JP2006184416A

JP2006184416A - Photographic optical system and imaging apparatus

Info

Publication number: JP2006184416A
Application number: JP2004376160A
Authority: JP
Inventors: Kenji Nabeta; 賢志鍋田; Mamoru Terada; 守寺田; Toru Nakatani; 通中谷
Original assignee: Konica Minolta Photo Imaging Inc
Current assignee: Konica Minolta Photo Imaging Inc
Priority date: 2004-12-27
Filing date: 2004-12-27
Publication date: 2006-07-13

Abstract

<P>PROBLEM TO BE SOLVED: To provide a photographic optical system having extremely high power variation ratio, moreover which is small-sized and of high performance, and which can be easily manufactured. <P>SOLUTION: The photographing optical system includes, in order from the side of an object to be photographed, a 1st lens group (G1) having positive power, a 2nd lens group (G2) having negative power, a 3rd lens group (G3) having positive power and a 4th lens group (G4) having positive power. Zooming is performed by using the 1st lens group (G1) to the 4th lens group (G4), and focusing is performed by using the 4th lens group (G4). If the focal distances of the photographing optical system as a whole at a wide-angle end and at a telephoto end are expressed as fw and ft, respectively, the focal distance of the 1st lens group (G1) is expressed as f1, the magnification of the 2nd lens group (G2) at the wide-angle end and at the telephoto end are expressed as β2w and β2t, respectively, the magnification of the 3rd lens group (G3) at the wide-angle end and at the telephoto end are expressed as β3w and β3t, respectively, the relations; 7.0≤f1/fw≤20.0, 0.38≤(β2t/β2w)/(ft/fw)≤0.8 and 1.1≤β3t/β3w≤4.0 are satisfied. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

本発明は、撮影光学系および撮像装置に関し、特に、撮像倍率が可変で変倍比の高い撮影光学系に関する。 The present invention relates to an imaging optical system and an imaging apparatus, and more particularly to an imaging optical system with a variable imaging magnification and a high zoom ratio.

近年、パーソナルコンピュータの普及に伴い、手軽に画像を取り込めるデジタルカメラが普及している。また、モバイルコンピュータ、携帯電話、情報携帯端末(ＰＤＡ：Personal Digital Assistant)等の情報処理機器にデジタルカメラを組み込むことも一般化している。このような状況のもと、より小型のデジタルスチルカメラが求められるようになっており、撮影光学系にもより一層の小型化が要望されている。 In recent years, with the spread of personal computers, digital cameras that can easily capture images have become widespread. In addition, it has become common to incorporate a digital camera into information processing equipment such as a mobile computer, a mobile phone, and a personal digital assistant (PDA). Under such circumstances, a smaller digital still camera has been demanded, and further downsizing of the photographing optical system has been demanded.

また、光を電気信号に変換する撮像素子も、画素数をはじめとする種々の点で高性能化が進み、デジタルカメラの製品サイクルは短縮の傾向にある。このため、撮影光学系には、単に小型であるだけでなく、高性能かつ製造が容易であることも要求されるようになっている。 In addition, image pickup devices that convert light into electric signals have been improved in performance in various respects including the number of pixels, and the product cycle of digital cameras tends to be shortened. For this reason, the taking optical system is required not only to be small but also to have high performance and easy manufacture.

さらに、デジタルカメラの撮影光学系としてはズーム光学系が用いられているが、変倍比を従来の２〜５程度から、その２倍以上にすることも求められている。この要求を満たし得る変倍比のきわめて高いズーム光学系は、従来より知られている。例えば、特許文献１には変倍比が１５以上のズーム光学系が開示されている。
特開平９−９０２２１号公報 Furthermore, a zoom optical system is used as a photographic optical system for a digital camera, but it is also required to change the zoom ratio from about 2 to 5 times that of the prior art. Zoom optical systems with extremely high zoom ratios that can satisfy this requirement have been known. For example, Patent Document 1 discloses a zoom optical system having a zoom ratio of 15 or more.
JP-A-9-90221

ところが、従来のズーム光学系は変倍比は大きいものの、小型とはいえず、また高性能とも言い難い。例えば、特許文献１のズーム光学系は、広角端での全長が大きく、収差補正も不十分である。 However, although the conventional zoom optical system has a large zoom ratio, it cannot be said that it is small and has high performance. For example, the zoom optical system of Patent Document 1 has a large total length at the wide-angle end and insufficient aberration correction.

本発明は、このような現状に鑑みてなされたもので、変倍比がきわめて大きく、しかも、小型かつ高性能で、製造も容易な撮影光学系を提供することを目的とする。また、そのような撮影光学系を備えた小型、高性能かつ低コストの撮像装置を提供することを目的とする。 The present invention has been made in view of such a situation, and an object of the present invention is to provide a photographing optical system having an extremely large zoom ratio, a small size, high performance, and easy manufacture. It is another object of the present invention to provide a small-sized, high-performance and low-cost imaging device equipped with such a photographing optical system.

上記目的を達成するために、本発明では、撮影対象からの光を撮像素子上に結像させる撮影光学系は、撮影対象側から順に、正のパワーを有する第１レンズ群と、負のパワーを有する第２レンズ群と、正のパワーを有する第３レンズ群と、正のパワーを有する第４レンズ群とを少なくとも有して、いずれかのレンズ群を移動させて変倍を行い、次の式１、式２および式３の関係を満たすものとする。
７．０ ≦ ｆ１／ｆｗ ≦ ２０．０・・・式１
０．３８ ≦ （β2t／β2w）／（ｆｔ／ｆｗ） ≦ ０．８・・・式２
１．１ ≦ β3t／β3w ≦ ４．０・・・式３
ただし、ｆｗは広角端での当該撮影光学系全体の焦点距離、ｆｔは望遠端での当該撮影光学系全体の焦点距離、ｆ１は第１レンズ群の焦点距離、β2wは広角端での第２レンズ群の倍率、β2tは望遠端での第２レンズ群の倍率、β3wは広角端での第３レンズ群の倍率、β3tは望遠端での第３レンズ群の倍率である。 In order to achieve the above object, according to the present invention, a photographing optical system that forms an image of light from a photographing target on an image sensor includes a first lens group having a positive power and a negative power in order from the photographing target side. At least a second lens group having positive power, a third lens group having positive power, and a fourth lens group having positive power, and performing zooming by moving any of the lens groups. It is assumed that the relations of Formula 1, Formula 2 and Formula 3 are satisfied.
7.0 ≦ f1 / fw ≦ 20.0 Equation 1
0.38 ≦ (β2t / β2w) / (ft / fw) ≦ 0.8 Expression 2
1.1 ≦ β3t / β3w ≦ 4.0 Equation 3
However, fw is the focal length of the whole photographing optical system at the wide angle end, ft is the focal length of the whole photographing optical system at the telephoto end, f1 is the focal length of the first lens group, and β2w is the second focal length at the wide angle end. The magnification of the lens group, β2t is the magnification of the second lens group at the telephoto end, β3w is the magnification of the third lens group at the wide-angle end, and β3t is the magnification of the third lens group at the telephoto end.

式１は、第１レンズ群の光学的パワーの適切な範囲を規定するものである。ｆ１／ｆｗの値が式１の下限に達しないと、第１レンズ群のパワーが強くなり、前玉の小径化や小型化という点では好ましいが、収差の発生が大きくなり、特に像面湾曲と歪曲収差が多く発生する。それを良好に補正するためには、レンズあるいは非球面の追加が必要となり、これは、小型化および製造の容易化の点で好ましくない。また、ｆ１／ｆｗの値が式１の上限を超えると、収差補正上有利ではあるが、前玉径の増大やそれに伴う大型化が避けられなくなる。 Formula 1 defines an appropriate range of the optical power of the first lens group. If the value of f1 / fw does not reach the lower limit of Formula 1, the power of the first lens group becomes strong, which is preferable in terms of reducing the diameter and size of the front lens, but increases the occurrence of aberrations, and in particular the curvature of field. Many distortions occur. In order to correct it satisfactorily, it is necessary to add a lens or an aspherical surface. Further, if the value of f1 / fw exceeds the upper limit of Expression 1, it is advantageous for aberration correction, but an increase in the front lens diameter and an accompanying increase in size are unavoidable.

式１に代えて次の式１’を満たすようにすると、一層高性能の撮影光学系になる。
７．０ ≦ ｆ１／ｆｗ ≦ １７．０・・・式１’ If the following expression 1 ′ is satisfied instead of expression 1, a higher-performance photographing optical system can be obtained.
7.0 <= f1 / fw <= 17.0 ... Formula 1 '

式２は、第２レンズ群の変倍比と撮影光学系全体の変倍比との比、つまり第２レンズ群が負担する変倍比の割合の適切な範囲を規定するものである。（β2t／β2w）／（ｆｔ／ｆｗ）の値が式２の下限に達しないと、第２レンズ群以降の変倍負担が大きくなり、それらのレンズ群の間隔変化が大きくなる。その間隔変化を抑えるためには、第２レンズ群以降のレンズ群の光学的パワーを強くする必要があり、それに伴って収差が発生し、その補正が困難になるため、好ましくない。 Expression 2 defines an appropriate range of the ratio between the zoom ratio of the second lens group and the zoom ratio of the entire photographing optical system, that is, the ratio of the zoom ratio borne by the second lens group. If the value of (β2t / β2w) / (ft / fw) does not reach the lower limit of Equation 2, the magnification burden after the second lens group becomes large, and the change in the distance between these lens groups becomes large. In order to suppress the change in the interval, it is necessary to increase the optical power of the second lens unit and subsequent lens units, which causes aberrations and makes correction difficult.

また、（β2t／β2w）／（ｆｔ／ｆｗ）の値が式２の上限を超えると、第２レンズ群の変倍負担が大きくなり、第２レンズ群の前後の間隔変化が大きくなる。その間隔変化を抑えるためには、第２レンズ群のパワーを強くする必要があり、その結果、収差、特に像面湾曲収差が発生する。この収差を良好に補正するためには、第２レンズ群内のレンズや非球面の数を増す必要が生じる。これは、小型化および製造の容易化の点で好ましくない。 Also, if the value of (β2t / β2w) / (ft / fw) exceeds the upper limit of Equation 2, the burden of zooming on the second lens group increases, and the change in the distance between the front and rear of the second lens group increases. In order to suppress the change in the interval, it is necessary to increase the power of the second lens group, and as a result, aberrations, particularly field curvature aberrations, occur. In order to correct this aberration satisfactorily, it is necessary to increase the number of lenses and aspheric surfaces in the second lens group. This is not preferable in terms of miniaturization and easy manufacture.

式２に代えて次の式２’を満たすようにすると、一層高性能の撮影光学系になる。
０．３８ ≦ （β2t／β2w）／（ｆｔ／ｆｗ） ≦ ０．７・・・式２’ If the following expression 2 ′ is satisfied instead of expression 2, a higher-performance photographing optical system can be obtained.
0.38 ≦ (β2t / β2w) / (ft / fw) ≦ 0.7 Equation 2 ′

式３は、第３レンズ群の変倍比の適切な範囲を規定するものである。第３レンズ群に変倍作用をもたせることで、第２レンズ群の変倍負担を軽減させることが可能になり、第２レンズ群の前後の間隔変化量を小さくできる。これで第２レンズ群のパワーを抑えることが容易になり、高性能な撮影光学系の実現に有利になる。 Expression 3 defines an appropriate range of the zoom ratio of the third lens group. By providing the third lens group with a zooming action, it is possible to reduce the zooming burden of the second lens group, and to reduce the distance between the front and rear of the second lens group. This makes it easy to suppress the power of the second lens group, which is advantageous for realizing a high-performance photographic optical system.

β3t／β3wの値が式３の下限に達しないと、第３レンズ群の変倍負担が小さくなり、第２レンズ群の変倍負担が大きくなる。その結果、第２レンズ群の前後の間隔変化が大きくなる。その間隔変化を小さくするためには、第２レンズ群のパワーを強くする必要があるが、それに伴って収差が発生し、その補正が困難になる。 If the value of β3t / β3w does not reach the lower limit of Equation 3, the zooming load of the third lens group is reduced, and the zooming load of the second lens group is increased. As a result, the change in the distance between the front and rear of the second lens group becomes large. In order to reduce the change in the interval, it is necessary to increase the power of the second lens group. However, along with this, aberration is generated and correction thereof becomes difficult.

