Focusing apparatus for optical systems
Photographic camera having independent viewfinder and reflex focusing system
Autofocus movie camera having focus correction means
Focus control system for interchangeable adjustable focus lenses
Automatic focusing camera
Ultrasonic ranging system for a camera
Camera focus detecting device Patent #: 4230401
AbstractA 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.