Nihon Beru-haueru Kabushiki Kaisha

Nihon Beru-haueru Kabuskiki Kaisha

Noriaki Osawa

Motohiko Kato

A method and apparatus for automatically focusing a camera is described in which the camera has a stationary optical path and a scanning optical path for developing focusing signals. The scanning optical path is caused to undergo a range-finding reciprocation in which it reciprocates between first and second limit positions, as between the minimum lens focusing position and the infinite lens focusing position. Two focusing signals are generated during the range-finding reciprocation and the interval between the focusing signals is used to derive the distance to the subject. The lens is then positioned in accordance with the derived distance to the subject.

Automatic focusing system

Disclosed is an improvement in an automatic focusing system for use with an optical instrument having a focusable objective which is adjustable in response to optical and electronic components of the system for determining object distance of a remote subject by comparing images of scanning and reference optical systems. The scanner of the optical system is driven oscillatably across an angle to detect a subject between infinity and the minimum focus condition of the objective lens. The present invention relates to improvements in an automatic focusing system for use with an optical instrument having a focusable objective. More particularly, the improvement relates to driving the focusing system to a preset fixed focus setting when the system senses difficult conditions for focus detection as those having low contrast or complex subject matter.

Automatic focus adjusting device

Disclosed is an improvement in an automatic focusing system for use with an optical instrument having a focusable objective which is adjustable in response to optical and electronic components of the system for determining object distance of a remote subject by comparing images of scanning and reference optical systems. The scanner of the optical system is driven oscillatably across an angle to detect a subject between infinity and the minimum focus condition of the objective lens. The present invention relates to improvements in an automatic focusing system for use with an optical instrument having a focusable objective. More particularly, the improvement relates to driving the focusing system to a preset fixed focus setting when the system senses difficult conditions for focus detection as those having low contrast or complex subject matter. A warning device is included to be activated thereby cautioning the operator that the automatic focus system has reached its operational limit. However, the repeated occurrences of irregular or error signals must be present before the warning device will operate.

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Tachikawa, Japan

Noriaki Osawa