Patent Application
20090041450
This invention relates to a device and method for illuminating color slide images that are to be photographed for duplication. In particular, this invention represents an improvement over the device and method shown in my earlier U.S. Pat. No. 6,711,347, the disclosure of which is incorporated herein by reference.
One way to duplicate a slide is to project it on a screen and photograph the projected image, a technique that requires extra equipment and space. There are numerous attachments for digital cameras that hold a slide to be duplicated, but none include any source of light.
My earlier invention provides a tabletop workstation system that firmly mounts a camera to focus on a diffuse light-transmissive aperture, the size of a 35-mm. slide, in one panel of a multi-panel ight diffuser chamber having an open top and one open side. Sunlight open side so that diffuse reflection illuminates a slide positioned over the aperture. In order to block extraneous light that interferes with an operator's viewing, it is usually necessary to provide hood or shroud around the viewing area. The chamber is mounted on a slotted rack that is adaptable by means of shims and mounting bolts to accommodate different camera parameters, viz., lens axis height above camera base, minimum macro focus distance, and camera mounting distance from lens axis. Although this device is highly functional, the requirement of a shroud and adjustment of the various components using an assortment of shims is somewhat inconvenient.
The present invention provides an improved slide copier system that provides all the advantages of my earlier invention but is simpler, easier to use and more convenient to adjust.
As in my previous invention, light is directed into a light diffuser chamber so as to illuminate a slide positioned over an aperture in the front wall of the chamber. A camera (preferably a digital camera) is then positioned on a support platform, along which it can be moved so that its lens is aimed directly at the aperture.
The present invention incorporates as an improvement, connecting the support platform to a rail and mounting the diffuser chamber on the bifurcate horizontally positioned leg of an angle iron bracket. The vertically positioned bifurcate leg of the angle iron bracket is connected to the rail so that it is adjustably and continuously positionable in three dimensions (toward or away from the camera, up and down, and right and left).
As a further improvement over my previous invention, the diffuser chamber is laterally closed, and a quartz halogen lamp is positioned in the open top, thereby providing a higher degree of illumination while eliminating the use of a hood to block spillover light from the work area.
More specifically, the present invention may be defined as a device for copying colored photographic transparencies, comprising a camera support platform having a laterally extending apertured configuration for mounting a camera at a desired location. Legs elevate the platform with respect to the remainder of the device. A rail, connected to the support platform and extending at a right angle thereto, is provided with an apertured configuration along its length to permit attachment of a bracket at different locations. An angle iron bracket having bifurcate legs is positioned with one leg in a generally vertical position at right angles to the rail and connected thereto, with the other generally horizontal leg extending away from the rail. A light diffuser chamber is mounted on the horizontal leg of the bracket. This chamber has a diffuse white base from which extend a plurality of diffuse panels connected to each other. One of the panels is taller than the others and has an aperture confronting a camera positioned on the support platform. A halogen lamp is mounted in the open top of the light diffuser chamber. The light diffuser chamber may thus conveniently be moved vertically, horizontally, and toward or away from the camera support platform.
In the currently preferred embodiment of the invention, the diffuser chamber is laterally closed and symmetrical with respect to the panel having the aperture. Light is provided by a halogen bulb positioned at the top of the chamber and directed downward and away from the aperture in the front panel, so that any image of the bulb filament does not strike the aperture without prior diffuse reflection. the bulb occupies a substantial part of the open top of the chamber, the amount of light that escapes is minimized, and the fact that the aperture-containing panel is taller than the other panels still further shields the operator from annoying light spillover. This arrangement is thus more energy efficient and provides higher illumination of the slide aperture than was the case in my prior invention. This permits the recording camera to operate at a higher F stop and greater depth of field, a preference of most photographers.
