JP2007047686A - Optical system for underwater photography and waterproof camera housing - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an optical system for underwater photography by which viewing angles in the air and under water are made to agree with each other when performing photography in the air and under water simultaneously by making the window glass of a housing for underwater photography spherical, and to provide a waterproof camera housing. <P>SOLUTION: The front surface 50 and the rear surface 52 of the window glass 20 of the waterproof camera housing 12 are made the spherical surfaces of a concentric sphere, and their spherical center position Q is aligned with the entrance pupil position S of a photographic lens 28 inside the housing 12. Thus, a light beam guided to an imaging surface by the photographic lens 28 is not refracted by the window glass 20, so that the viewing angles in the air and under water are made to agree with each other. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to an underwater photographing optical system and a waterproof camera housing, and more particularly to an underwater photographing optical system and a waterproof camera housing used for underwater photographing.

  When performing underwater photography, a camera device such as a television camera is generally housed in a waterproof camera housing (underwater blink) to prevent the camera device from being submerged (see, for example, Patent Document 1). The waterproof camera housing is generally provided with a window, and the camera device housed inside the housing can take an image of the outside through the window.

Patent Documents 2, 3, and 4 propose an optical system for an amphibious camera that exhibits high imaging performance regardless of whether it is in air or underwater.
JP 2003-69864 A JP-A-56-1411 JP-A-7-159687 Japanese Patent Laid-Open No. 7-159589

  By the way, although the waterproof camera housing is usually used in water, there are cases in which a part of the window of the housing is taken out into the air and the underwater and the air are photographed at the same time for the purpose of producing an image expression effect. In this case, since the refractive index in water is larger than that in air, the angle of view in water is narrower than in air when the shape of the glass installed in the window is, for example, a plane parallel plate. Therefore, for example, if two rods arranged vertically and parallel to the water from the air are photographed, the interval between the rods arranged in parallel is different between the air and the water, and the contour of each rod is not on the water surface. It will be continuous. Such a deviation of the contour may be extremely unnatural in terms of video expression. Conventionally, it has not been proposed to match the angles of view in the air and in the water when simultaneously photographing a subject in the air and in the water.

  The present invention has been made in view of such circumstances, and an underwater photographing optical system and a waterproof camera housing capable of matching the angles of view in air and underwater when simultaneously photographing in-air and underwater subjects. The purpose is to provide.

  In order to achieve the above object, the underwater photographing optical system according to claim 1 is disposed at the tip of the objective side among components of the underwater photographing optical system that forms an image of a subject, and is used for underwater photographing. A waterproof lens for preventing water from entering into the underwater photographing optical system on the front side, the front surface and the rear surface of the waterproof lens being formed in a spherical shape, and the front surface of the waterproof lens. And a waterproof lens arranged such that the spherical center of the rear surface and the entrance pupil position of the optical system by the constituent elements other than the waterproof lens among the constituent elements of the underwater photographing optical system coincide with each other. It is a feature.

  According to the present invention, the light beam that is incident on the underwater photographing optical system and forms an image intersects the waterproof lens at a substantially vertical angle, and thus is not refracted by the waterproof lens. Accordingly, when the subject in the air and the water are photographed at the same time, the angle of view in the air and the water matches, and the unnaturalness such that the contour of the originally continuous subject is shifted on the water surface is prevented.

  A waterproof camera housing according to claim 2 is a waterproof camera housing comprising the waterproof lens according to claim 1, and depends on components other than the waterproof lens among the components of the underwater photographing optical system. The camera device including the optical system is housed in a sealed state, and the waterproof lens is provided as a window member facing an external subject on the objective side of the optical system.

  The present invention is a waterproof camera housing window member for housing the camera device in a sealed state, and is a waterproof lens at the tip on the objective side of the underwater photographing optical system, and the front and rear surfaces of the waterproof lens are concentrically shaped. These spherical centers are made to coincide with the entrance pupil position of the optical system of the camera device.

  According to a third aspect of the present invention, there is provided a camera housing according to the second aspect, wherein the waterproof lens and the camera device are relatively moved back and forth along the optical axis of the underwater photographing optical system. And an adjustment mechanism for adjusting a relative position between the waterproof lens and the camera device.

