Canon Kabushiki Kaisha

Tatsuya Taguchi

Tokuichi Tsunekawa

Shinji Sakai

Takao Kinoshita

Kazuya Hosoe

Takashi Kawabata

Nobuaki Date

Nobuo Tezuka

Yukio Iura

Toshio Sakane

Yoshiyuki Takishima

David Fullagar

Disclosed is a method of detecting the focusing condition of an image forming optical system to an object, in which two images of the object are formed with respective light beams from the prescribed exit pupil areas lying in almost symmetry to each other with respect to the optical axis of the optical system and are sensed to obtain an equal number of picture element data for each of the images, and based on the thus-obtained picture element data, while sequential shifting for the first image is carried out from its one end to its opposite end, and a sequential shifting for the second image from its symmetric one end thereto to its opposite end, each by a predetermined number of picture elements, a correlation betweeen the first and second images in every predetermined equal number of picture elements is sought, whereby an optimum correlation is obtained, the corresponding mutual positional relationship between the above-described predetermined numbers of picture elements is detected to discriminate whether or not the above-described image forming optical system is in focus for the above-described object.

Focus detecting and/or focus adjustment method

A film takeup spool provided with pawls in the interior of a sleeve hub thereof at such a location that pivot pins of the pawls are off-set from the axis of rotation of the sleeve hub. The pawls are urged by respective springs to project their teeth radially outwardly of the sleeve hub into the perforations of the film. When the spool is driven to rotate with a sufficient tension of the film, the pawl teeth are retracted into the sleeve hub, thus permitting a smooth winding up of the film on the sleeve hub of the takeup spool.

Film takeup spool for camera

Disclosed is a TTL (Through-The-Lens) type focus detecting device for use in an interchangeable lens-equipped camera, in which a plurality of lenslets are positioned at or near the prescribed focal plane of the objective lens, each of the lenslets is associated with two or more pairs of photosensitive elements. Upon attachment of an objective lens to the camera body, one of the pairs of photosensitive elements for each lenslet is automatically selected to operate on the basis of the dimensions of the used objective lens. The outputs of the selected pairs of photosensitive elements for all the lenslets are processed to detect whether or not a positional difference between two images of an object formed with light beams from the objective lens at respective virtual exit pupils lying in almost symmetry with respect to the optical axis thereof is present, whereby the detection of whether or not the objective lens is in-focus is indicated.

Focus detecting device

A magnetic image recording system in which an image is electrically scanned to obtain a video signal and this is magnetically recorded on a magnetic recording medium. According to improvements of the present invention, for the image scanning means, use is made of a two-dimensional arrangement of a plurality of photo-sensitive elements and further of a self-scanning type solid-state image sensing device constructed so as to be capable of simultaneously reading out image scanning signals from the individual lines of the two-dimensional arrangement. With this solid-state image sensing device, in scanning an image, it is, for example, the individual odd number lines in the aforesaid two-dimensional arrangement that at first produce image scanning signals based on which the video signal is obtained. Then the video signal is recorded as an odd number field signal on the recording medium through a multi-head. Then, another video signal obtained by image scanning signals from the individual even number field signal is recorded on the recording medium through the multi-head. Compared with conventional systems in which horizontal field lines are sequentially scanned and recorded, all of the horizontal video scan line signals which constitute an entire field are simultaneously recorded in the present system. In other words, in contrast to conventional systems wherein images are recorded and played back at a rate of, for example, 60 fields per second, the system of the present invention enables a substantially greater number of fields to be recorded each second so that when the recorded fields are played back at a conventional rate, i.e., 60 fields per second, a substantial 'slow motion' reproduction can be obtained.

High speed image recording system

In the system disclosed, a feedback circuit connects the output of the last of a plurality of cascaded amplifier stages to the input of the first stage. A photoelectric transducer is connected to one of the stages. The feedback connection compresses the output signal relative to the signal at the photoelectric transducer, logarithmically. Preferably all the stages are linear and the feedback circuit is linear so that no logarithmic members are required. Preferably each of the stages is composed of an amplifier and a connection corresponding to an emitter-follower connection. A suitable system then utilizes the compression characteristic in a shutter control. This system may use a second compression circuit comparable to the first. Additional photographic information may be applied to the input of any of the stages in either compression circuit.

Control circuit for a memory type electric shutter

An exposure factor setting device for a photographic camera comprising manually adjustable shutter speed and diaphragm aperture setting components, an indicator cooperative with a shutter speed scale and capable of responding to either of the outputs of the shutter speed setting component and an exposure value computer, and first and second gates connected respectively between the shutter speed setting component and the indicator and between the computer and the indicator and arranged to be acted on alternately in sequence by a common pulse generator. When the previously selected combination of shutter speed and diaphragm aperture is not correct in conformity with the prevailing scene brightness, the indicator is caused to flicker between two positions for the automatic and manual shutter speed values. To attain correct adjustment of shutter speed and diaphragm aperture, the photographer may operate with either of the shutter speed and diaphragm aperture setting components until the amplitude of flickering of the indicator is reduced to zero, while looking through the finder as the indicator is visible in or adjacent the finder image field.

Exposure factor setting device for a camera

In a reflex camera a mirror support is composed of a base with flexible members and arms carried by the base. Each arm has one end bendable to position the mirror on the base, while the other end forms a stop to restrict movement of the mirror. The arms also have axle bearing support for positioning the base relative to the light path and the reflective plane of the mirror. The flexible members of the base are adhesively coated for holding the mirror in position relative to the light path.

Mirror supporting body at a single lens reflex camera

A separate annular actuator button surrounding the shutter release button and provided with its own mechanical stop is used to move the shutter release button just far enough to switch in the storage capacitor of a TTL light measuring system of a single-lens reflex camera. This annular button can conveniently and naturally be depressed in advance of direct manipulation of the shutter release button, assuring enough time for charging the capacitor rather than relying on the rate of direct manual depression of the shutter release button to interpose enough time between capacitor switch-in and shutter release. The capacitor charging which determines the timing of shutter closing is stopped by breaking the charging current before mirror movement or lens stop-down.

Growing community of inventors

Tokyo, Japan

Tatsuya Taguchi