Understanding of the invention will be facilitated by referring to the accompanying drawings, in which like numbers refer to like parts in the several views, and in which:
Diffuser chamber 20 comprises base 21, which supports panels 22a, 22b, and 22c, thereby defining a laterally closed open-top unit with aperture 23 in panel 22a. On the outer side of panel, 22a is transparency-supporting shelf 24. Halogen lamp 26, mounted on lamp support 27, is positioned at the open top of chamber 20 and tilted rearward, thereby insuring that no image of the lamp 26 filament will be imparted to a transparency positioned on shelf 24 without prior diffuse reflection. A 50-watt “Solux” 4700K quartz halogen lamp will enable exposures of 1/60 to 1/125 second for typical landscape scenes at f 6.6 for digital cameras set at ISO 80. As is shown in the drawings, panel 22a is taller than the remaining panels, substantially blocking any light flux into the camera-to-diffuser chamber area and obviating the need for a hood or shroud. The inner surfaces of light diffuser chamber 20 are provided with a flat white diffuse coating, thereby providing a uniform light source to illuminate aperture 23 and a transparency positioned on shelf 24. Louvers 25 in the lower parts of panels 22b and 22c, create a convection chimney that moves air upward and out of chamber 20 to reduce heat buildup.
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In connecting angle iron bracket 33 to rail 30, bolt 32 is inserted through slot 36 of vertical member 35 and then through slot 31 of rail 30, after which wing nut 32a is applied to hold bracket 33 in position. Bracket 33 is then moved vertically to align aperture 23 with the lens of camera 70 and horizontally along slot 31 to achieve the proper distance from the lens of camera 70, after which nut 32a is tightened to hold the alignment in fixed position.
In connecting bracket 33 to rail 50, bolt 32 is inserted through slot 36 of vertical member 35 and then through the hole 39 that will most closely approximate the desired distance between aperture 23 and the lens of camera 70. Precise positioning is then achieved by moving rail 50 along slotted holes 44 in camera support table 40 before locking bolts 43 in position. Bracket 33 is then moved vertically to align aperture 23 with the lens of camera 70. In order to prevent inadvertent pivoting of light diffuser chamber 20 around bolt 32, it is desirable to interpose alignment plate 52 between vertical member 35 and rail 50. Alignment plate 52 includes hole 55, through which bolt 32 passes, and positioning pins 54, which fit into laterally spaced holes 39 to hold plate 52 in fixed position. Positioning pins 54 comprise bolt 54a, surrounded by bushing 54b and fitted with nut 52c. Alignment pin 53, comprising bolt 53a, bushing 53b and nut 53c, extends from plate 52 and passes through slot 36 to stabilize bracket 33. Alignment plate 52 can, of course, be used in the embodiment of the invention shown in
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Although the camera used in practicing the invention can be either film type or digital, it is anticipated that the use of digital cameras will be more popular. Many film photographers have accumulated libraries of bulky carousels containing slides and would like to convert them to compact discs, for which digital cameras provide the logical storage means. When a digital camera is employed, it should be set in macro mode, so that it will automatically focus on the transparency being copied.
My previous invention assumed that sunlight provided the best source of light for illuminating slides to be copied. It has been found, however, that not only is the availability of sunlight unreliable but also that sunlight tends to impart a color that is bluer than normal. This phenomenon results from the fact that transparency film manufacturers have traditionally established color balance standards so that their film customers might shoot under perfect sunlit condition and then project their images on a screen using a lamp having a bluedeficient hot tungsten filament and achieve screen pictures that look as though they were in sunlight.
To copy a transparency using the device of this invention, the transparency is positioned on support shelf 24, lamp 26 is turned on, and, with camera 70 set at auto focus and automatic exposure, the shutter is released. A different transparency is then placed on support shelf 24 and the process repeated. It has been found that as many as 250 transparencies can be copied in an hour.
Numerous variations to the illustrative examples herein can be made without departing from the spirit of the invention. For example, where specific dimensions have been used for purposes of illustration, it is to be understood that the invention is not restricted thereby. Similarly, although the dimensions of aperture 23 have been indicated as corresponding to 35-mm. slides, larger or smaller apertures might be appropriate for other sizes of film. Likewise, although diffuser chamber 50 has been shown as having three sides, more sides could be incorporated, or panels 22b and 22c could be combined into a single curved panel if desired. Other modifications will readily occur to those skilled in the art. Accordingly, the invention is limited only by the scope of the appended claims.