  In the present invention, the relative position between the waterproof lens as the window member and the camera device can be adjusted according to the type of the camera device housed in the waterproof camera housing, and the ball center of the waterproof lens is adjusted to the camera device. It is possible to accurately match the entrance pupil position of the optical system.

  According to a fourth aspect of the present invention, in the waterproof camera housing of the third aspect, the waterproof lens and the camera device are relatively moved back and forth along the optical axis of the underwater photographing optical system by the adjusting mechanism. When the entrance pupil position of the optical system by a component other than the waterproof lens among the components of the underwater photographing optical system changes depending on the setting state of the optical system, and a driving unit that gives power for moving The drive means is controlled based on the set state of the optical system, and the waterproof lens and the camera device are relative to each other so that the front and rear sphere centers of the waterproof lens coincide with the entrance pupil position. And a control means for controlling the general position.

  According to the present invention, when the entrance pupil position of the optical system of the camera device changes, the entrance pupil position and the spherical center of the waterproof lens are automatically matched.

  According to the underwater photographing apparatus according to the present invention, it is possible to make the angle of view in air and underwater coincide when photographing a subject in air and underwater at the same time.

  Hereinafter, preferred embodiments of an underwater photographing optical system and an underwater camera housing according to the present invention will be described in detail with reference to the accompanying drawings.

  FIG. 1 is a configuration diagram showing a configuration of an underwater photographing apparatus to which the present invention is applied. The underwater photographing apparatus 10 shown in FIG. 1 mainly includes a waterproof camera housing 12 (hereinafter referred to as a housing 12) and a television camera 14 housed in the housing 12.

  The housing 12 seals the inside and can withstand water pressure in water. The housing 12 mainly includes a housing body 16 and a housing lid 18. The housing main body 16 is formed in a cylindrical shape, a window opening 22 facing the outside from the inside is formed in a circle on the front end side, and an opening 24 for inserting and removing the TV camera 14 is formed in a circle on the rear end side. Is formed. A spherical window glass 20, which will be described in detail later, is attached to the opening 22 on the front end side with a screw or the like, and the intrusion of water from the opening 22 to the inside is prevented. A housing lid 18 is detachably attached to the rear end of the housing main body 16 with a screw. When the housing lid 18 is attached to the housing main body 16, the opening 24 on the rear end side is blocked by the housing lid 18. The interior of the housing 12 is hermetically sealed, so that water can be prevented from entering the housing 12 when used in water.

  The television camera 14 housed in the housing 12 is a camera device that photographs, for example, video for television broadcasting. The television camera 14 has a camera body (camera head) 26 with a replaceable lens and a photographing lens having an optical system. (Lens device) 28.

  The camera body 26 is equipped with an image sensor, a signal processing circuit for performing required signal processing, and the like. The subject image formed by the optical system of the photographing lens 28 is photoelectrically converted by the image sensor, and then signal processing is performed. It is converted into a video signal of a required format by a circuit and output from the camera body 26.

  The taking lens 28 includes an optical system that forms an image of a subject and a control system (not shown) that electrically controls the optical system. The optical system of the photographic lens 28 shown in the figure is a so-called zoom lens having a variable focal length, and the components of the optical system held by the lens barrel are simply shown.

  As shown in the figure, the optical system includes, in order from the object side, a fixed focus lens group 32, a movable focus lens group 34, a zoom lens group 36 composed of a variable power system lens group and a correction system lens group, A diaphragm 38, a master lens group 40, and the like are disposed. The movable focus lens group 34 moves back and forth along the optical axis P, and focus adjustment is performed by adjusting the position of the focus lens group 34. The zoom lens group 36 is configured such that the variable power lens group and the correction system lens group move back and forth along the optical axis P in conjunction with each other in a predetermined positional relationship, and adjust the position of the zoom lens group 36. Thus, the zoom magnification (focal length) is adjusted. The diaphragm 38 opens and closes, and the amount of light is adjusted by adjusting the opening amount of the diaphragm 38.

  A control system (not shown) of the photographic lens 28 is configured such that the focus lens group 34, the zoom lens group 36, and the diaphragm 38 can be electrically driven and controlled by a motor.

