Digital Camera Patent Abstract
A kit for modifying a digital camera of the type including a built
in flash, to perform close-up photography includes a mounting plate
attached to a camera around a camera lens, a lens plate having a
secondary lens selectively attachable to the mounting plate so that
light entering the camera lens is first magnified by the secondary
lens. A bracket assembly is selectively attachable to each lens
plate to indicate the location of the focal plane and the size of
the image frame. A flash attachment adapted for close-up photography
includes a flash output window, a power switch, a mode switch and
a flash intensity switch. The flash attachment is secured to the
camera and wired thereto so that the mode switch may control which
flash unit, the flash of the camera or the close-up flash, activates.
The flash intensity switch is a rheostat and controls the amount
of light emanating from the flash source to the subject, according
to the distance between the camera and the subject. Digital Camera Patent Claims
What is claimed is:
1. An attachment for a digital camera of the type including an
integral primary flash unit and a primary lens that are adapted
to photograph subjects beyond a minimum predetermined distance from
the camera, said attachment allowing the camera to photograph subjects
located a distance that is shorter than said predetermined distance,
said attachment comprising:
a flash assembly including a secondary flash unit, a mode switch
and an intensity control, said secondary flash unit being adapted
to properly expose subjects located at a distance from said camera
which is less than said minimum predetermined distance, said mode
switch selectively activating either said secondary flash unit or
said primary flash unit during exposure;
means for attaching said flash assembly to said camera; and
a supplemental lens selectively attachable to said camera in front
of said primary lens for changing the effective magnification of
said primary lens and thereby allowing the camera to photograph
subjects located closer than said minimum predetermined distance.
Digital Camera Patent Description
This application is based on Applicants' provisional patent application,
Ser. No. 60/002,386, filed Aug. 17, 1995.
BACKGROUND OF THE INVENTION
This invention relates generally to attachments for cameras and
more particularly to such attachments for facilitating close range
photography with digital cameras.
Digital cameras that are currently available produce an electronic
digitized signal representative of image data when taking a "photograph"
of a subject. This signal is initially electronically stored in
the camera and can be later reproduced in a computer or video recorder
as a visual display of the subject. However, such cameras are generally
lacking in the ability to accomplish close range photography, such
as where the subject to be photographed is between two and eighteen
inches from the camera, as is often needed in various medical, dental,
journalistic and law enforcement applications, or scientific or
amateur photography of plants, insects, flowers, or the like. Photography
in this range of focus is generally referred to close-up photography.
Close-up photography presents problems which are not common to
standard photography. For example, positioning of the subject and
selection of the proper lens focal distance are necessarily more
exacting and require greater care in close-up photography than in
ordinary photographic applications. Attempts to solve such problems
in optical photography are the object of certain prior art patents
such as U.S. Pat. No. 3,687,030 issued Aug. 29, 1972, No. 3,836,927
issued Sep. 17, 1974, No. 4,755,838 issued Jul. 5, 1988 and Des.
283,820 and 283,821 issued May 13, 1986, as well as the prior art
references cited in those patents.
Another problem associated with close-up photography relates to
the source of light used to achieve proper exposure, e.g., an electronic
flash. For standard photography, where a focal length of a typical
lens allows focussing of subjects that are at least four feet or
more away from the camera, the location of a flash source is not
critical. A commonly used built-in electronic flash source is frequently
spaced away from the lens axis by a distance which is immaterial
for the more distant subjects, but which would prevent proper illumination
of close-up subjects (i.e., subjects that are from about two inches
to about eighteen inches from the lens). Also, as the distance between
the camera lens and the subject is varied, the intensity of the
light from the built-in camera flash projected onto the subject
correspondingly varies, so that light incident on a subject which
is, for example, at a distance such as eighteen inches from the
camera lens will be substantially less than if the same subject
was positioned at a two inch distance from the camera and illuminated
by the same amount of light from the flash source. Without control
of the flash output, the increase in intensity of light from a flash
at close range will invariably result in overexposed or otherwise
improperly exposed pictures of the subject. In such instance, the
subject will appear washed out in the reflected light of the flash
and image detail of the subject will be lost.
According to the present invention, an improved camera attachment
or kit for modification of an existing digital camera is provided
for assuring proper illumination of a subject photographed at various
close ranges, for use with digital camera equipment having a flash-type
light source.
