Camera employing zone focusing
First Claim
1. In photographic apparatus having a movable lens whose position at which a subject is in focus is a function of subject distance, means for sensing the position of the lens, and ranging means for determining the distance of a given subject from the apparatus, the improvement comprising:
- means for determining, in accordance with the sensed position of the lens, a focal zone defining a range of distances within which a subject must be located to be properly focused when the lens is in the sensed position; and
means for comparing the subject distance to said focal zone and for providing an error signal indicative of the relationship between the subject distance and said zone.
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Accused Products
Abstract
A camera having a displaceable lens includes a lens position sensor and a converter for converting the sensor output into a representation of the in-focus distance associated with that lens position. The in-focus distance of the lens is then compared to the distance of the subject as determined by a rangefinder (e.g., an ultrasonic rangefinder). A visual indication is provided in the viewfinder prompting the user to manually change the position of the lens in a direction that improves the focus or, alternately, the relationship is used for controlling a motor to move the lens to a position at which the subject is in focus.
38 Citations
28 Claims
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1. In photographic apparatus having a movable lens whose position at which a subject is in focus is a function of subject distance, means for sensing the position of the lens, and ranging means for determining the distance of a given subject from the apparatus, the improvement comprising:
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means for determining, in accordance with the sensed position of the lens, a focal zone defining a range of distances within which a subject must be located to be properly focused when the lens is in the sensed position; and means for comparing the subject distance to said focal zone and for providing an error signal indicative of the relationship between the subject distance and said zone. - View Dependent Claims (2, 3, 4, 5, 6)
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7. Apparatus for facilitating the focusing of a camera having a displaceable lens whose position at which a subject is in focus is a predetermined function of subject distance, the apparatus comprising:
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sensing means for producing an output representative of the position of the lens; a converter for converting the output of the sensing means to a representation of the focal zone associated with the output of the transducer, the focal zone being a zone of distances at which a subject will be in focus when the lens occupies the position represented by the output of the sensing means; a rangefinder for producing an output representing the actual subject distance; and a comparator for comparing the output of the rangefinder with the output of the converter and for producing an output corresponding to the relationship between the focal zone and the actual subject distance. - View Dependent Claims (8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18, 19, 20, 21, 22, 23)
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24. A method for focusing a camera having a displaceable lens whose position at which a subject is in focus is a predetermined function of subject distance, the method comprising:
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(a) determining the actual distance of the subject; (b) sampling the position of the lens and producing two outputs respectively representing the minimum and maximum in-focus distance of the lens which defines the boundary within which a subject must be located in order to be in focus when the lens occupies the position at which the sampling occurs; (c) comparing the actual distance of the subject with the minimum and maximum in-focus distances; and producing a signal in response to the comparison. - View Dependent Claims (25, 26, 27)
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28. A method of focusing a variable lens camera in accordance with subject distance, the method comprising the steps of:
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determining the lens position and in accordance therewith defining a zone of distances within which a subject will be in focus when the lens is in the determined position; determining the distance between the camera and a subject; comparing the defined zone to subject distance; and in response to said comparing step, producing an error signal indicating the direction of lens movement necessary to provide a lens position suitable for the given subject distance.
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Specification