  The TV camera 14 configured as described above is inserted into the housing body 16 through the opening 24 with the housing lid 18 removed, and the objective side of the optical system of the photographing lens 28 faces the window glass 20 of the housing body 16. Thus, it is installed inside the housing body 16. When the opening 24 of the housing body 16 is closed by the housing lid 18, the television camera 14 is stored in a sealed state inside the housing 12. As a result, the TV camera 14 can take an image outside the housing 12 through the window glass 20 without being submerged in water.

  The television camera 14 is fixed inside the housing body 16 so that the optical axis P of the optical system of the photographing lens 28 coincides with the central axis (rotation symmetry axis) of the spherical window glass 20 of the housing body 16. . Accordingly, an optical system (an underwater photographing optical system) that forms an image of a subject outside the housing 12 is configured by the window glass 20 and the optical system of the photographing lens 28. That is, the window glass 20 acts as a lens (waterproof lens) at the objective end of the underwater photographing optical system that forms an image of a subject outside the housing 12.

  In the present specification, the underwater photographing optical system means an optical system that can be used even in water, and can naturally be used in air (or in other media).

  Although not shown in the drawing, on the outer surface side of the housing 12, various switches related to the control of the camera body 26 and the photographing lens 28 of the television camera 14 housed therein, and images output from the camera body 26. A connector or the like for transmitting a signal to a device outside the housing 12 is provided, and a mechanism for electrically connecting those switches and connectors to the television camera 14 inside the housing 12 is provided. Thus, the operation of the TV camera 14 and the exchange of necessary information with the TV camera 14 can be performed from the outside of the housing 12 via the housing 12.

  FIG. 2 is an enlarged view of the lens 42 at the distal end on the objective side of the optical system of the window glass 20 and the photographing lens 28 of FIG. As shown in the figure, the front surface 50 and the rear surface 52 of the window glass 20 fixed to the housing 12 (housing body 16) are formed in a spherical shape. The front surface 50 and the rear surface 52 are concentric spherical surfaces whose spherical centers coincide with each other. When the TV camera 14 is installed inside the housing 12 as shown in FIG. 1, the spherical center positions Q of the front surface 50 and the rear surface 52 are arranged. (Hereinafter, referred to as the spherical center position Q of the window glass 20) is disposed on the optical axis P of the optical system of the photographing lens 28. The spherical center position Q of the window glass 20 coincides with the entrance pupil position S of the photographing lens 28.

  Therefore, as shown by light rays λ1 to λ5 in the figure, the light rays that enter the underwater photographing optical system including the optical system of the window glass 20 and the photographing lens 28 and enter the imaging surface of the camera body 26 are reflected on the window glass 20. Both the front surface 50 and the rear surface 52 intersect substantially vertically. That is, the light ray incident toward the point on the optical axis P at the entrance pupil position S is orthogonal to the front surface 50 and the rear surface 52 of the window glass 20.

  Therefore, even if the medium on the front glass 50 side of the window glass 20 is water or air, the light beam is not refracted by the window glass 20, and the underwater photographing optical system regardless of the medium on the front glass 50 side of the window glass 20. The angle of view is constant. Therefore, for example, even when a part of the window glass 20 is taken out from the water into the air and a continuous object is photographed simultaneously in the water and the air, the contour of the object is at the boundary between the water and the air. The unnaturalness that shifts does not occur.

  FIG. 3 is a diagram illustrating an image (image) when an object in water and air is simultaneously photographed. For example, it is assumed that a ladder 60 is installed on the pool side as shown in FIG. 3A, and the ladder 60 has two bars 60A and 60B in the vertical direction across the water and the air. Reference numeral 62 indicates a water surface. It is assumed that a part of the window glass 20 of the housing 12 is taken out from the water into the air and the ladder 60 is photographed simultaneously in the water and in the air. Assuming that the window glass is formed of a plane parallel plate as in the conventional housing, as shown in FIG. 5B, the image of the ladder 60 in water and in air is inconsistent with the water surface 62 and the vertical bar. The outlines of 60A and 60B are discontinuous. On the other hand, when the window glass 20 of the housing 12 is formed as a spherical concentric sphere as shown in FIGS. 1 and 2, the width of the ladder 60 in water and air as shown in FIG. And the contours of the vertical bars 60A and 60B are continuous. Therefore, an image without unnaturalness can be obtained.

