Abstract: An inverted-telephoto type wide angle lens system is provided which comprises from the object side to the image side: a first lens group of a negative refractive power; a second lens group of a positive refractive power; an aperture diaphragm; and a third lens group of a positive refractive power; wherein the second and third lens groups are shiftable to the object side along the optical axis of the lens system at different speeds from one another in a focusing operation to a closer object while the first lens group is stationary on the optical axis in the focusing operation.

Abstract: A multi-point photometric apparatus for use in a camera or the like operative to measure the luminance of several divided areas in an objective field. Among the luminance signals produced by the photometric circuit for the several areas, a signal from one area which is used for automatic focus adjustment is designated as a reference value, and the maximum and minimum values of luminance signals and the differences of these from the reference value are evaluated. The reference value and differences in the form of digital data and information on the film latitude are processed with a microprocessor to calculate the exposure value. The exposure value is modified to an extent that the reference remains within the film latitude.

Abstract: A focus detection apparatus for a camera comprising: a condensor lens being arranged close to or behind a predetermined focal plane of an objective lens of the camera. A pair of image separation members for separating the image of an object formed on the predetermined focal plane by use of light having been passed through the objective lens into two images which are arranged behind the condensor lens symmetrically with respect to the optical axis of the objective lens, wherein the correlation between the two images formed separately is measured in order to detect the focus condition of the objective lens. The image separating means including a mask for projecting the exit pupil of image separation member within an exit pupil of a cata-dioptric lens system as the objective lens.

Abstract: A light measuring device, for use in a camera having an objective lens, for measuring a brightness of a spot of an object, uses an autofocus detecting system which includes an array of light receiving elements for producing charges at a rate relative to an intensity of the light impinging thereon from the object, and a light receiver provided adjacent the light receiving element array for producing a photocurrent at an amount relative to an intensity of the light impinging thereon from said object. The charges produced from the light receiving elements are integrated in a plurality of charge accumulation portions, respectively, and the charges produced by the light receiver is integrated in a capacitor. A comparator is provided for comparing the integrated charges with a predetermined level, and for producing a stop integration signal when the integrated charges reaches the predetermined level so as to stop the integration in the first integration means.

Abstract: This invention is directed to a camera provided with an automatic focus adjusting apparatus in which, in addition to the function of carrying out an AE lock based on an in-focus detection, an AE lock can be carried out either before or after an AF operation is completed or when an AF operation is impossible. In other words, irrespective of the condition of an automatic focus adjusting means, an AE lock can be accomplished at any desired moment. Therefore, the degree of freedom in a photography operation is expanded.

Abstract: An exposure display device for a camera, which can display not only the density of the background to be photographed on a film but also the density of a primary object to be focused with respect to an exposure control value used for exposure control operation. In natural light photography, the brightness of the primary object area at which automatic focus detection is conducted and the brightness of divided object field areas are measured, the density distribution of the primary object area and those of the divided object field areas reproduced on the film are calculated basing on the measurement, and the results are displayed in correspondence to the exposure control value. In flash light photography, the expected brightness of the primary object area and divided object field areas are measured, and the density distribution of the primary object area and object field areas reproduced on the film are calculated and displayed in correspondence to the exposure control value.

Abstract: A multi-point photometric apparatus for use in a camera or the like operative to measure the luminance of several divided areas in an objective field. Among the luminance signals produced by the photometric circuit for the several areas, a signal from one area which is used for automatic focus adjustment is designated as a reference value, and the maximum and minimum values of luminance signals and the differences of these from the reference value are evaluated. The reference value and differences in the form of digital data and information on the film latitude are processed with a microprocessor to calculate the exposure value. The exposure value is modified to an extend that the reference remains within the film latitude.

Abstract: A flash photographing apparatus, including a camera and an electronic flash device, comprises a plurality of photoelectric elements for measuring brightness of a main and sub objects to be photographed. A diaphragm aperture value and shutter speed value of the camera are controlled according to the brightness of the sub object. A quantity of flash light emission is controlled according to a difference between the brightness information of the main and sub objects.

