at the same time, it is difficult to achieve miniaturization and cost reduction of the zoom lens.
From the viewpoint of obtaining these effects, the lower limit value in conditional expression (6) is more preferably 1.72, and still more preferably 1.75. The upper limit value is more preferably 1.99, and still more preferably 1.95.
The conditional formula (7) is explained below. Conditional expression (7) specifies the abbe number of the negative lens included in the first lens group with respect to the d-line. Since the first lens group includes the negative lens satisfying the conditional expression (7), the chromatic aberration on axis and the chromatic aberration of magnification generated by the positive lens included in the first lens group can be corrected satisfactorily by the negative lens, and a zoom lens having satisfactory chromatic aberration can be realized over the entire zoom range.
On the other hand, if the numerical value of the conditional expression (7) is equal to or greater than the upper limit value, the abbe number of the negative lens is larger than the appropriate range, which means that the negative lens is made of a glass material having a low dispersion as compared with the case where the conditional expression (7) is satisfied. In this case, the correction of the axial chromatic aberration and the magnification chromatic aberration generated by the positive lens included in the first lens group is insufficient, and it is difficult to realize a zoom lens having a good chromatic aberration over the entire zoom range.
On the other hand, if the value of the conditional expression (7) is the lower limit or less, the abbe number of the negative lens is smaller than the appropriate range, meaning that the negative lens is made of a glass material having high dispersion as compared with the case where the conditional expression (7) is satisfied. In this case, the chromatic aberration on axis and the chromatic aberration of magnification generated in the first lens group are excessively corrected, and it is difficult to realize a zoom lens having good chromatic aberration over the entire zoom range.
From the viewpoint of obtaining these effects, the lower limit value of conditional expression (7) is more preferably 20.00, and still more preferably 25.00. Further, the upper limit value is more preferably 35.00.
In the zoom lens, the first lens group includes at least 1 negative lens satisfying the conditional expression (6) and the conditional expression (7). The first lens group may include a plurality of negative lenses satisfying the conditional expressions (6) and (7), but from the viewpoint of achieving miniaturization and cost reduction of the zoom lens, 1 negative lens is sufficient.
1-2-7. conditional expression (8)
The zoom lens preferably satisfies the following conditional expression (8).
(8)0.10＜f1/ft＜1.00
Wherein the content of the first and second substances,
f 1: focal length of the first lens group
ft: the focal length of the whole system of the zoom lens at the telescopic end
The conditional expression (8) specifies the ratio of the focal length of the first lens group to the focal length of the entire zoom lens system at the telephoto end. By satisfying the conditional expression (8), the focal length of the first lens group is within an appropriate range with respect to the focal length of the entire zoom lens system at the telephoto end, and the optical performance is improved, and at the same time, the zoom lens is more easily downsized and reduced in cost.
On the other hand, if the numerical value of conditional expression (8) is equal to or greater than the upper limit value, the focal length of the first lens group is so large as to exceed the appropriate range with respect to the focal length of the entire zoom lens system at the telephoto end, and the refractive power of the first lens group becomes weak. At this time, if a prescribed zoom ratio is to be achieved, the amount of movement of each lens group upon zooming increases. Therefore, it is difficult to miniaturize the zoom lens at the telephoto end. Further, if the difference in total optical length between the wide-angle end and the telephoto end is large, it is difficult to achieve downsizing and cost reduction of the entire zoom lens unit for the same reason as described above, which is not preferable.
On the other hand, if the value of conditional expression (8) is the lower limit or less, the focal length of the first lens group is smaller than the appropriate range with respect to the focal length of the entire zoom lens system at the telephoto end, and the refractive power of the first lens group becomes stronger. At this time, in order to cancel out spherical aberration or coma aberration generated by the first lens group, it is necessary to increase refractive power disposed after the second lens group. In this case, in order to ensure good optical performance over the entire zoom range, the number of lens pieces required for aberration correction is increased, and it is difficult to configure the zoom lens with a small number of lens pieces, and therefore it is difficult to reduce the cost of the zoom lens.
From the viewpoint of obtaining these effects, the lower limit value of conditional expression (8) is more preferably 0.20, and still more preferably 0.30. The upper limit value is more preferably 0.70, and still more preferably 0.60.
1-2-8 conditional expressions (9) and (10)
In the zoom lens, it is preferable that a positive lens Gpi satisfying the following conditional expression (9) and conditional expression (10) is disposed adjacent to the object side of the negative lens Gni included in the i-th lens group.
(9)1.45＜Ndpi＜1.75
(10)50.00＜Vdpi＜80.00
Wherein the content of the first and second substances,
ndpi: refractive index of the positive lens Gpi to d-line
Vdpi: abbe number of the positive lens Gpi to d-line
Conditional expression (9) specifies the refractive index of the positive lens Gpi for the d-line. By satisfying the conditional expression (9), the refractive index of the positive lens Gpi with respect to the d-line falls within an appropriate range, spherical aberration and coma aberration generated by the positive lens Gpi can be suppressed, and aberration correction can be performed satisfactorily with a small number of lens sheets. Therefore, aberration correction can be performed well over the entire zoom range, and a high-performance zoom lens can be realized in a small size.
On the other hand, if the numerical value of conditional expression (9) is equal to or greater than the upper limit, the refractive index of the positive lens Gpi becomes larger than the appropriate range, and the refractive power of the positive lens Gpi becomes stronger. Therefore, in order to cancel out spherical aberration and coma aberration generated by the positive lens Gpi, it is necessary to dispose a negative lens having strong refractive power, and in order to ensure good optical performance over the entire zoom range, the number of lens pieces necessary for aberration correction is increased, and it is difficult to configure the zoom lens with a small number of lens pieces, and it is difficult to achieve cost reduction of the zoom lens.
On the other hand, if the value of conditional expression (9) is equal to or less than the lower limit, the refractive index of the positive lens Gpi is smaller than the appropriate range, and the refractive power of the positive lens Gpi is reduced. Therefore, if a specified zoom ratio is intended to be achieved, the moving amount of the i-th lens group increases. Therefore, it is difficult to miniaturize the zoom lens at the telephoto end. Further, if the difference in total optical length between the wide-angle end and the telephoto end is large, it is difficult to achieve downsizing and cost reduction of the entire zoom lens unit for the same reason as described above, which is not preferable.
In order to obtain these effects, the lower limit value in conditional expression (9) is more preferably 1.47. The upper limit value is more preferably 1.72, still more preferably 1.69, still more preferably 1.61, and still more preferably 1.57.