  Note that the above description does not show the correspondence to the change of the entrance pupil position in the optical system of the photographic lens 28. For example, if the entrance pupil position of the optical system of the photographing lens 28 is constant, the television camera 14 is fixed inside the housing 12 so that the entrance pupil position and the spherical center position of the window glass 20 coincide with each other during photographing. The angle of view in water and air will not be inconsistent.

  On the other hand, when the photographing lens 28 is a zoom lens as shown in FIG. 1, if a focus operation or a zoom operation is performed during photographing, the positions of the focus lens group 34 and the zoom lens group 36 change, and the entrance pupil position is changed. Change. As described above, when the entrance pupil position changes depending on the setting state of the photographing lens 28, if the position of the television camera 14 is fixed inside the housing 12, the spherical center position of the window glass 20 and the entrance pupil position may be inconsistent. is there. However, in actual underwater photography, the zoom is fixed at the wide end and the focus is often fixed at the closest end. If the television camera 14 is fixed inside the housing 12 so as to coincide with the entrance pupil position, there will be no problems in many underwater photography. Moreover, it can respond also by embodiment shown below.

  Next, a case where the housing 12 includes an adjustment mechanism that adjusts the relative position between the window glass 20 of the housing 12 and the television camera 14 housed in the housing 12 will be described. The relative position (distance) between the window glass 20 and the television camera 14 when the entrance pupil position of the photographic lens 28 (or its optical system) varies depending on the type of the photographic lens 28 or changes depending on the setting state of the photographic lens 28. It is effective that the spherical center position of the window glass 20 and the entrance pupil position can be made to coincide with each other accurately.

  FIG. 4 is a configuration diagram showing a configuration when an adjustment mechanism for adjusting the position of the television camera 14 is provided in the housing 12 of FIG. In FIG. 4, the configuration of the optical system of the housing 12 and the photographic lens 28 shown in FIG. 1 is omitted, but the components shown in FIG. 1 are similarly provided in the present embodiment. The same or similar components as those in FIG. 1 are denoted by the same reference numerals as those in FIG.

  The television camera 14 shown in FIG. 4 is housed inside the housing 12 in a state of being fixed to the pedestal 80. The base 80 engages with a guide rail (not shown) installed in the front-rear direction (left-right direction in the figure) inside the housing body 16 (see FIG. 1), and can move in the front-rear direction along the guide rail. Yes. The pedestal 80 is provided with a nut portion 82, and a feed screw 84 is engaged with the nut portion 82. A motor 86 is installed inside the housing body 16, and the feed screw 84 is rotated by the motor 86.

  Therefore, when the motor 86 rotates, the base 80 moves in the front-rear direction by the action of the feed screw 84 and the nut portion 82, and the TV camera 14 installed on the base 80 moves in the front-rear direction together with the base 80. Thus, the relative position of the window glass 20 of the housing 12 and the television camera 14 is changed by the television camera 14 moving in the front-rear direction.

  The motor 86 is driven and controlled by a control circuit 90 mounted on the housing body 16. In order to enable manual adjustment of the position of the television camera 14, for example, a switch 92 for designating the moving direction of the television camera 14 is installed on the outer surface of the housing body 16, and an operation signal indicating the operation of the switch 92 is provided. The control circuit 90 can be read. At this time, the control circuit 90 controls the rotation direction of the motor 86 based on the operation signal, and moves the television camera 14 in the direction instructed by the switch 92. According to this, the operator takes out a part of the window glass 20 from the water into the air with the television camera 14 housed in the housing 12 and shoots an image as shown in FIG. It is assumed that the position of the television camera 14 is adjusted by operating the switch 92 so that the contour of the object straddling underwater does not shift on the water surface. At this time, the spherical center position of the window glass 20 and the entrance pupil position of the photographic lens 28 match, and the angle of view in water and in air matches.

