Abstract:
A base, securely attachable to any type of watertight housing for an underwater camera without causing rotational displacement during its use for underwater photography, includes an elongated main body and a holder plate disposed on the main body which is transversely movable. The base has a protrusion for preventing transverse motion of a pedestal or a leg structure on the housing. A pair of set screws is provided in addition to a fixing screw that is passed through a fixing hole through the base main body to fasten the base to the camera housing. The base main body has a fixing hole for the fixing screw and a pair of elongated holes for passing the set screws so as to be transversely movable. The holder plate has an elongated hole for passing the fixing screw so as to be transversely movable and screw holes for engaging the set screws.

Description:
This application claims priority on Japanese Patent Application 2008-271354 filed Oct. 21, 2008. 
     BACKGROUND OF THE INVENTION 
     This invention relates to a base for fastening and carrying thereon an underwater camera contained inside a waterproof camera housing as it is being used for flash lighting, serving to attach thereto an arm having an external flash light provided at its tip. 
     External flash lamps are used in underwater photography because the quantity of available light is often insufficient. Since water contains small dust particles such as grains of sand as well as planktons that float around, external lamps are often placed away from a camera with its waterproof housing that surrounds it (hereinafter referred as an “underwater camera”) by distances of from ten and some centimeters to several tens of centimeters such that these dust particles, etc. will not appear conspicuously on the obtained image. For this reason, it has been known (as disclosed, for example, in Japanese Patent Publication Tokkai 11-237688) not only to fasten an underwater camera to a base but also to provide an external flash lamp at the tip of an arm and to connect the arm and the base together. In such a case, the base is a planar member to be screwed to the bottom of the housing of the underwater camera. In certain situations, a grip may be provided between the arm and the base. 
       FIG. 1  is a diagonal view for showing the structure of a conventional base for a general-purpose underwater camera, and  FIG. 2  is a diagonal view for showing the manner in which the base of  FIG. 1  may be attached to the underwater camera. For the sake of convenience, the main body of the camera is omitted in  FIGS. 1 and 2 , and the arm is not included in  FIG. 2 . 
     In these figures, numeral  1  indicates the base, numeral  2  indicates the waterproof camera housing (hereinafter also referred to simply as the housing), and numeral  3  indicates an arm. The bottom of the housing  2  is provided with a pedestal  4  with a screw hole  6  formed therethrough for attachment with a fixing screw  5 . Leg structures  7 A and  7 B are further provided to the right-hand and left-hand sides of the bottom of the housing  2  for stabilizing the underwater camera. 
     The base  1  has an elongated hole  8  therethrough for passing therethrough the fixing screw  5  such that only its axial part (that is, the screw part and the cylindrical part that is continuously connected to it) can be freely moved in the direction of the width (hereinafter referred to as the “transverse direction”), depending on the type of the housing  2  that is being used. A protrusion  9  with a specified length is also provided at one end part of the base  1  in the direction of the width for the purpose of positioning the housing  2 . 
     When the housing  2  is affixed to the base  1  thus structured, the axial part of the fixing screw  1  is firstly passed through the elongated hole  8  of the base  1  from below. While the tip of the fixing screw  5  has been somewhat inserted into the screw hole  6  of the housing  2 , the housing  2  is moved in the direction of the width of the base  1  for its positioning by pressing the back walls of the leg structures  7 A and  7 B against the protrusion  9  of the base  1 . After the positioning is completed, the fixing screw  5  is fully inserted into the screw hole  6 .  FIG. 1  shows the fully affixed condition thus achieved. 
     The housing  2  may be attached to the base  1  backward, as shown in  FIG. 3 , or in the reversed direction as compared to the attachment explained above. In this situation, the front wall of the pedestal  4  on the housing  2  comes to contact the protrusion  9  for the positioning of the housing  2 . 
     The positioning as described above is necessary because the structure of the housing  2  varies according to the type of the camera that is being used and hence the distance between the screw hole  6  and the protrusion  9  of the base  1  or the front wall of the pedestal  4  also varies. In order to use as a general-purpose base, it is necessary that these distances be adjustable according to the type of the housing  2 . 
