JP2006293093A - Lens barrel equipped with antireflection structure, imaging apparatus and camera equipped with the lens barrel - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a lens barrel which prevents the deterioration of image quality by suppressing reflection on the inside surface of the lens barrel. <P>SOLUTION: Regarding the lens barrel, a zoom lens system includes a 1st lens group positioned closest to the object, a 2nd lens group arranged second from the object side, and also, having power different from that of the 1st lens group, and a 3rd lens group arranged third from the object side, and the antireflection structure where a structural unit of a prescribed shape is periodically arranged in an array state at a pitch smaller than the shortest wavelength of incident light is arranged in an area corresponding to a position from the 1st lens group to the image side on the inside surface of the lens barrel. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a lens barrel, an imaging device including a lens barrel, and a camera, and more particularly, to a lens barrel including an antireflection structure, an imaging device including a lens barrel, and a camera.

  In recent years, digital still cameras and digital video cameras (hereinafter simply referred to as digital cameras) that can convert an optical image of a subject into an electrical image signal and output the signals are rapidly spreading. While a high-power zoom and a high-resolution digital camera are desired, a more compact digital camera is desired. On the other hand, it is possible to provide a more compact digital camera by miniaturizing the lens barrel and various optical components mounted on the digital camera.

  However, in a compact camera equipped with a miniaturized lens barrel and optical components, light incident on the lens is reflected by the lens barrel and components, and the reflected light is reflected on the imaging surface as unnecessary light that does not participate in image formation. May reach. Therefore, such unnecessary light causes flare and ghost, and adversely affects image quality.

  On the other hand, a technique for forming an antireflection film on the lens surface is known. This technique reduces the reflectance of incident light by depositing a multilayer antireflection film on the lens surface. However, the reflectance reduction effect by the antireflection film has an incident angle dependency, and there is a difference in the antireflection effect between the region near the optical axis of the lens surface and the lens peripheral region where the incident height is large. Arise. For this reason, the reflected light in the lens peripheral area has a problem that image quality deterioration such as flare and ghost is caused because the suppression of reflectance is insufficient.

  On the other hand, there is known a technique for preventing unnecessary light from reaching the imaging surface by subjecting the inner peripheral surface of the lens barrel to an inclination and a satin finish in consideration of a step and a reflection angle. However, since incident light is reflected in a complicated direction by components in the lens barrel, it has been difficult to sufficiently reduce reflection.

On the other hand, the light absorption member by which the black coating material and the matting coating material were apply | coated to the base-material surface is proposed (patent document 1). Patent Document 1 discloses that the inner surface of a lens barrel for incident light is provided by providing a light absorbing member coated with a black paint on the inner peripheral surface of the lens barrel, as compared with a lens barrel having only an inclination or a satin finish. It is said that reflection at the can be suppressed.
JP 2003-266580 A

  FIG. 9 is an example of a lens barrel provided with the light absorbing member described in Patent Document 1. The lens barrel 500 is provided with a light absorbing member coated with a black paint on the inner peripheral surface of a movable barrel 510 that holds the second lens group. However, off-axis light that does not contribute to the formation of the subject image incident on the lens barrel 500 is not completely absorbed by the light absorbing member, but is reflected at the interface between the painted surface and air. The reflected light becomes stray light in the lens barrel and reaches the image sensor 520. Therefore, the unnecessary light reflected in the lens barrel has a problem that flare, ghost, etc. are generated and image quality is deteriorated. In addition, the method of applying the black paint has a problem of high cost because it needs to be applied to the inner surface of the lens barrel having a cylindrical shape.

  SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a lens barrel and a camera including the lens barrel that prevent reflection of unnecessary light that causes image quality degradation and suppress degradation of image quality.

The present invention is achieved by a lens barrel having the following configuration.
A lens barrel including a zoom lens system that performs zooming by moving a plurality of lens groups in the optical axis direction,
The zoom lens system is arranged first from the first lens group located closest to the object side, second from the object side, second lens group having a power different from that of the first lens group, and third from the object side. A third lens group,
Antireflection in which structural units having a predetermined shape are periodically arranged in an array at a pitch smaller than the shortest wavelength of incident light on the inner surface of a lens barrel in a range corresponding to the position on the image side from the first lens group A structure is provided.

  With this configuration, the antireflection structure formed on the inner surface of the lens barrel prevents off-axis light incident on the lens group from being reflected in the lens barrel. Therefore, it is possible to provide a lens barrel in which deterioration of image quality due to unnecessary light is suppressed.