The conditional expression (10) is explained below. The conditional expression (10) specifies the abbe number of the positive lens Gpi for the d-line. By satisfying the conditional expression (10), the abbe number of the positive lens Gpi falls within an appropriate range, chromatic aberration on axis and chromatic aberration of magnification can be corrected satisfactorily with a small number of lens sheets, and a compact zoom lens with satisfactory chromatic aberration can be realized over the entire zoom range.
On the other hand, if the value of conditional expression (10) is equal to or greater than the upper limit value, the abbe number of the positive lens Gpi is greater than the appropriate range, which means that the positive lens Gpi is made of a glass material having low dispersion or a glass material having anomalous dispersion, as compared with the case where conditional expression (10) is satisfied. Therefore, for the same reason as described above, glass material cost and processing cost are required, and it is difficult to reduce the cost of the zoom lens.
On the other hand, if the value of the conditional expression (10) is the lower limit or less, the abbe number of the positive lens Gpi is smaller than the appropriate range, meaning that the positive lens Gpi is made of a glass material having high dispersion as compared with the case where the conditional expression (10) is satisfied. In this case, it is difficult to correct the axial chromatic aberration and the magnification chromatic aberration generated by the positive lens Gpi, and it is difficult to realize a zoom lens with good chromatic aberration over the entire zoom range.
From the viewpoint of obtaining these effects, the lower limit value in conditional expression (10) is more preferably 55.00, still more preferably 60.0, and yet more preferably 63.00. Further, the upper limit value is more preferably 75.00.
Here, the positive lens Gpi may be provided on the object side with respect to the negative lens Gni included in the i-th lens, and the presence or absence of an air gap between the negative lens Gni and the positive lens Gpi is not particularly limited. However, it is more preferable that the positive lens Gpi and the negative lens Gni are cemented, and a cemented lens composed of a positive lens Gpi and a negative lens Gni is included in the i-th lens group. Since the positive lens Gpi and the negative lens Gni are arranged without an air gap, it is possible to suppress the occurrence of decentering coma aberration caused by an assembly error, reduce a manufacturing error, and easily realize excellent optical performance.
1-2-9 conditional expression (11)
In the zoom lens, when a lens group subsequent to the second lens group is set as a j-th lens group (where j is a natural number of 2 or more), it is preferable that each j-th lens group satisfies the following expression.
(11)1.00≤Bj_t/Bj_w≤50.0
Bj _ t: the transverse magnification of the j lens group at the telephoto end of the zoom lens
Bj _ w: transverse magnification of the j lens group of the zoom lens at wide angle end
Conditional expression (11) represents a change ratio of lateral magnification of each lens group disposed after the second lens group in the zoom lens when zooming from the wide-angle end to the telephoto end. At this time, the j-th lens group means each lens group from the second lens group to the last lens group. For example, when the zoom lens is constituted by a three-group structure of the first lens group to the third lens group, the j-th lens group corresponds to each of the second lens group and the third lens group. Therefore, in the case where the zoom lens is configured by the three-group structure, when the lateral magnification of the second lens group at the telephoto end is B2_ t and the lateral magnification of the second lens group at the wide-angle end of the zoom lens is B2_ w, the value of B2_ t/B2_ w indicating the variation ratio of the lateral magnification of the second lens group satisfies the above conditional expression (11). Further, in the case of the third lens group, also when the lateral magnification of the third lens group at the telephoto end of the zoom lens is B3_ t and the lateral magnification of the third lens group at the wide-angle end of the zoom lens is B3_ w, the value of B3_ t/B3_ w indicating the variation ratio of the lateral magnification of the third lens group satisfies the above conditional expression (11). In the zoom lens, similarly to the case where the fourth lens group and the fifth lens group … … are provided, the values Bj _ t/Bj _ w indicating the change ratios of the lateral magnifications of the respective lens groups satisfy the conditional expression (11).
When the numerical value of conditional expression (11) relating to each lens group subsequent to the second lens group in the zoom lens is within the above range, the change ratio of the lateral magnification of each lens group subsequent to the second lens group is 1 or more, and therefore, the lateral magnification in any one lens group does not decrease upon zooming. Therefore, the movement amount of each lens group is within an appropriate range in addition to obtaining a predetermined zoom, and the entire zoom lens unit can be downsized and reduced in cost.
In contrast, if the zoom lens includes a lens group having the numerical value of conditional expression (11) equal to or less than the lower limit value, the lens group causes a reduction in lateral magnification upon zooming from the wide-angle end to the telephoto end. That is, the lens group that does not satisfy conditional expression (11) functions in a direction to shorten the focal length of the zoom lens at the telephoto end. Therefore, if a prescribed zoom ratio is to be obtained, it is necessary to ensure the zoom ratio by either increasing the amount of movement of the other lens groups upon zooming or enhancing the refractive power of the other lens groups. In this case, it is difficult to reduce the size and cost of the entire zoom lens unit. In addition, since insufficient correction of spherical aberration or coma aberration may be caused, it is difficult to achieve good optical performance in the entire zoom range.
On the other hand, if the zoom lens includes a lens group having the numerical value of conditional expression (11) of the upper limit or more, the lens group causes a large increase in lateral magnification upon zooming from the wide-angle end to the telephoto end. In this case, either an extremely large refractive power is allocated to the lens group or a larger movement amount than usual is required for zooming, and therefore, it is difficult to secure a good optical performance over the entire zoom range, and the size of the entire zoom lens unit is increased, which is not preferable because of an increase in cost.
From the viewpoint of obtaining these effects, "≧" is preferably ">" in conditional formula (11). That is, it is preferable in the zoom lens that a variation ratio of a lateral magnification of a lens group disposed after the second lens group is larger than 1 upon zooming from the wide-angle end to the telephoto end. The upper limit value is more preferably 25.00, still more preferably 15.00, and still more preferably 10.00.
The shape of the negative lens Gni included in the i-th lens is not particularly limited as long as it has negative refractive power. However, in order to obtain an appropriate refractive power and to perform aberration correction satisfactorily, the negative lens Gni is preferably shaped like a biconcave. The shape of the positive lens Gpi included in the i-th lens is not particularly limited as long as it has positive refractive power. However, in order to obtain an appropriate refractive power and to perform aberration correction satisfactorily, the positive lens Gpi is preferably biconvex.
