Hitachi, Ltd.

Hironobu Satoh

Takesuke Maruyama

Kenji Sano

Masahiko Yatsu

Shigeyuki Itoh

Kenji Ogiro

Takanori Hisada

Kenji Matsumoto

Yutaka Takami

Iwao Aizawa

Takanori Nishiyama

Manabu Wakabayashi

Hiroshi Tomita

Masaharu Deguchi

Takashi Azumi

Hiroto Takita

Kenji Kobayashi

Toshio Murakami

A video camera with a VTR for recording/playback of images communicates with a camera/VTR station by means of an opto-electronic link. A first opto-electronic link operates when the camera is positioned away from the camera/VTR station, and a second opto-electronic link operates when the camera is positioned on the camera/VTR station. The first opto-electronic link operates when the video camera does not record.

Video camera

A camera with a VTR communicates with a camera station by means of an opto-electronic link. A first opto-electronic link operates when the camera is positioned away from the camera station, and a second opto-electronic link operates when the camera is positioned on the camera station. The first opto-electronic link operates only when the VTR is reproducing.

Video camera/VTR and camera station with opto-electronic link between

A zoom lens system comprises, from an objective sequentially, a first lens group (1) having a positive power, a second lens group and a third lens group (2) and (3) having negative power and performing a zooming function by moving along an optical axis, a fourth lens group (4) having a positive power and being always stationary, and a fifth lens group (5) having a positive power and having a triplet structure including, from an object side sequentially, a first lens (9) having a positive power, a second meniscus lens (10) having a negative power and a third lens (11) having a positive power, the fourth lens group including a lens at least one surface of which is aspherical, the first or the fifth lens group being movable as a whole or partially along an optical axis to perform a focusing function. The first, second and third lens groups satisfy the following conditions:

Zoom lens system

There is provided an automatic focusing system which is used in a video camera or the like. A master lens is finely vibrated and moved by using a moving mechanism consisting of a stepping motor and a lead screw. A speed control circuit to set a moving speed of the master lens is provided. The moving speed of the master lens is set by an output signal of the speed control circuit and the master lens is moved by the moving mechanism. The moving speed of the master lens is optimally controlled and the out-of-step phenomenon in the stepping motor is eliminated. Since the master lens is accurately moved, the focusing operation is executed at a high accuracy. In addition, the influence by the unnecessary vibration (ringing) which is caused by the sudden change in moving speed of the master lens is eliminated. Therefore, since the master lens normally performs a predetermined micro vibration, the correct focusing can be accurately discriminated. Further, when a change in amount of the high frequency component of a video signal is large, since the moving speed of the master lens increases, the operating time until the correct focus is obtained is reduced.

Automatic focusing system

An automatic focusing apparatus configured such that a projected light from a light emitting element is reflected on an object and the reflection light is passed through a flat plate so as to be received by a light receiving element. The position where the reflection light is received on the light receiving element varies depending on the distance between the apparatus and the object. This positional variation is corrected so as to receive the reflection light at the same position by changing an angle of inclination of the flat plate. A focusing lens is moved in cooperation with the adjustment of the inclination angle of the flat plate, thereby achieving the automatic focusing operation.

Automatic focusing apparatus

An automatic focusing apparatus comprises a light emitting element emitting a beam of electromagnetic radiation directed toward a subject through a light projecting lens, a light receiving element receiving a beam spot reflected from the subject and passing through a light receiving lens, and a parallel-surface transparent plate disposed rotatably between the light receiving lens and the light receiving element. The parallel-surface transparent plate is rotated in interlocking relation with linear movement of an optical lens moving together with movement of a focus ring, thereby automatically attaining the focus by ceasing the movement of the lens optical system as soon as the output signal of the light receiving element attains a predetermined level.

Range finding automatic focusing system employing a rotatable

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Yokohama, Japan

Hironobu Satoh