摘要:
In a single-lens reflex camera having an objective lens, a focusing screen and a view finder, a photodetector array is arranged to receive a central part of an object image formed by the objective lens and a focusing condition of the objective lens is detected by calculating an evaluation function from image signals supplied from the photodetectors. A presetting dial for selecting given photodetectors whose image signals are used for detecting the focusing condition is provided at such a position that a part of the dial is exposed to the outside through an opening formed in a rear wall of a camera body at a position underneath a film winding lever. A light emitting diode array is provided on the focusing screen so as to be seen by a user through the view finder. Only desired light emitting diodes are lighted on under the control of a signal supplied by the dial to indicate the region of the photodetector array which is used for detecting the focusing condition.
摘要:
In a camera, a focus condition of an objective lens system is automatically detected in accordance with a combination of two different type detection methods. A light flux emanating from the objective lens system is divided into two light fluxes by means of a prism having a half mirror and a reflecting mirror and a first light flux transmitted through the half mirror is received by a first light receiving element array via a lenticular lens array and a second light flux reflected by the half mirror and reflecting mirror successively is directly received by a second light receiving element array. The lenticular lens array is so arranged that an exit pupil of the objective lens and the first light receiving element array are conjugated with each other and thus divided images of the exit pupil are projected upon respective elements of each pair of adjacent light receiving elements. At first, illumination signals supplied from the first image receiving element array are processed to derive a first evaluation value on the basis of an image lateral shift detection to indicate roughly a focal condition of the objective lens system. After the objective lens system has driven near the best focus position, illumination signals supplied from the first and second light receiving element arrays are processed to derive a second evaluation value on the basis of an image sharpness detection to indicate finely the focal condition of the objective lens system.
摘要:
In an analog-digital converting apparatus including a row of light receiving units with each unit having a light receiving element and a sample-hold circuit, a counter for producing a digital signal whose value is increased successively, a digital-analog converter for receiving the digital signal and producing an analog reference signal whose amplitude increases successively from a lower limit value to an upper limit value in step-shaped manner, comparators for comparing the output signals of the light receiving units with said analog reference signal, respectively, memories for receiving the digital signal and controlled by the comparators, respectively to store instantaneous digital values when the corresponding comparators change their states, there is provided a second light receiving unit having substantially the same construction as that of the first mentioned light receiving unit except that a light receiving element provided therein is covered with a light shielding mask so as to produce an output equivalent to a dark current component of the light receiving element, the output of which unit is used as a lower limit voltage source for said digital-analog converter. The apparatus may further include a third light receiving unit having substantially the same as that of the first light receiving unit except that the light receiving element is removed and the input of the sample-hold circuit is connected to a supply voltage so as to produce an output equivalent to a saturation value of the light receiving element, the output of which unit is used as an upper limit voltage source for the digital-analog converter.
摘要:
A method of automatically adjusting focus conditions of photographic optical system is disclosed. In the method at least a part of optical image formed on a predetermined focal plane by an optical system is projected onto first and second photocell arrays in the front and the rear of a surface conjugated to the predetermined focal plane, and onto at least one of other photocell arrays arranged between the first and second photocell arrays. Outputs of first, second and other photocell arrays are arithmetically operated in accordance with respective given evaluation functions thereby obtaining first, second and other evaluation values. These evaluation values are compared with each other and the optical system is intermittently shifted in the optical axis direction with first or second moving step in the case of decision from the compared result that the optical system is positioned within or outside a predetermined range including the in-focused position.
摘要:
A method and apparatus for detecting focus conditions of a photographic optical system is disclosed. The invention comprises a member for dividing the wavefront of a light beam from a photographic optical system in an image space thereof, a first light receiving device including two photocell arrays provided in the front and the rear of a surface conjugated to a predetermined focal plane of the optical system, and a second light receiving device including at least one photocell array provided at a surface conjugated to one of the photocell arrays in the first light receiving device. A first signal representing horizontal shift of an optical image is detected based on outputs of at least one photocell array in the second light receiving device and one photocell array in the first light receiving device having a relation conjugated to the photocell array in the second light receiving device. A second signal representing defocused amount of the image is detected based on outputs of two photocell arrays in the first light receiving device thereby detecting focus conditions by the first and the second signals.
摘要:
A method of detecting focusing conditions used for optical machinery is disclosed. The focusing conditions of an optical image projected onto photodetector arrays arranged on both sides of the focal plane with a certain optical distance are detected based on an evaluation function representing a sum of absolute values of differences between output signals of adjacent photodetectors. When a value of a first evaluation function represented by the largest absolute value is less than a predetermined threshold a second evaluation function represented by a sum of the maximum and next largest absolute values is used thereby detecting the focusing conditions for a graded image.
摘要:
In a method and apparatus for detecting focus condition of an imaging optical system, the focus condition is detected in accordance with a combination of two different detection methods such as an image sharpness detection and an image lateral shift detection by using first and second light receiving element arrays for the image sharpness detection and a third light receiving element array for the image lateral shift detection. For making the construction of the apparatus compact and simple, these light receiving element arrays are formed on the same semiconductor substrate. Further a light flux dividing prism and a lenticular lens array are formed integrally with each other. According to the focus detection method of the present invention, it is possible to detect the focus condition for various kinds of subjects accurately over a wide range by using both the image sharpness detection and image lateral shift detection even in a range near an in-focus position.
摘要:
A focus condition of an objective lens is detected on the basis of a lateral shift of two images formed by first and second light fluxes which are transmitted through right- and left-hand halves of the lens, respectively. In order to separate the first and second light fluxes, there is arranged an array of triangle prisms each having first and second surfaces which are inclined symmetrically with respect to the optical axis of lens by a critical angle so that one of the light fluxes is transmitted through the one of the surfaces, but is totally reflected by the other surface of each prism. The first and second light fluxes transmitted through the prisms are received by an array of light receiving elements in such a manner that the first and second light fluxes are selectively received by odd and even numbered light receiving elements, respectively.
摘要:
In order to effect an automatic focus control in an image pick-up apparatus, a photography lens for forming an image of the object onto a two-dimensional solid state image sensing device is arranged in a fixed position, while the two-dimensional solid state image sensing device is arranged movably in the optical axis direction of the photography lens, and the image sensing device is moved in accordance with a focusing error signal detected by a focusing condition detecting circuit having an additional light receiving element mounted on the same substrate as the image sensor but discrete from and operating independently of the image sensor. Since the light and small solid state image sensing device is moved for the focus control instead of the heavy and large photography lens, it is possible to perform the focus control in a prompt manner and to make a mechanism for driving the image sensing device small and simple.
摘要:
A method of comparing analog signals delivered from a number of light detecting elements with analog signals delivered from a digital-analog converter by means of a plurality of comparator circuits whose output analog signals are supplied as write enable signals to a plurality of digital memories which are controlled by means of digital signals delivered from a central control circuit such that an illumination intensity information of each picture element is read out as the digital signal in the digital memories, thereby obtaining a signal of detecting a focal point of cameras or the like optical devices.