β3t／β3wの値が式３の上限を超えると、第３レンズ群の変倍負担が大きくなって、第３レンズ群の前後の間隔変化が大きくなる。その間隔変化を小さくするためは、第３レンズ群のパワーを強くする必要がある。しかし、それに伴う収差の補正が困難になり、また、偏心誤差感度も強くなる。その結果、偏心公差が厳しくなり、またバラツキを抑えるための調整も必要になるため、コストアップを招いて好ましくない。 When the value of β3t / β3w exceeds the upper limit of Equation 3, the zooming burden on the third lens group becomes large, and the change in the distance between the front and rear of the third lens group becomes large. In order to reduce the change in the interval, it is necessary to increase the power of the third lens group. However, it is difficult to correct aberrations associated therewith, and the eccentricity error sensitivity is increased. As a result, the eccentricity tolerance becomes strict and an adjustment for suppressing variation is necessary, which is not preferable because of an increase in cost.

式３に代えて次の式３’を満たすようにすると、一層高性能の撮影光学系になる。
１．４ ≦ β3t／β3w ≦ ４．０・・・式３’ If the following expression 3 ′ is satisfied instead of expression 3, a photographic optical system with higher performance can be obtained.
1.4 ≤ β3t / β3w ≤ 4.0 ... Formula 3 '

広角端から望遠端への変倍に際して、第１レンズ群と第２レンズ群との間隔が増大し、第２レンズ群と第３レンズ群との間隔が減少し、第３レンズ群と第４レンズ群との間隔が増大するように、少なくとも第２レンズ群、第３レンズ群および第４レンズ群が移動するようにするとよい。 During zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, and the third lens group and the fourth lens group decrease. It is preferable that at least the second lens group, the third lens group, and the fourth lens group move so that the distance from the lens group increases.

従来の変倍比であれば、ほとんどの場合、変倍比のほとんど全てを第２レンズ群で負担し、第２レンズ群の移動量が大きくなる傾向がある。しかし、さらに変倍比を高くするためには、第２レンズ群だけの変倍負担ではレンズの増加が避けられず、小型化や製造の容易化の点で好ましくない。第１レンズ群に加えて第２、第３、第４レンズ群を移動させることによって、各レンズ群に変倍を分担させることにより、レンズ枚数の大幅な増大を招くことなく、小型化と高変倍化を達成できる。 In the conventional zoom ratio, almost all of the zoom ratio is borne by the second lens group, and the amount of movement of the second lens group tends to increase. However, in order to further increase the zoom ratio, an increase in the lens is unavoidable with a zooming load of only the second lens group, which is not preferable in terms of downsizing and ease of manufacturing. By moving the second, third, and fourth lens groups in addition to the first lens group, it is possible to reduce the size and height without causing a significant increase in the number of lenses by causing each lens group to share magnification. Scaling can be achieved.

さらに次の式４の関係を満たすようにすると、一層好ましい。ただし、ｆ３は第３レンズ群の焦点距離である。
０．０５ ≦ ｆ３／ｆｔ ≦ ０．２５・・・式４ Furthermore, it is more preferable to satisfy the relationship of the following formula 4. Here, f3 is the focal length of the third lens group.
0.05 ≤ f3 / ft ≤ 0.25 Formula 4

式４は、第３レンズ群のパワーの適切な範囲を規定するものである。ｆ３／ｆｔの値が式４の下限に達しないと、第３レンズ群のパワーが強くなることにより、第３レンズ群での収差発生が大きくなり、特に球面収差が大きく発生する。それを良好に補正するためには、レンズや非球面の数を増す必要が生じるが、これは小型化および製造の容易化の点で好ましくない。 Expression 4 defines an appropriate range of the power of the third lens group. If the value of f3 / ft does not reach the lower limit of Expression 4, the power of the third lens group becomes strong, so that the aberration generation in the third lens group becomes large, and in particular, the spherical aberration becomes large. In order to correct it satisfactorily, it is necessary to increase the number of lenses and aspheric surfaces, but this is not preferable in terms of miniaturization and ease of manufacture.

ｆ３／ｆｔの値が式４の上限を超えると、収差補正上有利ではあるが、第３レンズ群にある程度変倍を負担させるために、第３レンズ群の前後の間隔を大きく変化させなければならなくなって、大型化を招く。それを避けるために第３レンズ群のパワーを強くすると、収差、特に球面収差が大きくなって、その補正が困難になる。 If the value of f3 / ft exceeds the upper limit of Expression 4, it is advantageous in terms of aberration correction. However, in order to burden the third lens group with variable magnification to some extent, the distance between the front and rear of the third lens group must be largely changed. It becomes no longer inviting an increase in size. If the power of the third lens group is increased in order to avoid this, aberrations, particularly spherical aberrations, increase, making correction difficult.

式４に代えて次の式４’を満たすようにすると、一層高性能の撮影光学系になる。
０．１ ≦ ｆ３／ｆｔ ≦ ０．２２・・・式４’ If the following expression 4 ′ is satisfied instead of expression 4, a higher-performance photographing optical system can be obtained.
0.1 ≦ f3 / ft ≦ 0.22 Equation 4 ′

広角端から望遠端への変倍に際して、第３レンズ群が撮影対象側に単調移動し、第４レンズ群がまず撮影対象側に移動して次いで撮像素子側に移動し、第４レンズ群によって焦点調節を行うようにするとよい。これにより、広角端や望遠端付近で近距離の撮影対象に焦点を合わせる際に、第４レンズ群を繰り出すためのスペースを確保することが容易になる。 Upon zooming from the wide-angle end to the telephoto end, the third lens group moves monotonously toward the object to be imaged, the fourth lens group first moves toward the object to be imaged, and then moves toward the image sensor, and is moved by the fourth lens group. It is recommended to adjust the focus. This makes it easy to secure a space for extending the fourth lens group when focusing on an object at a short distance near the wide-angle end or the telephoto end.

第１レンズ群から第４レンズ群までのほかに第４レンズ群よりも撮像素子側に位置する第５レンズ群のみを有し、変倍に際して第５レンズ群が不動である構成とするとよい。第５レンズ群を備えることにより、第４レンズ群のパワーや射出瞳位置を制御する自由度が増す。第５レンズ群は結像面近傍に位置し収差の発生が少ないので、比較的自由にパワーを変化させることができる。また、第５レンズ群は、負のパワーよりも、正のパワーを有する方が、第４レンズ群の正のパワーを小さくできて、収差補正上好ましい。 In addition to the first lens group to the fourth lens group, only the fifth lens group positioned closer to the image sensor than the fourth lens group may be provided, and the fifth lens group may be stationary during zooming. By providing the fifth lens group, the degree of freedom for controlling the power and exit pupil position of the fourth lens group is increased. The fifth lens group is located in the vicinity of the image plane and generates less aberration, so that the power can be changed relatively freely. The fifth lens group has a positive power rather than a negative power because the positive power of the fourth lens group can be reduced, which is preferable in terms of aberration correction.

ここで、第５レンズ群が１枚のレンズのみを含むようにするとよい。鏡胴を簡単な構成にできる上、撮像素子の前に光学ローパスフィルタや赤外カットフィルタなどを配置する場合に、それらのフィルタまでを密封構造とするのにも好都合であり、撮像素子やフィルタへのごみ付着防止に有利である。また、第５レンズ群をプラスチックレンズ１枚で構成すれば、さらなるコストダウンや軽量化を達成することができて、一層好ましい。 Here, it is preferable that the fifth lens group includes only one lens. In addition to the simple structure of the lens barrel, when an optical low-pass filter or an infrared cut filter is placed in front of the image sensor, it is convenient to have a sealed structure up to these filters. It is advantageous for preventing dust from adhering to the surface. Further, if the fifth lens group is composed of one plastic lens, further cost reduction and weight reduction can be achieved, which is more preferable.

前記目的を達成するために、本発明ではまた、撮像装置は、撮像素子と、上記のいずれかの撮影光学系とを備えるものとする。 In order to achieve the above object, in the present invention, an imaging apparatus also includes an imaging element and any one of the above-described imaging optical systems.

本発明の撮影光学系は、第１レンズ群のパワーが適切である上、第２レンズ群および第３レンズ群の変倍比負担が適切であるため、これらのレンズ群による収差の発生が抑えられ、変倍比を大きくするのに適する。また、収差補正のためにレンズや非球面を多くする必要がないため、小型に構成することができ、製造も容易である。このような特長を有する撮影光学系を備えた本発明の撮像装置は、小型、高性能かつ低コストの装置となる。 In the photographing optical system of the present invention, since the power of the first lens group is appropriate and the magnification ratio burden of the second lens group and the third lens group is appropriate, the occurrence of aberration due to these lens groups is suppressed. It is suitable for increasing the zoom ratio. In addition, since it is not necessary to increase the number of lenses and aspherical surfaces for aberration correction, it can be made compact and easy to manufacture. The image pickup apparatus of the present invention including the photographing optical system having such features is a small, high-performance and low-cost apparatus.

以下、本発明の実施形態について図面を参照しながら説明する。第１の実施形態であるデジタルカメラ１の外観を図１に模式的に示す。図１において（ａ）は前面および上面を表す斜視図、（ｂ）は背面図である。デジタルカメラ１は、本体１０と、本体１０に取り付けられたレンズ鏡胴１１を有している。レンズ鏡胴１１は複数段より成り、撮影時には本体１０の前方に突出し、非撮影時には本体１０に収容し得るように、前後方向に可動に構成されている。レンズ鏡胴１１は、撮影光学系１２を収容し、保持している。 Hereinafter, embodiments of the present invention will be described with reference to the drawings. An appearance of the digital camera 1 according to the first embodiment is schematically shown in FIG. In FIG. 1, (a) is a perspective view showing a front surface and an upper surface, and (b) is a rear view. The digital camera 1 has a main body 10 and a lens barrel 11 attached to the main body 10. The lens barrel 11 is composed of a plurality of stages, and is configured to be movable in the front-rear direction so that it projects forward of the main body 10 when photographing and can be accommodated in the main body 10 when not photographing. The lens barrel 11 houses and holds the photographing optical system 12.

撮影光学系１２は、撮影対象からの光を本体１０に収容されている撮像素子２１（図２参照）に導き、撮像素子２１上に結像させる。撮影光学系１２の焦点距離は可変、つまり、撮影光学系１２はズーム光学系である。 The imaging optical system 12 guides light from the imaging target to the imaging device 21 (see FIG. 2) accommodated in the main body 10 and forms an image on the imaging device 21. The focal length of the photographing optical system 12 is variable, that is, the photographing optical system 12 is a zoom optical system.

デジタルカメラ１は、前面に光学ファインダーの対物窓１３ａとフラッシュ発光部１４、上面に電源ボタン１５とシャッターレリーズボタン１６、背面に光学ファインダーの接眼窓１３ｂと表示部１７とズームボタン１８と他の操作ボタン１９を備えている。光学ファインダーは撮影対象の光学像を提供し、フラッシュ発光部１４は撮影対象を照明するフラッシュ光を発する。電源ボタン１５は、撮像素子２１をはじめ電力で動作する各部への電力の供給と停止の指示のために操作され、シャッターレリーズボタン１６は、記録用画像の撮影の指示のために操作される。 The digital camera 1 has an optical finder objective window 13a and a flash light emitting unit 14 on the front, a power button 15 and a shutter release button 16 on the upper surface, an eyepiece window 13b, a display unit 17, a zoom button 18 and other operations on the back. A button 19 is provided. The optical viewfinder provides an optical image of the subject to be photographed, and the flash light emitting unit 14 emits flash light that illuminates the subject to be photographed. The power button 15 is operated for instructing the supply and stop of power to each unit operating with power, including the image sensor 21, and the shutter release button 16 is operated for instructing to capture a recording image.

表示部１７は液晶表示器より成り、撮影した画像およびデジタルカメラ１の設定状況、操作案内等の諸情報を表示する。ズームボタン１８は、撮影光学系１２の焦点距離の設定のために操作される。ズームボタン１８の一端部を押すと、撮影光学系１２の焦点距離が増大する方向に変化し、撮影画角は狭く、撮影倍率は大きくなる。ズームボタン１８の他端部を押すと、撮影光学系１２の焦点距離が減少する方向に変化し、撮影画角は広く、撮影倍率は小さくなる。撮影光学系１２の焦点距離の設定可能な範囲のうち、最長端を望遠端といい、最短端を広角端という。操作ボタン１９は、デジタルカメラ１の諸設定のために操作される。 The display unit 17 is composed of a liquid crystal display, and displays various information such as a photographed image, the setting status of the digital camera 1 and operation guidance. The zoom button 18 is operated to set the focal length of the photographing optical system 12. When one end of the zoom button 18 is pressed, the focal length of the photographic optical system 12 changes in the increasing direction, the photographic angle of view is narrowed, and the photographic magnification is increased. When the other end portion of the zoom button 18 is pressed, the focal length of the photographic optical system 12 is changed in a decreasing direction, the photographic field angle is wide, and the photographic magnification is small. Of the range in which the focal length of the photographing optical system 12 can be set, the longest end is called the telephoto end, and the shortest end is called the wide-angle end. The operation buttons 19 are operated for various settings of the digital camera 1.

