GB2087592A - Flash mounting for camera - Google Patents

Abstract

A flash mounting suitable for close-up and macrophotography with a single lens reflex camera, comprises an arm (10) for attachment to the camera and which supports an annular guide (26) on which is mounted a pair of rings (30, 32) for independent angular adjustment. A bracket arm (42, 44) for supporting a flash gun is mounted on each ring. This arrangement allows a pair of flash guns to be positioned without being affected by focussing movements of the lens and allows the flash gun positions to be readily adjusted. <IMAGE>

Description

SPECIFICATION Photographic apparatus accessory This invention relates to an accessory for photographic apparatus, and more specifically a flash mounting for close-up and macrophotography with a single lens reflex camera.

In such photography it is necessary to use a small lens aperture in order to provide acceptable depth of field in photographing three dimensional objects, and in most cases this involves supplementary lighting to avoid unacceptably long exposure times. Electronic flash is the normal lighting used because of the compact and portable nature of the equipment and the avoidance of heat problems, both in the field and in studio work.

It is know to mount a flash gun directly on the camera so that it will be adjusted in position with the camera relative to the object being photographed. For this purpose the camera is often provided with a shoe, usually located on top of the pentaprism housing, but this is unsuitable for close work because the flash fires parallel to the lens axis and above the lens, and an object located close in front of the lens, that is of the order of a few inches only from the front face of the lens, may be shadowed by the lens barrel or other structure, may not receive the maximum light intensity due to the limited angle of the flash beam, and in any case such frontal lighting is flat without good modelling.

Accessory brackets are also known, for example in the form of an arm adapted to be attached to the camera body by a screw engaged with the tripod bush, and carrying a shoe at one end so that the flash gun may be mounted on the shoe spaced to one side of the lens barrel and at an angle to the lens axis. However, this system does not provide a complete solution particularly because many macro lenses use a focussing method (e.g. bellows in some cases) where the front face of the lens moves through a relatively large distance with respect to the film plane over the focussing range and in any given situation (particularly in field work) it may become necessary to continually adjust the angle of the bracket and/or of the gun relative to the bracket, which is time consuming and inconvenient.

Moreover, a single flash gun is considered insufficient for many purposes, and it is preferred to use a main flash to provide the principal illumination and modelling of the subject, and a secondary or fill-in flash to complete the lighting.

In that case, the two flash guns may be required to be located generally on opposite sides of the lens axis, and either have different light outputs or be located at different distances from the subject or preferably both. It is known to use brackets which extend on both sides of the camera body with a shoe at each end for such purposes, but then the problem of adjustment of them combined with the focussing problem makes operation complex and cumbersome.

Another problem is that conventional 35 mm photography uses a rectangular format so that the camera is sometimes used in a vertical mode as well as the more common horizontal mode. The aim of the supplementary lighting in general is to produce an apparent "natural" effect which requires the main or modelling light to apparently originate from above the subject and at one side of the subject (because natural sunlight falls for example from an angle of 500 to 600). Moreover, with objects having a "front" and a "rear", for example many natural history subjects such as entomological specimens, it is preferred to have the light falling on the front rather than on the rear, and this requires the main modelling light to be located to the left or to the right of the lens whether the camera is in the horizontal or vertical mode.

Existing and known camera flash brackets are incapable of adjustments to cover all of these possibilities, or at the very best require parts to be detached from the camera and reassembled in a different position, and this is so time consuming as to be at best inconvenient and at worst (with living entomological specimens for example) means that by the time the adjustments have been completed the opportunity for photography has been lost.

Another prior art flash bracket has comprised a ring to be screwed into the front of the lens mount or barrel and an annular member mounted for rotation about the ring, the annular member carrying an arm to mount the flash gun. In practice, it has been found difficult to tighten the ring to prevent the weight of the flash gun turning the ring with the annular member, and the ring hoods the lens. Morerover, in lens construction where the front of the barrel or mount rotates during focussing this alters the pre-set flash position, so that again rapid focussing and exposure is impossible.

The object of the present invention is to provide an improved flash mounting particularly for close photography, which solves the above problems, enables a pair of flash guns to be positioned without being affected by focussing movements of the lens, and enables the flash gun position to be rapdily changed in convenient manner.

In accordance with the present invention, a flash mounting comprises an arm adapted for attachment to the camera so as to extend generally parallel to the lens barrel in use, an annular guide carried by the arm operatively surrounding the lens barrel, and at least two rings which are angularly adjustable about the guide, each ring carrying a bracket terminating in a flash gun shoe or other mounting means.

The arm may be adjustable in length, for example by comprising a first part to be fixed to the camera body or bellows mount and a second part fixed to the first part, so that the rings can be located adjacent the front face of the lens irrespective of the position of the latter, not only during focussing movements of the lens, but also in the event of lenses being interchanged. The arm may be connected to the camera by a screw engaged with the conventional tripod bush on the camera body, with a shim or spacer of appropriate thickness interposed in order to maintain the rings concentric to the lens axis with camera bodies of different dimensions.

The rings may be completely rotatable on the guide, or merely angularly adjustable, and in the latter case adjustability through an arc of 2700 or more is preferable to allow the camera to be' used in either the horizontal mode; or two alternate vertical modes with the pentaprism housing on the left or the right to suit different photographers' requirements.

The brackets are preferably detachably connected to the respective rings, for example the brackets may be metal rods which push fit into sockets in the rings with a grub screw for clamping, so as to enable the mounting to be rapidly dismantled to small dimensions for storage in a camera case or the like.

Preferably the flash gun shoes are of the so called "hot" shoe type and these may be connected by flexible co-axial leads to an appropriate junction box which itself is provided with the male complementary part to engage in an existing female hot shoe on the camera body, or alternatively with a conventional miniature co axial plug to engage in the flash lead socket on the camera body. The all hot shoe system is preferred where the camera is appropriately equipped, because of the greater security of engaged parts.

