IMAGING DEVICE AND CONTROL METHOD THEREOF
First Claim
1. An imaging device that takes an image of a subject by focusing the image on an imaging plane via an optical system including a zoom lens and a focusing lens, the imaging device comprising:
- an operation input unit configured to input a zoom operation;
a zoom controller configured to move the zoom lens in response to the input zoom operation, so as to change a magnification of the image;
a near limit position acquirer configured to obtain a near limit position of the focusing lens to the subject at a zoom lens position, to which the zoom lens is moved by the zoom controller; and
a focus controller configured to move the focusing lens in such a range that the focusing lens is not located on a near side of the near limit position, every time the zoom lens is moved by the zoom controller, so as to focus the image on the imaging plane, whereinwhen a target position of the focusing lens, which is required to keep the image in focus after the zoom lens is moved by the zoom controller, is located on the near side of a threshold position that is specified based on the near limit position, the focus controller moves the zoom lens to a wider position than the zoom lens position, to which the zoom lens is moved by the zoom controller, and subsequently moves the focusing lens to focus the image.
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Accused Products
Abstract
An imaging device moves a zoom lens, so as to change the magnification of an image of a subject, and obtains a near limit position of a focusing lens to the subject at a zoom lens position. When a target position of the focusing lens, which is required to keep the image in focus after the zoom lens is moved, is located on a near side, i.e., on an imaging plane side, of a threshold position determined based on the obtained near limit position, focus control is performed to move the focusing lens and thereby focus. When the target position of the focusing lens is not located on the near side but is located on a subject side of the threshold position, on the other hand, focus control is performed to move the zoom lens to a wider position and subsequently move the focusing lens to focus the image.
10 Citations
8 Claims
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1. An imaging device that takes an image of a subject by focusing the image on an imaging plane via an optical system including a zoom lens and a focusing lens, the imaging device comprising:
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an operation input unit configured to input a zoom operation; a zoom controller configured to move the zoom lens in response to the input zoom operation, so as to change a magnification of the image; a near limit position acquirer configured to obtain a near limit position of the focusing lens to the subject at a zoom lens position, to which the zoom lens is moved by the zoom controller; and a focus controller configured to move the focusing lens in such a range that the focusing lens is not located on a near side of the near limit position, every time the zoom lens is moved by the zoom controller, so as to focus the image on the imaging plane, wherein when a target position of the focusing lens, which is required to keep the image in focus after the zoom lens is moved by the zoom controller, is located on the near side of a threshold position that is specified based on the near limit position, the focus controller moves the zoom lens to a wider position than the zoom lens position, to which the zoom lens is moved by the zoom controller, and subsequently moves the focusing lens to focus the image. - View Dependent Claims (2, 3)
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4. An imaging device that takes an image of a subject by focusing the image on an imaging plane via an optical system including a zoom lens and a focusing lens, the imaging device comprising:
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an operation input unit configured to input a zoom operation; a zoom controller configured to move the zoom lens in response to the input zoom operation, so as to change a magnification of the image; a shortest shooting distance acquirer configured to obtain a shortest shooting distance of the subject at a zoom lens position, to which the zoom lens is moved by the zoom controller; a focus controller configured to move the focusing lens every time the zoom lens is moved by the zoom controller, so as to focus the image on the imaging plane; and an actual shooting distance acquirer configured to obtain an actual shooting distance to the subject, wherein when the actual shooting distance is less than the shortest shooting distance, the focus controller moves the zoom lens to a wider position than the zoom lens position, to which the zoom lens is moved by the zoom controller, and subsequently moves the focusing lens to focus the image. - View Dependent Claims (5, 6)
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7. A method of controlling an imaging device that takes an image of a subject by focusing the image on an imaging plane via an optical system including a zoom lens and a focusing lens, the method comprising:
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inputting a zoom operation; performing zoom control to move the zoom lens in response to the input zoom operation, so as to change a magnification of the image; obtaining a near limit position of the focusing lens to the subject at a zoom lens position, to which the zoom lens is moved by the zoom control; and performing focus control to move the focusing lens in such a range that the focusing lens is not located on a near side of the near limit position, every time the zoom lens is moved by the zoom control, so as to focus the image on the imaging plane, wherein when a target position of the focusing lens, which is required to keep the image in focus after the zoom lens is moved by the zoom control, is located on the near side of a threshold position that is specified based on the near limit position, the focus control moves the zoom lens to a wider position than the zoom lens position, to which the zoom lens is moved by the zoom control, and subsequently moves the focusing lens to focus the image.
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8. A method of controlling an imaging device that takes an image of a subject by focusing the image on an imaging plane via an optical system including a zoom lens and a focusing lens, the method comprising:
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inputting a zoom operation; performing zoom control to move the zoom lens in response to the input zoom operation, so as to change a magnification of the image; obtaining a shortest shooting distance of the subject at a zoom lens position, to which the zoom lens is moved by the zoom control; performing focus control to move the focusing lens every time the zoom lens is moved by the zoom control, so as to focus the image on the imaging plane; and obtaining an actual shooting distance to the subject, wherein when the actual shooting distance is less than the shortest shooting distance, the focus control moves the zoom lens to a wider position than the zoom lens position, to which the zoom lens is moved by the zoom control, and subsequently moves the focusing lens to focus the image.
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Specification