  On the other hand, when the position of the TV camera 14 can be automatically adjusted so that the spherical center position of the window glass 20 and the entrance pupil position of the photographing lens 28 coincide, the position of the focus lens group 34 of the photographing lens 28 is determined. In addition, the control circuit 90 can read the setting state of the photographic lens 28 that causes the entrance pupil position to change, such as the position of the zoom lens group 36, from the control system 94 of the photographic lens 28. Further, the position of the television camera 14 that matches the entrance pupil position of the photographic lens 28 and the spherical center position of the window glass 20 corresponding to the setting state of the photographic lens 28 is stored in advance. The control circuit 90 can know the current position of the television camera 14 from information from the position sensor 96 attached to the pedestal 80, and the setting of the photographic lens 28 read from the control system 94 of the photographic lens 28. Each time the state changes, the motor 86 is driven so that the television camera 14 moves to a position corresponding to the set state. Thereby, the position of the television camera 14 is automatically adjusted so that the position of the sphere center of the window glass 20 and the position of the entrance pupil of the photographing lens 28 always coincide with each other.

  When the position of the television camera 14 is manually adjusted, the television camera 14 may be moved by manual force instead of being moved by the power of the motor. Further, instead of moving the TV camera 14 relative to the housing 12 as in the above embodiment, the position of the window glass 20 may be moved, or both the window glass 20 and the TV camera 14 may be moved. You may make it make it.

  In the above embodiment, the window glass 20 of the housing 12 is made of glass, but may be made of other materials.

  Moreover, although the case where the television camera 14 is waterproofed by the housing 12 has been described in the above embodiment, when the camera device itself has a waterproof structure, the window of the above embodiment is provided at the distal end of the optical system on the objective side. By arranging a lens similar to that of the glass 20, the same effect as in the above embodiment can be obtained.

  In the above embodiment, the television camera is exemplified as the camera device. However, the present invention can be applied to other types of camera devices.

FIG. 1 is a configuration diagram showing a configuration of an underwater photographing apparatus to which the present invention is applied. FIG. 2 is an enlarged view of the lens on the objective side of the optical system of the window glass of the housing and the photographing lens. FIG. 3 is a diagram exemplifying an image when a continuous object in water and air is simultaneously photographed. FIG. 4 is a configuration diagram showing a configuration of a housing provided with an adjusting mechanism for adjusting the position of the stored television camera.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 ... Underwater imaging device, 12 ... Waterproof camera housing (housing), 14 ... Television camera, 16 ... Housing main body, 18 ... Housing lid, 20 ... Window glass, 22, 24 ... Opening, 26 ... Camera main body, 28 ... Shooting lens 34: Focus lens group 36: Zoom lens group 38: Aperture

Claims (4)

  Among the components of the underwater shooting optical system that forms an image of the subject, it is placed at the front end of the objective side, and is waterproof for preventing water from entering the underwater shooting optical system on the front side during underwater shooting A front surface and a rear surface of the waterproof lens are formed in a spherical shape, and the waterproof center of the front lens and the rear surface of the waterproof lens and the underwater photographing optical system. An underwater photographing optical system comprising a waterproof lens arranged so that an entrance pupil position of an optical system formed by components other than the lens coincides.   A waterproof camera housing comprising the waterproof lens according to claim 1, wherein a camera device including an optical system by a component other than the waterproof lens among components of the underwater photographing optical system is hermetically sealed. A waterproof camera housing comprising the waterproof lens as a window member that is housed and faces an external subject on the objective side of the optical system.   An adjustment mechanism that adjusts the relative position of the waterproof lens and the camera device by relatively moving the waterproof lens and the camera device back and forth along the optical axis of the underwater photographing optical system. The waterproof camera housing according to claim 2, further comprising: Drive means for applying power for moving the waterproof lens and the camera device back and forth relatively along the optical axis of the underwater photographing optical system by the adjustment mechanism;
When the entrance pupil position of the optical system by the components other than the waterproof lens among the components of the underwater photographing optical system changes depending on the setting state of the optical system, the driving is performed based on the setting state of the optical system Control means for controlling the relative positions of the waterproof lens and the camera device so that the front and rear sphere centers of the waterproof lens and the entrance pupil position coincide with each other,
The waterproof camera housing according to claim 3, further comprising:

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