Abstract: A demagnitizing apparatus erases, track by track, wide-band and high-frequency recorded signals such as signals which are frequency-modulated (FM) with video signals, and thus eliminates the need for a relay to switch a single magnetic head between erasing capability and recording or reproducing capability.

Abstract: In a still picture recording apparatus such as an electronic still camera, an audio signal compressed in its time base is recorded on a magnetic disk together with a video signal. In order to relate the timing of recording the audio signal to that of the video signal, the audio signal to be recorded is processed in an audio signal processing circuit in response to the manipulation of a manual switch, and the video signal to be recorded is processed in a video signal processing circuit after a required delay time relative to the audio signal, so that the audio signal and the video signal can be recorded in matching relation without the possibility of mismanipulation and without the need for troublesome recording procedures.

Abstract: In a field/frame conversion system in which a field signal recorded on a track of a recording medium is repeatedly reproduced, a field signal delayed by 1/2 horizontal scanning duration and a directly provided field signal are alternately selected by a switch at each vertical scanning duration, and one of the field signals is formed by an arithmetic mean of a signal delayed by 1 horizontal scanning duration and a directly provided signal, to provide a frame signal, a flicker preventing circuit device in a field/frame conversion comprises a circuit provided in a front stage of an arithmetic mean circuit of the field/frame conversion system for bringing a gamma value of the field signal to 1, and a gamma circuit provided in a rear stage of the arithmetic mean circuit for returning the gamma value of the field signal to its original value.

Abstract: A method for controlling the amount of the exposure of a television camera whereby a luminance signal from only a selected portion of an overall photometric range of the camera is employed for adjusting the exposure. A first signal is produced specifying the selected photometric range. In response to this signal, and further in response to horizontal and vertical synchronizing signals from the television camera in synchronization with the scanning of an electron beam in the camera, a range signal is produced when the scanning beam is within the specified photometric range. The luminance signal outputted by the television camera only at that time is employed for exposure control.

Abstract: An automatic focusing device for video camera in which the distance between a lens mounting section of a camera body and the imaging plane of an imaging unit is varied for focusing by moving at least either a lens mounting section or the imaging plane along the optical axis. The device comprises focus detector for receiving the data about an object through a light splitter and driving circuit for varying the distance between lens mounting section and imaging plane according to the output of the focus detector.

Abstract: A television camera of the type having an image pickup element for converting the image of an object to be photographed into an electrical signal having an exposure control circuit with a voltage detector and controlling the exposure according to the voltage level of said electrical signals. A spot selection circuit provides the exposure control apparatus with signals corresponding to a portion of the image less than the entire image. The exposure of the entire image is controlled in accordance with the detected voltage levels of electrical signals corresponding to the image portion.

Abstract: An automatic focusing device for moving a photographic lens to an optimum focusing position by detecting an object image contrast signal that changes with the varying position of the photographic lens. The device stops the photographic lens while it is being moved between an infinite distance photographing position to a least distance photographing position when the level of the detected contrast signal becomes less than a threshold level. The invention compares a first signal, which is set to correspond to a position at which the photographic lens is to be stopped, and a second signal, which is generated when the contrast signal level is less than the preset threshold level.

Abstract: A zooming device for a camera, which comprises a rocker which operates a plurality of successively operable switches provided on each side of the center of rotation. The rocker can be turned in either direction to operate the first one of the plurality of switches so as to obtain zooming by a corresponding multiple lens group in the corresponding direction and at a predetermined speed. The zooming speed can be changed to a next speed when a second one of the switches is operated by further turning of the rocker.