Abstract:
A photographic light diffusing device is provided. A flexible, transparent cowl is adapted to be mounted on a photographic light source, the cowl including a plurality of ribs and an opening through which the photographic light source is visible when the cowl is mounted on the photographic light source. The cowl elastically deforms to fit onto the photographic light source. A removable, flexible cover is placed over the opening of the cowl.

Description:
CROSS-REFERENCE TO RELATED APPLICATION 
     This application is a continuation-in-part of U.S. patent application Ser. No. 11/055,934, filed Feb. 11, 2005, which claims the benefit of the filing date of U.S. provisional patent application No. 60/630,637, filed Nov. 24, 2004, the contents of which are all hereby incorporated by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to photographic light diffusers and more particularly to portable light diffusers having compound geometry and separable components. 
     BACKGROUND 
     Diffuse lighting accessories are photography devices commonly used to provide soft lighting effects in photographs. To achieve a diffuse lighting effect, light can be either directly or indirectly passed through a semi-transparent material, or it may be reflected off a material which will cause it to scatter somewhat. Such diffuse lighting is commonly produced by light sources which are remote from the camera. Typically, such light diffusers are provided by stationary screens, umbrellas, soft boxes and the like. Such devices provide excellent lighting effects in fixed studio settings where there is no need to transport the lighting equipment including the diffusers from place to place. 
     Each particular shot to be lighted dictates the type and intensity of light needed to properly illuminate the subject. In some situations direct light from a light source without any alteration may be required. In other situations direct lighting may be too strong or cast overly distinct shadows, in which case a more diffuse light is desirable. In still other cases, an even more indirect diffuse light may be needed to create the proper lighting effect. It is important to have a certain amount of uniformity in the lighting used to illuminate the subject. This uniformity may be achieved using typical stationary diffusers provided that the equipment is of good quality and is employed in the proper fashion. 
     While the equipment described above provides good lighting effects in a fixed studio setting, it can be inconvenient if not impossible to use such stationary lighting accessories outside of the photography studio. For shoots which require the photographer to be mobile, outside of the photography studio. For shoots which require the photographer to be mobile, especially shoots where the photographer must capture action shots or cannot otherwise pose his subject, a small portable diffuser may be used which attaches directly to the camera itself. Such a light diffuser may be placed directly over an on-camera flash to provide a semi-transparent barrier to clear light transmission. Known diffusers exist which are small and portable with the camera and flash itself, and these diffusers are used by photographers in shoots where it is impractical to employ fixed lighting equipment. However, known portable diffusers for use with on-camera flashes are less than ideal in terms of the quality of lighting produced. These diffusers tend to create hotspots and may also leave noticeable, undesirable shadows. 
     SUMMARY OF THE INVENTION 
     In an exemplary embodiment, a photographic light diffuser is provided made from a translucent thermoplastic such as polypropylene or vinyl. In a further embodiment, the photographic light diffuser is made from flexible polyvinylchloride. The photographic light diffuser may be mounted directly to the head of an on-camera flash unit. The diffuser has a tapered cylindrical body which produces a soft, highly diffused and flattering light quality. The diffuser also includes a rectangular base with a flat surface to add an amount of specular or focused light. Because of the tapered cylindrical shape of the body of the diffuser, regardless of whether shots are taken in the vertical or horizontal position or under high or low ceilings the diffuser produces the same soft, flattering light quality. The present diffuser allows a photographer to achieve studio-quality lighting and greatly minimize shadows while providing a desirable light balance. In an alternative embodiment, the diffuser is provided with a removable dome which helps to diffuse light even further, especially in environments with low ceilings. Because the dome is removable, it allows one to easily shoot “flash direct” without needing to first remove the cowl that comprises the base of the diffuser. 
     In another exemplary embodiment, a photographic light diffuser comprises a semi-transparent cowl which is adapted to be mounted on a photographic light source, the cowl including an opening through which the photographic light source is visible when the cowl is mounted thereon, and a removable semi-transparent cover detachably mounted on the cowl. 