図２にデジタルカメラ１の構成を模式的に示す。デジタルカメラ１は、撮影光学系１２および表示部１７のほか、撮像素子２１、信号処理部２２、記録部２３、操作部２４、撮影光学系駆動部２５および制御部２６を有している。撮像素子２１はＣＣＤエリアセンサであり、画素ごとの受光量を表す信号を出力する。信号処理部２２は撮像素子２１の出力信号を処理して、撮影した画像を表す画像データを生成する。記録部２３は信号処理部２２が生成した画像データを着脱可能な記録媒体２３ａに記録し、また、画像の再生表示のために、記録媒体２３ａから画像データを読み出す。操作部２４は前述の諸ボタン１６〜１９の総称であり、使用者の操作を制御部２６に伝達する。 FIG. 2 schematically shows the configuration of the digital camera 1. In addition to the photographing optical system 12 and the display unit 17, the digital camera 1 includes an imaging element 21, a signal processing unit 22, a recording unit 23, an operation unit 24, a photographing optical system driving unit 25, and a control unit 26. The image sensor 21 is a CCD area sensor and outputs a signal indicating the amount of received light for each pixel. The signal processing unit 22 processes the output signal of the image sensor 21 and generates image data representing the captured image. The recording unit 23 records the image data generated by the signal processing unit 22 on a detachable recording medium 23a, and reads the image data from the recording medium 23a for reproducing and displaying the image. The operation unit 24 is a general term for the above-described buttons 16 to 19, and transmits user operations to the control unit 26.

撮影光学系駆動部２５は、いくつかのモータとその駆動力を撮影光学系１２のレンズ群に伝達する伝達機構を有しており（不図示）、撮影光学系１２の焦点距離と焦点位置を設定する。制御部２６は操作部２４を介して与えられる指示に応じて各部を制御する。 The photographic optical system drive unit 25 has a transmission mechanism (not shown) that transmits several motors and driving force thereof to the lens group of the photographic optical system 12, and determines the focal length and focal position of the photographic optical system 12. Set. The control unit 26 controls each unit according to an instruction given via the operation unit 24.

撮影光学系１２の構成を図３に示す。撮影光学系１２は、撮影対象側から順に第１レンズ群Ｇ１、第２レンズ群Ｇ２、第３レンズ群Ｇ３、第４レンズ群Ｇ４を有する。 The configuration of the photographing optical system 12 is shown in FIG. The photographing optical system 12 includes a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4 in order from the photographing target side.

第１レンズ群Ｇ１は、３枚のレンズＬ１、Ｌ２、Ｌ３より成り、全体として正の光学的パワーを有する。第２レンズ群Ｇ２は、３枚のレンズＬ４、Ｌ５、Ｌ６より成り、全体として負の光学的パワーを有する。第３レンズ群Ｇ３は、３枚のレンズＬ７、Ｌ８、Ｌ９より成り、全体として正の光学的パワーを有する。第４レンズ群Ｇ４は、２枚のレンズＬ１０、Ｌ１１より成り、全体として正の光学的パワーを有する。 The first lens group G1 includes three lenses L1, L2, and L3, and has a positive optical power as a whole. The second lens group G2 includes three lenses L4, L5, and L6, and has a negative optical power as a whole. The third lens group G3 includes three lenses L7, L8, and L9, and has a positive optical power as a whole. The fourth lens group G4 includes two lenses L10 and L11, and has a positive optical power as a whole.

第２レンズ群Ｇ２と第３レンズ群Ｇ３の間には、開口径が可変の絞りＳが設けられている。絞りＳは第３レンズ群Ｇ３と共に移動する。また、撮像素子２１の直前にはローパスフィルターＦが配置されている。 A diaphragm S having a variable aperture diameter is provided between the second lens group G2 and the third lens group G3. The diaphragm S moves together with the third lens group G3. Further, a low-pass filter F is disposed immediately before the image sensor 21.

図３に示した符号ｒ１〜ｒ２５はレンズＬ１〜Ｌ１１、絞りＳ、およびフィルターＦの面である。レンズＬ１〜Ｌ１１およびフィルターＦはそれぞれ２つの面を有する。同一のレンズ（フィルター）の２つの面のうち、符号の数字の値が小さいものの方がより撮影対象に近い面である。例えば、レンズＬ３は面ｒ５と面ｒ６を有するが、面ｒ５が撮影対象側に位置し、面ｒ６が撮像素子２１側に位置する。絞りＳは１つの面ｒ１３のみを有する。なお、絞りＳの面ｒ１３の前後の媒質は空気であり、当然、面ｒ１３の前後で屈折率は変化しない。 Reference numerals r1 to r25 illustrated in FIG. 3 are surfaces of the lenses L1 to L11, the diaphragm S, and the filter F. The lenses L1 to L11 and the filter F each have two surfaces. Of the two surfaces of the same lens (filter), the one with the smaller numerical value of the sign is the surface closer to the object to be photographed. For example, the lens L3 has a surface r5 and a surface r6, but the surface r5 is located on the imaging target side, and the surface r6 is located on the imaging element 21 side. The stop S has only one surface r13. The medium before and after the surface r13 of the stop S is air, and naturally the refractive index does not change before and after the surface r13.

レンズＬ７の面ｒ１４、レンズＬ１０の面ｒ２０およびレンズＬ１１の面ｒ２３はいずれも非球面である。また、レンズＬ１とレンズＬ２は接着されており、面ｒ２と面ｒ３の間には接着剤が存在する。レンズＬ５とレンズＬ６も接着されており、面ｒ１０と面ｒ１１の間にも接着剤が存在する。同様に、レンズＬ１０とレンズＬ１１も接着されており、面ｒ２１と面ｒ２２の間にも接着剤が存在する。 The surface r14 of the lens L7, the surface r20 of the lens L10, and the surface r23 of the lens L11 are all aspherical surfaces. The lens L1 and the lens L2 are bonded, and an adhesive is present between the surface r2 and the surface r3. The lens L5 and the lens L6 are also bonded, and an adhesive is also present between the surface r10 and the surface r11. Similarly, the lens L10 and the lens L11 are also bonded, and an adhesive exists between the surface r21 and the surface r22.

図３に示した矢印はズーミングに際してのレンズ群Ｇ１〜Ｇ４の位置を表している。矢印の基端が広角端、先端が望遠端に対応する。ズーミングは第１レンズ群Ｇ１、第２レンズ群Ｇ２、第３レンズ群Ｇ３および第４レンズ群を移動させて、それらの間隔を変化させることによって行われる。広角端から望遠端へのズーミングに際し、第１レンズ群Ｇ１と第２レンズ群Ｇ２との間隔は増大し、第２レンズ群Ｇ２と第３レンズ群Ｇ３との間隔は減少し、第３レンズ群Ｇ３と第４レンズ群Ｇ４との間隔は増大する。その際、第３レンズ群Ｇ３は、撮影対象側に単調に移動する（撮像素子２１側には戻らない）。また、第４レンズ群Ｇ４を前方に繰り出すことにより、無限遠物体から近距離物体へのフォーカシングを行う。広角端から望遠端へのズーミングに際し、第４レンズ群Ｇ４は、まず撮影対象側に移動し、次いで撮像素子２１側に移動する。 The arrows shown in FIG. 3 represent the positions of the lens groups G1 to G4 during zooming. The base end of the arrow corresponds to the wide-angle end, and the tip corresponds to the telephoto end. Zooming is performed by moving the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group and changing their intervals. During zooming from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group. The interval between G3 and the fourth lens group G4 increases. At that time, the third lens group G3 monotonously moves toward the object to be imaged (does not return to the image sensor 21 side). Further, the fourth lens group G4 is extended forward to perform focusing from an infinitely distant object to a close object. During zooming from the wide-angle end to the telephoto end, the fourth lens group G4 first moves to the photographing target side, and then moves to the image sensor 21 side.

広角端および望遠端での焦点距離はそれぞれ６．００ｍｍおよび９３．００ｍｍであり、したがって、変倍比は１５．５である。広角端および望遠端でのＦ数はそれぞれ２．８８および４．４８である。また、焦点距離が中間の２３．６３ｍｍのときのＦ数は３．８０である。 The focal lengths at the wide-angle end and the telephoto end are 6.00 mm and 93.00 mm, respectively, and thus the zoom ratio is 15.5. The F numbers at the wide-angle end and the telephoto end are 2.88 and 4.48, respectively. Further, the F number when the focal length is an intermediate 23.63 mm is 3.80.

撮影光学系１２のコンストラクションデータを表１に示す。表１において、各行の軸上面間隔はその行の面と次の行の面との間隔であり、各行の屈折率およびアッベ数もその行の面と次の行の面の間の媒質の屈折率およびアッベ数（空気については省略）である。屈折率およびアッベ数はｄ線に対するものである。距離の単位はｍｍである。また、ズーミングにより変化する軸上面間隔については、広角端と上記の中間の焦点距離と望遠端での値を、左から順に表している。なお、非球面については符号の末尾にアスタリスク（＊印）を付している。 The construction data of the photographing optical system 12 is shown in Table 1. In Table 1, the axial top surface spacing of each row is the spacing between the surface of the row and the surface of the next row, and the refractive index and Abbe number of each row are also the refraction of the medium between the surface of the row and the surface of the next row. Rate and Abbe number (omitted for air). The refractive index and Abbe number are for the d-line. The unit of distance is mm. In addition, with respect to the axial top surface distance that changes due to zooming, values at the wide-angle end, the intermediate focal length, and the telephoto end are shown in order from the left. For aspheric surfaces, an asterisk (* mark) is added to the end of the reference numeral.

[表１]
面曲率半径軸上面間隔屈折率アッベ数
r1 56.592 2.000 1.84666 23.78
r2 34.012 0.010 1.51400 42.83
r3 34.012 4.828 1.49700 81.61
r4 -401.072 0.100
r5 29.243 3.704 1.71300 53.94
r6 79.633 1.000〜16.824〜28.406
r7 47.466 1.100 1.88300 40.79
r8 7.783 6.027
r9 -19.146 0.900 1.49700 81.61
r10 10.715 0.010 1.51400 42.83
r11 10.715 2.340 1.84666 23.78
r12 35.459 22.148〜 5.182〜 1.153
r13 ∞ 1.000
r14* 9.256 1.823 1.49700 81.61
r15 44.034 5.722
r16 -169.730 2.019 1.49700 81.61
r17 -6.927 1.069
r18 -6.076 0.900 1.71736 29.50
r19 -12.756 2.510〜 4.194〜23.349
r20* 15.521 2.131 1.53048 55.72
r21 -45.628 0.010 1.51400 42.83
r22 -45.628 0.900 1.62017 24.01
r23* -1775.757 8.251〜14.720〜 1.000
r24 ∞ 3.500 1.51633 64.14
r25 ∞ [Table 1]
Surface Curvature Radius Axis Top Surface Refractive Index Abbe Number
r1 56.592 2.000 1.84666 23.78
r2 34.012 0.010 1.51400 42.83
r3 34.012 4.828 1.49700 81.61
r4 -401.072 0.100
r5 29.243 3.704 1.71300 53.94
r6 79.633 1.000-16.824-28.406
r7 47.466 1.100 1.88300 40.79
r8 7.783 6.027
r9 -19.146 0.900 1.49700 81.61
r10 10.715 0.010 1.51400 42.83
r11 10.715 2.340 1.84666 23.78
r12 35.459 22.148〜 5.182〜 1.153
r13 ∞ 1.000
r14 * 9.256 1.823 1.49700 81.61
r15 44.034 5.722
r16 -169.730 2.019 1.49700 81.61
r17 -6.927 1.069
r18 -6.076 0.900 1.71736 29.50
r19 -12.756 2.510〜 4.194〜23.349
r20 * 15.521 2.131 1.53048 55.72
r21 -45.628 0.010 1.51400 42.83
r22 -45.628 0.900 1.62017 24.01
r23 * -1775.757 8.251 to 14.720 to 1.000
r24 ∞ 3.500 1.51633 64.14
r25 ∞

非球面は次の式５で定義している。
Ｘ（Ｈ）＝Ｃ・Ｈ²／｛１＋（１−ε・Ｃ²・Ｈ²）^1/2｝＋ΣＡｋ・Ｈ^k ・・・式５
ここで、Ｈは光軸に対して垂直な方向の高さ、Ｘ（Ｈ）は高さＨの位置での光軸方向の変位量（面頂点基準）、Ｃは近軸曲率、εは２次曲面パラメータ、ｋは非球面の次数、Ａｋはｋ次の非球面係数である。非球面に関するデータを表２に示す。 The aspherical surface is defined by the following formula 5.
X (H) = C · H ² / {1+ (1−ε · C ² · H ² ) ^1/2 } + ΣAk · H ^k Formula 5
Here, H is the height in the direction perpendicular to the optical axis, X (H) is the amount of displacement in the optical axis direction at the position of the height H (based on the surface vertex), C is the paraxial curvature, and ε is 2 The quadratic surface parameter, k is the order of the aspheric surface, and Ak is the k-th order aspheric coefficient. Table 2 shows data relating to the aspheric surface.