Preferably, the zoom lens system is
In order from the object side, a first lens group having a negative power, a second lens group having a positive power, and a third lens group having a positive power,
An antireflection structure is provided on the inner surface of the lens barrel in a range corresponding to the second lens group.

Preferably, the zoom lens system is
In order from the object side, 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 subsequent subsequent lens group,
An antireflection structure is provided on the inner surface of the lens barrel in a range corresponding to the third lens group.

  With this configuration, for example, the antireflection structure is disposed adjacent to the stop, and prevents reflection of off-axis light incident on the inner peripheral surface of the lens barrel in a range corresponding to the lens group in which the light beam is focused and concentrated. Therefore, it is possible to provide a lens barrel in which deterioration of image quality due to unnecessary light is suppressed.

Preferably, the zoom lens system is
In order from the object side, a first lens group having a negative power, a second lens group having a positive power, and a third lens group having a positive power,
An antireflection structure is provided on the inner surface of the lens barrel in a range corresponding to the distance between the first lens group and the second lens group at the wide angle end.

Preferably, the zoom lens system is
In order from the object side, 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 subsequent subsequent lens group,
An antireflection structure is provided on the inner surface of the lens barrel in a range corresponding to the distance between the first lens group and the third lens group at the wide-angle end.

  With this configuration, the antireflection structure prevents reflection of off-axis light incident on the inner surface of the lens barrel because the effective diameter difference between the first lens group and the second lens group is large at the wide-angle end. be able to. Therefore, it is possible to provide a lens barrel in which deterioration of image quality due to unnecessary light is suppressed.

The object of the present invention is achieved by an imaging apparatus having the following configuration.
An imaging apparatus capable of converting an optical image of a subject into an electrical image signal,
A lens barrel including a photographing optical system for forming an optical image of the subject;
An image sensor that converts an optical image formed by the imaging optical system into an electrical image signal;
The shooting optical system
A zoom lens system that performs zooming by moving a plurality of lens groups in the optical axis direction,
The zoom lens system is disposed first from the first lens group located closest to the object side, second from the object side, and second lens group having a different power from the first lens group, and third from the object side. A third lens group,
Antireflection in which structural units having a predetermined shape are periodically arranged in an array at a pitch smaller than the shortest wavelength of incident light on the inner surface of the lens barrel in a range corresponding to the position on the image side from the first lens group A structure is provided.

  With this configuration, since the imaging apparatus includes an antireflection structure on the inner surface of the lens barrel, it is possible to prevent reflection of incident off-axis light and to provide an imaging apparatus in which deterioration in image quality is suppressed. Can do.

The object of the present invention is achieved by a camera having the following configuration.
A camera capable of converting an optical image of a subject into an electrical image signal and outputting the image signal,
A lens barrel including a photographing optical system for forming an optical image of the subject;
An image sensor that converts an optical image formed by the imaging optical system into an electrical image signal;
Image recording means for recording an image signal output by the image sensor;
Image display means for displaying a captured image based on the image signal,
The shooting optical system
A zoom lens system that performs zooming by moving a plurality of lens groups in the optical axis direction,
The zoom lens system is arranged first from the first lens group located closest to the object side, second from the object side, second lens group having a power different from that of the first lens group, and third from the object side. A third lens group,
Antireflection in which structural units having a predetermined shape are periodically arranged in an array at a pitch smaller than the shortest wavelength of incident light on the inner surface of a lens barrel in a range corresponding to the position on the image side from the first lens group A structure is provided.

  Specifically, it is a digital still camera that can acquire a still image of a subject.

  Specifically, it is a digital video camera capable of acquiring a moving image of a subject.

  With this configuration, the camera includes the antireflection structure that prevents the incident off-axis light from being reflected by the inner surface of the lens barrel, so that it is possible to suppress deterioration in the image quality of a high-resolution moving image.

  According to the present invention, it is possible to provide a lens barrel and a camera including the lens barrel that prevent unnecessary light from being reflected, which is a cause of image quality deterioration, and suppresses the deterioration of image quality.

(Embodiment 1)
FIG. 1 is a diagram showing an arrangement of a zoom lens system included in a lens barrel according to Embodiment 1 of the present invention. The zoom lens system according to Embodiment 1 includes, in order from the object side, a first lens group G1 having a negative power, a diaphragm A, a second lens group G2 having a positive power, and a first lens group having a positive power. The three lens group G3 is mainly configured. The lens barrel according to the present embodiment performs zooming by moving each lens group along the optical axis and changing the relative distance.