2. Image pickup apparatus
The imaging device of the present invention is explained below. The image pickup apparatus according to the present invention includes the zoom lens according to the present invention and an image pickup device that is provided on an image side of the zoom lens and converts an optical image formed by the zoom lens into an electric signal. Here, the imaging element is not particularly limited, and a solid-state imaging element such as a CCD sensor or a CMOS sensor may be used. The imaging device of the present invention is suitable as an imaging device such as a digital video camera or a video camera using these solid-state imaging elements. The imaging device may be a lens-fixed type imaging device in which a lens is fixed to a housing, or may be a lens-interchangeable type imaging device such as a single lens reflex camera or a single lens reflex-less camera.
The present invention will be specifically described below by way of examples and comparative examples. However, the present invention is not limited by the following examples. The optical systems of the following embodiments are photographic optical systems used in imaging devices (optical devices) such as digital video cameras, and silver-halide film cameras. In each lens cross-sectional view, the left side is the object side and the right side is the image side, facing the drawing.
Example 1
(1) Construction of optical system
Fig. 1 is a lens cross-sectional view showing a configuration of a zoom lens according to embodiment 1 of the present invention. The zoom lens is a zoom lens which is composed of a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a third lens group G3 having positive refractive power, arranged in this order from the object side, and performs zooming by changing the intervals of the respective lens groups.
In the zoom lens according to embodiment 1, the third lens group is an i-th lens group according to the present invention. The lens denoted by the symbol L9 is the negative lens Gni described in the present invention, and the lens denoted by the symbol L8 disposed on the object side of the negative lens Gni is the positive lens Gpi described in the present invention. The negative lens Gni and the positive lens Gpi are joined to each other to form a joint lens. Further, the lens denoted by the symbol L1 disposed on the most object side in the first lens group is a negative lens satisfying the conditional expression (6) and the conditional expression (7).
In the figure, "S" denotes an aperture stop, "I" denotes an image plane at the image side of the zoom lens, and specifically denotes an image pickup plane of a solid-state image pickup device such as a CCD sensor or a CMOS sensor, a film plane of a silver halide film, or the like. The specific lens configuration of each lens group is as shown in fig. 1. Since these symbols represent the same objects in the drawings shown in examples 2 to 6, the description thereof will be omitted below.
The zoom lens may further include an anti-shake group that corrects image blur by moving in a direction perpendicular to the optical axis, and a focus group that moves along the optical axis when focusing from an object at infinity to an object at a close distance. In this case, in the first to third lens groups shown in fig. 1, any one of the lens groups (or a partial lens group composed of at least 1 lens constituting the lens group) may be an anti-shake group or a focus group, but it is preferable that, for example, the second lens group is an anti-shake group and the first lens group is a focus group.
(2) Numerical example
Further, as for the aspherical surface, the aspherical surface coefficient and the conic constant when the shape thereof is expressed by the following expression are shown in table 2. The aspherical surface is defined by the following equation.
z＝ch2/[1+{1-(1+k)c2h2}1/2]+A4h4+A6h6+A8h8+A10h10
Where c is the curvature (1/r), h is the height from the optical axis, k is a conic coefficient, and a4, a6, A8, a10 are aspheric coefficients of powers.
Table 3 shows the F value (Fno) of each focal length (F), the half angle of view (W), and the lens interval on the image side of each lens group (movable group) that moves during zooming.
The same applies to the tables shown in examples 2 to 6, and therefore, the description thereof will be omitted below.
Fig. 2 to 4 are longitudinal aberration diagrams of the zoom lens at the time of infinity focusing at the wide angle end, the intermediate focal length, and the telephoto end, respectively. Each longitudinal aberration diagram shows spherical aberration, astigmatism, and distortion in order from the left. In the graph showing spherical aberration, the ordinate represents the ratio to the open F value, the abscissa represents defocus, the solid line represents d-line (587.5600nm), and the broken line represents g-line (435.8400 nm). In the graph showing astigmatism, the vertical axis represents the viewing angle, the horizontal axis is defocused, the solid line represents the sagittal direction (X) of the d-line, and the broken line represents the meridional direction (Y) of the d-line. In the figure showing distortion aberration, the ordinate represents the angle of view and the abscissa represents%. The order of the aberrations and the contents indicated by the solid line, the broken line, and the like in the figures are the same as those in the figures of examples 2 to 6, and therefore, the description thereof will be omitted below.
Table 19 shows the numerical values of conditional expressions (1) to (3), conditional expression (8), and conditional expression (11), and the composite focal lengths (f1, f2, and f3) of the respective lens groups. Here, in the present embodiment, since the third lens group is the i-th lens group, as the value of conditional expression (3), the value of "H3 _ t/Hstop _ t" is shown in table 19. H3 — t is the maximum height from the optical axis at the telephoto end of the zoom lens when the on-axis light beam passes through the most object-side surface of the third lens group. In addition, "B2 _ t/B2_ w" shown in table 19 is a value of conditional expression (11) for the second lens group, "B3 _ t/B3_ w" is a value of conditional expression (11) for the third lens group, and "B4 _ t/B4_ w" is a value of conditional expression (11) for the fourth lens group, with respect to conditional expression (11). The zoom lens of embodiment 1 has no fourth lens group, and therefore, is represented by [ - ] in table 19. The symbols in conditional expressions (3) and (11) are the same in other embodiments. The numerical values of conditional expressions (4) to (7), (9), and (10) can be referred to table 1.