［表２］
面r14
ε = 1.0000
A4 = -0.15717526×10^-3 A6 = -0.19389654×10^-5 A8 = -0.15573656×10^-6
A10 = 0.69643896×10^-8 A12 = -0.49551177×10^-9
面r20
ε = 1.0000
A4 = -0.34607537×10^-4 A6 = -0.61736587×10^-6 A8 = 0.36334220×10^-6
A10 = -0.12239069×10^-7
面r23
ε = 1.0000
A4 = -0.10389724×10^-4 A6 = -0.29111256×10^-5 A8 = 0.64550962×10^-6
A10 = -0.27171011×10^-7 A12 = 0.26629674×10^-9 [Table 2]
Surface r14
ε = 1.0000
A4 = -0.15717526 × 10 ^-3 A6 = -0.19389654 × 10 ^-5 A8 = -0.15573656 × 10 ^-6
A10 = 0.69643896 × 10 ^-8 A12 = -0.49551177 × 10 ^-9
Surface r20
ε = 1.0000
A4 = -0.34607537 × 10 ^-4 A6 = -0.61736587 × 10 ^-6 A8 = 0.36334220 × 10 ^-6
A10 = -0.12239069 × 10 ^-7
Surface r23
ε = 1.0000
A4 = -0.10389724 × 10 ^-4 A6 = -0.29111256 × 10 ^-5 A8 = 0.64550962 × 10 ^-6
A10 = -0.27171011 × 10 ^-7 A12 = 0.26629674 × 10 ^-9

広角端での撮影光学系１２全体の焦点距離をｆｗ、望遠端での撮影光学系１２全体の焦点距離をｆｔ、第１レンズ群Ｇ１の焦点距離をｆ１、広角端での第２レンズ群Ｇ２の倍率をβ2w、望遠端での第２レンズ群Ｇ２の倍率をβ2t、広角端での第３レンズ群Ｇ３の倍率をβ3w、望遠端での第３レンズ群Ｇ３の倍率をβ3tで表すとき、ｆ１／ｆｗ＝７．７３５、（β2t／β2w）／（ｆｔ／ｆｗ）＝０．６５４、β3t／β3w＝１．８４１である。したがって、前述の式１、式２、式３の関係は全て満たされており、式１’、式２’、式３’の関係も全て満たされている。また、ｆ３／ｆｔ＝０．２０５０であり、式４、式４’の関係も満たされている。 The focal length of the entire photographic optical system 12 at the wide angle end is fw, the focal length of the entire photographic optical system 12 at the telephoto end is ft, the focal length of the first lens group G1 is f1, and the second lens group G2 at the wide angle end. Β2w, the magnification of the second lens group G2 at the telephoto end is represented by β2t, the magnification of the third lens group G3 at the wide-angle end is represented by β3w, and the magnification of the third lens group G3 at the telephoto end is represented by β3t. f1 / fw = 7.735, (β2t / β2w) / (ft / fw) = 0.654, β3t / β3w = 1.841. Therefore, all the relations of the above-described Expression 1, Expression 2, and Expression 3 are satisfied, and all the relations of Expression 1 ', Expression 2', and Expression 3 'are also satisfied. Further, f3 / ft = 0.050, and the relations of Expression 4 and Expression 4 ′ are also satisfied.

撮影光学系１２の収差を図４に示す。図４において、（ａ）は広角端、（ｂ）は上記の中間の焦点距離、（ｃ）は望遠端でのものである。球面収差の線ｄはｄ線の収差、線ｇはｇ線の収差である。線ＳＣは正弦条件不満足量を表している。また、非点収差の線ＤＭおよび線ＤＳはそれぞれメリジオナル面およびサジタル面での収差である。単位は、歪曲の横軸のみ百分率であり、他の軸については全てｍｍである。 Aberrations of the photographing optical system 12 are shown in FIG. In FIG. 4, (a) is at the wide-angle end, (b) is at the above intermediate focal length, and (c) is at the telephoto end. The spherical aberration line d is the d-line aberration, and the line g is the g-line aberration. Line SC represents the unsatisfactory amount of the sine condition. Astigmatism lines DM and DS are aberrations on the meridional surface and the sagittal surface, respectively. The unit is percentage only for the horizontal axis of the distortion, and mm for all other axes.

本実施形態のデジタルカメラ１の撮影光学系１２は、変倍比が１５．５と大きいが、図４より明らかなように諸収差が良好に抑えられており、高い結像特性を有する。また、全長がフィルターＦまで含めても７４ｍｍ程度（広角端）であり、小型になっている。しかも、レンズの総数が１１と少なく、非球面の数も３と少ないため、製造が容易である。 The photographing optical system 12 of the digital camera 1 of the present embodiment has a large zoom ratio of 15.5, but various aberrations are well suppressed as shown in FIG. 4, and has high imaging characteristics. In addition, the total length including the filter F is about 74 mm (wide-angle end), and is small. Moreover, since the total number of lenses is as small as 11 and the number of aspheric surfaces is as small as 3, manufacturing is easy.

以下、他の実施形態のデジタルカメラについて説明するが、撮影光学系以外の構成は第１の実施形態のものと同様なので、重複する説明は省略し、撮影光学系についてのみ述べる。なお、以下に示す図５〜図１２においては図３および図４と同様の表記方法を採用している。また、非球面の定義は前述の式５に従っており、表３〜表１０においては表１および表２と同様の表記方法を採用している。 Hereinafter, a digital camera according to another embodiment will be described. However, since the configuration other than the photographing optical system is the same as that of the first embodiment, a duplicate description will be omitted, and only the photographing optical system will be described. 5 to 12 shown below employ the same notation as in FIG. 3 and FIG. In addition, the definition of the aspherical surface follows the formula 5 described above, and in Tables 3 to 10, the same notation method as in Tables 1 and 2 is adopted.

第２の実施形態のデジタルカメラ２の撮影光学系１２の構成を図５に示す。デジタルカメラ２の撮影光学系１２は、撮影対象側から順に第１レンズ群Ｇ１、第２レンズ群Ｇ２、第３レンズ群Ｇ３、第４レンズ群Ｇ４、第５レンズ群Ｇ５を有する。 FIG. 5 shows a configuration of the photographing optical system 12 of the digital camera 2 according to the second embodiment. The photographing optical system 12 of the digital camera 2 includes a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5 in order from the photographing target side.

第１レンズ群Ｇ１は、３枚のレンズＬ１、Ｌ２、Ｌ３より成り、全体として正の光学的パワーを有する。第２レンズ群Ｇ２は、３枚のレンズＬ４、Ｌ５、Ｌ６より成り、全体として負の光学的パワーを有する。第３レンズ群Ｇ３は、４枚のレンズＬ７、Ｌ８、Ｌ９、Ｌ１０より成り、全体として正の光学的パワーを有する。第４レンズ群Ｇ４は、２枚のレンズＬ１１、Ｌ１２より成り、全体として正の光学的パワーを有する。第５レンズ群Ｇ５は、単一のレンズＬ１３より成り、正の光学的パワーを有する。 The first lens group G1 includes three lenses L1, L2, and L3, and has a positive optical power as a whole. The second lens group G2 includes three lenses L4, L5, and L6, and has a negative optical power as a whole. The third lens group G3 includes four lenses L7, L8, L9, and L10, and has a positive optical power as a whole. The fourth lens group G4 includes two lenses L11 and L12, and has a positive optical power as a whole. The fifth lens group G5 includes a single lens L13, and has positive optical power.

第２レンズ群Ｇ２と第３レンズ群Ｇ３の間には絞りＳが設けられている。絞りＳは第３レンズ群Ｇ３と共に移動する。また、撮像素子２１の直前にはローパスフィルターＦが配置されている。 A diaphragm S is provided between the second lens group G2 and the third lens group G3. The diaphragm S moves together with the third lens group G3. Further, a low-pass filter F is disposed immediately before the image sensor 21.

本実施形態では、撮影光学系１２は撮影対象側から順に面ｒ１〜ｒ２９を有する。レンズＬ４の面ｒ７、レンズＬ７の面ｒ１４、レンズＬ１０の面ｒ２０、ｒ２１およびレンズＬ１３の面ｒ２６、ｒ２７はいずれも非球面である。また、レンズＬ１とレンズＬ２、レンズＬ５とレンズＬ６、レンズＬ７とレンズＬ８、レンズＬ１１とレンズＬ１２はそれぞれ接着されており、面ｒ２と面ｒ３の間、面ｒ１０と面ｒ１１の間、面ｒ１５と面ｒ１６の間、面ｒ２３と面２４の間には、それぞれ接着剤が存在する。 In the present embodiment, the photographing optical system 12 has surfaces r1 to r29 in order from the photographing target side. The surface r7 of the lens L4, the surface r14 of the lens L7, the surfaces r20 and r21 of the lens L10, and the surfaces r26 and r27 of the lens L13 are all aspherical surfaces. Further, the lens L1 and the lens L2, the lens L5 and the lens L6, the lens L7 and the lens L8, the lens L11 and the lens L12 are bonded, respectively, between the surface r2 and the surface r3, between the surface r10 and the surface r11, and the surface r15. There are adhesives between the surface r16 and the surface r16, and between the surface r23 and the surface 24, respectively.

第１レンズ群Ｇ１と第５レンズ群Ｇ５は固定であり、ズーミングは第２レンズ群Ｇ２、第３レンズ群Ｇ３および第４レンズ群Ｇ４を移動させることによって行われる。広角端から望遠端へのズーミングに際し、第１レンズ群Ｇ１と第２レンズ群Ｇ２との間隔は増大し、第２レンズ群Ｇ２と第３レンズ群Ｇ３との間隔は減少し、第３レンズ群Ｇ３と第４レンズ群Ｇ４との間隔は増大する。その際、第３レンズ群Ｇ３は、撮影対象側に単調に移動する。また、第４レンズ群Ｇ４を前方に繰り出すことにより、無限遠物体から近距離物体へのフォーカシングを行う。広角端から望遠端へのズーミングに際し、第４レンズ群Ｇ４は、まず撮影対象側に移動し、次いで撮像素子２１側に移動する。 The first lens group G1 and the fifth lens group G5 are fixed, and zooming is performed by moving the second lens group G2, the third lens group G3, and the fourth lens group G4. During zooming from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group. The interval between G3 and the fourth lens group G4 increases. At that time, the third lens group G3 monotonously moves toward the photographing target side. Further, the fourth lens group G4 is extended forward to perform focusing from an infinitely distant object to a close object. During zooming from the wide-angle end to the telephoto end, the fourth lens group G4 first moves to the photographing target side, and then moves to the image sensor 21 side.

広角端および望遠端での焦点距離はそれぞれ６．００ｍｍおよび１０５．００ｍｍであり、したがって、変倍比は１７．５である。広角端および望遠端でのＦ数はそれぞれ２．８８および４．６０である。また、焦点距離が中間の２５．１０ｍｍのときのＦ数は４．００である。 The focal lengths at the wide-angle end and the telephoto end are 6.00 mm and 105.00 mm, respectively, and thus the zoom ratio is 17.5. The F numbers at the wide-angle end and the telephoto end are 2.88 and 4.60, respectively. The F number when the focal length is an intermediate 25.10 mm is 4.00.