  The first lens group G1 includes, in order from the object side, a negative meniscus lens L11 that is convex toward the object side, and a positive meniscus lens L12 that is convex toward the object side. The second lens group G2 is composed of a positive meniscus lens L21 convex toward the object side, a biconvex positive lens L22, a biconcave negative lens L23, and a negative lens L24 convex toward the image side in order from the object side. It consists of. In the second lens group G2, the meniscus lens L21 and the cemented lens are disposed with an air gap. The third lens group G3 is composed of a biconvex positive lens L31.

  FIG. 2 is a schematic enlarged view of the second lens group G2 of the lens barrel according to the present embodiment. As described above, in the second lens group G2, the positive lens L21 and the cemented lens are arranged with an air gap therebetween. For this reason, off-axis light that does not contribute to the formation of the subject image enters the first lens group and then reaches the second lens group on the inner peripheral surface of the lens barrel in a range corresponding to the air interval. When off-axis light reaches the inner peripheral surface of the lens barrel and is reflected, the reflected light becomes stray light and reaches the imaging surface S, causing flare and ghost. Therefore, as shown in FIGS. 1 and 2, in the lens barrel according to the present embodiment, the antireflection structure 1 is provided on the inner peripheral surface of the barrel in the range corresponding to the air interval in the second lens group.

  Here, the antireflection structure is a structure in which structural units having a predetermined shape are periodically arranged in an array at a pitch smaller than the lower limit value of the wavelength of incident light, that is, a pitch smaller than the shortest wavelength of incident light. Is. By periodically arranging the structural units having a predetermined shape in an array, the apparent refractive index is continuously changed for incident light, and the transmission / reflection characteristics at the interface with the air layer It is possible to form an antireflection functional surface with little incidence angle dependency and wavelength dependency.

  Further, the antireflection structure means a member having a fine structure formed on the surface in order to prevent reflection of light whose reflection should be reduced, and only in an aspect in which the light whose reflection should be reduced is not completely reflected. In addition, an aspect having an effect of preventing reflection of light whose reflection at a predetermined wavelength should be reduced is also included. As an antireflection structure that can be used in this embodiment, for example, cone-shaped projections having a height H as shown in the schematic enlarged view of FIG. In particular, there are structures arranged in an array.

  The pitch means the pitch in the densest arrangement direction when the antireflection structure is constituted by a two-dimensional arrangement of a large number of fine structural units.

  The pitch P of the structural unit is substantially constant in one arrangement direction in the antireflection structure and may be smaller than the shortest wavelength of incident light, but the incident angle dependence and wavelength of transmission / reflection characteristics at the interface From the viewpoint that the dependency can be further reduced, the pitch P is preferably about 0.1 μm to 1 μm, more preferably about 0.15 μm to 0.5 μm.

  Further, the height H of the structural unit is not particularly limited, and the height H of all the structural units in the antireflection structure may not necessarily be constant. However, the higher the height H, the higher the incident light with respect to incident light. There is an advantage that the antireflection function is improved. Therefore, the height H is preferably about 10 times the pitch P, more preferably about 2 to 3 times.

  Such an antireflection structure may be formed integrally with the lens barrel, or a light absorbing member having the antireflection structure may be installed on the inner peripheral surface of the lens barrel. For example, a sheet having an antireflection structure as a light absorbing member can be manufactured as follows. That is, first, a heat-softened glass is press-molded using a master die that has been precisely processed into the same shape as the antireflection structure, thereby producing an antireflection structure molding die made of glass. Furthermore, the sheet | seat which has an antireflection structure can be manufactured by press-molding resin using this metal mold | die. On the other hand, when the antireflection structure and the lens barrel are integrally formed, for example, they can be manufactured as follows. That is, it is manufactured by injection molding a resin using a high-precision master mold that has been precisely machined into the same shape as the antireflection structure 1 or a mold that has been machined by a semiconductor process. Thereby, a lens barrel provided with the antireflection structure can be manufactured inexpensively and in large quantities. At this time, the light absorption effect can be further enhanced by adding a black paint or the like to the resin that is the material of the light absorbing member or the lens barrel.

  In addition, although the structure body has a conical structure as the antireflection structure, the structure is not necessarily limited to such a structure. For example, the structural unit may be a pyramid-shaped structure such as a regular hexagonal pyramid shape or a quadrangular pyramid shape. In addition, the shape of such a structural unit is not necessarily limited to a cone shape, and may be a columnar shape such as a columnar shape or a prismatic shape, a bell shape with a rounded tip, a truncated cone shape or a pyramid shape. A frustum shape such as a trapezoid may be used. Moreover, each structural unit does not need to be a strict geometric shape, and may be substantially a cone shape, a column shape, a bell shape, a frustum shape, or the like. Moreover, the antireflection structure should just be formed with the pitch smaller than the wavelength of incident light at least.