TABLE 1
| No. | R | | Nd | vd | |
| 1 | 185.5842 | 1.2001 | 1.72825 | 28.46 | |
| 2 | 80.9079 | 7.3376 | 1.48749 | 70.44 | |
| 3 | -155.9215 | 0.3000 | |||
| 4 | 75.1270 | 3.8949 | 1.48749 | 70.44 | |
| 5 | 221.3655 | D(5) | |||
| 6 | -341.6612 | 3.3329 | 1.84666 | 23.78 | |
| 7 | -35.1952 | 1.0017 | 1.69688 | 55.46 | |
| 8 | 51.5556 | 3.1898 | |||
| 9 | -36.9591 | 1.0610 | 1.74330 | 49.22 | |
| 10 | -1761.6372 | D(10) | |||
| 11 | 61.6555 | 4.3970 | 1.48749 | 70.44 | |
| 12 | -64.2786 | 0.5000 | |||
| 13Stop | 0.0000 | 4.4100 | |||
| 14 | 41.4614 | 5.3464 | 1.48749 | 70.44 | |
| 15 | -40.6126 | 1.0340 | 1.90366 | 31.31 | |
| 16 | 101.7472 | 0.5132 | |||
| 17 | 52.9046 | 3.8512 | 1.58144 | 40.89 | |
| 18 | -307.2159 | 21.8763 | |||
| 19ASPH | -90.5490 | 2.5182 | 1.61467 | 25.57 | |
| 20ASPH | -42.5272 | 17.6221 | |||
| 21ASPH | -17.3667 | 2.0006 | 1.53522 | 56.16 | |
| 22ASPH | -29.5599 | D(22) | |||
| 23 | inf. | 2.0000 | 1.51680 | 64.20 | |
| 24 | inf. | 1.0000 |
TABLE 2
| No. | k | A4 | A6 | A8 | A10 |
| 19 | 0.00000E+00 | -3.03425E-06 | 2.77380E-08 | 3.20185E-11 | 0.00000E+00 |
| 20 | 0.00000E+00 | -2.80911E-06 | 2.76230E-08 | 2.33344E-11 | 0.00000E+00 |
| 21 | 0.00000E+00 | -2.94721E-07 | 1.50830E-07 | -2.71077E-10 | 0.00000E+00 |
| 22 | 0.00000E+00 | -4.07059E-06 | 1.01696E-07 | -2.81056E-10 | 0.00000E+00 |
TABLE 3
| Wide angle end | Intermediate focal length | Inspection and transportation end | |
| F | 72.18850 | 149.33140 | 291.06460 |
| Fno | 4.62640 | 5.07290 | 6.48360 |
| W | 17.10200 | 8.01340 | 4.15410 |
| Y | 21.60 | 21.60 | 21.60 |
| D(5) | 6.39130 | 39.20320 | 52.32060 |
| D(10) | 35.00010 | 20.70060 | 3.20020 |
| D(22) | 51.50240 | 60.37700 | 82.80240 |
Example 2
(1) Construction of optical system
Fig. 5 is a lens cross-sectional view showing the configuration of a zoom lens according to embodiment 2 of the present invention. The zoom lens is a zoom lens which is composed of a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a third lens group G3 having positive refractive power, arranged in this order from the object side, and performs zooming by changing the intervals of the respective lens groups.
In the zoom lens according to embodiment 2, the third lens group is an i-th lens group according to the present invention. The lens denoted by the symbol L8 is the negative lens Gni described in the present invention, and the lens denoted by the symbol L7 disposed on the object side of the negative lens Gni is the positive lens Gpi described in the present invention. The negative lens Gni and the positive lens Gpi are joined to each other to form a joint lens. The lens denoted by the symbol L1 disposed closest to the object side in the first lens group is a negative lens satisfying the conditional expression (6) and the conditional expression (7).
The zoom lens may be provided with an anti-shake group and a focusing group. In this case, any one of the first to third lens groups shown in fig. 5 (or a partial lens group) may be an anti-shake group or a focus group, but it is preferable that, for example, the second lens group is an anti-shake group and the first lens group is a focus group.
(2) Numerical example
Numerical embodiment 2 of specific numerical values suitable for the zoom lens is explained below. Shown in table 4 are lens data of the zoom lens. Table 5 shows aspheric coefficients and conic constants for aspheric surfaces. Table 6 shows the F value (Fno) of each focal length (F), the half angle of view (W), and the lens interval on the image side of each lens group (movable group) moved during zooming. Fig. 5 to 8 show longitudinal aberration diagrams of the zoom lens in infinity focusing. Further, the numerical values of conditional expressions (1) to (3), conditional expression (8), and conditional expression (11), and the composite focal lengths (f1, f2, f3) of the respective lens groups are shown in table 19. The numerical values of conditional expressions (4) to (7), (9), and (10) can be referred to table 4.
TABLE 4
| N0. | R | | Nd | vd | |
| 1 | 74.1493 | 1.4000 | 1.80610 | 33.27 | |
| 2 | 45.5364 | 0.5000 | |||
| 3 | 45.3172 | 9.6604 | 1.51633 | 64.14 | |
| 4 | -230.3462 | D(4) | |||
| 5 | -211.1058 | 3.6000 | 1.84666 | 23.78 | |
| 6 | -36.9928 | 1.0000 | 1.69680 | 55.46 | |
| 7 | 77.1479 | 2.5711 | |||
| 8 | -43.9124 | 1.0000 | 1.77250 | 49.62 | |
| 9 | 10951.1822 | D(9) | |||
| 10 | 57.2412 | 3.8677 | 1.51680 | 64.2 | |
| 11 | -93.2109 | 1.5000 | |||
| 12Stop | 0.0000 | 1.0000 | |||
| 13 | 43.8002 | 5.0526 | 1.48749 | 70.44 | |
| 14 | -43.8002 | 1.0000 | 1.80610 | 33.27 | |
| 15 | 63.4781 | 0.2000 | |||
| 16 | 33.5809 | 3.9029 | 1.51823 | 58.96 | |
| 17 | -741.4460 | 23.8461 | |||
| 18ASPH | 38.4706 | 3.1866 | 1.58547 | 29.91 | |
| 19ASPH | 223.9396 | 9.4109 | |||
| 20ASPH | -18.1137 | 1.0000 | 1.52528 | 55.95 | |
| 21ASPH | -76.7526 | D(21) | |||
| 22 | inf. | 2.0000 | 1.51680 | 64.20 | |
| 23 | inf. | 1.0000 |
TABLE 5
| No. | k | A4 | A6 | A8 | A10 |
| 18 | 0.000000E+00 | -1.667410E-05 | -1.815360E-07 | 1.261400E-09 | -5.555240E-12 |
| 19 | 0.000000E+00 | -3.162840E-05 | -1.895660E-07 | 1.923810E-09 | -7.810050E-12 |
| 20 | 0.000000E+00 | -1.382370E-05 | 8.248150E-07 | -4.082630E-09 | 4.972230E-12 |
| 21 | 0.000000E+00 | 8.013620E-06 | 7.018200E-07 | -4.907170E-09 | 1.025800E-11 |
TABLE 6
| Wide angle end | Intermediate focal length | Telescope end | |
| F | 72.0000 | 135.0000 | 291.4000 |
| Fno | 4.5961 | 4.9958 | 6.4946 |
| W | 17.1178 | 8.8247 | 4.1350 |
| Y | 21.6 | 21.6 | 21.6 |
| D(4) | 1.7000 | 41.2577 | 61.4556 |
| D(9) | 33.3140 | 20.9470 | 1.5000 |
| D(21) | 48.9692 | 55.6292 | 81.0276 |
Example 3
(1) Construction of optical system
Fig. 9 is a lens cross-sectional view showing a configuration of a zoom lens according to embodiment 3 of the present invention. The zoom lens is a zoom lens which is composed of a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a third lens group G3 having positive refractive power, arranged in this order from the object side, and performs zooming by changing the intervals of the respective lens groups.