     In an alternative embodiment, a photographic light diffuser which is adapted to be mounted on a photographic light source comprises a base of a shape adapted to be mounted on a light source, a body extending from the base having both a generally convex outer surface as well as a smaller flat portion, and a cover connected to the body. 
     In yet another embodiment, a camera flash system comprises a camera flash unit, and a diffuser unit having an adaptor and a tapered cylindrical body. The adaptor is formed to match the shape of the housing of the camera flash unit so that it may be fitted thereto, and the adaptor extends between the camera flash unit and the tapered cylindrical body of the diffuser unit. The diffuser unit widens from the adaptor to meet the tapered cylindrical body. 
     In an exemplary embodiment, a photographic light diffusing device includes an at least partially transparent cowl adapted to be mounted on a photographic light source. The cowl includes a plurality of ribs and an opening through which the photographic light source is visible when the cowl is mounted on the photographic light source. The photographic light diffusing device can include a cover, where the cover at least partially fills the opening. The cover may be dome shaped and removable, and may extend outwardly or inwardly from the cowl. The cowl may be tinted and made from a flexible transparent material, and may include a flexible base adapted to fit on a plurality of different photographic light sources. The flexible base of the cowl may include a plurality of contact arms adapted to grip the photographic light source. 
     In another embodiment, the photographic light diffusing device includes an at least partially transparent cowl adapted to be mounted to a photographic light source. The cowl includes a base including a socket adapted to be mounted to the photographic light source. A tapered body with an opening opposite the base through which the photographic light source is directly visible when the base is mounted to the photographic light source. The tapered body further includes a convex portion through which light from the photographic light source is diffused. The photographic light diffusing device may include a cover adapted to fit over the opening. The cover may be removable and of a dome shape. The dome shape may extend outwardly or inwardly from the cowl. The tapered body of the cowl may be generally cylindrical. The cowl may be formed of a flexible transparent material and may include a plurality of ribs. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  shows a front view of a photographic light diffuser according to one embodiment of the present invention; 
         FIG. 2  shows a bottom view of the photographic light diffuser of  FIG. 1 ; 
         FIG. 3  shows a bottom view of an alternative embodiment of a photographic light diffuser; 
         FIG. 4  shows a side view in section of the photographic light diffuser of  FIG. 3 ; 
         FIG. 5  shows a top view of the photographic light diffuser of  FIG. 1 ; 
         FIG. 6  shows a cross section of a photographic light diffuser according to one embodiment of the present invention; 
         FIG. 7  shows a perspective view of the photographic light diffuser of  FIG. 1 ; 
         FIG. 8  shows a perspective view of a diffuser in use atop a flash head; and 
         FIG. 9  shows a perspective view of an alternative embodiment of the photographic light diffuser. 
     
    
    
     Before any embodiment of the invention is explained in detail, it is to be understood that the invention is not limited in its application to the details of construction and arrangements of components set forth in the following description, or illustrated in the drawings. The invention is capable of alternative embodiments and of being practiced or being carried out in various ways. Also, it is to be understood that the terminology used herein is for the purpose of illustrative description and should not be regarded as limiting. 
     DETAILED DESCRIPTION 
     The present photographic flash diffuser provides high quality lighting effects when used with on-camera flashes, allowing photographers to achieve studio-quality lighting using electronic on-camera flashes without the need for separate lighting equipment. By doing so, the present diffuser does away with needing to carry around and use cumbersome lighting equipment such as brackets, umbrellas, soft boxes and the like, allowing for truly mobile, spontaneous photography. 
       FIG. 1  shows a front view of a photographic light diffuser  120  according to one embodiment of the present invention. This diffuser  120  may in one exemplary embodiment be formed from plastics using a vacuum molding process. It may also be made from other molding and non-molding plastic forming processes, as well as being formed from other appropriate semi-transparent or translucent materials as will be understood by one skilled in the art. The mold surface may be roughened to provide the diffuser  120  with a semi-transparent or translucent finish. This roughened surface may be created by treating the mold with a sand or bead blasting process. In one embodiment, the diffuser  120  may be formed having two separable parts. However, in an alternative embodiment, the diffuser  120  may be formed as a single piece having roughly the same overall shape as the embodiments shown. 