撮影光学系１２のコンストラクションデータを表３に示し、非球面に関するデータを表４に示す。 The construction data of the photographing optical system 12 is shown in Table 3, and the data relating to the aspherical surface is shown in Table 4.

[表３]
面曲率半径軸上面間隔屈折率アッベ数
r1 59.712 2.000 1.84666 23.78
r2 35.515 0.010 1.51400 42.83
r3 35.515 5.135 1.49700 81.61
r4 -351.240 0.100
r5 33.930 3.660 1.72916 54.67
r6 106.693 1.000〜18.762〜30.324
r7* 190.681 1.100 1.77250 49.77
r8 10.025 6.192
r9 -9.809 1.000 1.49700 81.61
r10 32.768 0.010 1.51400 42.83
r11 32.768 2.481 1.84666 23.78
r12 -66.763 40.107〜13.774〜 1.300
r13 ∞ 1.800
r14* 10.923 3.635 1.58913 61.25
r15 -28.036 0.010 1.51400 42.83
r16 -28.036 2.400 1.80610 33.27
r17 45.900 1.000
r18 19.625 2.500 1.49700 81.61
r19 -57.497 8.334
r20* -6.587 1.200 1.53048 55.72
r21* -13.059 2.694〜 2.883〜11.060
r22 20.706 3.076 1.48749 70.44
r23 -12.080 0.010 1.51400 42.83
r24 -12.080 2.006 1.80518 25.46
r25 -19.021 1.482〜 9.864〜 2.599
r26* -25.419 1.560 1.53048 55.72
r27* -18.182 1.000
r28 ∞ 3.500 1.51633 64.14
r29 ∞ [Table 3]
Surface Curvature Radius Axis Top Surface Refractive Index Abbe Number
r1 59.712 2.000 1.84666 23.78
r2 35.515 0.010 1.51400 42.83
r3 35.515 5.135 1.49700 81.61
r4 -351.240 0.100
r5 33.930 3.660 1.72916 54.67
r6 106.693 1.000-18.762-30.324
r7 * 190.681 1.100 1.77250 49.77
r8 10.025 6.192
r9 -9.809 1.000 1.49700 81.61
r10 32.768 0.010 1.51400 42.83
r11 32.768 2.481 1.84666 23.78
r12 -66.763 40.107〜13.774〜 1.300
r13 ∞ 1.800
r14 * 10.923 3.635 1.58913 61.25
r15 -28.036 0.010 1.51400 42.83
r16 -28.036 2.400 1.80610 33.27
r17 45.900 1.000
r18 19.625 2.500 1.49700 81.61
r19 -57.497 8.334
r20 * -6.587 1.200 1.53048 55.72
r21 * -13.059 2.694〜 2.883〜11.060
r22 20.706 3.076 1.48749 70.44
r23 -12.080 0.010 1.51400 42.83
r24 -12.080 2.006 1.80518 25.46
r25 -19.021 1.482 to 9.864 to 2.599
r26 * -25.419 1.560 1.53048 55.72
r27 * -18.182 1.000
r28 ∞ 3.500 1.51633 64.14
r29 ∞

[表４]
面r7
ε = 1.0000
A4 = 0.48037046×10^-4 A6 = -0.12998324×10^-8 A8 = -0.32660067×10^-8
A10 = 0.36726880×10^-10 A12 = -0.59543386×10^-13
面r14
ε = 1.0000
A4 = -0.44372786×10^-4 A6 = -0.20247616×10^-6 A8 = 0.43913988×10^-8
A10 = -0.60699374×10^-9 A12 = 0.15490022×10^-10
面r20
ε = 1.0000
A4 = -0.36655741×10^-3 A6 = 0.25220861×10^-4 A8 = 0.17418822×10^-6
A10 = -0.29126750×10^-8
面r21
ε = 1.0000
A4 = -0.24718709×10^-3 A6 = 0.20036043×10^-4 A8 = -0.11982312×10^-6
面r26
ε = 1.0000
A4 = 0.40122081×10^-3 A6 = 0.53569246×10^-5 A8 = -0.31021429×10^-6
A10 = -0.20511969×10^-7
面r27
ε = 1.0000
A4 = 0.67276552×10^-3 A6 = 0.16243678×10^-4 A8 = -0.12561839×10^-5
A10 = -0.67194647×10^-8 [Table 4]
Surface r7
ε = 1.0000
A4 = 0.48037046 × 10 ^-4 A6 = -0.12998324 × 10 ^-8 A8 = -0.32660067 × 10 ^-8
A10 = 0.36726880 × 10 ^-10 A12 = -0.59543386 × 10 ^-13
Surface r14
ε = 1.0000
A4 = -0.44372786 × 10 ^-4 A6 = -0.20247616 × 10 ^-6 A8 = 0.43913988 × 10 ^-8
A10 = -0.60699374 × 10 ^-9 A12 = 0.15490022 × 10 ^-10
Surface r20
ε = 1.0000
A4 = -0.36655741 × 10 ^-3 A6 = 0.25220861 × 10 ^-4 A8 = 0.17418822 × 10 ^-6
A10 = -0.29126750 × 10 ^-8
Surface r21
ε = 1.0000
A4 = -0.24718709 × 10 ^-3 A6 = 0.20036043 × 10 ^-4 A8 = -0.11982312 × 10 ^-6
Surface r26
ε = 1.0000
A4 = 0.40122081 × 10 ^-3 A6 = 0.53569246 × 10 ^-5 A8 = -0.31021429 × 10 ^-6
A10 = -0.20511969 × 10 ^-7
Surface r27
ε = 1.0000
A4 = 0.67276552 × 10 ^-3 A6 = 0.16243678 × 10 ^-4 A8 = -0.12561839 × 10 ^-5
A10 = -0.67194647 × 10 ^-8

広角端での撮影光学系１２全体の焦点距離をｆｗ、望遠端での撮影光学系１２全体の焦点距離をｆｔ、第１レンズ群Ｇ１の焦点距離をｆ１、広角端での第２レンズ群Ｇ２の倍率をβ2w、望遠端での第２レンズ群Ｇ２の倍率をβ2t、広角端での第３レンズ群Ｇ３の倍率をβ3w、望遠端での第３レンズ群Ｇ３の倍率をβ3tで表すとき、ｆ１／ｆｗ＝８．１５５、（β2t／β2w）／（ｆｔ／ｆｗ）＝０．５８０、β3t／β3w＝１．８４１である。したがって、前述の式１、式２、式３の関係は全て満たされており、式１’、式２’、式３’の関係も全て満たされている。また、ｆ３／ｆｔ＝０．１９３９であり、式４、式４’の関係も満たされている。 The focal length of the entire photographic optical system 12 at the wide angle end is fw, the focal length of the entire photographic optical system 12 at the telephoto end is ft, the focal length of the first lens group G1 is f1, and the second lens group G2 at the wide angle end. Β2w, the magnification of the second lens group G2 at the telephoto end is represented by β2t, the magnification of the third lens group G3 at the wide-angle end is represented by β3w, and the magnification of the third lens group G3 at the telephoto end is represented by β3t. f1 / fw = 8.155, (β2t / β2w) / (ft / fw) = 0.580, β3t / β3w = 1.841. Therefore, all the relations of the above-described Expression 1, Expression 2, and Expression 3 are satisfied, and all the relations of Expression 1 ', Expression 2', and Expression 3 'are also satisfied. Further, f3 / ft = 0.1939, and the relations of Expression 4 and Expression 4 ′ are also satisfied.

撮影光学系１２の収差を図６に示す。本実施形態のデジタルカメラ２の撮影光学系１２は、変倍比が１７．５と大きいが、図６より明らかなように諸収差が良好に抑えられており、高い結像特性を有する。また、全長がフィルターＦまで含めても１０６ｍｍ程度であり、小型になっている。しかも、レンズの総数が１３と少なく、非球面の数も６と少ないため、製造が容易である。 The aberrations of the photographing optical system 12 are shown in FIG. The photographing optical system 12 of the digital camera 2 of the present embodiment has a large zoom ratio of 17.5, but various aberrations are well suppressed as shown in FIG. Moreover, even if the total length including the filter F is about 106 mm, it is small. Moreover, since the total number of lenses is as small as 13 and the number of aspheric surfaces is as small as 6, manufacturing is easy.

第３の実施形態のデジタルカメラ３の撮影光学系１２の構成を図７に示す。デジタルカメラ３の撮影光学系１２は、撮影対象側から順に第１レンズ群Ｇ１、第２レンズ群Ｇ２、第３レンズ群Ｇ３、第４レンズ群Ｇ４、第５レンズ群Ｇ５を有する。 FIG. 7 shows the configuration of the photographing optical system 12 of the digital camera 3 according to the third embodiment. The photographing optical system 12 of the digital camera 3 includes a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5 in order from the photographing target side.

第１レンズ群Ｇ１は、３枚のレンズＬ１、Ｌ２、Ｌ３より成り、全体として正の光学的パワーを有する。第２レンズ群Ｇ２は、３枚のレンズＬ４、Ｌ５、Ｌ６より成り、全体として負の光学的パワーを有する。第３レンズ群Ｇ３は、４枚のレンズＬ７、Ｌ８、Ｌ９、Ｌ１０より成り、全体として正の光学的パワーを有する。第４レンズ群Ｇ４は、２枚のレンズＬ１１、Ｌ１２より成り、全体として正の光学的パワーを有する。第５レンズ群Ｇ５は、単一のレンズＬ１３より成り、負の光学的パワーを有する。 The first lens group G1 includes three lenses L1, L2, and L3, and has a positive optical power as a whole. The second lens group G2 includes three lenses L4, L5, and L6, and has a negative optical power as a whole. The third lens group G3 includes four lenses L7, L8, L9, and L10, and has a positive optical power as a whole. The fourth lens group G4 includes two lenses L11 and L12, and has a positive optical power as a whole. The fifth lens group G5 includes a single lens L13, and has negative optical power.

撮影光学系１２のコンストラクションデータを表５に示し、非球面に関するデータを表６に示す。 Table 5 shows construction data of the photographing optical system 12 and Table 6 shows data related to the aspherical surface.

［表５］
面曲率半径軸上面間隔屈折率アッベ数
r1 51.264 2.00 1.846660 23.78
r2 35.190 0.01 1.514000 42.83
r3 35.190 5.79 1.497000 81.61
r4 -919.485 0.10
r5 33.618 3.51 1.668292 58.46
r6 76.757 1.00 〜18.02 〜32.04
r7* 76.340 1.10 1.806100 33.27
r8 8.868 6.77
r9 -16.080 1.00 1.497000 81.61
r10 15.767 0.01 1.514000 42.83
r11 15.767 3.24 1.846660 23.78
r12 378.217 47.42 〜17.76 〜 1.32
r13 ∞ 1.80
r14* 9.091 6.64 1.589130 61.24
r15 -26.364 0.01 1.514000 42.83
r16 -26.364 2.40 1.834224 42.58
r17 9.829 1.00
r18 9.939 2.50 1.497000 81.61
r19 -19.027 3.52
r20* 76.839 2.47 1.530480 55.72
r21* 22.045 3.51 〜13.52 〜18.07
r22 33.597 2.73 1.487490 70.45
r23 -13.067 0.01 1.514000 42.83
r24 -13.067 0.80 1.765027 26.89
r25 -21.635 3.67 〜 6.29 〜 4.16
r26* -17.903 1.50 1.530480 55.72
r27* -26.647 1.00
r28 ∞ 3.50 1.516330 64.14
r29 ∞ 1.00 [Table 5]
Surface Curvature Radius Axis Top Surface Refractive Index Abbe Number
r1 51.264 2.00 1.846660 23.78
r2 35.190 0.01 1.514000 42.83
r3 35.190 5.79 1.497000 81.61
r4 -919.485 0.10
r5 33.618 3.51 1.668292 58.46
r6 76.757 1.00 -18.02 32.04
r7 * 76.340 1.10 1.806100 33.27
r8 8.868 6.77
r9 -16.080 1.00 1.497000 81.61
r10 15.767 0.01 1.514000 42.83
r11 15.767 3.24 1.846660 23.78
r12 378.217 47.42-17.76-1.32
r13 ∞ 1.80
r14 * 9.091 6.64 1.589130 61.24
r15 -26.364 0.01 1.514000 42.83
r16 -26.364 2.40 1.834224 42.58
r17 9.829 1.00
r18 9.939 2.50 1.497000 81.61
r19 -19.027 3.52
r20 * 76.839 2.47 1.530480 55.72
r21 * 22.045 3.51 to 13.52 to 18.07
r22 33.597 2.73 1.487490 70.45
r23 -13.067 0.01 1.514000 42.83
r24 -13.067 0.80 1.765027 26.89
r25 -21.635 3.67 to 6.29 to 4.16
r26 * -17.903 1.50 1.530480 55.72
r27 * -26.647 1.00
r28 ∞ 3.50 1.516330 64.14
r29 ∞ 1.00