     The conventional general-purpose base  1  as described above had many problem points. For example, as the user holds the housing  2  in water for underwater photography, the position of the external flash lamp must be adjusted according to the target object to be photographed if flash lighting is required. The user will carry out this adjustment by varying the angle of the external flash lamp at the tip of the arm  3  affixed to the base  1 . Since the arm  3  and the external flash lamp attached to its tip are quite heavy, however, the housing  2  tends to easily undergo a rotational displacement around the leg structures  7 A and  7 B or the pedestal  4  in contact with the protrusion  9  of the base  1 , as shown in  FIG. 4 . If the housing  2  thus undergoes a rotational displacement, the fixing screw  5  in contact with the bottom surface of the base  1  also rotates by the same amount, becoming loose. This makes it still easier for the housing  2  to rotate, thereby initiating a vicious cycle. 
     In view of this problem, it has recently been proposed to prevent the rotational displacement of the housing  2  by pasting a frictional sheet of a rubber material on the surface of the base  1  where the bottom part of the pedestal  4  of the housing  2  comes into contact such that the rotational displacement of the housing  2  can be prevented. Since the arm  3  and the external flash lamp at its tip are very heavy, however, this approach has been proved insufficient for dependably preventing the rotational displacement. Since this problem of preventing rotational displacement is distracting to the user from concentrating on the target object to be photographed, there has been a significant demand for an improvement. 
     Another problem associated with the conventional general-purpose base  1  has been that the loosened screw must be tightened frequently while the user is holding the equipment while being engaged in underwater photography, causing a significant stress on the user while diving. 
     SUMMARY OF THE INVENTION 
     It is therefore an object of this invention to eliminate these problems of prior art technologies by providing an improved base for an underwater camera, which can be used for different housings of different types, not causing its fixing screw to become loose during underwater photography while the user is diving, and allowing the housing to be securely affixed to the base. 
     In view of the object described above, this invention relates to a base for an underwater camera with a camera enclosed inside a watertight housing, serving to have the underwater camera affixed and to attach an arm with a flash lamp provided at its tip part when flash lighting is carried out and comprising a base main body having an elongated planar fixing part where the underwater camera is fastened, a mobile holder plate for fastening the underwater camera, having a protrusion for limiting displacement of the camera housing in the direction of the width of the base (defined as the transverse direction) and being disposed on the base main body so as to be movable in the transverse direction, a pair of set screws for attaching the mobile holder plate to the base main body, and a fixing screw for fastening the underwater camera, wherein the base main body has a fixing hole for allowing only an axial part of the fixing screw to pass through and a pair of elongated holes formed on both sides of the fixing hole for allowing only axial parts of the set screws to pass through and to be movable in the transverse direction, and wherein the mobile holder plate has an elongated fixing hole for allowing the axial part of the fixing screw to pass through and to be movable in the transverse direction and fixing screw holes for engaging with the pair of set screws. 
     Such a base may have a guide part that guides the mobile holder plate from both sides in the transverse direction. 
     Such a base may further comprise a pair of supplementary mobile holder plates on both sides of the mobile holder plate on the base main body, each of the pair of supplementary mobile holder plates having a protrusion on one end part in the transverse direction on a front surface, having an adjusting set screw passed through corresponding one of the elongated holes provided in the transverse direction of the base main body for adjusting its position in the transverse direction and being adapted to be fastened by sandwiching leg structure of the camera housing by inner walls of the protrusions of the pair of supplementary mobile holder plates. 
     In the above, each of the pair of supplementary mobile holder plates may have a backside protrusion on one end part in the transverse direction on a back surface and be adapted to be fastened as outer walls of the backside protrusions push and open the leg structures of the camera housing when the pair of supplementary mobile holder plates is inverted to be attached to the base main body. 
     In the above, the base main body may have supplementary guide parts formed thereon for guiding the pair of supplementary mobile holder plates from both sides in the transverse direction. 
     In the above, the base main body may have an arm-attaching part formed on at least one longitudinal end part thereof for attaching the arm. 
     In the above, the base main body may have a grip-attaching part formed on at least one longitudinal end part thereof for attaching the arm through a grip. 
     In the above, the base main body and the grip may be integrally formed. 
     The invention further relates to a base for an underwater camera with a camera enclosed inside a watertight housing, serving to have the underwater camera affixed and to attach an arm with a flash lamp provided at its tip part when flash lighting is carried out and comprising a base main body having an elongated planar fixing part where the underwater camera is fastened and a protrusion formed at one end part in the transverse direction on a front surface for preventing the camera housing from moving in the transverse direction, a pair of mobile holder plates disposed on the base main body so as to be movable in the transverse direction, each having a protrusion at one end part on a front surface in the transverse direction, a set screw for attaching each of the pair of mobile holder plates to the base main body, and a fixing screw for fastening the underwater camera, the base main body having an elongated fixing hole for allowing only an axial part of the fixing screw to pass through and to be movable in the transverse direction and a pair of elongated setting holes formed on both sides of the elongated fixing hole for allowing only axial parts of the set screws to pass through and to be movable in the transverse direction, the mobile holder plates each having an elongated fixing screw hole for engaging with the pair of set screws, and the camera housing being adapted to be fastened by sandwiching leg structures of the camera housing with inner walls of the protrusions of the mobile holder plates. 
