ZOOM FLASH WITH NO MOVING PARTS
A camera system having an electronic flash with a variable illumination angle, comprising: an image forming system having a user-selectable field-of-view for forming an image of a scene onto an image plane; an electronic flash system including a plurality of fixed focal length illumination lenses having two or more different focal lengths and one or more light emitters positioned behind each of the illumination lenses, the light emitters being positioned relative to their respective illumination lenses to provide two or more different illumination angles onto the scene; and a flash controller that selectively fires different subsets of the light emitters responsive to the selected field-of-view of the image forming system.
1 . A camera system having an electronic flash with a variable illumination angle, comprising:
an image forming system having a user-selectable field-of-view for forming an image of a scene onto an image plane;
an electronic flash system including:
a plurality of fixed focal length illumination lenses, each having an associated focal length, wherein at least two of the illumination lenses have focal lengths that are different from one another; and
one or more light emitters positioned behind each of the illumination lenses, the light emitters being positioned relative to their respective illumination lenses to provide two or more different illumination angles onto the scene, wherein an array of two or more light emitters is positioned behind at least one of the illumination lenses; and
a flash controller that selectively fires different subsets of the light emitters responsive to the selected field-of-view of the image forming system.
2 . The camera system of claim 1 further including a subject distance determining subsystem for determining a subject distance between the camera system and a subject in the scene, and wherein the selection of the subset of the light emitters that are selectively fired is also responsive to a subject distance determined by the subject distance determining subsystem.
3 . The camera system of claim 1 further including a subject distance determining subsystem for determining a subject distance between the camera system and a subject in the scene, and wherein a power level for at least some of the light emitters is adjusted responsive to a determined subject distance.
4 . The camera system of claim 3 wherein the power level of the light emitters is adjusted by controlling a time duration that the light emitters are activated or by controlling an electrical current level provided to the light emitters.
5 . The camera system of claim 1 wherein the image forming system includes a variable focal length zoom lens system for providing the user-selectable field-of-view.
6 . The camera system of claim 1 wherein the image forming system having a user-selectable field-of-view includes a data processor for performing a digital zoom operation using a user-selectable zoom factor to provide the user-selectable field-of-view.
7 . The camera system of claim 1 wherein the light emitters are arranged in a linear array, a square array, a rectangular array or a hexagonal array.
8 . The camera system of claim 1 wherein the light emitters are arranged in a plurality of arrays that are spatially separated from each other on the camera body.
9 . The camera system of claim 8 wherein the image forming system includes an imaging lens, and wherein at least some of the arrays of light emitters that are arranged in spatially separated positions around the imaging lens.
10 . (canceled)
11 . The camera system of claim 1 wherein the position of the light emitters relative to the illumination lenses is specified to control an illumination direction.
12 . The camera system of claim 11 wherein different light emitters are directed to illuminate different portions of the scene.
13 . The camera system of claim 12 wherein a plurality of light emitters are used to illuminate the scene for at least one selected field-of-view such that illumination patterns from the plurality of light emitters combine to illuminate the scene over the selected field-of-view with sufficient uniformity.
14 . The camera system of claim 1 wherein the flash controller selects the subset of the light emitters to be fired by:
defining a plurality of field-of-view ranges;
defining a subset of the light emitters to be associated with each of the field-of-view ranges;
determining the field-of-view range that corresponds to the selected field-of-view of the image forming system; and
selecting the subset of light emitters corresponding to the determined field-of-view range.
15 . The camera system of claim 1 wherein at least some of the illumination lenses are compound lenses including a plurality of lens elements.
16 . The camera system of claim 1 wherein at least some of the illumination lenses are cylinder lenses.
17 . The camera system of claim 1 wherein the light emitters are LEDs, OLEDs or flash lamp sources or a combination thereof.
18 . The camera system of claim 1 further including an image sensor array located at the image plane for capturing a digital image of the scene.