[表６]
面r7
ε = 1.0000
A4 = 2.49041×10^-5 A6 = 8.13758×10^-8 A8 = -4.49554×10^-9
A10 = 4.73610×10^-11 A12 = -1.67504×10^-13
面r14
ε = 1.0000
A4 = -6.65843×10^-5 A6 = 2.51873×10^-7 A8 = -5.29869×10^-8
A10 = 1.29513×10^-9 A12 = -1.31597×10^-11
面r20
ε = 1.0000
A4 = -1.20828×10^-3 A6 = -9.85746×10^-6 A8 = 3.88854×10^-7
A10 = -1.66592×10^-8
面r21
ε = 1.0000
A4 = -1.09887×10^-3 A6 = 7.22544×10^-6 A8 = -6.77749×10^-8
面r26
ε = 1.0000
A4 = -3.50821×10^-4 A6 = -1.50755×10^-5 A8 = 0.00000×10⁰
面r27
ε = 1.0000
A4 = -6.98374×10^-4 A6 = -1.05709×10^-5 A8 = -2.24731×10^-7
A10 = 1.06287×10^-8 A12 = 4.53933×10^-16 [Table 6]
Surface r7
ε = 1.0000
A4 = 2.49041 × 10 ^-5 A6 = 8.13758 × 10 ^-8 A8 = -4.49554 × 10 ^-9
A10 = 4.73610 × 10 ^-11 A12 = -1.67504 × 10 ^-13
Surface r14
ε = 1.0000
A4 = -6.65843 × 10 ^-5 A6 = 2.51873 × 10 ^-7 A8 = -5.29869 × 10 ^-8
A10 = 1.29513 × 10 ^-9 A12 = -1.31597 × 10 ^-11
Surface r20
ε = 1.0000
A4 = -1.20828 × 10 ^-3 A6 = -9.85746 × 10 ^-6 A8 = 3.88854 × 10 ^-7
A10 = -1.66592 × 10 ^-8
Surface r21
ε = 1.0000
A4 = -1.09887 × 10 ^-3 A6 = 7.22544 × 10 ^-6 A8 = -6.77749 × 10 ^-8
Surface r26
ε = 1.0000
A4 = -3.50821 × 10 ^-4 A6 = -1.50755 × 10 ^-5 A8 = 0.00000 × 10 ⁰
Surface r27
ε = 1.0000
A4 = -6.98374 × 10 ^-4 A6 = -1.05709 × 10 ^-5 A8 = -2.24731 × 10 ^-7
A10 = 1.06287 × 10 ^-8 A12 = 4.53933 × 10 ^-16

広角端での撮影光学系１２全体の焦点距離をｆｗ、望遠端での撮影光学系１２全体の焦点距離をｆｔ、第１レンズ群Ｇ１の焦点距離をｆ１、広角端での第２レンズ群Ｇ２の倍率をβ2w、望遠端での第２レンズ群Ｇ２の倍率をβ2t、広角端での第３レンズ群Ｇ３の倍率をβ3w、望遠端での第３レンズ群Ｇ３の倍率をβ3tで表すとき、ｆ１／ｆｗ＝９．０４５、（β2t／β2w）／（ｆｔ／ｆｗ）＝０．４１４、β3t／β3w＝２．４６０である。したがって、前述の式１、式２、式３の関係は全て満たされており、式１’、式２’、式３’の関係も全て満たされている。また、ｆ３／ｆｔ＝０．２０９１であり、式４、式４’の関係も満たされている。 The focal length of the entire photographic optical system 12 at the wide angle end is fw, the focal length of the entire photographic optical system 12 at the telephoto end is ft, the focal length of the first lens group G1 is f1, and the second lens group G2 at the wide angle end. Β2w, the magnification of the second lens group G2 at the telephoto end is represented by β2t, the magnification of the third lens group G3 at the wide-angle end is represented by β3w, and the magnification of the third lens group G3 at the telephoto end is represented by β3t. f1 / fw = 9.045, (β2t / β2w) / (ft / fw) = 0.414, β3t / β3w = 2.460. Therefore, all the relations of the above-described Expression 1, Expression 2, and Expression 3 are satisfied, and all the relations of Expression 1 ', Expression 2', and Expression 3 'are also satisfied. Further, f3 / ft = 0.2091, and the relations of Expressions 4 and 4 'are also satisfied.

撮影光学系１２の収差を図８に示す。本実施形態のデジタルカメラ３の撮影光学系１２は、変倍比が１７．５と大きいが、図８より明らかなように諸収差が良好に抑えられており、高い結像特性を有する。また、全長がフィルターＦまで含めても１１０ｍｍ程度であり、小型になっている。しかも、レンズの総数が１３と少なく、非球面の数も６と少ないため、製造が容易である。 The aberration of the photographing optical system 12 is shown in FIG. The imaging optical system 12 of the digital camera 3 of the present embodiment has a large zoom ratio of 17.5, but various aberrations are well suppressed as shown in FIG. 8, and has high imaging characteristics. Moreover, even if the total length includes the filter F, it is about 110 mm, and it is small. Moreover, since the total number of lenses is as small as 13 and the number of aspheric surfaces is as small as 6, manufacturing is easy.

第４の実施形態のデジタルカメラ４の撮影光学系１２の構成を図９に示す。デジタルカメラ４の撮影光学系１２は、撮影対象側から順に第１レンズ群Ｇ１、第２レンズ群Ｇ２、第３レンズ群Ｇ３、第４レンズ群Ｇ４、第５レンズ群Ｇ５を有する。 FIG. 9 shows the configuration of the photographing optical system 12 of the digital camera 4 of the fourth embodiment. The photographing optical system 12 of the digital camera 4 includes a first lens group G1, a second lens group G2, a third lens group G3, a fourth lens group G4, and a fifth lens group G5 in order from the photographing target side.

第１レンズ群Ｇ１は、３枚のレンズＬ１、Ｌ２、Ｌ３より成り、全体として正の光学的パワーを有する。第２レンズ群Ｇ２は、４枚のレンズＬ４、Ｌ５、Ｌ６、Ｌ７より成り、全体として負の光学的パワーを有する。第３レンズ群Ｇ３は、４枚のレンズＬ８、Ｌ９、Ｌ１０、Ｌ１１より成り、全体として正の光学的パワーを有する。第４レンズ群Ｇ４は、２枚のレンズＬ１２、Ｌ１３より成り、全体として正の光学的パワーを有する。第５レンズ群Ｇ５は、単一のレンズＬ１４より成り、正の光学的パワーを有する。 The first lens group G1 includes three lenses L1, L2, and L3, and has a positive optical power as a whole. The second lens group G2 includes four lenses L4, L5, L6, and L7, and has a negative optical power as a whole. The third lens group G3 includes four lenses L8, L9, L10, and L11, and has a positive optical power as a whole. The fourth lens group G4 includes two lenses L12 and L13, and has a positive optical power as a whole. The fifth lens group G5 includes a single lens L14, and has positive optical power.

本実施形態では、撮影光学系１２は撮影対象側から順に面ｒ１〜ｒ３１を有する。レンズＬ８の面ｒ１６、レンズＬ１１の面ｒ２２、ｒ２３およびレンズＬ１４の面ｒ２８、ｒ２９はいずれも非球面である。また、レンズＬ１とレンズＬ２、レンズＬ５とレンズＬ６、レンズＬ１２とレンズＬ１３はそれぞれ接着されており、面ｒ２と面ｒ３の間、面ｒ１０と面ｒ１１の間、面ｒ２５と面ｒ２６の間には、それぞれ接着剤が存在する。 In the present embodiment, the photographing optical system 12 has surfaces r1 to r31 in order from the photographing target side. The surface r16 of the lens L8, the surfaces r22 and r23 of the lens L11, and the surfaces r28 and r29 of the lens L14 are all aspherical surfaces. The lens L1 and the lens L2, the lens L5 and the lens L6, and the lens L12 and the lens L13 are bonded, respectively, between the surface r2 and the surface r3, between the surface r10 and the surface r11, and between the surface r25 and the surface r26. Each has an adhesive.

第５レンズ群Ｇ５は固定であり、ズーミングは第１レンズ群Ｇ１、第２レンズ群Ｇ２、第３レンズ群Ｇ３および第４レンズ群Ｇ４を移動させることによって行われる。広角端から望遠端へのズーミングに際し、第１レンズ群Ｇ１と第２レンズ群Ｇ２との間隔は増大し、第２レンズ群Ｇ２と第３レンズ群Ｇ３との間隔は減少し、第３レンズ群Ｇ３と第４レンズ群Ｇ４との間隔は増大する。その際、第３レンズ群Ｇ３は、撮影対象側に単調に移動する。また、第４レンズ群Ｇ４を前方に繰り出すことにより、無限遠物体から近距離物体へのフォーカシングを行う。広角端から望遠端へのズーミングに際し、第４レンズ群Ｇ４は、まず撮影対象側に移動し、次いで撮像素子２１側に移動する。 The fifth lens group G5 is fixed, and zooming is performed by moving the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4. During zooming from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group. The interval between G3 and the fourth lens group G4 increases. At that time, the third lens group G3 monotonously moves toward the photographing target side. Further, the fourth lens group G4 is extended forward to perform focusing from an infinitely distant object to a close object. During zooming from the wide-angle end to the telephoto end, the fourth lens group G4 first moves to the photographing target side, and then moves to the image sensor 21 side.

広角端および望遠端での焦点距離はそれぞれ６．０１ｍｍおよび１０４．９１ｍｍであり、したがって、変倍比は１７．５である。広角端および望遠端でのＦ数はそれぞれ２．８８および４．６０である。また、焦点距離が中間の２５．１１ｍｍのときのＦ数は４．００である。 The focal lengths at the wide-angle end and the telephoto end are 6.01 mm and 104.91 mm, respectively, and thus the zoom ratio is 17.5. The F numbers at the wide-angle end and the telephoto end are 2.88 and 4.60, respectively. The F number when the focal length is an intermediate 25.11 mm is 4.00.

撮影光学系１２のコンストラクションデータを表７に示し、非球面に関するデータを表８に示す。 Table 7 shows construction data of the photographing optical system 12 and Table 8 shows data related to the aspherical surface.