Another object of the invention is to provide a new and improved
camera attachment or modification for digital cameras to control
the illumination of the subject by flash light at various close-range
distances from the camera lens.
Another object of the present invention is to provide a new and
improved camera attachment and modification to facilitate proper
focusing and framing of close-range subjects, while providing proper
illumination by flash exposure.
Another object of the present invention is to provide a new and
improved camera attachment for digital cameras that enable such
cameras to perform close-up photography and which may be easily
detached to allow the camera to perform standard non-close-up photography.
SUMMARY OF THE INVENTION
A kit for modifying a digital camera of the type including a built-in
flash, to perform close-up photography, includes a mounting plate
attached to a camera around a camera lens, and a lens plate having
a secondary lens selectively attachable to the mounting plate so
that light entering the camera lens is first magnified by the secondary
lens. A bracket assembly is selectively attachable to each lens
plate to indicate the location of the focal plane and the size of
the image frame. A flash attachment adapted for close-up photography
includes a flash output window, a power switch, a mode switch and
a flash intensity switch. The flash attachment is secured to the
camera and wired thereto so that the mode switch may control which
of two available flash units, the flash of the camera or the close-up
flash, activates. The flash intensity switch is a rheostat and controls
the amount of light emanating from the flash source to the subject,
according to the distance between the camera and the subject.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete appreciation of the invention and of the advantages
thereof will be obtained by reference to the following detailed
description considered in connection with the accompanying drawings.
FIGS. 1A and 1B are schematic perspective front and rear diagrams
of a conventional digital camera;
FIG. 2 shows a front elevation view of a digital camera modified
according to the invention, and lens/frame attachments used with
the camera;
FIGS. 3A and 3B are perspective and side views of the supplemental
lens and framing device used in the present invention;
FIG. 4 shows a partial enlarged front view of the camera of FIG.
2 without the lens/frame attachment;
FIG. 5 shows a bottom view of the camera of FIG. 2 including a
lens/frame attachment secured thereto;
FIG. 6 shows a top plan view of the camera shown in FIG. 5;
FIG. 7 is a diagrammatic perspective view of the front of the camera
of the invention; and
FIG. 8 is a partial sectional side view of the lens frame attachment,
according to another embodiment of the invention.
DESCRIPTION OF A PREFERRED EMBODIMENT
FIGS. 1A and 1B show diagrammatically front and rear perspective
views of a representative digital camera 10, such as that commercially
sold by Eastman Kodak Company under the designation Kodak Digital
Camera 40. This camera 10 includes a lens 12, a view finder 14,
light sensors 16, a flash window 18 and a timer light 20 on a front
surface 22 of a camera housing 24, to which is attached a hand strap
26. A battery compartment 28 (shown covered) holds a battery (not
shown) serving as a power supply for the camera. An adapter connection
30 (shown covered) is provided for receiving an adapter to supply
the necessary electrical power to operate camera 10 and to charge
a rechargeable battery in battery compartment 28. A serial port
connector 32 (shown covered) is also provided on the side of camera
housing 24 to which may be electrically connected a cable (not shown)
leading and also electronically connected to electronic apparatus
(such as a video recorder or monitor) for transmitting the digital
image signal produced and stored within camera 10 to such apparatus.
An "off/on" switch 34 is provided to control the power
supplied to the electronic circuits (not shown) from battery 28.
Switch 34 also mechanically or electro-mechanically positions a
lens cover (not shown) over lens 1 2 when switch 34 is moved to
an "off" position. A shutter button 36 is provided to
actuate camera 10 to record a digitized signal of light entering
lens 12 representing the reflected light from a subject being viewed
through viewfinder 14.
Along a rear surface 38 of camera 10, as shown in FIG. 1B, is a
view-finder eye piece 40 and a display 42 used to show the image
being viewed. A feature button 44 and a select button 46 are used
to determine and select any one of the various modes of operation
of the camera.
As mentioned above, lens 12 may for example have a fixed focus
of four feet or more. It is generally not suitable for close-up
photography because such a lens is designed for a minimum distance
of about four feet before the subject "enters" the depth
of field or window of focus of the lens. Furthermore, flash 18 in
such a camera 10 is designed to concentrate its projected light
at a point located a relatively long distance from camera 10, (e.g.,
at least four feet) and is not able (without modification) to project
its light to any subject located at a close range from camera 10.