  FIG. 4 is a diagram illustrating an arrangement of another zoom lens system included in the lens barrel according to the first embodiment. The zoom lens system shown in FIG. 4 is different from the zoom lens system shown in FIG. 1 in that order from the object side is a first lens group G1 having a positive power, a second lens group G2 having a negative power, and a stop A. The third lens group G3 having positive power and the fourth lens group G4 having positive power are mainly configured. The lens barrel according to the present embodiment performs zooming by moving each lens group along the optical axis and changing the relative distance.

  The first lens group G1 includes, in order from the object side, a cemented lens of a concave meniscus lens L11 and a convex lens L12, and a positive meniscus lens L13. The second lens group G2 includes, in order from the object side, a negative meniscus lens L21, a negative lens L22 having a concave surface facing the image side, a concave meniscus lens L23, a biconvex positive lens, and a concave meniscus lens. It consists of a cemented lens L24. The third lens group G3 includes a positive lens L31 that is convex on the object side, and a cemented lens L32 of a positive lens that is convex on the object side and a concave meniscus lens via an air gap. The fourth lens group G4 is composed of a cemented lens of a biconvex lens, a biconcave lens, and a biconvex lens, from the object side.

  The lens barrel shown in FIG. 4 is different from the lens barrel of FIG. 1 in that the antireflection structure 1 is provided on the inner peripheral surface of the third lens group in a range corresponding to the air interval. The antireflection structure 1 can sufficiently prevent unnecessary light from being reflected and can absorb unnecessary light. Accordingly, off-axis light incident on the lens group can be prevented from being reflected by the inner peripheral surface of the lens barrel, and unnecessary light can be prevented from reaching the imaging surface.

  As described above, the lens barrel according to the present embodiment includes the antireflection structure on the inner peripheral surface of the lens barrel in a range corresponding to the position of the lens group disposed adjacent to the stop. Thereby, the lens barrel according to the present embodiment can sufficiently prevent the unnecessary light from being reflected on the inner peripheral surface of the lens barrel and can substantially completely absorb the incident unnecessary light. . Therefore, it is possible to provide a lens barrel that suppresses deterioration in image quality of a subject image formed by the optical system.

  In addition, since the lens barrel and the antireflection structure can be integrally formed, the cost can be reduced and a high antireflection effect compared to the case of using a light absorbing member coated with black paint or the like. Can be provided.

  The lens barrel according to the present embodiment includes the antireflection structure on the inner peripheral surface of the lens barrel in a range corresponding to the air interval of the lens group, but is not limited thereto. For example, as shown in FIG. 5A, an antireflection structure may be formed on a holding member on which off-axis light is incident. Moreover, as shown in (b), you may form an antireflection structure in the site | part where a lens and a holding member contact.

(Embodiment 2)
6 and 7 are schematic views showing a lens barrel according to the second embodiment. The lens configuration of the lens barrel according to the present embodiment is substantially the same as that of the first embodiment, but differs in the following points. That is, the lens barrel shown in FIG. 6 is different in that an antireflection structure is formed on the inner peripheral surface of the lens barrel in a range corresponding to the distance between the first lens group G1 and the second lens group G2 at the wide angle end. . In the lens barrel shown in FIG. 7, an antireflection structure is formed on the inner peripheral surface of the barrel corresponding to the distance between the second lens group G2 and the third lens group G3. FIG. 7 shows a part of the lens barrel including a portion where the antireflection structure is formed.

  As shown in FIG. 6, when the difference in effective diameter between the first lens group and the second lens group is large at the wide angle end of the zoom lens, off-axis light that does not contribute to image formation is reflected on the inner peripheral surface of the lens barrel. To reach. Therefore, when incident unnecessary light is reflected by the inner peripheral surface of the lens barrel, ghosts and flares are generated, and the image quality is deteriorated. Therefore, by forming an antireflection structure on the inner peripheral surface of the lens barrel in a range corresponding to the interval between the first lens group G1 and the second lens group G2 where unnecessary light enters, the inner peripheral surface of the lens barrel is formed. Can absorb ghosts and prevent ghosts and flares. Similarly, as shown in FIG. 6, at the wide-angle end, it is unnecessary by forming an antireflection structure on the lens barrel inner peripheral surface in a range corresponding to the distance between the second lens group G2 and the third lens group G3. Light can be absorbed by the inner peripheral surface of the lens barrel.