     In the above, the base main body may have a guide part that guides the mobile holder plate from both sides in the transverse direction. 
     In the above, each of the pair of mobile holder plates may have a backside protrusion on one end part in the transverse direction on a back surface and may be adapted to be fastened as outer walls of the backside protrusions push and open the leg structures of the camera housing when the pair of mobile holder plates is inverted to be attached to the base main body. 
     In the above, the base main body may have an arm-attaching part formed on at least one longitudinal end part thereof for attaching the arm. 
     In the above, the base main body may have a grip-attaching part formed on at least one longitudinal end part thereof for attaching the arm through a grip. 
     In the above, the base main body and the grip may be integrally formed. 
     Such a base may further comprise a connecting protrusion that connects the protrusions on the pair of mobile holder plates, the connecting protrusion and the protrusions on the pair of mobile holder plates together serving to fasten the camera housing. 
     A base according to this invention, being characterized as above, can be used with different types of camera housings without allowing the camera-fixing screw to become loosened and without causing any rotational displacement of the housing with respect to the base while the user is engaged in underwater photography. Since the camera housing can be so securely attached to the base and the base can behave as if it had been produced especially for the individual camera housing, the user can concentrate on diving or underwater photography. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a diagonal view for showing the structure of a conventional base for a general-purpose underwater camera. 
         FIG. 2  is a diagonal view for showing the manner in which the base of  FIG. 1  may be attached to the underwater camera. 
         FIG. 3  is a diagonal view for showing the housing attached to the base of  FIG. 1  in the reversed direction. 
         FIG. 4  is a diagonal view for showing the housing undergoing a rotational displacement. 
         FIG. 5  is a diagonal view for explaining the structure of a base according to a first embodiment of this invention. 
         FIG. 6  is a diagonal exploded view of the base of  FIG. 5  as seen from below. 
         FIG. 7  is a diagonal exploded view of the base of  FIG. 5  as seen from above. 
         FIG. 8  is an exploded diagonal view for explaining the structure of a base according to a second embodiment of this invention as seen from below. 
         FIG. 9  is a diagonal view showing a camera housing attached to the base of  FIG. 8 . 
         FIG. 10  is a diagonal view for explaining the structure of a base according to a third embodiment of the invention as seen from below. 
         FIG. 11  is a diagonal view of the base of  FIG. 10  as seen from above. 
         FIG. 12  is a diagonal view of a base for an underwater camera which is preferably usable with a large camera housing. 
         FIG. 13  is a diagonal view of a base for an underwater camera integrated with a grip. 
         FIG. 14  is a diagonal view for explaining the structure of a base for an underwater camera according to a fourth embodiment of the invention. 
         FIG. 15  is an exploded diagonal view of the base of  FIG. 14  as seen from above. 
         FIG. 16  is a diagonal view of a large camera housing in a fixed condition. 
         FIG. 17  is a diagonal view for explaining the structure of a base for an underwater camera according to a fifth embodiment of the invention. 
         FIG. 18  is an exploded diagonal view of the base of  FIG. 17  as seen from above. 
         FIG. 19  is a diagonal view of a large camera housing in a fixed condition. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     Embodiments of this invention will be described next in detail. 
       FIG. 5  is a diagonal view for explaining the structure of a base according to a first embodiment of this invention,  FIG. 6  is a diagonal exploded view of the same base as seen from below, and  FIG. 7  is a diagonal exploded view of the same base as seen from above. A situation in which an arm is attached to the base through a grip will be explained with reference to these figures. It is to be noted that the main body of the camera is omitted from  FIG. 7 , and the grip and the arm are omitted from  FIGS. 5-7 . 
     In  FIGS. 5-7 , numeral  11  indicates the base, and numeral  12  indicates a watertight camera housing. The base  11  comprises an elongated planar main body  13  and a planar mobile holder plate  14  which is shorter than the base main body  13  in the longitudinal direction. 
