Automatic optimization of photographic exposure parameters through determination and utilization of extra system speed
First Claim
1. Apparatus for capturing an image of a scene using a flash exposure, said scene having a subject with primary and background elements, said apparatus having a flash unit and an image sensing device with a variable aperture lens, said apparatus comprising:
- means for determining an initial value of said aperture for use during the flash exposure;
means for ascertaining corresponding exposure levels that will result in said flash exposure for said primary and background elements; and
means, responsive to a difference occurring between said primary and background exposure levels, for changing the value of said aperture from said initial value to a second value in order to provide an increased depth-of-field in said flash exposure, whereby said second value at least partially satisfies an increased depth-of-field requirement in said scene caused by an increase in background lighting level attributable to flash illumination.
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Accused Products
Abstract
Apparatus, and an accompanying method, for use in a photographic camera for selecting a lens aperture setting for a full flash exposure of a scene based upon re-assessed depth-of-field requirements for that scene. Specifically, full flash lighting will cause the exposure of both the primary and background subjects in a scene to increase. Inasmuch as increased background illumination attributable to the full flash will render the background subject increasingly visible in the flash exposure, a lens will need to provide additional depth-of-field in order to sharply photograph the entire scene including not only the primary subject but also the background subject. As such, once the initial aperture setting is determined, then the depth-of-field required to photograph the scene including both the primary and background subjects is determined followed by selectively changing the lens aperture size from its initial value to a smaller value that will impart additional depth-of-field to the photographed scene in order to account for increased visibility of the background subject. The lens aperture is changed only if the resulting overall exposure of background subject will lie within a given margin (threshold) of the resulting overall exposure of the primary subject.
48 Citations
20 Claims
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1. Apparatus for capturing an image of a scene using a flash exposure, said scene having a subject with primary and background elements, said apparatus having a flash unit and an image sensing device with a variable aperture lens, said apparatus comprising:
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means for determining an initial value of said aperture for use during the flash exposure; means for ascertaining corresponding exposure levels that will result in said flash exposure for said primary and background elements; and means, responsive to a difference occurring between said primary and background exposure levels, for changing the value of said aperture from said initial value to a second value in order to provide an increased depth-of-field in said flash exposure, whereby said second value at least partially satisfies an increased depth-of-field requirement in said scene caused by an increase in background lighting level attributable to flash illumination. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
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11. In apparatus for capturing an image of a scene using a flash exposure, said scene having of a subject with primary and background elements, said apparatus having a flash unit and an image sensing device with a variable aperture lens, a method comprising the steps of:
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first determining an initial value of said aperture for use during the flash exposure; ascertaining corresponding exposure levels that will result in said flash exposure for said primary and background elements; and changing, in response to a difference occurring between said primary and background exposure levels, the value of said aperture from said initial value to a second value in order to provide an increased depth-of-field in said flash exposure, whereby said second value at least partially satisfies an increased depth-of-field requirement in said scene caused by an increase in background lighting level attributable to flash illumination. - View Dependent Claims (12, 13, 14, 15, 16, 17, 18, 19, 20)
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Specification