Abstract: A real image of an object is projected by an objective lens to at least a pair of photosensitive elements on opposite side of a prescribed focal plane, wherein use is made of a secondary image forming lens between the objective lens and the pair of photosensitive elements to achieve a great increase in the range of detection of in-focus condition.

Abstract: A battery checking device for cameras of the type having a booster circuit the output of which is fed as electrical power to a load is disclosed. In the case of the camera of the type described, when the battery voltage is checked at the output of the booster circuit, an accurate checking operation cannot be carried out. The present invention, therefore allows the voltage at the input of the booster circuit to be checked. Since another problem is that the booster circuit, after having been actuated, takes a predetermined time before its operation is stabilized, and the value of voltage as sensed during this time does not provide an accurate representation, the present invention provides that checking of that input voltage begins after the elapse of a predetermined time from the actuation of the booster circuit when the operation of the booster circuit becomes stable. Accordingly, it is made possible to achieve always an accurate and reliable battery checking operation.

Abstract: In the disclosed viewfinder, a focusing plate receives light from an objective via a reflex mirror, and after focusing, passes light to an eyepiece via a penta prism. A by-pass optical system receives light from outside the view field of the viewfinder and directs the light through an information carrier outside the optical path of the photographic light and into the penta prism so that the information can be displayed close to the view field of the viewfinder.

Abstract: Disclosed is a solid state imaging device which comprises an imaging unit having a plurality of picture cells arranged in at least one line for producing electrical information in response to incident radiation; a read-out unit for reading out said electrical information from said imaging unit, said read-out unit including m separate read-out channels, where m is an integer no smaller than three; and an input unit for dividing the electrical information in one line of said imaging unit into m groups, parallel-to-serial converting the respective groups of electrical information and supplying the serial information to said read-out unit.

Abstract: The disclosed automatic focusing device operates by detecting a motor signal which is produced according to the lens movement and by forming a limit signal when the motor signal is not produced for a period longer than a predetermined time. A reference signal forming circuit produces a reference signal corresponding to the shift in focus per unit time. The motor signal is compared with the reference signal and the lens drive speed is adjusted to reduce the difference between the two signals. The invention avoids a mechanical limit switch and maintains an unvarying shift in focus per unit time for different kinds of lenses.

Abstract: A focusing state discriminating system of the invention discriminates the focusing state of an image forming optical system, based on signals F1, F2 and F3 representing image formation states of images formed at first, second and third positions of the optical system which substantially correspond to positions slightly in front of, coincident with and slightly behind the predetermined focal plane of the image forming optical system. The operation for discrimination in this system includes at least a comparison of .vertline.F1-F3.vertline. and K(F1+F2+F3), where K is a constant.

Abstract: An automatic focusing optical apparatus comprises an automatic focusing device which automatically controls the focal point of an optical system and is arranged to be operatable in such a manner that, once the optical system is focused on an object, the focal point of the optical system is fixed to be unvarying irrespectively of changes in the distance to the object; a display device which is capable of displaying the in-focus and defocus states of the optical system independently of the automatic focusing device; and control means for allowing the display device to display solely the in-focus state when the automatic focusing device fixes the focal point of the optical system to be unvarying irrespectively of changes in the distance to the object after the optical system is once focused on the object.

Abstract: A camera includes a viewfinder with an indicator having two opposing substrates sandwiching a liquid crystal between them. One substrate includes a common electrode arrangement with a plurality of electrodes. The other substrate includes a segmented electrode arrangement with a number of electrodes facing the respective electrodes of the common electrode arrrangement. Short-circuit connectors connect predetermined electrodes in the segmented electrode arrangement. A first contactor has a number of conductors connected to the respective electrodes of the segmented electrode arrangement to deliver predetermined drive signals thereto. At least one of the short-circuiting connectors is arranged at the input portion of the first contactor. A second contactor with a number of conductors is connected to respective electrodes of the common electrode arrangement so as to deliver predetermined drive signals thereto.

Abstract: A focusing device for an optical system detects a continuous photographing state and allows no focusing operation when a degree of defocus exceeds a prescribed value during the continuous photographing operation.

Abstract: A focus detecting system of the invention has a signal processing circuit for processing output signals from photoelectric transducer elements. The signal processing circuit has a circuit for obtaining an absolute value of the output signal and for producing power thereof. This circuit is constructed to operate in a current mode.

Abstract: The present invention relates to a liquid crystal cell having a plural number of electrode pairs arranged on both sides of the liquid crystal matter so as to be opposed to each other, being characterized in that a pulse wave generating device for generating the first pulse wave with smaller amplitude than the threshold valve for lighting the liquid crystal and the second pulse wave with larger amplitude than the threshold value for lighting the liquid crystal in reversed phase to each other and a gate device for selectively applying the outputs of the pulse wave generating device to each electrode of the liquid crystal cell in accordance with the input signal are provided. Thus only the voltage between the selecting electrodes is highter than the threshold value. An input change over device is provided so as to change over the input signal group in a time dividing way in such a manner that a plural number of dots can be displayed visually at the same time, as a result, the wiring is simplified.