     The bottom part of the housing  12  is provided with a pedestal  15  for fastening to the base  11 , and a camera-fixing screw hole  17  is formed near the center of this pedestal  15  for accepting a fixing screw  16 . This screw hole  17  may be of a type for fastening a tripod screw. 
     The base main body  13  is formed with a circular camera-fixing hole  18  for allowing only the axial part of the fixing screw  16  to pass through and also a pair of elongated holes  20 A and  20 B for set screws on both sides of this circular fixing hole  18  in the longitudinal direction, elongated in the direction of the width of the base main body  13  (hereinafter also referred to as the “transverse direction”), for allowing only the axial parts of a pair of set screws  19 A and  19 B such that they can be moved in the direction of the width of the base main body  13 . Screw holes  21 A and  21 B for attaching a grip are also provided on both ends of the base main body  13 . 
     The mobile holder plate  14  is provided nearly at its center with an elongated hole  22 , elongated in the direction of the width, for allowing the axial part of the fixing screw  16  to pass through so as to be able to move in the direction of the width and a pair of circular holes  23 A and  23 B on both sides of this elongated hole  22  in the longitudinal direction for screwing in the pair of set screws  19 A and  19 B. The circular hole  18  and the pair of elongated holes  20 A and  20 B formed in the base main body  13  are located so as to match the elongated hole  22  and the pair of circular holes  23 A and  23 B formed in the mobile holder plate  14 . A protrusion  24  is formed at one end part on the surface of the mobile holder plate  14  in the direction of its width so as to extend in the longitudinal direction for contacting the front wall of the pedestal  15  of the housing  12  for the purpose of positioning. 
     The base  11  as described above may be fastened to the housing  12 , for example, as follows. Firstly, the axial part of the set screw  19 A is passed through the elongated hole  20 A from the lower side of the base main body  13  so as to enter the hole  23 A below the mobile holder plate  14  for temporary holding. Similarly, the axial part of the other set screw  19 B is passed through the elongated hole  20 B from the lower side of the base main body  13  so as to enter the other hole  23 B below the mobile holder plate  14  for temporary holding. By these operations for temporary holding, the mobile holder plate  14  come to be fixed on the base main body so as to be movable in the direction of the width. Under this condition, the head parts of the pair of set screws  19 A and  19 B are in contact with the back surface of the base main body  13 , while the axial parts of these set screws  19 A and  19 B are prevented from moving in the longitudinal direction although they can freely move in the direction of the width. 
     Next, the housing  12  is placed above the mobile holder plate  14 , and the mobile holder plate  14  is moved slidingly in the direction of the width such that the front wall of the pedestal  15  comes to contact the protrusion  25 . Then, the axial part of the fixing screw  16  is passed sequentially through the circular camera-fixing hole  18  of the base main body  13  and the elongated hole  22  of the mobile holder plate  14 . Next, not only the camera-fixing screw  16  but also the pair of set screws  19 A and  19 B is tightened completely under the condition that the axial positions of the fixing screw  16  and the screw hole  17  of the pedestal  15  of the housing  12  are matched. As a result, the movement of the housing  12  in the direction of the width is limited by the protrusion  24  of the mobile holder plate  14  and the fixing screw  16  while its longitudinal movement is limited since the pair of set screws  19 A and  19 B is inserted into the elongated holes  20 A and  20 B. In other words, no rotational displacement is allowed to occur. 
     Although the first embodiment of the invention was explained above by way of an example with a housing having a pedestal and using a grip while not having any leg structure, it goes without saying that this is not intended to limit the scope of the invention. The invention is intended to include situations where leg structures are provided and an arm is directly to be attached. 
     Next, a second embodiment of the invention is described.  FIG. 8  is an exploded diagonal view for explaining the structure of a base for an underwater camera according to the second embodiment of the invention as seen from below, and  FIG. 9  is a diagonal view showing a housing attached to this base. In these two figures, the components which are similar to or like those already explained with reference to the first embodiment of the invention are indicated by the same numerals and will not be repetitively explained. For simplifying the disclosure, the camera main body is not illustrated in  FIGS. 8 and 9 . 
     The base  11  according to this embodiment of the invention, like the base according to the first embodiment, comprises an elongated planar base main body  13  and a planar mobile holder plate  14  which is shorter than the base main body  13  in the longitudinal direction. 