In the zoom lens according to embodiment 3, the third lens group is the i-th lens group according to the present invention. The lens denoted by the symbol L8 is the negative lens Gni described in the present invention, and the lens denoted by the symbol L7 disposed on the object side of the negative lens Gni is the positive lens Gpi described in the present invention. The negative lens Gni and the positive lens Gpi are joined to each other to form a joint lens. The lens denoted by the symbol L1 disposed closest to the object side in the first lens group is a negative lens satisfying the conditional expression (6) and the conditional expression (7).
The zoom lens may be provided with an anti-shake group and a focusing group. In this case, any one of the first to third lens groups shown in fig. 9 (or a partial lens group) may be an anti-shake group or a focus group, but it is preferable that, for example, the second lens group is an anti-shake group and the first lens group is a focus group.
(2) Numerical example
Numerical embodiment 3 of specific numerical values suitable for the zoom lens is explained below. Shown in table 7 are lens data of the zoom lens. Table 8 shows aspheric coefficients and conic constants for aspheric surfaces. Table 9 shows the F value (Fno) of each focal length (F), the half angle of view (W), and the lens interval on the image side of each lens group (movable group) moved during zooming. Fig. 10 to 12 are longitudinal aberration diagrams of the zoom lens at infinity focusing. Further, the numerical values of conditional expressions (1) to (3), conditional expression (8), and conditional expression (11), and the composite focal lengths (f1, f2, f3) of the respective lens groups are shown in table 19. The numerical values of conditional expressions (4) to (7), and (9) and (10) can be referred to table 7.
TABLE 7
| No. | R | | Nd | vd | |
| 1 | 71.4197 | 1.4000 | 1.80610 | 33.27 | |
| 2 | 43.9745 | 0.5000 | |||
| 3 | 43.8600 | 10.1117 | 1.51633 | 64.14 | |
| 4 | -219.4001 | D(4) | |||
| 5 | -174.5053 | 3.2485 | 1.84666 | 23.78 | |
| 6 | -33.8949 | 1.0000 | 1.69680 | 55.46 | |
| 7 | 71.5939 | 2.5599 | |||
| 8 | -41.5574 | 1.0000 | 1.77250 | 49.62 | |
| 9 | 11535.1706 | D(9) | |||
| 10 | 50.0852 | 3.6593 | 1.51680 | 64.20 | |
| 11 | -137.0062 | 1.5000 | |||
| 12Stop | 0.0000 | 1.0000 | |||
| 13 | 40.0344 | 5.2519 | 1.48749 | 70.44 | |
| 14 | -40.0344 | 1.0000 | 1.80610 | 33.27 | |
| 15 | 52.0250 | 0.2000 | |||
| 16 | 28.7759 | 4.2718 | 1.51823 | 58.96 | |
| 17 | -686.3080 | 16.6721 | |||
| 18ASPH | 40.0167 | 3.3000 | 1.58547 | 29.91 | |
| 19ASPH | 1130.1976 | 9.8337 | |||
| 20ASPH | -17.0827 | 1.0000 | 1.52528 | 55.95 | |
| 21ASPH | -52.2358 | D(21) | |||
| 22 | inf. | 2.0000 | 1.51680 | 64.20 | |
| 23 | inf. | 1.0000 |
TABLE 8
| Wide angle end | Intermediate focal length | Telescope end | |
| F | 102.8763 | 194.0279 | 388.0109 |
| Fno | 5.6778 | 6.1837 | 8.3455 |
| W | 11.8585 | 6.2329 | 3.1482 |
| Y | 10.8 | 10.8 | 10.8 |
| D(5) | 17.3040 | 42.4483 | 53.2803 |
| D(10) | 27.7187 | 15.4059 | 1.0000 |
| D(22) | 54.7449 | 67.0350 | 105.8804 |
TABLE 9
| Wide angle end | Intermediate focal length | Telescope end | |
| F | 71.9926 | 135.0048 | 291.4556 |
| Fno | 4.6007 | 5.0894 | 6.5023 |
| W | 17.146 | 8.8526 | 4.1402 |
| Y | 21.6 | 21.6 | 21.6 |
| D(4) | 5.9834 | 41.1757 | 61.2631 |
| D(9) | 31.0602 | 19.4507 | 1.5000 |
| D(21) | 56.1124 | 64.8891 | 90.3984 |
Example 4
(1) Construction of optical system
Fig. 13 is a lens cross-sectional view showing the configuration of a zoom lens according to embodiment 4 of the present invention. The zoom lens is a zoom lens which is composed of a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a third lens group G3 having positive refractive power, arranged in this order from the object side, and performs zooming by changing the intervals of the respective lens groups.
In the zoom lens according to embodiment 4, the third lens group is the i-th lens group according to the present invention. The lens denoted by the symbol L9 is the negative lens Gni described in the present invention, and the lens denoted by the symbol L8 disposed on the object side of the negative lens Gni is the positive lens Gpi described in the present invention. The negative lens Gni and the positive lens Gpi are joined to each other to form a joint lens. The lens denoted by the symbol L2, which is disposed second from the object side in the first lens group, is a negative lens satisfying the conditional expression (6) and the conditional expression (7).
The zoom lens may be provided with an anti-shake group and a focusing group. In this case, any one of the first to third lens groups shown in fig. 13 (or a partial lens group) may be an anti-shake group or a focus group, but it is preferable that, for example, the second lens group is an anti-shake group and the first lens group is a focus group.
(2) Numerical example
Numerical embodiment 4 of specific numerical values suitable for the zoom lens is explained below. Shown in table 10 are lens data of the zoom lens. Table 11 shows aspheric coefficients and conic constants for aspheric surfaces. Table 12 shows the F value (Fno) of each focal length (F), the half angle of view (W), and the lens interval on the image side of each lens group (movable group) moved during zooming. Fig. 14 to 16 are longitudinal aberration diagrams in infinity focusing of the zoom lens. Further, the numerical values of conditional expressions (1) to (3), conditional expression (8), and conditional expression (11), and the composite focal lengths (f1, f2, f3) of the respective lens groups are shown in table 19. The numerical values of conditional expressions (4) to (7), (9), and (10) can be referred to table 10.