The present invention supplies certain additional and replacement
parts to adapt digital camera 10 for use with close-up subjects.
These parts may be in the form of a kit for attachment of the camera
or may be built into the camera.
Referring to FIGS. 2-7, according to the invention, camera 10 is
provided with a separate flash attachment 48 having a casing 50,
a flash output window 52, a power switch 54, a mode switch 56, and
a control knob 58. Flash attachment 48 may either include its own
power supply, such as an internal battery (not shown) or include
appropriate power supply wiring which is connected to the proper
power circuitry of camera 10, as is understood by those in the art.
In the former instance, the flash attachment 48 may simply be secured
to housing 24 of camera 10 in an appropriate location and using
an appropriate fastener, such as Velcro, a screw fastener, or an
appropriate pressure sensitive tape or adhesive. In the latter instance,
flash attachment 48 is electrically connected to the circuitry of
camera 10 so that power switch 54 may replace on/off switch 34 (FIG.
1A) and control the power supplied to camera 10. Regardless how
the power to flash attachment 48 is supplied, such power is controlled
by power switch 54 in a manner well known in the art.
The specific intensity of the flash, i.e., the light emitted from
flash output window 52 is controlled in a known manner using a rheostat
which is adjusted by turning knob 58. The setting of the flash intensity
may be indicated by a graduated dial 60. Mode switch 56 is used
to control the operation of flash attachment 48 for use with either
close-up subjects, distant subjects (i.e., standard photography)
or both. If flash attachment is electrically isolated from the circuitry
of camera 10, mode switch 56 may mechanically or optically redirect
the flash output to project its light from window 52 and concentrate
the light at a predetermined distance, either close-up or farther
away from camera 10. This type of isolated flash may include circuitry
and sensors for instantly detecting the light from another local
flash unit, such as flash 18 of camera 10 to determine that shutter
button 36 had been depressed and thereby activate its own "close-up"
flash 52.
If flash attachment 48 is wired into the circuitry of camera 10
as a modification, mode switch 56 controls the operations of both
the originally supplied flash 18 (see FIG. 1 A) and the flash output
of flash attachment 48. In this instance, mode switch 56 in a first
position activates the flash of flash attachment 48 when close-up
photography is to be performed, and in a second position activates
flash 18 for subjects located a distance outside a predetermined
close-up range (e.g., about two to about eighteen inches) such as
in the case of standard photography. Another position may be provided
for mode switch 56 to activate both flashes simultaneously to increase
total flash light reaching the subject regardless of its location
with respect to the camera.
Referring to FIGS. 2-6, a bracket assembly 62, according to the
invention, is shown, including a secondary lens 64, a lens plate
66, spacer bar 68, and a frame indicator 70. Frame indicator 70
is secured to one end of spacer bar 68 using any appropriate permanent
or removable fastener 69 including a spot weld, an adhesive, rivets,
bolts, screws, Velcro, or a friction-fit connection. Frame indicator
70 is a U-shaped bracket which defines the location of the focal
plane of secondary lens 64. This focal plane lies parallel to lens
64 and perpendicular to spacer bar 68. The purpose of frame indicator
70 is to provide a physical representation of the actual size of
the image frame as "seen" by lens 64 of camera 10. The
size and shape of frame indicator 70 will vary depending on the
power and type of lens 64 used. If a particular secondary lens 64
has a depth of field equal to 1/4 inch which includes a focal plane
located 2 inches from camera 10, then spacer bar 68 will be 2 inches
long so that frame indicator 70 lies just at the focal plane, within
the 1/4 inch depth of field. Three different sizes of frame indicators
70 are shown in FIG. 2, each having a secondary lens 64 of varying
power and therefore each having different focal lengths, perhaps
values from two to eighteen inches.
The remaining end of spacer bar 68 (opposite frame indicator 70)
is attached to lens plate 66 using any appropriate fastener 67 including
the above-listed fasteners, or any other appropriate connector not
listed. In a preferred embodiment, lens 64 of a predetermined power
is secured to lens plate 66, across a central aperture 72 formed
within lens plate 66. Lens 64 may be secured to lens plate 66 using
known techniques for securing lenses to lens holders, such as using
a threaded ring 73. Each lens 64 of a specific power is dedicated
to a lens plate 66. Similarly, each frame indicator 70 is preferably
permanently secured to a spacer bar 68 of predetermined length.