［表７］
面曲率半径軸上面間隔屈折率アッベ数
r1 50.953 1.800 1.84666 23.78
r2 36.545 0.010 1.51400 42.83
r3 36.545 5.184 1.49700 81.61
r4 -421.145 0.100
r5 42.190 2.525 1.62041 60.34
r6 74.796 1.000〜22.821〜42.652
r7 23.801 1.100 1.88300 40.79
r8 9.396 4.963
r9 -148.533 0.800 1.67003 47.20
r10 7.727 0.010 1.51400 42.83
r11 7.727 3.384 1.84666 23.78
r12 46.614 2.508
r13 -10.799 0.800 1.72916 54.67
r14 -50.197 20.922〜 6.389〜 1.500
r15 ∞ 2.000
r16* 8.393 3.256 1.58913 61.25
r17 -47.186 0.600
r18 89.880 0.800 1.80610 33.27
r19 9.296 1.098
r20 11.264 2.646 1.49700 81.61
r21 -37.064 1.075
r22* 253.863 1.621 1.53048 55.72
r23* 221.963 3.691〜 6.824〜23.722
r24 18.159 2.508 1.49700 81.61
r25 62.579 0.010 1.51400 42.83
r26 62.579 1.491 1.67003 47.20
r27 44.935 4.450〜13.848〜 4.551
r28* -19.088 1.787 1.53048 55.72
r29* -14.198 1.000〜 1.000〜 1.000
r30 ∞ 3.500 1.51633 64.14
r31 ∞ [Table 7]
Surface Curvature Radius Axis Top Surface Refractive Index Abbe Number
r1 50.953 1.800 1.84666 23.78
r2 36.545 0.010 1.51400 42.83
r3 36.545 5.184 1.49700 81.61
r4 -421.145 0.100
r5 42.190 2.525 1.62041 60.34
r6 74.796 1.000-22.821-42.652
r7 23.801 1.100 1.88300 40.79
r8 9.396 4.963
r9 -148.533 0.800 1.67003 47.20
r10 7.727 0.010 1.51400 42.83
r11 7.727 3.384 1.84666 23.78
r12 46.614 2.508
r13 -10.799 0.800 1.72916 54.67
r14 -50.197 20.922〜 6.389〜 1.500
r15 ∞ 2.000
r16 * 8.393 3.256 1.58913 61.25
r17 -47.186 0.600
r18 89.880 0.800 1.80610 33.27
r19 9.296 1.098
r20 11.264 2.646 1.49700 81.61
r21 -37.064 1.075
r22 * 253.863 1.621 1.53048 55.72
r23 * 221.963 3.691〜 6.824〜23.722
r24 18.159 2.508 1.49700 81.61
r25 62.579 0.010 1.51400 42.83
r26 62.579 1.491 1.67003 47.20
r27 44.935 4.450 to 13.848 to 4.551
r28 * -19.088 1.787 1.53048 55.72
r29 * -14.198 1.000 to 1.000 to 1.000
r30 ∞ 3.500 1.51633 64.14
r31 ∞

[表８]
面r16
ε = 1.0000
A4 = -0.15086371×10^-3 A6 = -0.43013186×10^-5 A8 = 0.24186975×10^-6
A10 = -0.10426824×10^-7 A12 = 0.15727119×10^-9
面r22
ε = 1.0000
A4 = -0.23382801×10^-4 A6 = 0.44151149×10^-5 A8 = -0.98965393×10^-7
面r23
ε = 1.0000
A4 = 0.18416651×10^-3 A6 = 0.55132901×10^-5 A8 = -0.68891492×10^-7
A10 = 0.45219416×10^-10
面r28
ε = 1.0000
A4 = 0.10093154×10^-2 A6 = -0.35553820×10^-4 A8 = 0.12710906×10^-5
A10 = -0.58154686×10^-7
面r29
ε = 1.0000
A4 = 0.14841642×10^-2 A6 = -0.43512515×10^-4 A8 = 0.11033650×10^-5
A10 = -0.55064467×10^-7 [Table 8]
Surface r16
ε = 1.0000
A4 = -0.15086371 × 10 ^-3 A6 = -0.43013186 × 10 ^-5 A8 = 0.24186975 × 10 ^-6
A10 = -0.10426824 × 10 ^-7 A12 = 0.15727119 × 10 ^-9
Surface r22
ε = 1.0000
A4 = -0.23382801 × 10 ^-4 A6 = 0.44151149 × 10 ^-5 A8 = -0.98965393 × 10 ^-7
Surface r23
ε = 1.0000
A4 = 0.18416651 × 10 ^-3 A6 = 0.55132901 × 10 ^-5 A8 = -0.68891492 × 10 ^-7
A10 = 0.45219416 × 10 ^-10
Surface r28
ε = 1.0000
A4 = 0.10093154 × 10 ^-2 A6 = -0.35553820 × 10 ^-4 A8 = 0.12710906 × 10 ^-5
A10 = -0.58154686 × 10 ^-7
Surface r29
ε = 1.0000
A4 = 0.14841642 × 10 ^-2 A6 = -0.43512515 × 10 ^-4 A8 = 0.11033650 × 10 ^-5
A10 = -0.55064467 × 10 ^-7

広角端での撮影光学系１２全体の焦点距離をｆｗ、望遠端での撮影光学系１２全体の焦点距離をｆｔ、第１レンズ群Ｇ１の焦点距離をｆ１、広角端での第２レンズ群Ｇ２の倍率をβ2w、望遠端での第２レンズ群Ｇ２の倍率をβ2t、広角端での第３レンズ群Ｇ３の倍率をβ3w、望遠端での第３レンズ群Ｇ３の倍率をβ3tで表すとき、ｆ１／ｆｗ＝１１．２８２、（β2t／β2w）／（ｆｔ／ｆｗ）＝０．３７５、β3t／β3w＝２．６６９である。したがって、前述の式１、式２、式３の関係は全て満たされており、式１’、式２’、式３’の関係も全て満たされている。また、ｆ３／ｆｔ＝０．１５１０であり、式４、式４’の関係も満たされている。 The focal length of the entire photographic optical system 12 at the wide angle end is fw, the focal length of the entire photographic optical system 12 at the telephoto end is ft, the focal length of the first lens group G1 is f1, and the second lens group G2 at the wide angle end. Β2w, the magnification of the second lens group G2 at the telephoto end is represented by β2t, the magnification of the third lens group G3 at the wide-angle end is represented by β3w, and the magnification of the third lens group G3 at the telephoto end is represented by β3t. f1 / fw = 111.22, (β2t / β2w) / (ft / fw) = 0.375, β3t / β3w = 2.669. Therefore, all the relations of the above-described Expression 1, Expression 2, and Expression 3 are satisfied, and all the relations of Expression 1 ', Expression 2', and Expression 3 'are also satisfied. Further, f3 / ft = 0.1510, and the relations of Expressions 4 and 4 'are also satisfied.

撮影光学系１２の収差を図１０に示す。本実施形態のデジタルカメラ４の撮影光学系１２は、変倍比が１７．５と大きいが、図１０より明らかなように諸収差が良好に抑えられており、高い結像特性を有する。また、全長がフィルターＦまで含めても７７ｍｍ程度（広角端）であり、小型になっている。しかも、レンズの総数が１４と少なく、非球面の数も５と少ないため、製造が容易である。 The aberrations of the photographing optical system 12 are shown in FIG. The photographing optical system 12 of the digital camera 4 of the present embodiment has a large zoom ratio of 17.5, but various aberrations are well suppressed as shown in FIG. 10, and has high imaging characteristics. Further, the total length including the filter F is about 77 mm (wide-angle end), and it is small. Moreover, since the total number of lenses is as small as 14 and the number of aspheric surfaces is as small as 5, manufacturing is easy.

第５の実施形態のデジタルカメラ５の撮影光学系１２の構成を図１１に示す。デジタルカメラ５の撮影光学系１２は、撮影対象側から順に第１レンズ群Ｇ１、第２レンズ群Ｇ２、第３レンズ群Ｇ３、第４レンズ群Ｇ４を有する。 FIG. 11 shows the configuration of the photographing optical system 12 of the digital camera 5 of the fifth embodiment. The photographing optical system 12 of the digital camera 5 includes a first lens group G1, a second lens group G2, a third lens group G3, and a fourth lens group G4 in order from the photographing target side.

本実施形態では、撮影光学系１２は撮影対象側から順に面ｒ１〜ｒ２５を有する。レンズＬ７の面ｒ１４、レンズＬ１０の面ｒ２０およびレンズＬ１１の面ｒ２３はいずれも非球面である。また、レンズＬ１とレンズＬ２、レンズＬ５とレンズＬ６、レンズＬ１０とレンズＬ１１はそれぞれ接着されており、面ｒ２と面ｒ３の間、面ｒ１０と面ｒ１１の間、面ｒ２１と面ｒ２２の間には、それぞれ接着剤が存在する。 In the present embodiment, the photographing optical system 12 has surfaces r1 to r25 in order from the photographing target side. The surface r14 of the lens L7, the surface r20 of the lens L10, and the surface r23 of the lens L11 are all aspherical surfaces. The lens L1 and the lens L2, the lens L5 and the lens L6, the lens L10 and the lens L11 are respectively bonded, and between the surface r2 and the surface r3, between the surface r10 and the surface r11, and between the surface r21 and the surface r22. Each has an adhesive.

ズーミングは第１レンズ群Ｇ１、第２レンズ群Ｇ２、第３レンズ群Ｇ３および第４レンズ群Ｇ４を移動させることによって行われる。広角端から望遠端へのズーミングに際し、第１レンズ群Ｇ１と第２レンズ群Ｇ２との間隔は増大し、第２レンズ群Ｇ２と第３レンズ群Ｇ３との間隔は減少し、第３レンズ群Ｇ３と第４レンズ群Ｇ４との間隔は増大する。その際、第３レンズ群Ｇ３は、撮影対象側に単調に移動する。また、第４レンズ群Ｇ４を前方に繰り出すことにより、無限遠物体から近距離物体へのフォーカシングを行う。広角端から望遠端へのズーミングに際し、第４レンズ群Ｇ４は、まず撮影対象側に移動し、次いで撮像素子２１側に移動する。 Zooming is performed by moving the first lens group G1, the second lens group G2, the third lens group G3, and the fourth lens group G4. During zooming from the wide-angle end to the telephoto end, the distance between the first lens group G1 and the second lens group G2 increases, the distance between the second lens group G2 and the third lens group G3 decreases, and the third lens group. The interval between G3 and the fourth lens group G4 increases. At that time, the third lens group G3 monotonously moves toward the photographing target side. Further, the fourth lens group G4 is extended forward to perform focusing from an infinitely distant object to a close object. During zooming from the wide-angle end to the telephoto end, the fourth lens group G4 first moves to the photographing target side, and then moves to the image sensor 21 side.

広角端および望遠端での焦点距離はそれぞれ６．００ｍｍおよび１１７．００ｍｍであり、したがって、変倍比は１９．５である。広角端および望遠端でのＦ数はそれぞれ２．８８および４．９０である。また、焦点距離が中間の２６．５０ｍｍのときのＦ数は４．００である。 The focal lengths at the wide-angle end and the telephoto end are 6.00 mm and 117.00 mm, respectively, and thus the zoom ratio is 19.5. The F numbers at the wide-angle end and the telephoto end are 2.88 and 4.90, respectively. The F number when the focal length is an intermediate 26.50 mm is 4.00.

撮影光学系１２のコンストラクションデータを表９に示し、非球面に関するデータを表１０に示す。 Table 9 shows construction data of the photographing optical system 12 and Table 10 shows data related to the aspherical surface.

［表９］
面曲率半径軸上面間隔屈折率アッベ数
r1 61.263 2.500 1.84666 23.78
r2 45.347 0.010 1.51400 42.83
r3 45.347 4.992 1.49700 81.61
r4 -574.326 1.044
r5 47.758 4.095 1.58913 61.25
r6 79.399 1.000〜28.202〜50.891
r7 37.682 1.500 1.83400 37.34
r8 8.819 6.021
r9 -20.677 1.209 1.49700 81.61
r10 13.479 0.010 1.51400 42.83
r11 13.479 2.769 1.84666 23.78
r12 55.128 31.482〜 7.120〜 1.149
r13 ∞ 2.120
r14* 8.124 2.622 1.53048 55.72
r15 46.770 1.750
r16 15.646 0.892 1.84666 23.78
r17 8.111 1.530
r18 20.237 1.952 1.49700 81.61
r19 -32.104 4.780〜12.754〜40.179
r20* 12.844 2.455 1.53048 55.72
r21 125.441 0.010 1.51400 42.83
r22 125.441 1.200 1.62017 24.01
r23* 32.666 7.751〜14.070〜 1.287
r24 ∞ 3.500 1.51633 64.14
r25 ∞ [Table 9]
Surface Curvature Radius Axis Top Surface Refractive Index Abbe Number
r1 61.263 2.500 1.84666 23.78
r2 45.347 0.010 1.51400 42.83
r3 45.347 4.992 1.49700 81.61
r4 -574.326 1.044
r5 47.758 4.095 1.58913 61.25
r6 79.399 1.000 to 28.202 to 50.891
r7 37.682 1.500 1.83400 37.34
r8 8.819 6.021
r9 -20.677 1.209 1.49700 81.61
r10 13.479 0.010 1.51400 42.83
r11 13.479 2.769 1.84666 23.78
r12 55.128 31.482〜 7.120〜 1.149
r13 ∞ 2.120
r14 * 8.124 2.622 1.53048 55.72
r15 46.770 1.750
r16 15.646 0.892 1.84666 23.78
r17 8.111 1.530
r18 20.237 1.952 1.49700 81.61
r19 -32.104 4.780〜12.754〜40.179
r20 * 12.844 2.455 1.53048 55.72
r21 125.441 0.010 1.51400 42.83
r22 125.441 1.200 1.62017 24.01
r23 * 32.666 7.751 ~ 14.070 ~ 1.287
r24 ∞ 3.500 1.51633 64.14
r25 ∞