Watch 10
| No. | R | | Nd | vd | |
| 1 | 80.9902 | 4.5038 | 1.51680 | 64.20 | |
| 2 | 388.2779 | 0.2152 | |||
| 3 | 103.1111 | 1.1000 | 1.79138 | 36.97 | |
| 4 | 48.4503 | 0.0100 | 1.56732 | 42.84 | |
| 5 | 48.4503 | 8.5881 | 1.48749 | 70.44 | |
| 6 | -482.7547 | D(6) | |||
| 7 | -254.9403 | 2.8017 | 1.82115 | 24.06 | |
| 8 | -39.3066 | 0.7000 | 1.61716 | 63.43 | |
| 9 | 62.1094 | 3.2393 | |||
| 10 | -41.4065 | 0.7000 | 1.78004 | 47.81 | |
| 11 | 1456.6158 | D(11) | |||
| 12 | 50.3920 | 3.5267 | 1.48749 | 70.44 | |
| 13 | -164.8417 | 1.5000 | |||
| 14Stop | 0.0000 | 1.0000 | |||
| 15 | 35.4727 | 6.0000 | 1.48749 | 70.44 | |
| 16 | -49.3146 | 0.9000 | 1.81010 | 34.91 | |
| 17 | 57.7161 | 1.2000 | |||
| 18 | 33.0494 | 5.5000 | 1.48749 | 70.44 | |
| 19 | -317.3487 | 17.5383 | |||
| 20ASPH | 68.1764 | 3.0000 | 1.61422 | 25.57 | |
| 21ASPH | -400.0000 | 10.9907 | |||
| 22ASPH | -17.7141 | 1.3000 | 1.53446 | 57.04 | |
| 23ASPH | -50.3265 | D(23) | |||
| 24 | inf. | 2.0000 | 1.51680 | 64.20 | |
| 25 | inf. | 1.0000 |
TABLE 11
| Wide angle end | Intermediate focal length | Telescope end | |
| F | 72.1002 | 135.0006 | 291.0030 |
| Fno | 4.6350 | 4.9945 | 6.5698 |
| W | 17.1776 | 8.8608 | 4.1535 |
| Y | 21.6 | 21.6 | 21.6 |
| D(6) | 1.6306 | 35.5225 | 51.5892 |
| D(11) | 35.1313 | 21.4298 | 0.2000 |
| D(23) | 50.1497 | 56.2225 | 83.1497 |
TABLE 12
| Wide angle end | Intermediate focal length | Telescope end | |
| F | 72.1002 | 135.0006 | 291.0030 |
| Fno | 4.6350 | 4.9945 | 6.5698 |
| W | 17.1776 | 8.8608 | 4.1535 |
| Y | 21.6 | 21.6 | 21.6 |
| D(6) | 1.6306 | 35.5225 | 51.5892 |
| D(11) | 35.1313 | 21.4298 | 0.2000 |
| D(23) | 50.1497 | 56.2225 | 83.1497 |
Example 5
(1) Construction of optical system
Fig. 17 is a lens cross-sectional view showing a configuration of a zoom lens according to embodiment 5 of the present invention. The zoom lens is a zoom lens which is composed of a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, and a fourth lens group G4 having negative refractive power, which are arranged in this order from the object side, and performs zooming by changing the intervals of the respective lens groups.
In the zoom lens according to embodiment 5, the third lens group is the i-th lens group according to the present invention. The lens denoted by the symbol L9 is the negative lens Gni described in the present invention, and the lens denoted by the symbol L8 disposed on the object side of the negative lens Gni is the positive lens Gpi described in the present invention. The negative lens Gni and the positive lens Gpi are joined to each other to form a joint lens. The lens denoted by the symbol L1 disposed closest to the object side in the first lens group is a negative lens satisfying the conditional expression (6) and the conditional expression (7).
The zoom lens may be provided with an anti-shake group and a focusing group. In this case, any one of the first to fourth lens groups shown in fig. 17 (or a partial lens group) may be an anti-shake group or a focus group, but it is preferable that, for example, the second lens group is an anti-shake group and the first lens group is a focus group.
(2) Numerical example
Watch 13
| No. | R | | Nd | vd | |
| 1 | 241.6257 | 1.9996 | 1.72825 | 28.46 | |
| 2 | 90.8410 | 6.9365 | 1.48749 | 70.44 | |
| 3 | -149.3762 | 0.3000 | |||
| 4 | 74.4519 | 4.0931 | 1.48749 | 70.44 | |
| 5 | 237.9446 | D(5) | |||
| 6 | -329.4506 | 3.4680 | 1.84666 | 23.78 | |
| 7 | -36.8973 | 3.4617 | 1.69680 | 55.46 | |
| 8 | 60.2641 | 2.8868 | |||
| 9 | -39.5217 | 1.0000 | 1.74330 | 49.22 | |
| 10 | 435.8312 | D(10) | |||
| 11 | 56.6898 | 5.7872 | 1.48749 | 70.44 | |
| 12 | -66.7000 | 0.5005 | |||
| 13Stop | 0.0000 | 1.3993 | |||
| 14 | 43.3153 | 5.1718 | 1.48749 | 70.44 | |
| 15 | -40.1011 | 1.2063 | 1.90366 | 31.31 | |
| 16 | 110.7632 | 0.5000 | |||
| 17 | 59.4231 | 3.5024 | 1.58144 | 40.89 | |
| 18 | -213.6796 | D(18) | |||
| 19ASPH | -64.1549 | 2.5000 | 1.61467 | 25.57 | |
| 20ASPH | -35.8075 | 17.3536 | |||
| 21ASPH | -16.7915 | 2.0000 | 1.53522 | 56.16 | |
| 22ASPH | -28.4421 | D(22) | |||
| 23 | inf. | 2.0000 | 1.51680 | 64.20 | |
| 24 | inf. | 1.0000 |
TABLE 14
| No. | k | A4 | A6 | A8 | A10 |
| 19 | 0.00000E+00 | -3.14861E-06 | 3.03097E-08 | -1.22402E-10 | 0.00000E+00 |
| 20 | 0.00000E+00 | -2.53626E-06 | 3.07209E-08 | -1.28553E-10 | 0.00000E+00 |
| 21 | 0.00000E+00 | -2.88041E-06 | 1.54934E-07 | -1.82746E-10 | 0.00000E+00 |
| 22 | 0.00000E+00 | -7.66075E-06 | 1.03332E-07 | -2.38463E-10 | 0.00000E+00 |
Watch 15
| Wide angle end | Intermediate focal length | Telescope end | |
| F | 72.0302 | 149.3415 | 290.9534 |
| Fno | 4.6212 | 5.0622 | 6.4712 |
| W | 17.2332 | 8.0703 | 4.1574 |
| Y | 21.6 | 21.6 | 21.6 |
| D(5) | 6.1789 | 36.9522 | 52.6560 |
| D(10) | 35.6321 | 20.3992 | 2.0000 |
| D(18) | 20.5940 | 20.6597 | 23.6648 |
| D(22) | 51.5009 | 64.2782 | 79.0082 |
Example 6
(1) Construction of optical system
Fig. 21 is a lens cross-sectional view showing a configuration of a zoom lens according to embodiment 6 of the present invention. The zoom lens is a zoom lens which is composed of a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, and a third lens group G3 having positive refractive power, arranged in this order from the object side, and performs zooming by changing the intervals of the respective lens groups.
