FOCUS ADJUSTING METHOD AND FOCUS ADJUSTING DEVICE
First Claim
1. A focus adjusting method for adjusting focus by moving a focusing lens group of a photographing optical system,wherein said focus adjusting method performs a focus search process in which a focus state is obtained to detect an in-focus position of said focusing lens group based on a contrast of an image formed by said photographing optical system, in one of at least one large focus area and each of a plurality of small focus areas included in said large focus area, while said focusing lens group is moved stepwise from one toward the other of a near extremity and a far extremity, and moves said focusing lens group to said in-focus position,wherein said focus adjusting method comprises:
- a first search stage at which a focus search operation is performed based on an image formed in said large focus area while said focusing lens group is moved stepwise over an entire range of movement thereof from said near extremity to said far extremity, anda second search stage at which said focus search operation is performed, based on images formed in said plurality of small focus areas, at front and rear close vicinities of said in-focus position while said focusing lens group is moved stepwise over a portion of said entire range of movement thereof.
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Accused Products
Abstract
A focus adjusting method for adjusting focus by moving a focusing lens group of a photographing optical system, wherein the focus adjusting method includes a first search stage at which a focus search operation is performed based on an image formed in a large focus area while the focusing lens group is moved stepwise over an entire range of movement thereof from the near extremity to the far extremity, and a second search stage at which the focus search operation is performed, based on images formed in small focus areas, at front and rear close vicinities of the in-focus position while the focusing lens group is moved stepwise over a portion of the entire range of movement thereof.
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Citations
16 Claims
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1. A focus adjusting method for adjusting focus by moving a focusing lens group of a photographing optical system,
wherein said focus adjusting method performs a focus search process in which a focus state is obtained to detect an in-focus position of said focusing lens group based on a contrast of an image formed by said photographing optical system, in one of at least one large focus area and each of a plurality of small focus areas included in said large focus area, while said focusing lens group is moved stepwise from one toward the other of a near extremity and a far extremity, and moves said focusing lens group to said in-focus position, wherein said focus adjusting method comprises: -
a first search stage at which a focus search operation is performed based on an image formed in said large focus area while said focusing lens group is moved stepwise over an entire range of movement thereof from said near extremity to said far extremity, and a second search stage at which said focus search operation is performed, based on images formed in said plurality of small focus areas, at front and rear close vicinities of said in-focus position while said focusing lens group is moved stepwise over a portion of said entire range of movement thereof. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15)
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16. A focus adjusting device comprising:
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a lens driving device for moving a focusing lens group of a photographing optical system stepwise in a range of movement from one toward the other of a near extremity and a far extremity; an image pickup device for capturing an image formed by said photographing optical system; and a controller which performs a focus search stage in which said image pickup device is activated to capture an object image at each of a plurality of different positions of said focusing lens group while said focusing lens group is moved stepwise from one toward the other of a near extremity and a far extremity to obtain an in-focus state based on a contrast of an image formed by said photographing optical system in one of at least one large focus area and each of a plurality of small focus areas included in said large focus area.
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Specification