     The base main body  13  according to this embodiment has a guide groove  25  formed with a shape which is complementary to the shape of the mobile holder plate  14  such that the mobile holder plate  14  can move in the direction of the width by being guided along the both wall surfaces of this guide groove  25 . In other respects, the structure of this embodiment is the same as that of the first embodiment.  FIG. 9  shows a situation where a grip  26  is in an attached condition. 
     Being thus structured, the second embodiment is advantageous, in addition to having the advantages of the first embodiment, in that the displacement of the mobile holder plate  14  in the longitudinal direction can be limited without strictly matching the measurements of the set screws  19 A and  19 B and the elongated holes  20 A and  20 B because the mobile holder plate  14  is guided by the walls of the guide groove  25 . This embodiment is advantageous also because of the ease of attachment. 
     Next, a third embodiment of the invention is described.  FIG. 10  is a diagonal view for explaining the structure of a base for an underwater camera according to the third embodiment of the invention as seen from below, showing the situation before the housing  12  is attached to the base  11 , and  FIG. 11  is a diagonal view of the same base as seen from above after the housing  12  has been attached to the base  11 . In these two figures, the components which are similar to or like those already explained with reference to the first embodiment of the invention are indicated by the same numerals and will not be repetitively explained. For simplifying the disclosure, the camera main body is not illustrated in  FIGS. 10 and 11 . 
     The base  11  according to this embodiment of the invention is preferably used when the housing  12  is structured with leg structures  27 A and  27 B in addition to a pedestal  15  on its bottom, comprising not only an elongated planar main body  13  and a planar mobile holder plate  14  which is shorter than the base main body  13  in the longitudinal direction but also a pair of supplementary mobile holder plates  28 A and  28 B. For this reason, the base main body  13  has additional elongated holes  30 A and  30 B for set screws formed on each side of the elongated holes  20 A and  20 B, elongated in the direction of the width such that the axial parts of set screws  29 A and  29 B can be passed therethrough while allowing them to move in the direction of the width. Moreover, the base main body  13  has not only a guide groove  25  formed with a shape which is complementary to the shape of the mobile holder plate  14  but also additional guide grooves  31 A and  31 B on each of its sides in the shape which is complementary to the shape of the supplementary mobile holder plates  28 A and  28 B. The supplementary mobile holder plates  28 A and  28 B are movable in the direction of the width, being guided respectively by the wall surfaces of these guide grooves  31 A and  31 B. Protrusions  32 A and  32 B are formed at one end on the front surface respectively of the supplementary mobile holder plates  28 A and  28 B, and circular screw holes (not shown) are formed on the back surfaces for the set screws  29 A and  29 B. The length of the supplementary mobile holder plates  28 A and  28 B in the longitudinal direction is shorter than that of the mobile holder plate  14 . The supplementary mobile holder plates  28 A and  28 B are disposed such that the protrusions  32 A and  32 B are on the side opposite to the protrusion  24  of the mobile holder plate  14 . The housing  12  is fastened such that the leg structures  27 A and  27 B are sandwiched by the front walls of the protrusions  32 A and  32 B of the supplementary mobile holder plates  28 A and  28 B. 
     A base thus structured will have not only the advantages described above but also the advantage of being capable of making the fastening even securer, and this additional advantage will be particularly demonstrated when the housing  12  is large. 
       FIG. 12  shows a base  11  which is preferable for using with a large housing. This example is characterized wherein the pair of supplementary mobile holder plates  28 A and  28 B is provided with protrusions  33 A and  33 B at places somewhat removed inwardly from one end part of the back surface in the direction of the width such that it can be fastened by turning the pair of supplementary mobile holder plates  28 A and  28 B around to attach them to the base main body  13  and by opening the leg structures  27 A and  27 B of the housing  12  wider with the outer walls of the protrusions  33 A and  33 B on the back surfaces of the pair of supplementary mobile holder plates  28 A and  28 B. 
     The screw holes to be provided to the pair of supplementary mobile holder plates  28 A and  28 B are preferably throughholes such that any of the protrusions  32 A,  32 B,  33 A and  33 B can be used. 
       FIG. 13  is a diagonal view of a base  11  for an underwater camera integrated with a grip  34 . Such a base may be conveniently selected by the user according to the type and size of the flash lamp to be used and the purpose of the use. 
     Next, a fourth embodiment of the invention is described.  FIG. 14  is a diagonal view for explaining the structure of a base for an underwater camera according to the fourth embodiment of the invention, and  FIG. 15  is an exploded diagonal view of this base as seen from above. A situation where an arm is attached to the base through a grip will be explained as an example. For the convenience of explanation, the camera main body is not illustrated in  FIG. 15  and the grip and the arm are not illustrated in  FIGS. 14 and 15 . 