In the zoom lens according to embodiment 6, the third lens group is the i-th lens group according to the present invention. The lens denoted by the symbol L98 is the negative lens Gni described in the present invention, and the lens denoted by the symbol L7 disposed on the object side of the negative lens Gni is the positive lens Gpi described in the present invention. The negative lens Gni and the positive lens Gpi are joined to each other to form a joint lens. The lens denoted by the symbol L1 disposed closest to the object side in the first lens group is a negative lens satisfying the conditional expression (6) and the conditional expression (7).
The zoom lens may be provided with an anti-shake group and a focusing group. In this case, any one of the first to third lens groups shown in fig. 21 (or a partial lens group) may be an anti-shake group or a focus group, but it is preferable that, for example, the second lens group is an anti-shake group and the first lens group is a focus group.
(2) Numerical example
Numerical embodiment 6 of specific numerical values suitable for the zoom lens is explained below. Shown in table 16 are lens data of the zoom lens. Table 17 shows aspheric coefficients and conic constants for aspheric surfaces. Table 18 shows the F value (Fno) of each focal length (F), the half angle of view (W), and the lens interval on the image side of each lens group (movable group) moved during zooming. Fig. 22 to 24 show longitudinal aberration diagrams of the zoom lens in infinity focusing. Further, the numerical values of conditional expressions (1) to (3), conditional expression (8), and conditional expression (11), and the composite focal lengths (f1, f2, f3) of the respective lens groups are shown in table 19. The numerical values of conditional expressions (4) to (7), (9), and (10) can be referred to table 1.
TABLE 16
| No. | R | | Nd | vd | |
| 1 | 170.0000 | 1.2000 | 1.72825 | 28.46 | |
| 2 | 78.2877 | 7.0768 | 1.48749 | 70.44 | |
| 3 | -156.1945 | 0.3000 | |||
| 4 | 68.9611 | 4.0259 | 1.48749 | 70.44 | |
| 5 | 134.8341 | D(5) | |||
| 6 | -642.2893 | 5.1312 | 1.84666 | 23.78 | |
| 7 | -36.8482 | 1.0000 | 1.69680 | 55.46 | |
| 8 | 51.4579 | 4.2882 | |||
| 9 | -36.0473 | 1.0000 | 1.74330 | 49.22 | |
| 10 | -984.5773 | D(10) | |||
| 11 | 55.8303 | 4.5302 | 1.48749 | 70.44 | |
| 12 | -55.1070 | 0.5000 | |||
| 13Stop | 0.0000 | 0.5000 | |||
| 14 | 48.6461 | 5.1271 | 1.48749 | 70.44 | |
| 15 | -41.6675 | 1.0000 | 1.90366 | 31.31 | |
| 16 | 143.2969 | 0.5170 | |||
| 17 | 54.5684 | 2.7661 | 1.58144 | 40.89 | |
| 18 | 1643.1175 | 27.1210 | |||
| 19ASPH | -1214.2030 | 2.9535 | 1.61467 | 25.57 | |
| 20ASPH | -76.0151 | 17.1585 | |||
| 21ASPH | -20.0043 | 2.0075 | 1.53522 | 56.16 | |
| 22ASPH | -44.4132 | D(22) | |||
| 23 | inf. | 2.0000 | 1.51680 | 64.20 | |
| 24 | inf. | 1.0000 |
TABLE 17
| No. | k | A4 | A6 | A8 | A10 |
| 19 | 0.00000E+00 | -2.23061E-06 | 1.71846E-08 | 3.33575E-10 | 0.00000E+00 |
| 20 | 0.00000E+00 | -2.13191E-06 | 1.80569E-08 | 3.61378E-10 | 0.00000E+00 |
| 21 | 0.00000E+00 | -2.90441E-06 | 1.19629E-07 | -8.38105E-11 | 0.00000E+00 |
| 22 | 0.00000E+00 | -4.45647E-06 | 8.54748E-08 | -1.62689E-10 | 0.00000E+00 |
Watch 18
| Wide angle end | Intermediate focal length | Telescope end | |
| F | 102.8763 | 194.0279 | 388.0109 |
| Fno | 5.6778 | 6.1837 | 8.3455 |
| W | 11.8585 | 6.2329 | 3.1482 |
| Y | 10.8 | 10.8 | 10.8 |
| D(5) | 17.3040 | 42.4483 | 53.2803 |
| D(10) | 27.7187 | 15.4059 | 1.0000 |
| D(22) | 54.7449 | 67.0350 | 105.8804 |
Watch 19
Industrial applicability
According to the present invention, it is possible to provide a zoom lens that can achieve the object of the present invention and can achieve high performance and low cost, and an image pickup apparatus including the zoom lens.
Claims (7)
1. A zoom lens comprising, in order from an object side, a first lens group having positive refractive power, a second lens group having negative refractive power, and a rear group including at least one lens group,
the zoom lens performs zooming by changing the interval of each lens group, has an aperture stop after the first lens group, and satisfies the following conditional expression (8),
the first lens group satisfies the following conditional expressions (1) and (2),
when the lens group having positive refractive power included in the rear group is set as the i-th lens group, at least 1 group of the i-th lens group satisfies the following conditional expression (3), where i is a natural number of 3 or more, and includes at least 1 negative lens Gni satisfying the following conditional expression (4) and conditional expression (5),
(1)1.45＜Ndp1ave＜1.56
(2)50.00＜Vdp1ave＜71.00
(3)0.50＜Hi_t/Hstop_t＜1.60
(4)1.82＜Ndni＜2.10
(5)26.00＜Vdni＜37.00
(8)0.10＜f1/ft＜0.70
wherein the content of the first and second substances,
ndp1 ave: an average value of refractive indexes of the positive lenses included in the first lens group to the d-line,
vdp1 ave: an average value of Abbe numbers of the positive lenses included in the first lens group to d-lines,
hi _ t: at the telephoto end of the zoom lens, the maximum height from the optical axis of the on-axis light beam passing through the surface of the i-th lens group closest to the object side,
hstop _ t: at the telephoto end of the zoom lens, the maximum height from the optical axis when the outermost ray of the on-axis light beam passes through the aperture stop,
ndni: the refractive index of the negative lens Gni included in the i-th lens group to d-line,
vdni: the abbe number of the negative lens Gni for d-line included in the i-th lens group,
f 1: a focal length of the first lens group,
ft: the focal length of the whole system of the zoom lens at the telephoto end.