The invention will now be more particularly described with reference to the accompanying drawings wherein: Fig. 1 is a perspective view showing a flash mounting fitted to a camera, and Fig. 2 is a side elevation with part of the flash brackets omitted.

The mounting comprises an arm first part 10 which is operatively connected via an interposed shim or spacer 12 to the camera body 14 by means of a screw 1 6 engaged with the conventional tripod bush in the camera body. The arm part 10 is of shallow channel section so as to accommodate a second arm part 1 8 which is adjustable along the length of the part 10 by means of a clamping screw 20 engaged in a tapered aperture in the part 1 8 and slidable along the length of a slot 22 in the part 10. As best seen in Fig. 2, a series of tapped apertures 24 may be provided to give an additional degree of extension.

The arm part 18 is made integral with, or connected to an annular guide 26 which comprises a short tubular portion 28 together with a pair of flanges or equivalents so as to confine a pair of rings 30, 32 on the tubular portion, enabling the two rings to rotate independently on the tubular portion but maintaining them in axial position. As illustrated, there may be a flange on one side and a series of clips 34 on the opposite side of the pair of rings.

Each of the rings is provided with a clamping screw 36, 38 engaged in a tapped bore in the corresponding ring and provided with milled or knurled heads so that they can be tightened against the tubular portion 28 to fix the angular position of the relative ring. Each ring is also provided with a socket 40 to receive one end of a flash bracket 42, 44 formed from metal rod, each clamped in position by screws 46, 48 which are similar to screws 36.

The brackets 42, 44 may be provided with a flat portion at the end which engages in the socket, for engagement by the screws 46, 48, to restrict the possibility of swivelling of the brackets in the sockets, and if desired a range of brackets of different lengths and curvature can be provided.

It will be appreciated that each bracket is provided with a shoe or other means for mounting a flash gun at its outer end (as shown in broken lines in Fig. 1) preferably a "hot" shoe which provides electrical connection to the flash gun when mounted ther.ein (provided the flash gun has the appropriate complementary part). The cables connecting the shoes to the camera shoe or other svnchronising socket are omitted for clarity.

Assuming that the arrangement as illustrated in Fig. 1 is set up for horizontal format macrophotography with a high power gun attached to one bracket providing the main light and a low power gun attached to the other bracket providing the fill-in light, it will be seen that the main light falls from the left and above as seen from the eye of the photographer.If the reverse is required, the screws 36, 38 are loosened, the rings are rotated in opposite directions for equal amounts, the screws retightened, and it may then be necessary to adjust the flash gun positions relative to the brackets, for example by conventional swivel joints, ball joints or the like (not shown) provided between the accessory shoes and the brackets 42, 44, although with some arrangements this may not be necessary as if the guns are arranged to fire towards a point coincident with the lens axis, rotation about that axis causes no alteration in this relationship.

Similarly, if the set up is to be used for vertical format photography the rings are again swivelled to appropriate positions in either direction, according to whether the camera has been turned through 900 clockwise or anti-clockwise from the illustrated position.

The drawings illustrate a prototype mounting made for experimental purposes. Where the parts are (or may be) made of aluminium alloy or the like for rigidity and lightness, it is contemplated that they may be anodised matt black to minimise unwanted reflections and make the mounting less conspicuous. However, in production versions it is contemplated to reduce manufacturing costs at least some of the parts may be made of plastics, for example the rings could be of a suitable glass filled nylon so as to be moulded cheaply and provided with the required sockets for the brackets and for clamp screws and the like by subsequent machining. Similarly, the parts 10 and 18 could be made of suitable rigid plastics materials, or possibly of aluminium extrusions cut to length, and many other changes will be apparent to the ordinary development engineer, without affecting the use of the ideas expressed in the foregoing description.

Further, each bracket may comprise two hinged parts with an adjustable clamp to lock the hinge so as to simplify alteration of flash gun angles on the brackets.

If the invention is utilised with bellows mounted on guide rails, the rings may be mounted on the guide rails instead of on the camera body.

Claims (11)

1. A flash mounting comprising an arm adapted for attachment to the camera so as to extend generally parallel to the lens barrel in use, an annular guide carried by the arm operatively surrounding the lens barrel, and at least two rings which are angularly adjustable about the guide, each ring carrying a bracket terminating in a flash gun shoe or other mounting means.

2. A mounting as claimed in Claim 1 in which the arm is adjustable in length.

3. A mounting as claimed in Claim 2 in which the arm comprises a first part to be fixed to the camera body or bellows mount and a second part fixed to the first part.

4. A mounting as claimed in any one of Claims 1-3 in which the arm is connected to the camera by a screw engaged with the conventional tripod bush on the camera body.

5. A mounting as claimed in any one of Claims 1-4 in which each ring is adjustable independently of the other.

6. A mounting as claimed in any one of Claims 1-5 in which each ring is provided with means for securing it in a selected position of angular adjustment with respect to the guide.

7. A mounting as claimed in any one of Claims 1-6 in which each bracket is detachably connected to the respective ring.

8. A mounting as claimed in any one of Claims 1-7 in which the brackets each comprise a rod which is insertable into a socket on the respective ring.

9. A mounting as claimed in Claim 8 in which each rod is non-rotatably engageable in the respective socket.

10. A mounting as claimed in any one of Claims 1-9 in which each bracket comprises two hinged parts with an adjustable clamp to lock the hinge whereby the flash guns can be adjusted to and held at selected angles.

11. A flash mounting substantially as herebefore described with reference to, and as shown in, the accompanying drawings.