     In these figures, numeral  11  indicates the base, and numeral  12  indicates a watertight camera housing. The base  11  comprises an elongated planar main body  13  and a pair of planar mobile holder plates  41 A and  41 B which are shorter than the base main body  13  in the longitudinal direction. 
     The bottom part of the housing  12  is provided with a pedestal  15  for fastening to the base  11  and a pair of leg structures  27 A and  27 B. A screw hole  17  is formed near the center of this pedestal  15  for accepting a fixing screw  16 . This screw hole  17  may be of a type for fastening a tripod screw. 
     The base main body  13  is formed with an elongated hole  42  for allowing only the axial part of the fixing screw  16  to pass through such that it can be moved in the direction of the width of the base main body  13 . Guide grooves  43 A and  43 B are formed on both sides of the base main body  13  with a shape which is complementary to the shape of a pair of mobile holder plates  41 A and  41 B. These guide grooves  43 A and  43 B are provided with elongated holes  30 A and  30 B, elongated in the direction of the width of the base main body  13 , so as to pass set screws  19 A and  19 B therethrough while allowing them to move in the direction of the width of the base main body  13 . Screw holes  21 A and  21 B for attaching a grip are also provided on both ends of the base main body  13 . 
     The mobile holder plates  41 A and  41 B are provided with circular fixing holes  44 A and  44 B, respectively for having the set screws  19 A and  19 B screwed in. Protrusions  45 A and  45 B are formed, extending in the longitudinal direction, at one end part in the direction of the width on the surface of the mobile holder plates  41 A and  41 B so as to contact the front wall of the pedestal  15  of the housing  12  for the purpose of positioning. The housing  12  is fastened by sandwiching the leg structures  27 A and  27 B with the front walls of the protrusions  45 A and  45 B of the mobile holder plates  41 A and  41 B. Moreover, the mobile holder plates  41 A and  41 B are provided with protrusions  46 A and  46 B at places somewhat removed inwardly from one end part of the back surface in the direction of the width for contacting, extending in the longitudinal direction so as to contact the front walls of the leg structures  27 A and  27 B for positioning. When these protrusions  46 A and  46 B are used for positioning, the mobile holder plates  41 A and  41 B are turned over upside down, the housing  12  being fastened with the back walls of the protrusions  46 A and  46 B of the mobile holder plates  41 A and  41 B pushing and opening the leg structures  27 A and  27 B wider. 
     The fixing holes  44 A and  44 B provided to the pair of mobile holder plates  41 A and  41 B are preferably throughholes such that any of the protrusions  45 A,  45 B,  46 A and  46 B can be used.  FIG. 16  shows a large housing  12  in a fastened condition. 
     Next, a fifth embodiment of the invention is described.  FIG. 17  is a diagonal view for explaining the structure of a base for an underwater camera according to the fifth embodiment of the invention, and  FIG. 18  is an exploded diagonal view of this base as seen from above. A situation where an arm is attached to the base through a grip will be explained as an example. For the convenience of explanation, the camera main body is not illustrated in  FIG. 18  and the grip and the arm are not illustrated in  FIGS. 17 and 18 . 
     In  FIG. 11 , numeral  11  indicates the base, and numeral  12  indicates a watertight camera housing. The base  11  comprises an elongated planar main body  13  and a planar mobile holder plate  14  which is shorter than the base main body  13  in the longitudinal direction. 
     The base  11  according to this embodiment of the invention is of a structure having a pair of planar mobile holder plates  41 A and  41 B (as in the fourth embodiment of the invention) connected by a connector  47 . Protrusions  48  and  49  are shown as being formed respectively on the front surface and the back surface of this connector  47  but there may be only one of these protrusions present. The base  11  according to the fifth embodiment of the invention is the same as that according to the fourth embodiment of the invention in other respects. 
     The base  11  according to the fifth embodiment of the invention is fastened as the protrusion  48  is pressed against the pedestal  15  but the position of the housing  12  may be reversed in the forward-backward direction such that it may be fastened as described above. 
     With the base  11  thus structured, too, the housing  12  can be fastened to the base  11  securely without causing any rotational displacement. 
       FIG. 19  shows a large camera housing in a fixed condition. 
     Although the present invention has been described above by way of several embodiments, it goes without saying that they are not intended to limit the scope of the invention and that many modifications and variations are intended to be included within the scope of this invention.