GB2238136A - Underwater camera housing - Google Patents

Abstract

A housing for a camera 50 which allows use of the camera 50 underwater or in other hostile environments comprises a hollow housing body 10, a plurality of camera control drive units 60, 84, 52A, the positions of which within the housing body 10 are adjustable, a plurality of externally accessible housing controls 62, 32, 68, and means, e.g. circuits 84 and 86, and flexible drive linkage 66, flexibly connecting the drive units 60, 64, 52A with the housing controls 62, 32, 68. A housing for an underwater camera 50 comprises a tubular housing body 10 of circular cross-section, at least one removable end cover 12, and a viewfinder port 20 formed in the wall of the housing body 10. At least one adjustable handle 30 may be mounted on the housing body 10. <IMAGE>

Description

UNDERWATER CAMERA HOUSING This invention relates to a housing for a camera which allows use of the camera underwater or in other environments which would result in damage to the camera if used unprotected. In particular, the housing comprises a waterproof and pressure-resistant container having transparent apertures for allowing light from the scene to be photographed to reach the camera lens and for the user to view the scene by means of the camera viewfinder system.

Underwater camera housings are well known. Commonly, such a housing is provided with a pair of handles, one mounted on each side of the housing so that the diver can hold the camera securely ahead of him or her while swimming, and a plurality of exterior controls for operating the camera controls, such as the shutter release, shutter speed and aperture controls, a focussing control, and a film advance lever. The position of these controls on the camera varies from camera to camera and, consequently, it has been necessary to construct different housings for different cameras so that the linkages from controls accessible on the exterior of the housing are properly located to operate the controls on the camera. This means that if the user changes camera type, a new housing must be purchased. For the manufacturer, different housings must be designed and built for different cameras.

Another disadvantage with such known housings is that the positions of the exterior controls are to a large extent dictated by the positions of the controls on the camera, resulting in less than ideal control positioning for underwater operation. For example, the user may be required to let go of one of the handles to operate a particular control, and to look at the control to ascertain the setting. This leads to difficulties in holding the camera steady and in composing the picture, especially if the subject is moving relative to the user.

It is an object of this invention to provide an underwater camera housing which at least reduces the difficulties encountered with the prior art housing described above.

According to a first aspect of this invention, a housing for a camera which allows use of the camera underwater or in other hostile environments comprises a hollow housing body, at least one camera control drive unit the position of which within the housing body is adjustable, a plurality of externally accessible housing controls, and means flexibly connecting the drive unit with one of the housing controls.

The flexible connecting means may be electrical connections forming part of a plurality of servo systems, whereby operation of one or more of the housing controls results in operation of an electrical motor or solenoid in the respective drive unit. Alternatively, the connecting means may be mechanical, such as a Bowden cable or a flexible shaft drive. In this way, it can be possible not only to arrange the positions of the housing controls more easily for convenience of use, but also to adjust the position of the drive units largely without alteration of the housing body or housing controls to suit different cameras. The housing thus becomes adaptable to a number of cameras, which has cost benefits arising from economy of scale.

Preferably, the housing includes a removable base member on which the camera is mounted within the housing body, and which also supports one or more of the drive units. The advantage of this construction is that the drive units can be mounted in their operating relationship with respect to the camera while still outside the housing body as a complete assembly including the camera, this complete assembly then being fitted as a whole into the housing body.

The base member may be a base plate which forms a camera platform to which the camera is secured by a screw threaded in a bore in the camera bottom plate normally used for mounting the camera on a tripod. Guide rails may be provided in the housing body for engaging the edges of the base plate, which is slidably inserted.

For some cameras, particularly certain medium format cameras, the housing may include one or more drive units arranged to be mounted on the camera itself. This is of use especially if one camera control moves with respect to the camera body when another of the camera controls is operated.

Electrical operation of the camera controls using servo systems or stepper motors lends itself to the provision of an electrical display for indicating control settings adjacent to or in the viewfinder.

According to another aspect of the invention, a housing for a camera which allows the use of the camera underwater or in other hostile environments comprises a tubular housing body of circular cross-section, at least one removable end cover, and a viewfinder port formed in the wall of the housing body. The housing body may be metallic, and therefore may be formed from a length of metal pipe stock, the end cover comprising a transparent port arranged to allow light from the subject to reach the camera lens, with the viewfinder port being formed ds a flat, apertured plate welded into a cut-out in the wall of the housing body. A second removable end cover may be attached to the other end of the body to give access to the camera back without removing the camera from the housing for film changing.The base plate referred to above may be mounted between rails fixed to the inside of the housing body and extending parallel to the central axis of the body.