  Thus, since the lens barrel according to the present embodiment has the antireflection structure formed on the inner peripheral surface of the lens barrel, the difference in effective diameter between the first lens group and the second lens group is large. The reflection of off-axis light incident on the inner peripheral surface of the lens barrel can be prevented. Thereby, it is possible to prevent unnecessary light from reaching the imaging surface even at the wide-angle end of the zoom lens. Therefore, the lens barrel according to the present embodiment can prevent the occurrence of ghost and flare even at the wide-angle end, and can prevent the deterioration of the image quality of the formed subject image.

(Embodiment 3)
FIG. 8 is a schematic diagram showing the configuration of the digital still camera 50 according to the second embodiment. The digital still camera 50 is configured around a lens barrel, a casing 55, and a display unit 54 that have substantially the same configuration as in the first embodiment. Similar to the first embodiment, the lens barrel performs zooming by moving each lens group in the optical axis direction.

  The lens barrel includes a first lens group G1, a diaphragm A, a second lens group G2, a third lens group G3, and an image sensor 53 in order from the object side. Each lens group is held by a holding member. The lens barrel includes a moving cylinder 57, a cylindrical cam cylinder 58, and a main cylinder 56 with the optical axis as the central axis. The main cylinder 56 has a cylindrical shape with the optical axis as the central axis and extending in a direction parallel to the optical axis. The cylindrical cam cylinder 58 is configured on the inner peripheral side of the main cylinder 56, has a cylindrical shape with the optical axis as a central axis, and has a cam groove (not shown). The cylindrical cam cylinder 58 can be rotated by the driving force of the motor. The moving cylinder 57 is configured on the inner peripheral side of the cylindrical cam cylinder 58 and has a cylindrical shape with the optical axis as the central axis. The moving cylinder 57 moves in the optical axis direction as the cylindrical cam cylinder rotates.

  The image sensor 53 is a CCD (Charge Coupled Device), and converts an optical image formed by the optical system into an electrical signal. Note that the image sensor 53 may be a MOS image sensor. The MOS image sensor includes a CMOS (Complementary Metal-Oxide Semiconductor).

  The display unit 54 includes a liquid crystal monitor and displays the image signal converted by the image sensor 53 as a visible image. The display unit 54 is installed on the subject side of the housing 55.

  Off-axis light incident on the lens group is reflected on the inner peripheral surface of the lens barrel in a range corresponding to the air interval of the second lens group. The reflected light becomes stray light and enters the imaging surface S, and flare and ghost are generated. Therefore, the image quality of the captured image displayed on the display unit 54 may be deteriorated. Therefore, the digital camera according to the present embodiment includes the antireflection structure 60 on the inner peripheral surface of the cylindrical cam cylinder 58 in a range corresponding to the air interval of the second lens group. The structure, action, and effect of the antireflection structure 60 are the same as those shown in the first embodiment.

  As described above, since the digital camera according to the present embodiment includes the antireflection structure on the inner peripheral surface of the lens barrel on which unnecessary light is incident, flare and ghost are caused at the interface at the air interval of the lens group. It is possible to sufficiently prevent the unnecessary light from being reflected and to absorb the incident unnecessary light substantially completely. Therefore, it is possible to provide a digital camera in which the deterioration of the image quality of the captured image is suppressed.

  Although the lens barrel of the first embodiment is used as the lens barrel in the digital camera according to the present embodiment, the present invention is not limited to this. The same effect can be obtained even if the lens barrel described in the second embodiment is used. Accordingly, it is possible to provide a digital camera in which the deterioration of the image quality of the captured image is suppressed even at the wide angle end of the zoom lens.

  Although the camera according to the present embodiment is used in a digital camera that targets still images, the present invention is not limited to this. The camera may be a digital video camera for moving images. Thereby, it is possible to prevent deterioration of image quality due to unnecessary light even for a high-resolution moving image.

  Although the lens barrel included in the first to third embodiments has a cylindrical shape, the present invention is not limited to this. The same effect can be obtained even if a lens barrel including a square shape and other shapes is provided with an antireflection structure.

  The lens barrel and the digital camera of the present invention can be applied to a PDA (Personal Digital Assistance), a surveillance camera, a Web camera, an in-vehicle camera, and the like. It is suitable for a portable cellular phone terminal.