     As shown in the embodiment of  FIG. 1 , the diffuser  120  is provided having two component parts; a cowl  130  and a removable dome  160 . The cowl  130  is provided with a generally rectangular base  140  allowing it to attach directly to the head of an on-camera flash unit. In one embodiment, the generally rectangular base  140  may be friction fitted to the head of the on-camera flash unit. In alternative embodiments, the generally rectangular base  140  of the diffuser  120  may be mounted on the flash unit using a bracket permanently or removably attached to the flash unit, or it may be mounted using a threaded collar, a bayonet style mount, using Velcro, or by other appropriate methods known to those skilled in the art. 
       FIG. 2  shows a bottom view of the photographic light diffuser  120  of  FIG. 1 .  FIG. 2  illustrates that the generally rectangular base  140  of the present diffuser  120  may be provided with a basal socket  170  of specific interior dimensions in order to match the exterior dimensions of standard camera flashes. This particular embodiment of a basal socket is designed to be friction fit to a Nikon SB-800 Speedlight flash unit. Other basal sockets may be configured for a friction fit with other models of camera flash units. 
     In yet another embodiment,  FIGS. 3 and 4  show a photographic light diffuser with a generally rectangular base  240  that differs in size from the generally rectangular base  140  of the diffuser  120  shown in  FIG. 2 . In this embodiment, the basal socket  270  of the diffuser  220  is of a predetermined size to accept any one of a number of different adaptors  290 , and it is the adaptor  290 , rather than the basal socket  270 , which sized to fit the exterior dimensions of the desired camera flash. The adaptor  290  may be a gasket-style adapter made from a flexible material to fit various flash units from different manufacturers, or it may be made from a stiffer material and designed to fit a single flash unit. The use of a diffuser with a “universal-mount” base of this embodiment permits a single diffuser to be used with various different flash units of widely different shapes by use of different adaptors. 
     Returning to the diffuser  120  of  FIG. 2 , in an exemplary embodiment the base  140  extends past a minimum length of about one half inch to permit the base to fit over a flash unit, as well as to provide a generally rectangular base  140  between the flash unit itself and the body of cowl  130  of the diffuser  120  through which light from the flash travels. This relatively small generally rectangular base  140  adds an amount of direct or specular lighting to the flash effect created by the diffuser  120 . This effect is caused by the close proximity of the walls of the diffuser  120  in the area of the generally rectangular base  140  to the flash itself, causing light to be refracted through this area of the diffuser  120  with a greater intensity than through the tapered cylindrical body  150  of the diffuser  120 . 
     Accordingly, the lighting properties of the diffuser  120  can be varied by varying the relative proportions of the diffuser  120 , specifically the length and breadth of the passage through the generally rectangular base  140  with respect to the size of the tapered cylindrical body  150  of the diffuser  120 . A shorter passage and a larger tapered cylindrical body would cause the diffuser  120  to provide less of a direct and more of a diffused lighting effect. Conversely, a relatively longer passage and smaller tapered cylindrical body would affect the balance of the lighting effect created by the diffuser  120  in the opposite manner. 
     While the purpose the of the diffuser  120  is to ameliorate the harsh effects of direct lighting, some amount of direct light, or “key light” is desirable to provide an amount of specularity in an exposed image. The higher intensity gives a catchlight to the eyes of photographic subjects and prevents the image from appearing too soft. The compound geometry in the present diffuser  120  is designed to strike a balance between an image that is too harsh and one that is too soft. 
     As shown in  FIG. 1 , the rectangular base of the diffuser  120  melds seamlessly into the tapered cylindrical body  150 , which helps to reduce hot spots and smoothly transitions the light distribution of the diffuser  120  from the more direct light of the rectangular base to the more diffuse light provided by the tapered cylindrical body  150 . The side view of the diffuser  120  of  FIG. 1  also shows a cowl  130  of which the tapered cylindrical body  150  is a part, as is the generally rectangular base  140 . To this cowl  130  is connected the removable dome  160 . In contrast,  FIG. 5  shows a top view of a photographic light diffuser  120  having a dome  160 . Finally,  FIG. 7  shows a perspective view of a photographic light diffuser  120  according to one embodiment of the present invention having a cowl  130  comprising a generally rectangular base  140  and a tapered cylindrical body  150 , and a dome  160  attached thereto. 