The invention will now be described by way of example with reference to the drawings in which : Figure 1 is an exploded perspective view of a camera in accordance with the invention showing the main components which form a sealed container for the camera; Figure 2 is a front view of the housing with the front cover removed to show a camera mounted inside; Figure 3 is a diagrammatic partly sectioned plan view of the housing and camera; Figure 4 is a diagrammatic sectioned side view of the housing and camera with the end covers of the housing shown spaced from the housing body; and Figure 5 is a block diagram of an electrical control system.

Referring to Figure 1 of the drawings, a housing in accordance with the invention for a medium format camera may be comparatively inexpensively produced by forming the housing body 10 from a length of aluminium alloy pipe stock. A front end port 12 may be constructed as an optically flat circular glass plate 12A mounted in an aluminium alloy ring 12B with a planar rear sealing surface. For wide-angle photography a dome port 14 is preferred. To accommodate long lenses an extension tube 16, made from the same pipe stock as the body 10, may be placed between port 12 or 14 and the body 10. The rear end of the body 10 may be closed by a welded on plate, but preferably comprises a part-circular metal plate 18 having a planar sealing surface. Each pair of mating surfaces is preferably sealed by a flexible 0-ring seated in an annular groove (not shown in Figure 1) in one of the surfaces of the pair. A plurality of overcentre toggle catches 19 are mounted on the outside of the housing body 10 and extension tube 16 for clamping the end ports 12, 14, the extension tube 16 and the body 10 together with the 0-rings compressed.

A viewfinder port 20 is preferably formed by cutting out a segment of the housing body 10 over part of its length and welding a flat apertured plate 22 to the edges of the cut-out, the plate 22 being parallel to the axis of the body 10. A small segmental wall (not shown in Figure 1) is welded to the body 10 to close the opening between the front end of the plate 22 and the wall of the body 10. Set into the plate 22 is a flat glass viewfinder window 24 or a prism unit 26 which are secured in position by bolts 28 and sealed with the plate 22 by a flexible 0-ring seated in a groove in the plate mating surface.

Holes are drilled in the wall of the body 10 for mounting handles 30 and, for instance, an external aperture control 32 with a sealed shaft.

The handles 30 are attached to the housing body 10 by means of respective hollow bosses 34 welded to either side of the housing body 10. Each of the handles is seen to comprise a sleeve member 36, a slotted bar member 38, and a hand gripping member 40 which are connected together by means of first 42 and second 44 screw clamps. The outwardly facing end of the sleeve member 36 is shaped to engage a longitudinal slot 38A provided in the bar member 38 and the first clamp 42 is screwed into this end of the sleeve member 38. The second clamp 44 engages aligned apertures (not shown) provided in a lug 46 on the grip 40 and in the bar member 38, and is screwed into an end cap 48. The clamps 42, 44 have respective outwardly facing adjustment knobs 42A, 44A by means of which the clamps may be screwed and unscrewed.By unscrewing the first clamp 42 to loosen the connection, the sleeve member 36 can be rotated about the horizontal axis of the first clamp 42 together with the bar member 38 if required. Loosening of the second clamp 44 allows the bar member 38, and the grip 40 to be rotated about the horizontal axis of the second clamp 44. In this way, the position of the handle 30 may be adjusted as desired and fixed in the adjusted position by tightening the clamps 42,44. The provision of a longitudinal slot 38A in the bar member 38 allows the length of the handle 30 to be adjusted after loosening of the first clamp 42 by sliding the bar member 38 longitudinally on the slot engaging portion of the sleeve member 36 to a desired position, and then tightening the first clamp 42.In this way, the orientation of the handle grips 40 with respect to the housing body 10 may be altered while maintaining them in registry with operating controls on the housing body such as aperture control 32.

The internal configuration of the housing is shown in Figures 2, 3 and 4 which show a medium format camera 50 having a lens 50A, a rotary shutter speed control 52 in the side of the camera, a focussing ring 54 at the base of the lens 50A, and an aperture control ring 56 at the distal end of the lens. This particular camera has a removable motorised film back 50B.