The length of spacer bar 68 is dependent on the magnification power
of the particular lens 64 in use. As shown in FIG. 8, the free end
of spacer bar 68 is preferably removably attachable to lens plate
66 using an alignment block 86 which includes a slot 88 sized and
shaped for snugly receiving a stem portion 90 of spacer bar 68.
Alignment block 86 further includes a threaded bore 92 into which
a thumb screw 94 engages. Bore 92 is positioned orthogonally to
and in overlapping relationship with slot 88 so that tightening
screw 94 frictionally engages clamps stem portion 90 (and therefore
spacer bar 68 and frame indicator 70) within slot 88at a predetermined
orientation with respect to lens plate 66.
To ensure that each frame indicator 70 and spacer bar 68 matches
its proper lens 64, according to one embodiment, a color code is
used wherein a color indicator of a spacer bar 68 must match a color
indicator located on a lens plate 66 before attaching the two elements
together. In another embodiment (not shown) a spacer bar 68 is "keyed"
to fit only a single lens plate 66 holding a single lens 64 of a
predetermined power. The "keying" fastener may include
a recess of a particular shape which only matches spacer bars 68
having a similar crosssection shape.
Referring to FIGS. 4, 5 and 6, lens plate 66 is secured to camera
10 using a mounting plate 74 which is includes a central aperture
76 which is aligned with aperture 72 of lens plate 66. Along a perimeter
of mounting plate 74 is at least two threaded openings 78 adapted
to align with two openings 79 located along the perimeter of lens
plate 66. Thumb screws 80 may pass through openings 79 and engage
with threaded openings 78 for holding lens plate 66 flush against
mounting plate 74. Another two openings 82 may be provided on mounting
plate 74 for receiving fasteners for securing mounting plate 74
to front surface 22 of camera housing 24. In another embodiment,
mounting plate 74 includes a rearwardly directed flange (not shown)
along the perimeter of central aperture 76 and having external threads
which are adapted to engage internal threads located within a lens
tube used to hold lens 12 to camera 10, as is known by those skilled
in the art. In yet another embodiment, mounting plate 74 may be
formed integrally with front surface 22, wherein threaded openings
78 are provided directly into front surface 22.
In another embodiment, as shown in FIG. 2, a length of chain 84
having one end attached to lens plate 66 and being a predetermined
length (perhaps between two and eighteen inches) equal to the distance
between the focal plane (of the combined lenses 12 and 64) and lens
64 so that the operator of camera 10 may simply hold the free end
of chain 84 against the subject and position camera 10 accordingly,
(i.e., until chain 84 is taut) to be assured that the subject is
positioned within the focal plane.
In operation, a lens 64 is chosen according to desired magnification
and image size of the subject to be photographed. Lens plate 66
having the chosen lens 64 is positioned flush against mounting plate
74 and thumb screws 80 are inserted through openings 79 of lens
plate 66 and threaded into threaded openings 78 of mounting plate
74 until lens mount 66 is held flush to mounting plate 74.
Once secured, depending on the type of lens plate 66 selected,
an appropriate frame indicator 70 (if not already attached to lens
plate 66) may be secured to lens plate 66 using fastener 69. The
above described lens mount 66 which includes a length of chain 84
to determine the location of the focal plane does not receive a
frame indicator.
To ensure proper exposure to a recorded image, power switch 54
is switched to the "on" position and mode switch 58 is
switched so that only the "close-up" flash 52 from flash
attachment 48 will activate during exposure. Finally, rheostat knob
58 is rotated until a prescribed value of flash output intensity
is selected, according to lens 64. Such flash intensity values would
be predetermined and provided to the operator in a booklet or as
a value stamped on camera 10 or lens plate 66.
Once the flash is ready, the operator moves camera 10 close to
the subject so that the subject is positioned within frame indicator
70 and located a distance equal to or just greater than the length
of spacer bar 68. This ensures that the subject is positioned within
the depth of field and will be recorded in focus.
Shutter button 36 is depressed and only flash from flash attachment
48 activates and the subject is recorded by camera 10 with proper
focus and exposure. The resulting digital photograph is electronically
stored in the digital camera, until it is transmitted by coupling
the camera output port to the desired peripheral device to show
or electronically process the image.
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