Automatic focus control device for use in a camera system
AssigneeMinolta Camera Kabushiki Kaisha
InventorsTokuji Ishida, Masataka Hamada, Kenji Ishibashi
Life of this patent
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Abstract
In an automatic focus detection device for use in a camera, a focus condition detecting unit detects a focus condition of a photographic lens in a camera based on the output of a light receiving device and calculates the amount of defocus of the photographic lens. An auxiliary light emitting device emits auxiliary light and comparator compares the stored output of memory and the output of the light receiving device under the ambient light; and then the detected defocus amount under the auxiliary light emission is corrected in accordance with the result of comparison so as to eliminate the bad effect of the color aberration of the lens of the camera, whereby a correct focus position can be detected.
Claims14
An automatic focus control device for use in a camera, comprising:
- a photographic lens;
- light receiving means including a plurality of photocells which receives light passing through said photographic lens from an object;
- focus condition detecting means for detecting a focus condition of said photographic lens based on the output of said light receiving means and calculating the amount of defocus of said photographic lens;
- auxiliary light emitting means for emitting auxiliary light to said object;
- comparing means for comparing the output of said light receiving means under the auxiliary light emission and ambient light with the output of said light receiving means under the ambient light;
- and
- means for correcting the detected defocus amount under the auxiliary light emission and ambient light in accordance with the result of said comparison.
An automatic focus control device for use in a camera, comprising:
- a photographic lens;
- light receiving means including a plurality of photocells which receives light passing through said photographic lens from an object;
- contrast detecting means for detecting the contrast of the object based on the output of said light receiving means;
- focus condition detecting means for detecting a focus condition of said photographic lens based on the output of said light receiving means and calculating the amount of defocus of said photographic lens;
- auxiliary light emitting means for emitting auxiliary light to said object;
- comparing means for comparing the output of said contrast detecting means under the auxiliary light emission and ambient light with the output of said contrast detecting means under the ambient light;
- and
- means for correcting the detecting defocus amount under the auxiliary light emission and ambient light in accordance with the result of said comparison.
An automatic focus control device for use in a camera comprising;
- a photographic lens;
- light receiving means including a plurality of photocells which receives light passing through said photographic lens from an object for producing an output indicative of the received light;
- focus condition detecting means for detecting a focus condition of said photographic lens based on the output of said light receiving means and calculating the amount of defocus of said photographic lens;
- auxiliary light emitting means for emitting auxiliary light to illuminate said object;
- first storing means for storing a first value of the output of said light receiving means under a first illumination having a first wave length;
- second storing means for storing a second value of the, output of said light receiving means under a second light condition having a second wave length different from the first wave length;
- comparing means for comparing the first value stored in said first storing means with said second value stored in said second storing means;
- and
- means for correcting the detected defocus amount under the auxiliary light emission and ambient light in accordance with the result of said comparison.
An automatic focus control device for use in a camera, comprising:
- a photographic lens;
- light receiving means including a plurality of photocells which receives light passing through said photographic lens from an object for producing an output indicative of the received light;
- contrast detecting means for detecting the contrast of the object based on the output of said light receiving means;
- focus condition detecting means for detecting a focus condition of said photographic lens based on the output of said light receiving means and for calculating the amount of defocus of said photographic lens;
- auxiliary light emitting means for emitting auxiliary light to said object;
- comparing means for comparing an output of said contrast detecting means under a first light condition having a first wave length with the output of said contrast detecting means under a second light condition having a second wave length different from the first wave length;
- and
- means for correcting the detected defocus amount under the auxiliary light emission and ambient light in accordance with the result of said comparison.
Dependencies are inferred from the claim text.