Minolta Camera Kabushiki Kaisha

Tohru Matsui

Takeshi Egawa

Nobuyuki Taniguchi

Norio Ishikawa

Takanobu Omaki

Akiyoshi Nakamura

Shuzo Matsushita

Yoshihiro Tanaka

Motonobu Matsuda

Yasuhiro Nanba

Kayoshi Tsujimoto

Mitsuaki Horimoto

Haruo Abe

An auto-focusing system includes a focus condition detector which detects focus condition based on the infrared light. A data producer is provided for producing a deflection signal indicating a difference between an image forming distance for the infrared light and that for the visible light, due to aberration. In accordance with the detected focus condition and deflection signal, an objective lens is shifted to a position for properly focusing an image of visible light on an image forming plane.

Auto-focusing system for cameras with in interchangeable objective lens

In an interchangeable lens including an optical system adjustable for focusing and adapted to be detachably mounted on a camera body which is provided with focus detection means for detecting an amount of defocus of an object image formed by the optical system, and drive means for driving the optical system for the focus adjustment thereof in accordance with the detected amount of defocus. The interchangeable lens comprises, inter alia, a code plate for producing a plurality of digital photographic distance signals representing given discrete photographic distances of the optical system in accordance with the adjustment of the optical system for focusing. Circuit means output a predetermined one of a plurality of inputs, the plurality of outputs including a plurality of conversion coefficients needed for converting the detected amount of defocus into the amount of drive to be effected by the driving means, the conversion coefficients being intrinsic to the interchangeable lens and having values depending upon the discrete photographic distances of the optical system represented by the digital photographic distance signals, respectively. The digital photographic distance signals are applied to the circuit means as the predetermined input to cause the circuit means to output one of the conversion coefficients as the predetermined output, the value of which depends upon the photographic distance of the optical system represented by the one digital photographic distance signal being produced. The output conversion coefficient are transmitted to the camera body.

Data input/output device for a camera

A lighting device such as an electronic flash device attachable to a camera body includes first and second light projecting optical systems which project first and second light fluxes for illuminating an object to aid focus detection by a focus detection device. The second light flux spreads at a larger solid angle than the first light flux and illuminates a fist distance zone which extends to a closer distance side while covering the whole of a second distance zone illuminated by the first light flux. An optical wedge disposed in the second light projecting optical system deflects a part of the second light flux towards the closer distance side of the first distance zone. Another lighting device includes a single light projecting optical system but it also includes an optical wedge for deflecting a part of a light flux projected by the light projecting optical system to widen a distance zone illuminated by the light flux towards a closer distance. The optical wedge also serves to produce a difference in intensity distribution of the light flux such that the light flux has higher intensity at a part thereof for illuminating a farther distance side of the distance zone than at a part thereof for illuminating a closer distance side of the distance zone. A light source of the light projecting optical system(s) is provided with a conical light reflector surrounding a light emitting diode to reflect light emitted from side surfaces of the light emitting diode forward.

Focus detection system and lighting device therefor

A lighting device such as an electronic flash device attachable to a camera body includes first and second light projecting optical systems which project first and second light fluxes for illuminating an object to aid focus detection by a focus detection device. The second light flux spreads at a larger solid angle than the first light flux and illuminates a first distance zone which extends to a closer distance side while covering the whole of a second distance zone illuminated by the first light flux. An optical wedge disposed in the second light projecting optical system deflects a part of the second light flux towards the closer distance side of the first distance zone. Another lighting device includes a single light projecting optical system but it also includes an optical wedge for deflecting a part of a light flux projected by the light projecting optical system to widen a distance zone illuminated by the light flux towards a closer distance. The optical wedge also serves to produce a difference in intensity distribution of the light flux such that the light flux has higher intensity at a part thereof for illuminating a farther distance side of the distance zone than at a part thereof for illuminating a closer distance side of the distance zone. A light source of the light projecting optical system(s) is provided with a conical light reflecter surrounding a light emitting diode to reflect light emitted from side surfaces of the light emitting diode forward.

A lighting device such as an electronic flash device attachable to a camera body includes first and second light projecting optical systems which project first and second light fluxes for illuminating an object to aid focus detection by a focus detection device. The second light flux spreads at a larger solid angle than the first light flux and illuminates a first distance zone which extends to a closer distance side while covering the whole of a second distance zone illuminated by the first light flux. An optical wedge disposed in the second light projecting optical system deflects a part of the second light flux towards the closer distance side of the first distance zone. Another lighting device includes a single light projecting optical system but it also includes an optical wedge for deflecting a part of a light flux projected by the light projecting optical system to widen a distance zone illuminated by the light flux towards a closer distance. The optical wedge also serves to produce a difference in intensity distribution of the light flux such that the light flux has higher intensity at a part thereof for illuminating a farther distance side of the distance zone that at a part thereof for illuminating a closer distance side of the distance zone. A light source of the light projecting optical system(s) is provided with a conical light reflector surrounding a light emitting diode to reflect light emitted from side surfaces of the light emitting diode forward.

An auto-focusing system includes a focus condition detector which detects the focus condition based on infrared light. A data producer is provided for producing a deflection signal indicating the difference between an image forming distance for infrared light and that for visible light, due to aberration. In accordance with the detected focus condition and deflection signal, an objective lens is shifted to a position for properly focusing an image of visible light on an image forming plane.

Auto-focusing system

A distance measuring device is disclosed which includes a light emitting diode for projecting a light beam and photoresponsive elements for receiving the reflected light beam from an object. The photoresponsive elements are coupled to a circuit for producing a signal indicative of the distance between the device and the object. A circuit is provided for generating a timing signal in relation to the phase of the alternative fluctuations in the intensity of the ambient light. The light emitting diode is so controlled as to be allowed to project light beam when the timing signal is produced. The timing signal is arranged to occur during periods of zero or minimal ambient light fluctuations so that the distance measuring device is immune to the ambient light fluctuations.

Distance measuring device

This invention is directed to a rangefinding system which includes a light beam source, a plurality of light receiving elements disposed to receive an image light spot reflected from a target object existing in any one of a group of distance zones in such manner that the image light spot is projected on one or more of the light receiving elements, the light receiving elements being adapted to produce a combination of outputs, the contents of which vary depending on the distance between the target object and the rangefinding system the invention also includes a logic circuit for producing signals indicating the distance zone in which the target object exists, the signal generated in response to the combination of outputs, so that the space occupied by the light receiving elements can be advantageously decreased and the precision of rangefinding can be improved.

Rangefinding system

A varifocal lens assembly of a type including at least two lens groups, a first lens group being axially movable parallel to the optical axis of the varifocal lens assembly for varying the focal length of the optical system of the varifocal lens assembly. An automatic focusing device is associated with the varifocal lens assembly to axially move the lens groups as a whole, the other or second lens group or a part of lens elements of the other or second lens group a predetermined distance to compensate for the image shift which takes place during the adjustment of the focal length effected by axially moving the first lens group.

Growing community of inventors

Sakai, Japan

Tohru Matsui