Abstract: This invention is directed to a camera provided with an automatic focus adjusting apparatus in which, in addition to the function of carrying out an AE lock based on an in-focus detection, an AE lock can be carried out either before or after an AF operation is completed or when an AF operation is impossible. In other words, irrespective of the condition of an automatic focus adjusting means, an AE lock can be accomplished at any desired moment. Therefore, the degree of freedom in a photography operation is expanded.

Abstract: An exposure control device for a camera in flash photography comprising;first means for measuring light from a central area of an object field; second means for measuring light from another area surrounding the central area; means responsive to said first and second measuring means for detecting a rear light condition; means for controlling exposure in response to said second measuring means to cause an over-exposure by a given value when said detecting means detects the back light condition; means for directing a flash light emission; and means for integrating light reflected from the object field upon the flash light emission to stop the flash light emission when the integrated light reaches a predetermined level.

Abstract: An improved eyepiece for a viewfinder of a single lens reflex camera is provided. This improved eyepiece includes a negative first lens element and a positive second lens element with an air space formed between the first and second lens elements. The second lens element has an aspheric surface at its object side. The configuration of the aspheric surface is a hyperboloid of revolution.

Abstract: A light measuring device for a single lens reflex camera includes a principal or main mirror capable of dividing light passing through an objective lens towards a finder system and towards a film plane. A submirror is provided behind the main mirror and directs the light passed therethrough towards the film plane for ultimately determining a focusing condition and a measurement of light intensity. A pair of focus detecting photosensor arrays, as well as a spotlight measuring photocell, is arranged relative to the submirror to receive the object light. The auxiliary mirror can be formed with a center portion for reflecting the light through the photocell arrays and a second light-reflecting plane having light diffusive characteristics for directing light for the detection of light measurement.

Abstract: In a focus condition detecting device of the type in which a pair of re-imaging lenses together with a condenser lens form a pair of re-images of an object image on a line sensor such that the distance between the corresponding points of the re-images on the line-sensor varies with the focus condition of a camera objective lens forming the objective image, the line sensor is located in front of a plane conjugate with a predetermined focal plane of the camera objective lens with respect to the condenser lens and the re-imaging lenses, so that the distance between the corresponding points of the first and second re-images on the line-sensor can be detected with resolution higher than one pitch length of the photocells of the line sensor.

Abstract: A focus condition detecting device of the type in which a pair of re-imaging lenses together with a condenser lens form a pair of re-images of an object image on a linesensor, such that the distance between the corresponding points of the re-images on the linesensor varies with the focus condition of a camera objective lens has an improved construction for positioning the linesensor with respect to the device with high accuracy. A field aperture mask having a field aperture is arranged optically behind a plane conjugate with the linesensor with respect to the re-imaging lenses and the condenser lens such that a pair of defocused images of the field aperture are formed on the linesensor by the re-imaging lenses and the condenser lens with respective one side blurred borders of the defocused images overlapping one another to make a V-shaped peak or dip of illuminance on a photocell of the linesensor located on the optical axis of the device, when the field aperture mask is uniformly illuminated.

Abstract: In a focus condition detecting device wherein an object image formed by an objective lens of a camera is re-imaged as first and second images on first and second photocell arrays through a pair of re-imaging lenses, a pair of plano-convex lenses are used as the re-imaging lenses to improve the accuracy of focus condition detection. The device is formed into a module and the plano-convex lenses are formed on a transparent plate supported on a main body of the module. An extremely thin masking member for blocking a part of light rays incident on the plano-convex lenses to form the first and second images is sandwiched between the transparent plate and a surface of the module main body. This arrangement prevents the masking member from rising and/or warping which otherwise causes inconsistency in luminous levels between the first and second images on the first and second photocell arrays. Various examples of the arrangement of the masking member to prevent its rising and/or warping are proposed.