In the embodiment of the invention shown in Figures 2 to 4, two of the camera controls, the focussing and aperture rings, are operated via electrical servocontrolled motors so that the only connections of these controls with the externally accessible controls of the housing are by electrical conductors. It will be appreciated, however, that flexible mechanical drive connections can be used for these controls. The shutter speed control is operated via a flexible shaft drive.

The camera 50 is mounted in the body 10 on a base plate 55 slidably located in longitudinal channels formed by guide rails 58 fixed on the inner surface of the body 10. A focussing drive unit 60 including a high-torque electrical motor is bolted to the base plate 55, slots 55A (Figure 3) being cut in the plate 56 to allow longitudinal adjustment of the unit 60 to suit the position of the focussing ring 54. A friction drive wheel 60A coupled to the motor engages with the focussing ring 54. Modified base plates can be provided to suit different cameras having different lens heights, for example base plates with a raised or sunken platform for mounting the focussing drive unit 60 may be provided, to ensure that the friction drive wheel 60A is in engagement with the focussing ring 54.A potentiometer or other position-sensing device is included in the drive unit 60 to generate a feedback signal indicative of the position of the focussing ring 54. Circuitry supplying the drive unit 60 with a drive signal is actuated by a focussing lever 62 (see Figure 1) on one side of the handles 30, the lever 62 being coupled to a three-position switch (not shown) for focussing in either direction according to which way the lever 62 is pushed.

Drive for the aperture control ring 56 is provided by a similar motorised aperture drive unit 64 with a friction drive wheel 64A engaging the lens barrel 50A. In this case the drive unit 64 is clamped to the aperture control ring 56 by a strap 64B so that the operation of the focussing ring 54 does not cause relative longitudinal movement between the aperture drive unit 64 and the aperture control ring 56.

In this case, therefore, operation of the aperture control ring 56 causes the aperture drive unit 64 to move with the aperture control ring. Electrical servo control for the aperture drive unit 64 is similar to that described above for the focussing drive unit 60, actuation being via a rotatable knob 32 adjacent the left hand handle 30 and coupled to a potentiometer or optical encoder 32A.

The shutter speed control 52 is most conveniently operated in this case mechanically by a cap 52x fitted over the control 52, and a flexible drive linkage 66 which passes through a sealed hole in the housing body 10 to an external control knob 68 adjacent the right hand handle 30. A potentiometer or encoder 68A generates an electrical output for electrical display of the shutter speed.

The shutter release is a trigger button (not shown) on the right hand handle 30 coupled by means of an electrical connection 88 to an electronic shutter release socket 72 (Figures 2 and 4) on the side of the camera 50.

A plug 74 is fitted in an electronic flash 'hotshoe' 74A and is electronically connected to an outside flash unit (not shown).

Visible in Figures 3 and 4 are the viewfinder port 20 and an LED display array 76 for displaying aperture, shutter speed, focussing distance, and exposure count.

A warning light 78 mounted adjacent the LED display array 76 is electronically connected to a conductivity sensor (not shown) located at the botton of the housing 10 to detect the presence of water in the housing.

An electronic control unit 80 including a microprocessor and memory is located inside the upper part of the housing above the camera 50 as shown in Figure 2. This unit responds to signals from transducers associated with the external controls, such as one or more potentiometers and feeds appropriate signals to the electrical drive units. Optical encoders on the drive motor shafts sense the positions of the shafts so that each external control and associated electrical drive unit act as a servo system. Alternatively, feedback can be avoided by using stepper motors.

The electronic control unit 80 is accessible from the front of the housing 10 when the lens 12 or 14 is removed. The unit has, associated with it, a memory for storing reference data for various different cameras and lenses. A removable camera PROM key 80A and a similar lens PROM key BOB on the unit 80 allow selection of the information in the microprocessor memory for the particular camera and lens being used. A reset button 80C is used for automatically initialising the unit 80. Circuitry for the housing is shown by solid lines(Figures 2 and 4), of which line 82 represents the circuit for the handle mounted controls 62, line 84 represents the circuit for the focussing drive unit 60, line 86 represents the circuit for the aperture control unit 64 and line 88 represents the circuit for the shutter control 72.Electrical connecting leads are plugged into their respective control units. Batteries 90 for the housing are mounted at respective inner sides of the housing on side rails 58. Preferred batteries are rechargeable Dryft or Nicad.