FIG. 5 is a diagram illustrating an arrangement of a zoom lens system included in the lens barrel according to the first embodiment. Schematic enlarged view of the second lens group of the lens barrel according to Embodiment 1. FIG. Outline enlarged view of antireflection structure FIG. 5 is a diagram illustrating an arrangement of a zoom lens system included in the lens barrel according to the first embodiment. The figure which shows an example of the formation location of an antireflection structure in the lens-barrel which concerns on Embodiment 1. FIG. Schematic showing a lens barrel according to Embodiment 2 Schematic showing a lens barrel according to Embodiment 2 Schematic which shows the structure of the digital still camera concerning Embodiment 3. FIG. Schematic showing a lens barrel provided with a conventional light absorbing member

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Antireflection structure 50 Digital still camera 53 Image pick-up element 54 Display part 55 Case 56 Main cylinder 57 Moving cylinder 58 Cylindrical cam cylinder 60 Antireflection structure G1 1st lens group G2 2nd lens group G3 3rd lens group G4 1st 4 lens group A Aperture S Imaging surface

Claims (9)

A lens barrel including a zoom lens system that performs zooming by moving a plurality of lens groups in the optical axis direction,
The zoom lens system includes a first lens group located closest to the object side, a second lens group disposed from the object side, a second lens group having a different power from the first lens group, and a third lens group disposed from the object side. A third lens group,
Reflection in which structural units having a predetermined shape are periodically arranged in an array at a pitch smaller than the shortest wavelength of incident light on the inner surface of a lens barrel in a range corresponding to the image side position from the first lens group A lens barrel comprising a prevention structure. The zoom lens system includes:
In order from the object side, a first lens group having a negative power, a second lens group having a positive power, and a third lens group having a positive power,
The lens barrel according to claim 1, wherein the antireflection structure is provided on an inner surface of a lens barrel in a range corresponding to the second lens group. The zoom lens system includes:
In order from the object side, 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 subsequent subsequent lens group,
The lens barrel according to claim 1, wherein the antireflection structure is provided on an inner surface of a lens barrel in a range corresponding to the third lens group. The zoom lens system includes:
In order from the object side, a first lens group having a negative power, a second lens group having a positive power, and a third lens group having a positive power,
2. The lens according to claim 1, wherein the antireflection structure is provided on an inner surface of a lens barrel in a range corresponding to a distance between the first lens group and the second lens group at a wide angle end. The lens barrel. The zoom lens system includes:
In order from the object side, 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 subsequent subsequent lens group,
2. The lens mirror according to claim 1, wherein the antireflection structure is provided on an inner surface of a lens barrel in a range corresponding to a distance between the first lens group and the third lens group at a wide-angle end. Tube. An imaging apparatus capable of converting an optical image of a subject into an electrical image signal,
A lens barrel including a photographing optical system for forming an optical image of the subject;
An image sensor that converts an optical image formed by the imaging optical system into an electrical image signal;
The photographing optical system is
A zoom lens system that performs zooming by moving a plurality of lens groups in the optical axis direction,
The zoom lens system includes a first lens group located closest to the object side, a second lens group disposed from the object side, a second lens group having a different power from the first lens group, and a third lens group disposed from the object side. A third lens group,
Reflection in which structural units having a predetermined shape are periodically arranged in an array at a pitch smaller than the shortest wavelength of incident light on the inner surface of a lens barrel in a range corresponding to the image side position from the first lens group An imaging apparatus comprising a prevention structure. A camera capable of converting an optical image of a subject into an electrical image signal and outputting the image signal,
A lens barrel including a photographing optical system for forming an optical image of the subject;
An image sensor that converts an optical image formed by the imaging optical system into an electrical image signal;
Image recording means for recording an image signal output by the imaging element;
Image display means for displaying a captured image based on the image signal;
The photographing optical system is
A zoom lens system that performs zooming by moving a plurality of lens groups in the optical axis direction,
The zoom lens system includes a first lens group located closest to the object side, a second lens group disposed from the object side, a second lens group having a different power from the first lens group, and a third lens group disposed from the object side. A third lens group,
Reflection in which structural units having a predetermined shape are periodically arranged in an array at a pitch smaller than the shortest wavelength of incident light on the inner surface of a lens barrel in a range corresponding to the image side position from the first lens group A camera comprising a prevention structure.   The digital still camera according to claim 7, wherein a still image of the subject can be acquired.   The digital video camera according to claim 7, wherein a moving image of the subject can be acquired.

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