Abstract:
A light diffuser for a camera used in macro photography, the diffuser formed from a prism having a body that includes an opening to accommodate the camera lens such that the body is positioned adjacent the camera flash unit for receiving and redirecting light throughout the body to exit a front face thereof around the lens and illuminate the subject in a desirable manner. Ideally the body is a unitary transparent material having facets formed thereon to provide internal reflection. One or more filter elements aid in conditioning the light processed in the diffuser body, such as diffusing, adding color to, and focusing the light.

Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   A device for distributing and redirecting light in association with photographic devices and, more particularly, to a diffuser having a prism for directing light onto a subject, particularly for use in macro photography. 
   2. Description of the Related Art 
   Macro photography commonly refers to close-up photography. Photographing subjects in close proximity requires positioning of the camera lens near the subject. However, in order to obtain the necessary magnification, the lens must be as far away from the film plane as possible. Methods of doing this generally include the use of extension tubes, bellows, close-up filters, and macro lenses, typically having the shape of a cylinder referred to as a barrel. A lens is mounted on one end of the barrel and focusing requires a simple twist of the lens barrel to move the lens element away from the film plane. Generally, macro photography presents challenges for lighting the subject. 
     FIG. 1  illustrates a typical flash camera  10  having a camera body  12  to which is attached a lens  14 . The lens  14  is generally cylindrically shaped having a first end  16  attached to the body  12  and a second free end  18  projecting out from the camera  12 , usually at a 90° angle to which is attached a lens element  15 . The lens  14  may be removably attached or integrally formed with the camera body  12 . 
   A flash unit  20  is associated with the camera  10  to provide additional illumination in low light or dark conditions. Many cameras have built-in flash units on the front  22  of the camera  12 , while other cameras have the flash unit  20  removably mounted on the camera body  12 . The construction and operation of these flash units  20  will not be described in detail herein because the same are readily commercially available. 
   Briefly, the flash unit  20  is physically and electrically coupled to the camera shutter actuator mechanism  24  to provide a timed flash of light towards the subject of the photograph so that desired illumination is present at the time the shutter opens and until the shutter closes. Most camera models provide little to no control over the direction, duration, and timing of the flash. As such, these general purpose cameras and flash units are designed for illumination of subjects that are more than twelve inches away from the end  18  of the camera lens element  15 . 
   Attempts to use conventional camera flash units for macro photography result in inadequate lighting of the subject.  FIG. 2  illustrates the effect of inadequate lighting conditions. In  FIG. 2 , the center  26  of the subject  28  is dark because the lens  14  protrudes into the field of illumination from the flash unit  20 , casting a shadow on the subject  28  and creating the dark spot on the final image. In other cameras, the flash is concentrated in the area directly in front of the lens  14 , causing over-lighting conditions and washing out of the final image. Attempts to overcome these disadvantages include the development of ring flashes for close-up photographic work.  FIG. 3  illustrates a commercially-available ring flash  40  utilizing eight small built-in LED&#39;s  42  spaced equidistantly around an opening  44  that is placed over the lens  46  of the camera  48 , as shown in  FIG. 4 . While the object of this device is to provide more even illumination on a subject, there are several disadvantages to the use of this device. First, the ring flash may block a flash sensor in the camera. Second, this device does not provide adequate illumination to the subject due to the limited power output of the light source. Third, the light amplitude is constant and cannot be modulated to provide the necessary illumination for the photograph. Conventional ring flashes that have the ability to modulate the light intensity are limited to a small number of high-end camera models and are expensive. In general, they employ complex circuitry for determining light output for proper exposure of the photograph and for interfacing with the camera. Such complex circuitry are bulky and require an independent power source. 
   Hence, there is a need for a method and device that distributes the light from a conventional flash unit on to a subject in a manner that enables flash macro photography without having to replace or tamper with the existing flash unit. 