     Returning now to  FIG. 1 , an exemplary embodiment of the present diffuser  120  is shown wherein the tapered cylindrical body  150  is radially symmetric with respect to an axis extending along the direction of the flash unit on which the diffuser  120  is mounted. In this embodiment, the tapered cylindrical body  150  of the diffuser  120  is slightly tapered, flaring out as it extends away from the rectangular base. This tapered shape, while not required, helps to further reduce the hot spots which would otherwise occur as the light energy from the flash strikes the nearer parts of the tapered cylindrical body  150  with greater intensity than the farther, reducing the diffuse effect otherwise created by the tapered cylindrical body  150 . While some direct lighting effect is desired as discussed above, it can be provided more evenly and reliably by the generally rectangular base  140 , and as such it is desirable in the embodiment shown to emphasize the diffuse lighting function of the tapered cylindrical body  150  at the expense of the direct lighting function by providing this taper. With the present diffuser  120 , the softness of the lighting effect produced comes as much if not more so from the shape of the diffuser  120  itself and especially the manner in which light is evenly refracted through the surface of the tapered cylindrical body  150  as from the dispersal of light around the room, including light reflected by the walls and ceilings. 
     In one embodiment, the tapered cylindrical body  150  of the diffuser  120  allows it to provide similar lighting effects when used in either the vertical or horizontal positions, regardless of its orientation. Accordingly, unlike prior art diffusers, no flash bracket is needed with the present diffuser  120  to keep the flash in an upright position during both vertical and horizontal photography. In alternative embodiments, the tapered cylindrical body  150  of the diffuser  120  may form an ellipse in cross section, or one of a set of n-sided polygons. In still other embodiments, the tapered cylindrical body  150  may be longer or shorter than is shown in the figures, or may be of a cylindrical or other shape such as a non-tapered shape. In one embodiment, the height and width of the diffuser are about equal to one another. In another embodiment, the diffuser is generally spherical in shape. In yet another embodiment, the diffuser is proportioned so that it is easy to pack and transport in that it may be placed over the camera&#39;s lens when packed together with a camera in a standard camera/gadget bags, thus saving space. For example, the cowl  130  of the diffuser  120  may be placed directly over the lens of the camera, and the dome  160  may be placed in turn over the generally rectangular base  140  of the diffuser  120 . In this way, the parts of the diffuser nest within each other in a compact arrangement. 
     In an exemplary embodiment, the present diffuser  120  is convertible for use with both low and high ceilings. To this end,  FIG. 1  additionally shows the diffuser  120  provided with dome  160  which may be removably attached to the cowl  130  so that the diffuser  120  can be used to provide a more diffuse lighting effect with the dome  160  in place while easily converting for direct flash lighting by removing the dome  160 . 
     When shooting with the diffuser in a vertical position in environments with high ceilings, the cowl  130  may be employed without the dome  160 . In one embodiment, the cowl  130  is provided with an open top which lets light energy from the flash shine upwards to reflect off the ceiling in the absence of the dome  160 . Due to the shape and orientation of the cowl  130 , enough light strikes the sides of the tapered cylindrical body  150  of the cowl  130  to cast some amount of light forward onto the subject even without employing the removable dome  160 . This gives a great lighting ratio for shots taken with the diffuser in the vertical position, reducing-shadows on the subject and giving a diffuse, soft light all around the room as well as on the subject. For large group shots, the lighting quality is soft, beautiful and diffuse. The open top allows a great deal of light to bounce off the ceiling onto the subject yielding a beautiful, natural lighting effect. 