2. A zoom lens comprising, in order from an object side, a first lens group having positive refractive power, a second lens group having negative refractive power, and a rear group including at least one lens group,
the zoom lens performs zooming by changing the interval of each lens group, has an aperture stop after the first lens group, and satisfies the following conditional expression (8),
the first lens group satisfies the following conditional expressions (1) and (2),
when the lens group having positive refractive power included in the rear group is set as the i-th lens group, at least 1 group of the i-th lens group satisfies the following conditional expression (3), where i is a natural number of 3 or more, and includes at least 1 negative lens Gni satisfying the following conditional expression (4) and conditional expression (5),
(1)1.45＜Ndp1ave＜1.56
(2)50.00＜Vdp1ave＜71.00
(3)0.50＜Hi_t/Hstop_t＜1.20
(4)1.79＜Ndni＜2.10
(5)26.00＜Vdni＜37.00
(8)0.10＜f1/ft＜0.70
wherein the content of the first and second substances,
ndp1 ave: an average value of refractive indexes of the positive lenses included in the first lens group to the d-line,
vdp1 ave: an average value of Abbe numbers of the positive lenses included in the first lens group to d-lines,
hi _ t: at the telephoto end of the zoom lens, the maximum height from the optical axis of the on-axis light beam passing through the surface of the i-th lens group closest to the object side,
hstop _ t: at the telephoto end of the zoom lens, the maximum height from the optical axis when the outermost ray of the on-axis light beam passes through the aperture stop,
ndni: the refractive index of the negative lens Gni included in the i-th lens group to d-line,
vdni: the abbe number of the negative lens Gni for d-line included in the i-th lens group,
f 1: a focal length of the first lens group,
ft: the focal length of the whole system of the zoom lens at the telephoto end.
3. The zoom lens according to claim 1 or 2, wherein the first lens group includes at least 1 negative lens satisfying the following conditional expression (6) and conditional expression (7),
(6)1.70＜Ndn1＜2.10
(7)15.00＜Vdn1＜37.00
wherein the content of the first and second substances,
ndn 1: a refractive index of the negative lens included in the first lens group to a d-line,
vdn 1: the abbe number of the negative lens pair d-line included in the first lens group.
4. The zoom lens according to claim 1 or 2, wherein a positive lens Gpi satisfying the following conditional expression (9) and conditional expression (10) is disposed adjacent to the object side of the negative lens Gni,
(9)1.45＜Ndpi＜1.75
(10)50.00＜Vdpi＜80.00
wherein the content of the first and second substances,
ndpi: the refractive index of the positive lens Gpi for the d-line,
vdpi: the abbe number of the positive lens Gpi for d-line.
5. The zoom lens according to claim 4, wherein the i-th lens group includes a cemented lens composed of the negative lens Gni and the positive lens Gpi.
6. The zoom lens according to claim 1 or 2, wherein, in the zoom lens, when a lens group subsequent to the second lens group is set as a j-th lens group, each j-th lens group satisfies a conditional expression (11) below, where j is a natural number of 2 or more,
(11)1.0≤Bj_t/Bj_w≤50.0
bj _ t: the lateral magnification of the j lens group at the telephoto end of the zoom lens,
bj _ w: the zoom lens has a lateral magnification of the j-th lens group at a wide-angle end.
7. An image pickup apparatus having a zoom lens according to any one of claims 1 to 6 and an image pickup element which is disposed on an image side of the zoom lens and converts an optical image formed by the zoom lens into an electric signal.
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| JP2017088804A JP6826941B2 (en) | 2017-04-27 | 2017-04-27 | Zoom lens and imaging device |
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| CN108802981B true CN108802981B (en) | 2021-11-12 |
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| JPH116958A (en) * | 1997-06-16 | 1999-01-12 | Minolta Co Ltd | Zoom lens |
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| CN103728714A (en) * | 2012-10-16 | 2014-04-16 | 深圳市涞卡光电技术有限公司 | Zoom lens |
| JP2015191064A (en) * | 2014-03-27 | 2015-11-02 | 株式会社ニコン | Variable power optical system, imaging apparatus, and method for manufacturing the variable power optical system |
| CN106468826A (en) * | 2015-08-21 | 2017-03-01 | 佳能株式会社 | Zoom lens and the image pick-up device comprising zoom lens |
Family Cites Families (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| KR101431539B1 (en) * | 2008-01-11 | 2014-08-19 | 삼성전자주식회사 | Zoom lens system |
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- 2017-04-27 JP JP2017088804A patent/JP6826941B2/en active Active
- 2017-12-14 CN CN201711336321.9A patent/CN108802981B/en active Active
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| JPS6169016A (en) * | 1984-07-31 | 1986-04-09 | Canon Inc | Zoom lens |
| JPS63298210A (en) * | 1987-05-29 | 1988-12-06 | Sigma:Kk | Zoom lens |
| JPH01314219A (en) * | 1988-06-14 | 1989-12-19 | Minolta Camera Co Ltd | Compact zoom lens system having high variable power rate |
| JPH116958A (en) * | 1997-06-16 | 1999-01-12 | Minolta Co Ltd | Zoom lens |
| JP2008070410A (en) * | 2006-09-12 | 2008-03-27 | Olympus Imaging Corp | Zoom lens |
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| CN103728714A (en) * | 2012-10-16 | 2014-04-16 | 深圳市涞卡光电技术有限公司 | Zoom lens |
| JP2015191064A (en) * | 2014-03-27 | 2015-11-02 | 株式会社ニコン | Variable power optical system, imaging apparatus, and method for manufacturing the variable power optical system |
| CN106468826A (en) * | 2015-08-21 | 2017-03-01 | 佳能株式会社 | Zoom lens and the image pick-up device comprising zoom lens |
Also Published As
| Publication number | Publication date |
|---|---|
| JP2018185489A (en) | 2018-11-22 |
| JP6826941B2 (en) | 2021-02-10 |
| CN108802981A (en) | 2018-11-13 |
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