Abstract: A switch has a detection portion that contains a magnetic-field-sensing element and an attraction member. The attraction member generates a magnetically attracting force. The detection portion generates a switching signal based on an output of the magnetic-field-sensing element.

Abstract: A switch has a detection portion that contains a magnetic-field-sensing element and an attraction member. The attraction member generates a magnetically attracting force. The detection portion generates a switching signal based on an output of the magnetic-field-sensing element.

Abstract: An autofocus apparatus of an imaging apparatus is one having an estimation-value calculating unit for obtaining a plurality of estimation values by using a plurality of areas and a plurality of filters for extracting a horizontal-direction frequency component in a specific image area of a video signal corresponding to a specific image area and supplied from an imaging apparatus for effectively carrying out an autofocus operation of a television camera, a signal processing unit for calculating a control value used for controlling an image pickup lens drive unit of the imaging apparatus in response to an estimation value calculated by the above estimation-value calculating unit, and an output unit for supplying the above control value to the above image pickup lens drive unit.

Abstract: Focus control is provided by estimating an estimation value by extracting a high-frequency component of a video signal for each focus lens position. The correct focus lens position for focusing a target object is determined as that focus lens position where the estimation value for a plurality of conditions at a particular focus lens position becomes maximum. The estimation value is determined to be maximum when, for successive focus lens positions, the estimation value decreases continuously. The various conditions for imaging, according to an aspect of the focus control, includes the filter coefficients for extracting the high-frequency component of the video signal and the size of the windows from which the video signal is imaged.