Abstract: A liquid crystal display device for a camera includes a display member having liquid crystal material for providing a display of photographic information, and a focusing glass for forming an image of an object which is to be photographed. A mask is arranged to face the display member and the focusing glass, the mask including a first transparent part which faces a display part of the display member, and a second transparent part which faces the object image formed on the focusing glass. A light shading part is provided between the first and second transparent parts of the mask to shade an end part of the display member from light. The mask enables view finder optics provided in the camera to display a rectangular view field having straight sides to the camera user.

Abstract: In the disclosed focus adjusting device, at least part of an image forming optical system and a focus adjusting mechanism is arranged within a housing attachable to and detachable from a camera body. A focus condition detector includes a photo-sensor disposed on a plane corresponding to the camera image plane, an electrical detection circuit connected to the photo-sensor, and a detecting optical system for forming an image of at least a part of the object on the surface of the photo-sensor. An aural indicator emits a sound to inform a photographer of the condition of the image formed on the surface of the predetermined focal plane as determined by the focusing condition detector.

Abstract: A signal processing system for processing output signals from an accumulating-type photoelectric transducer element is disclosed which has a squaring circuit and a threshold level control circuit which vary the threshold level of the output signals from the photoelectric transducer element at least at a part of a processing circuit, depending upon the ambient temperature and/or the intensity of light incident on the photoelectric transducer element, so that noise components included in the output signals from the photoelectric transducer element can be suppressed.

Abstract: This invention relates to cameras capable of making exposures in shutter priority, or manual and program modes. Since in the program mode the shutter time and diaphragm aperture are unequivocally determined, the computed value of shutter time is liable to exceed a limit such that effects of shaking of the operator's hand become noticeable. The present invention solves this problem by making use of the shutter dial used for selection of the shutter priority or manual mode to set the limit value. When a longer shutter time than this limit is derived, the diaphragm aperture is readjusted in accordance with this limit of shutter time and the object brightness, while the shutter is adjusted to that limit value.

Abstract: A focus detecting system detects an image formation state of an image of an object by processing a time-serial output from a photoelectric transducer element through a high-pass filter. In order to suppress the outputs from the high-pass filter corresponding to the time-serial signal at the initial moment of light reception by the photoelectric transducer element or immediately thereafter, an amplifier is provided which performs the initial setting of the high-pass filter. The input and output ends of the amplifier are connected to parts of the high-pass filter, and the output impedance of the amplifier may be changed in response to a signal from an external source.

Abstract: In the disclosed focus detecting system, the focusing condition of an objective lens relative to an object is determined by a number of pairs of radiation sensitive elements arranged in a linear array, and a number of lens elements arranged in a linear array corresponding to the linear array of the pairs of radiation sensitive elements. Each lens element is disposed so that one radiation sensitive element in each pair of radiation sensitive elements is arranged to cause one radiation sensitive element in each pair of radiation sensitive elements to receive radiation from a first portion of the objective lens and to cause the other radiation sensitive element to receive radiation from a second portion of the objective lens.

Abstract: In a photoelectric transducer device such as a solid state image pick-up device or sensor having a great number of minute photoelectric transducer elements with their image-receiving surfaces of certain shape arranged in a one-dimensional or two-dimensional manner so that brightness informations of the various individual sections of the object image are sensed by the respective photoelectric transducer elements which then produce outputs in the form of time-sequential signals, the above-described shape of the image-receiving surface area of each of the minute photoelectric transducer elements is made to be such that, as the distance from the center of the image receiving area toward the margin increases, the proportion of the area of a progressively farther concentric zone of the same width is decreased. The shape takes such a form or such characteristics as to be represented by a sampling function or other analogous functions with respect to the scanning direction of the image pick-up device.

Abstract: The invention provides a camera which uses a signal integrating and accumulating type image sensor for receiving light from a photographing optical system prior to the photographing operation and for producing an output which can be utilized for a predetermined purpose, with the integrating time of the image sensor being controlled in accordance with the output from the image sensor. According to the improvements of the present invention, the signal integrating time of the image sensor is fixed, in association with the photographing operation, at the value of that of the integrating operation just before the photographing operation.

Abstract: Disclosed is an image sharpness detecting system in which an image formed by an image forming optical system is received by an array of a plurality of optical-electronic transducer elements, and an illumination difference in each individual minute compartment of the above-described image is detected on the basis of the concurrently obtained output signal from a corresponding one of the optical-electronic transducer elements, while all the illumination differences are summed up over the entire area of a sensing region of the above-described image, whereby is obtained a signal representing the degree of sharpness of the image on the above-described array of optical-electronic transducer elements.