   BRIEF SUMMARY OF THE INVENTION 
   A camera flash diffuser is provided for use with existing cameras and flash units in macro photography situations. In accordance with one embodiment of the invention, a device for distributing light is provided. The device includes a body having a central opening formed therein, means for receiving light from a first side of the body, and means for redirecting light around the central opening to exit a second side of the body. 
   In accordance with another embodiment of the invention, a device for distributing light in conjunction with a camera having a lens and a flash unit is provided. The device includes a body having a central opening sized and shaped to be received over the lens of the camera, the body having a first side configured to receive light from the flash, means for redirecting the light from the first side of the body to exit a second side of the body around the central opening. 
   In accordance with yet another embodiment of the invention, a camera flash diffuser is provided that includes a body having a central aperture sized and shaped to be received over a lens associated with the camera, the body including a first side for receiving light from the camera flash, means for redirecting light within the body, and a second side through which the light exits. 
   In accordance with yet a further embodiment of the invention, a camera is provided, preferably a photographic camera for creating photographs, including still photographs, moving photographs, digital photographs, television images, and the like that includes a camera body having a lens and a flash unit associated therewith; a diffuser body for distributing light from the flash in an even manner around the lens, the body including an opening sized and shaped to receive the lens; means for receiving light from a first side of the body; and means for redirecting light around the aperture to exit a second side of the body. 

   
     BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS 
     The foregoing features and advantages of the present invention will be more readily appreciated as the same become better understood from the following detailed description when taken in conjunction with the accompanying drawings, wherein: 
       FIG. 1  illustrates a known camera; 
       FIG. 2  illustrates a macro photograph taken with existing flash units; 
       FIG. 3  illustrates a conventional ring flash device; 
       FIG. 4  illustrates an existing camera having the ring flash unit mounted on the lens thereof; 
       FIG. 5  is an exploded isometric view of a known camera in association with a camera flash diffuser of the present invention; 
       FIG. 6  is an assembled isometric view of the known camera and the camera flash diffuser of  FIG. 5 ; 
       FIG. 7  is an isometric view of the diffuser of the present invention; 
       FIG. 8  is a front plan view of the diffuser of  FIG. 7 ; 
       FIG. 9  is a side view of the diffuser of  FIG. 7 ; and 
       FIG. 10  is a photograph of the subject of  FIG. 2  with correct lighting provided by the present invention. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
   Referring initially to  FIG. 5 , shown therein is the conventional camera  10  described above in conjunction with  FIG. 1  along with a diffuser  50  formed in accordance with one embodiment of the present invention. The diffuser  50  as shown has a unitary body  52  formed preferably from a single piece of material having an opening  54  formed therethrough. Ideally the opening  54  has a size and shape that allows it to be slidably received over the lens  14  of the camera  10 , as shown in  FIG. 6 . A grommet or rubber boot may be attached around the periphery  56  of the opening  54  to prevent damage to the diffuser  50  and to the lens  14  and to provide a means of retaining the body  52  on the lens  14 . 
   In the depicted embodiment, the diffuser  50  is preferably constructed from a single piece of Lucite material in the form of a prism having a front face  58 , a rear face  60 , a top face  62 , a bottom face  64 , and first and second side faces  66 ,  68 . When used with the camera  10 , the front face  58  faces toward the subject, and the rear face  60  faces towards the camera body  12  to receive light from the flash unit  20 . 
   In order to distribute light from the flash unit  20  throughout the diffuser body  52  and to direct the light towards the subject beyond the lens  14 , at least one angled face is preferably formed in the diffuser body  52 . As shown in  FIG. 5  and more clearly in  FIG. 9 , one angled face  70  is formed at the intersection of the rear face  60  and, in this case, the first side face  66 . Ideally this angled face  70  is formed at a 45° angle with respect to the rear face  60  and the first side face  66 . It is to be understood that other angles may be used, as desired, in order to obtain different diffusion patterns. In addition, other angled faces may be formed at other intersections or other locations on the body  52 , such as intersections of the front face  58  and the top face  62 , the front face  58  and the bottom face  64 , the rear face  60  and the first or second side faces  66 ,  68 , or combinations thereof, such as the front, bottom, and second side faces  58 ,  64 , and  68 . 