     The dome  160  is provided for indoor environments with low ceilings where reflected light from the ceiling would cast harsh shadows on the subject. In one embodiment, the dome  160  acts as a diffusion device to spread light evenly all around the room, lighting the subject as well as brightening dark backgrounds and ceilings. The dome  160  may snap directly onto the cowl  130  of the diffuser  120  to accomplish this diffusion. Specifically,  FIG. 6  shows a cross section of a photographic light diffuser detailing one embodiment of a snap-on system for connecting the dome  160  to the tapered cylindrical body  150 , wherein the former is provided with a recess which fits over a snap ridge  185  on the latter. Furthermore, the present combination of cowl  130  and dome  160  loses less power than other diffusers, making it more efficient. With the employment of the dome  160  with the diffuser  120  for use with low ceilings, studio-quality lighting using a flash can be achieved with a portable photography platform. 
     Additionally, when it is desirable to directly light a subject, it is not necessary to remove the entire diffuser  120  from the flash unit of the camera. The dome  160  only may be removed, and the flash pointed directly at the subject through the open top of the cowl  130  which remains attached to easily and directly illuminate the subject with no power loss. 
     On occasion, photographers will want the reflected light in their shots to have a particular color quality. This can be provided with alternative embodiments of the present diffuser wherein the material of the entire diffuser itself, or specific portions of the diffuser such as the cowl or the base are formed having a particular hue. For example, the dome  160  can be made amber for inside shots to provide warmer skin tones and for overall warming in flash filled available light shots, and green for shots where there is a good deal of florescent lighting. 
       FIG. 8  shows a perspective view of a diffuser  120  in use atop a flash unit  610 . In the embodiment shown, the diffuser  120  is employed without the removable dome shown in the previous figures. The generally rectangular base  140  of the diffuser  120  is socketed over the head of the flash unit  610  so that the light emitted by the flash may be diffused by the components of the cowl  130  of the diffuser  120 , specifically the generally rectangular base  140  and the tapered cylindrical body  150 . 
       FIG. 9  shows a perspective view of an alternative embodiment of a diffuser  300  in use atop a flash unit  610 . A cowl  301  of the diffuser  300  includes a neck portion  302  and a body portion  304 . The diffuser  300  can be formed from any suitable material. For example, the diffuser can be formed of a vinyl material which is capable of stretching. The vinyl used to form the diffuser  300  can be clear and bead blasted, which allows for greater dispersion of light through the diffuser. In this embodiment, a variety of flash units having different shapes can be inserted into the cowl  301  without the need to use the adaptor  290  (see  FIG. 3 ). The neck portion  302  of the cowl  301  stretches to fit many flash units of various manufacturers, which are placed into the cowl  300  as described above. Contact arms  306  may extend along the basal socket  170  (see  FIG. 2 ) from the bottom of the cowl  301  along the inside thereof. The contact arms  306  grip the flash unit  610  to ensure that the diffuser  300  does not fall off the flash unit during camera operation. 
     Ribs  308  extend along an inside surface in the body portion  304  of the cowl  301 . The ribs can extend substantially parallel to the flash unit  610 , or, they can extend around the circumference of the body portion  304  of the cowl  301 . The ribs  308  can also extend on an outer surface of the cowl  301 . The ribs  308  allow light to be more effectively diffused as it passes through the cowl  301  and into the area in which a photograph is being taken. 
     The cowl  301  can be operated by itself or in conjunction with a dome cover  310  which may optionally include ribs  312 . When the cowl  301  is used by itself, the light from the flash unit  610  escapes from the top without being diffused, throwing a concentration of direct light upward into the surrounding area. In an enclosed space, the direct light can lighten the room in colliding with the ceiling, without casting the harsh light of the flash directly onto the subject. An upper portion of the body portion of the cowl  301  can be trimmed around a circumference of the cowl  301  as desired to allow a greater amount of light to escape from the top without being diffused. 
     Where the room is sufficiently lighted such that the direct light is not needed, the dome cover  310  can be used in an upright or an inverted position to avoid the effects of direct flash lighting. The inverted dome  310  can be snapped into the cowl  301 , or can be formed integrally with the cowl  301 . 
     As in previous embodiments discussed herein, the diffuser  300  can be tinted with amber or another color to vary the color and intensity of the light on the subjects of the photograph. Due to its flexible nature, the diffuser  300  can be easily stored and transported in a camera bag. A photographer carrying many different diffusers can stack them for ease in storage and transport.