Electrical control of the drive units is performed by means of a microprocessor-based circuitry shown in block diagram form in Figure 5. The microprocessor 80 receives inputs from the shutter release trigger button, the focussing control encoder 92, the shutter speed encoder 68A, and the aperture encoder 32, and generates outputs for the camera shutter release solenoid 70, the focussing drive unit 60, the shutter speed drive unit 52A and the aperture drive unit 64. Since the majority of these input and output devices involve analogue signals, A/D and D/A convertors 94, 96 are coupled to the microprocessor ports where appropriate.Another output from the electronic control unit 80 is coupled to the LED display array 76 via an LED driver circuit 98, while yet another output is coupled to a memory interface device 100 for transmitting exposure information which can be read out if required after a dive.

One of the features of the control circuitry is that it can be adapted to yield control signals to match the characteristics of various camera and lens combinations.

This is achieved in this preferred embodiment by arranging for the microprocessor outputs to be determined by a pre-selected plug-in read-only memory (ROM) 102. By supplying different RO.M's for different cameras, the system is quickly and easily adapted to a new camera.

The above described embodiment may be modified to suit a camera of the type having a shutter speed control in the form of a ring located distally of the aperture control ring on the lens. Since this control would also move longitudinally when the focussing ring is operated, its motorised servo unit (driving the aperture ring) would also be mounted on the lens barrel, for example by being clamped on the barrel between the shutter speed ring and the aperture ring. Electrical actuation would occur by way of the external shutter speed control knob and encoder as before. The aperture and shutter speed drive units would in this case be arranged on opposite sides of the camera lens due to their occupying overlapping longitudinal positions, for example they may be below and above the lens respectively or the aperture drive unit may be side mounted.

The above described embodiments assume that the camera has an automatic film winder. However, if a manual film winder is present, the invention may include a separate motor drive mounted on the base plate and coupled to the film winder by, for example, a toothed drive belt.

Claims (19)

1. A housing for a camera, comprising a hollow housing body, at least one camera control unit the position of which within the housing body is adjustable, a plurality of externally accessible housing controls, and means flexibly connecting the drive unit with one of the housing controls.

2. A housing according to claim 1, wherein the flexible connecting means comprises an electrical connection forming part of an electrical control system including the said drive unit and operable such that operation of the associated housing control results in actuation of the drive unit.

3. .R housing according to claim 1, wherein the flexible connecting means includes a mechanical connection.

4. R housing according to claim 3, wherein the connecting means is a Bowden cable or a flexible shaft drive.

5. A housing according to any one of the preceding claims, including a removable base member for mounting the camera within the housing body.

6. R housing according to claim 5, wherein the removable base member supports the drive unit.

7. A housing according to claim 5 or claim 6, wherein the base member is a base plate which forms a camera platform for receiving the camera.

8. A housing according to claim 7, wherein the base plate has longitudinal slots for receiving securing means for the camera and the drive unit.

9. A housing according to claim 7 or claim 8, including guide rails in the housing body for engaging the edges of the base plate.

10. A housing according to any one of the preceding claims, wherein the drive unit is arranged to be mounted on the camera.

11. A housing according to any one of the preceding claims, further comprising an electrical display for indicating control settings.

12. A housing for a camera, comprising a tubular housing body of circular cross-section, at least one removable end cover, and a viewfinder port formed in the wall of the housing body.

13. A housing according to claim 12, wherein the housing body is metallic.

14. A housing according to claim 13, wherein the housing body is formed from a length of metal pipe stock, the end cover comprises a transparent port arranged to allow light for the subject to reach the camera lens, and the viewfinder port is formed as a flat, apertured plate fixed in a cut-out in the wall of the housing body.

15. A housing according to any one of claims 12 to 14, wherein a second removable end cover is attached to the other end of the body to give access to the camera back.

16. A housing according to any one of claims 12 to 15, further comprising guide rails fixed to the inside of the housing body and extending parallel to the central axis of the body for receiving a base plate for supporting the camera within the housing body.

17. A housing according to any one of claims 12 to 16, further comprising one or more handles mounted on the housing body.

18. A housing according to claim 17, wherein the handle or handles are arranged to be adjustable in position and/or length.

19. A housing for a camera substantially as herein described with reference to the drawings.