   While the angled faces are one means for redirecting light within the diffuser body  52 , other means may be used. For example, as shown in  FIGS. 5-9 , a diffusing element  72  is placed across the top half of the front face  58  of the diffuser body  52  and over the top face  62 . The diffusing element  72  allows a portion of light from the flash unit  20  to pass therethrough while the remaining light is reflected into the diffuser body  52  for distribution around the central opening  54  and out the front face  58 . 
   While the diffuser body  52  is generally symmetrical with respect to the opening  54 , it can be seen that the top face  62  angles downward towards the front face  58  from the rear face  60 , terminating at an intersection  61  above the opening  54 , while the bottom face  64  angles downward from the rear face  60  to the front face  58 . This is more clearly shown in  FIG. 9 . 
   The diffusing element  72  also extends a portion of the way down the front face  58  of the diffuser body  52 , as shown in  FIG. 9 . In one embodiment, the diffusing element  72  is constructed of paper, ideally white paper, although other materials that are readily commercially available may be used for providing a similar effect. 
   As shown in  FIG. 9 , light emanating from the flash unit  20  associated with the camera  10  (shown in phantom) enters the diffuser body  52  through the rear surface  60 . A portion of the light  100  passes through the filter element  72  and the diffuser body  52  to exit the front face  58 . Another portion of the light  100  is reflected off the top face  62  throughout the diffuser body  52 , some of which reflects off the rear face  60  and the first and second side faces  66 ,  68  to exit through the front face  58  around the opening  54 . More of the light  100  continues through the diffuser body  52  to reflect off the bottom face  64  and out through the front face  58  below the opening  54  and the camera lens  14 . Thus, the bright flash of light  100  is redirected and distributed throughout the diffuser body  52  to exit around the opening  54  and the camera lens  14  to illuminate a subject  102 . 
     FIG. 10  illustrates the subject of  FIG. 1  photographed using the diffuser  50  of the present invention wherein the light is now evenly directed on to the subject. 
   In order to retain the diffuser  50  on the lens  14 , various means may be used, including an elastomeric or flexible grommet or lining around the opening  54 , mechanical means, such as set screws and the like, or a tongue and groove arrangement where the diffuser body  52  matches external configurations on the lens  14  to prevent rotation of the diffuser body  52  with respect to the lens  14 . In other embodiments, however, it may be desirable to allow the prism body  52  to rotate relative to the lens to provide or enable adjustment in the direction of light exiting from the diffuser  50 . 
   Attachments can also be used in conjunction with the diffuser  50 , such as a magnifier to be placed in front of the lens  14 . The magnifier can be attached to the diffuser  50  and configured to be lowered over the lens  14  or raised away from the lens  14  and the front face  58  of the diffuser  50 . The magnifier can be clipped on or permanently mounted to the diffuser or, less preferably, to the camera. Color filters and other accessories may also be used in this manner. 
   The diffuser  50  can also be implemented for use with an active flash that is either slaved to the camera flash or triggered by the camera. The diffuser could also be implemented with a modular light source as an aid in focusing of the camera or as main illumination for the photograph. 
   While a preferred embodiment of the invention has been illustrated and described, it is to be understood that various changes may be made therein without departing from the spirit and scope of the invention. For example, the diffuser body  52  may be configured to redirect light by any method, including reflection, refraction, scattering, selective attenuation or concentration of the incoming light. Various configurations in the shape of the diffuser  52  may be used, including round, or round with enlarged sides, or various geometric shapes including square, rectangular, pentagonal, hexagonal, octagonal, or a combination of rounded and straight sides. In addition, the diffuser  50  can be hollow with internally-mounted or formed reflectors. Also, light pipes or other light conductors may be used for redirecting and redistributing the light. 
   Hence, the present invention is not to be limited except by the accompanying claims and the equivalence thereof. 
   All of the above U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, are incorporated herein by reference, in their entirety. 
   From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.