[表１０]
面r14
ε = 1.0000
A4 = -0.13682746×10^-3 A6 = -0.72457285×10^-6 A8 = -0.87262517×10^-7
A10 = 0.33174754×10^-8 A12 = -0.60857073×10^-10
面r20
ε = 1.0000
A4 = 0.26498358×10^-4 A6 = -0.80216661×10^-5 A8 = 0.47464775×10^-6
A10 = -0.89457829×10^-8
面r23
ε = 1.0000
A4 = 0.84078718×10^-4 A6 = -0.11462763×10^-4 A8 = 0.67249678×10^-6
A10 = -0.10297467×10^-7 A12 = -0.11715768×10^-9 [Table 10]
Surface r14
ε = 1.0000
A4 = -0.13682746 × 10 ^-3 A6 = -0.72457285 × 10 ^-6 A8 = -0.87262517 × 10 ^-7
A10 = 0.33174754 × 10 ^-8 A12 = -0.60857073 × 10 ^-10
Surface r20
ε = 1.0000
A4 = 0.26498358 × 10 ^-4 A6 = -0.80216661 × 10 ^-5 A8 = 0.47464775 × 10 ^-6
A10 = -0.89457829 × 10 ^-8
Surface r23
ε = 1.0000
A4 = 0.84078718 × 10 ^-4 A6 = -0.11462763 × 10 ^-4 A8 = 0.67249678 × 10 ^-6
A10 = -0.10297467 × 10 ^-7 A12 = -0.11715768 × 10 ^-9

広角端での撮影光学系１２全体の焦点距離をｆｗ、望遠端での撮影光学系１２全体の焦点距離をｆｔ、第１レンズ群Ｇ１の焦点距離をｆ１、広角端での第２レンズ群Ｇ２の倍率をβ2w、望遠端での第２レンズ群Ｇ２の倍率をβ2t、広角端での第３レンズ群Ｇ３の倍率をβ3w、望遠端での第３レンズ群Ｇ３の倍率をβ3tで表すとき、ｆ１／ｆｗ＝１３．７４１、（β2t／β2w）／（ｆｔ／ｆｗ）＝０．５２０、β3t／β3w＝１．８４１である。したがって、前述の式１、式２、式３の関係は全て満たされており、式１’、式２’、式３’の関係も全て満たされている。また、ｆ３／ｆｔ＝０．１７７５であり、式４、式４’の関係も満たされている。 The focal length of the entire photographic optical system 12 at the wide angle end is fw, the focal length of the entire photographic optical system 12 at the telephoto end is ft, the focal length of the first lens group G1 is f1, and the second lens group G2 at the wide angle end. Β2w, the magnification of the second lens group G2 at the telephoto end is represented by β2t, the magnification of the third lens group G3 at the wide-angle end is represented by β3w, and the magnification of the third lens group G3 at the telephoto end is represented by β3t. f1 / fw = 13.741, (β2t / β2w) / (ft / fw) = 0.520, β3t / β3w = 1.841. Therefore, all the relations of the above-described Expression 1, Expression 2, and Expression 3 are satisfied, and all the relations of Expression 1 ', Expression 2', and Expression 3 'are also satisfied. Further, f3 / ft = 0.1775, and the relations of Expression 4 and Expression 4 ′ are also satisfied.

撮影光学系１２の収差を図１２に示す。本実施形態のデジタルカメラ５の撮影光学系１２は、変倍比が１９．５と大きいが、図１２より明らかなように諸収差が良好に抑えられており、高い結像特性を有する。また、全長がフィルターＦまで含めても８７ｍｍ程度（広角端）であり、小型になっている。しかも、レンズの総数が１１と少なく、非球面の数も３と少ないため、製造が容易である。 The aberrations of the photographing optical system 12 are shown in FIG. The photographing optical system 12 of the digital camera 5 of the present embodiment has a large zoom ratio of 19.5, but various aberrations are satisfactorily suppressed as shown in FIG. 12, and has high imaging characteristics. Further, the total length including the filter F is about 87 mm (wide-angle end), and it is small. Moreover, since the total number of lenses is as small as 11 and the number of aspheric surfaces is as small as 3, manufacturing is easy.

なお、上記の各実施形態ではスチル画像を撮影するデジタルカメラの例を掲げたが、本発明の撮影光学系は、動画を撮影するデジタルビデオカメラや、モバイルコンピュータ、携帯電話、情報携帯端末等の情報処理機器に組み込まれるカメラに採用することも可能である。 In each of the above embodiments, an example of a digital camera that captures a still image has been described. However, the imaging optical system of the present invention is applicable to a digital video camera that captures a moving image, a mobile computer, a cellular phone, an information portable terminal, and the like. It can also be employed in cameras incorporated into information processing equipment.

各実施形態のデジタルカメラの外観を模式的に示す斜視図（ａ）および背面図（ｂ）。The perspective view (a) and back view (b) which show typically the appearance of the digital camera of each embodiment. 各実施形態のデジタルカメラの構成を模式的に示す図。The figure which shows typically the structure of the digital camera of each embodiment. 第１の実施形態のデジタルカメラの撮影光学系の構成を示す図。1 is a diagram illustrating a configuration of a photographing optical system of a digital camera according to a first embodiment. 第１の実施形態のデジタルカメラの撮影光学系の広角端（ａ）、中間焦点距離（ｂ）、望遠端（ｃ）での収差を示す図。The figure which shows the aberration in the wide angle end (a), intermediate | middle focal distance (b), and telephoto end (c) of the imaging optical system of the digital camera of 1st Embodiment. 第２の実施形態のデジタルカメラの撮影光学系の構成を示す図。The figure which shows the structure of the imaging | photography optical system of the digital camera of 2nd Embodiment. 第２の実施形態のデジタルカメラの撮影光学系の広角端（ａ）、中間焦点距離（ｂ）、望遠端（ｃ）での収差を示す図。The figure which shows the aberration in the wide-angle end (a), intermediate | middle focal distance (b), and telephoto end (c) of the imaging optical system of the digital camera of 2nd Embodiment. 第３の実施形態のデジタルカメラの撮影光学系の構成を示す図。The figure which shows the structure of the imaging optical system of the digital camera of 3rd Embodiment. 第３の実施形態のデジタルカメラの撮影光学系の広角端（ａ）、中間焦点距離（ｂ）、望遠端（ｃ）での収差を示す図。The figure which shows the aberration at the wide angle end (a), intermediate | middle focal distance (b), and telephoto end (c) of the imaging optical system of the digital camera of 3rd Embodiment. 第４の実施形態のデジタルカメラの撮影光学系の構成を示す図。The figure which shows the structure of the imaging optical system of the digital camera of 4th Embodiment. 第４の実施形態のデジタルカメラの撮影光学系の広角端（ａ）、中間焦点距離（ｂ）、望遠端（ｃ）での収差を示す図。The figure which shows the aberration at the wide-angle end (a), intermediate | middle focal distance (b), and telephoto end (c) of the imaging optical system of the digital camera of 4th Embodiment. 第５の実施形態のデジタルカメラの撮影光学系の構成を示す図。The figure which shows the structure of the imaging optical system of the digital camera of 5th Embodiment. 第５の実施形態のデジタルカメラの撮影光学系の広角端（ａ）、中間焦点距離（ｂ）、望遠端（ｃ）での収差を示す図。The figure which shows the aberration at the wide angle end (a), intermediate | middle focal distance (b), and telephoto end (c) of the imaging optical system of the digital camera of 5th Embodiment.

符号の説明Explanation of symbols

１〜５デジタルカメラ
１０カメラ本体
１１レンズ鏡胴
１２撮影光学系
１３ａ、１３ｂ光学ファインダー窓
１４フラッシュ発光部
１５電源ボタン
１６シャッターレリーズボタン
１７表示部
１８ズームボタン
１９操作ボタン
２１撮像素子
２２信号処理部
２３記録部
２３ａ記録媒体
２４操作部
２５撮影光学系駆動部
２６制御部
Ｇ１〜Ｇ５レンズ群
Ｌ１〜Ｌ１４レンズ
Ｓ絞り
Ｆローパスフィルター
ｒ１〜ｒ３１面 1-5 Digital camera 10 Camera body 11 Lens barrel 12 Shooting optical system 13a, 13b Optical viewfinder window 14 Flash light emitting unit 15 Power button 16 Shutter release button 17 Display unit 18 Zoom button 19 Operation button 21 Image sensor 22 Signal processing unit 23 Recording unit 23a Recording medium 24 Operation unit 25 Shooting optical system driving unit 26 Control unit G1 to G5 Lens group L1 to L14 Lens S Aperture F Low pass filter r1 to r31 surface

Claims

撮影対象からの光を撮像素子上に結像させる撮影光学系において、
撮影対象側から順に、正のパワーを有する第１レンズ群と、負のパワーを有する第２レンズ群と、正のパワーを有する第３レンズ群と、正のパワーを有する第４レンズ群とを少なくとも有して、いずれかのレンズ群を移動させて変倍を行い、広角端での当該撮影光学系全体の焦点距離をｆｗ、望遠端での当該撮影光学系全体の焦点距離をｆｔ、第１レンズ群の焦点距離をｆ１、広角端での第２レンズ群の倍率をβ2w、望遠端での第２レンズ群の倍率をβ2t、広角端での第３レンズ群の倍率をβ3w、望遠端での第３レンズ群の倍率をβ3tで表すとき、
７．０ ≦ ｆ１／ｆｗ ≦ ２０．０
０．３８ ≦ （β2t／β2w）／（ｆｔ／ｆｗ） ≦ ０．８
１．１ ≦ β3t／β3w ≦ ４．０
の関係を満たすことを特徴とする撮影光学系。 In a photographic optical system that forms an image of light from a subject on an image sensor,
A first lens group having a positive power, a second lens group having a negative power, a third lens group having a positive power, and a fourth lens group having a positive power in order from the photographing target side. And at least one lens unit is moved to perform zooming, the focal length of the entire photographing optical system at the wide-angle end is fw, the focal length of the entire photographing optical system at the telephoto end is ft, The focal length of one lens group is f1, the magnification of the second lens group at the wide angle end is β2w, the magnification of the second lens group at the telephoto end is β2t, the magnification of the third lens group at the wide angle end is β3w, the telephoto end When the magnification of the third lens unit at is expressed as β3t,
7.0 ≦ f1 / fw ≦ 20.0
0.38 ≦ (β2t / β2w) / (ft / fw) ≦ 0.8
1.1 ≦ β3t / β3w ≦ 4.0
An imaging optical system characterized by satisfying the above relationship.

広角端から望遠端への変倍に際して、第１レンズ群と第２レンズ群との間隔が増大し、第２レンズ群と第３レンズ群との間隔が減少し、第３レンズ群と第４レンズ群との間隔が増大するように、少なくとも第２レンズ群、第３レンズ群および第４レンズ群が移動することを特徴とする請求項１に記載の撮影光学系。 During zooming from the wide-angle end to the telephoto end, the distance between the first lens group and the second lens group increases, the distance between the second lens group and the third lens group decreases, and the third lens group and the fourth lens group decrease. The photographing optical system according to claim 1, wherein at least the second lens group, the third lens group, and the fourth lens group move so that the distance from the lens group increases.

広角端から望遠端への変倍に際して、第３レンズ群が撮影対象側に単調移動し、第４レンズ群がまず撮影対象側に移動して次いで撮像素子側に移動し、第４レンズ群によって焦点調節を行うことを特徴とする請求項１または請求項２に記載の撮影光学系。 Upon zooming from the wide-angle end to the telephoto end, the third lens group moves monotonously toward the object to be imaged, the fourth lens group first moves toward the object to be imaged, and then moves toward the image sensor, and is moved by the fourth lens group. 3. The photographing optical system according to claim 1, wherein focus adjustment is performed.

第１レンズ群から第４レンズ群までのほかに第４レンズ群よりも撮像素子側に位置する第５レンズ群のみを有し、変倍に際して第５レンズ群が不動であることを特徴とする請求項１に記載の撮影光学系。 In addition to the first lens group to the fourth lens group, there is only a fifth lens group located closer to the image sensor than the fourth lens group, and the fifth lens group is stationary during zooming. The imaging optical system according to claim 1.

第５レンズ群が１枚のレンズのみを含むことを特徴とする請求項４に記載の撮影光学系。 The photographing optical system according to claim 4, wherein the fifth lens group includes only one lens.

撮像素子と、請求項１から請求項５までのいずれか１項に記載の撮影光学系を備えることを特徴とする撮像装置。 An imaging apparatus comprising: an imaging element; and the photographing optical system according to claim 1.