Abstract: An image pickup apparatus includes: an image pickup device that includes a pixel used for focus detection, a plurality of the pixels being arranged in a matrix; a correction memory that stores correction information used for correcting a difference in amounts of received light that depend on pixel positions of the pixels used for focus detection; a correcting section that reads the correction information to correct a pixel value of the pixel used for focus detection; and a focus detecting section that detects a focal point by using the pixel value corrected by the correcting section. Focus accuracy is increased by correcting the pixel value for an AF pixel depending on the pixel position.

Abstract: An image pickup apparatus includes: an optical imaging system; an image pickup device; a defocus quantity calculation circuit for calculating a defocus quantity based on a phase difference between a plurality of signals for focus detection obtained from a plurality of pixels for focus detection that respectively receive a light flux that has passed through a different pupil region of the optical imaging system; a focusing section for driving the optical imaging system so as to achieve an in-focus state in accordance with the calculated defocus quantity; and a thinning-out circuit for thinning out a plurality of signals for focus detection that are not used for calculating the defocus quantity, based on an analysis result of a signal component of an object image.

Abstract: Provided are a variable power optical system in which the value of the entire length with respect to the image height is reduced and the aberration is well corrected, and an image pickup device comprising the same. Specifically provided is a variable power optical system comprising, in order from the object side, at least a first lens group having negative refractive power, a variable power group having positive refractive power, and a final lens group having positive refractive power, wherein the variable power group is provided with, in order from the object side, a first lens element having positive refractive power, a second lens element, and a third lens element, the second lens element has a convex shape on the object side, and the final lens group comprises a positive lens, the variable power optical system satisfying the following conditional expression: 10?VdLg?45 ?1.0<(R2a?R2b)/(R2a+R2b)<1.

Abstract: An image pickup apparatus in which, a taking lens is installable or fixed, includes an image pickup element in which, pixels having a photoelectric conversion portion are arranged two dimensionally. The pixels include focal-point detection pixels which are arranged to restrict a direction of incidence of a light beam which is incident, and image-pickup pixels which are arranged such that, the direction of incidence of the light beam which is incident is not restricted more than the direction of incidence restricted by the focal-point detection pixel. The focal-point detection pixel outputs at least a signal for ranging, and the image-pickup pixel outputs at least a signal for an image. The image pickup apparatus includes an overflow judging section which judges whether or not the photoelectric conversion portion has overflowed, and a calculating section which calculates an amount of defocus based on a judgment result of the overflow judging section and the signal for ranging.

Abstract: A variable power optical system includes, in order from the object side, a first lens group having negative refractive power, a variable power group having positive refractive power, and a final lens group having positive refractive power. The variable power group is provided with, in order from the object side, a first lens element having positive refractive power, a second lens element, and a third lens element. The second lens element has a convex shape on the object side. The final lens group includes a positive lens. The variable power optical system satisfies the following conditions: 10?VdLg?45 ?1.0<(R2a?R2b)/(R2a+R2b)<1.0 where VdLg is the Abbe number of the positive lens of the final lens group with respect to the d line, R2a is the curvature radius of the object-side surface of the second lens element, and R2b is the curvature radius of the image-side surface of the third lens element.

Abstract: An image pickup apparatus includes: an image pickup device that includes a pixel used for focus detection, a plurality of the pixels being arranged in a matrix; a correction memory that stores correction information used for correcting a difference in amounts of received light that depend on pixel positions of the pixels used for focus detection; a correcting section that reads the correction information to correct a pixel value of the pixel used for focus detection; and a focus detecting section that detects a focal point by using the pixel value corrected by the correcting section. Focus accuracy is increased by correcting the pixel value for an AF pixel depending on the pixel position.

Abstract: A zoom optical system comprising, in order from the object side, a first lens unit with negative power, a second lens unit with positive power, a third lens unit with positive power, and a fourth lens unit, wherein spacing between the first lens unit and the fourth lens unit is fixed to an image surface, and the second lens unit and the third lens unit are moved on an optical axis so as to change spacings between the respective lens units when the magnification of the zoom optical system is changed. The third lens unit comprises lens elements more than three, including an aperture stop, at least a lens element with positive power and at least a lens element with negative power, and the most image-side lens element of the third lens unit is a meniscus lens element with a concave surface facing the image side.

Abstract: A variable power optical system includes, in order from the object side, a first lens group having negative refractive power, a variable power group having positive refractive power, and a final lens group having positive refractive power. The variable power group is provided with, in order from the object side, a first lens element having positive refractive power, a second lens element, and a third lens element. The second lens element has a convex shape on the object side. The final lens group includes a positive lens. The variable power optical system satisfies the following conditions: 10?VdLg?45 ?1.0<(R2a?R2b)/(R2a+R2b)<1.0 where VdLg is the Abbe number of the positive lens of the final lens group with respect to the d line, R2a is the curvature radius of the object-side surface of the second lens element, and R2b is the curvature radius of the image-side surface of the third lens element.

Abstract: At least some of the pixels on which color filters that give the largest weight to a brightness signal or color filters that have the highest transmittance among the plurality of color filters are provided are pixels for focus detection that are designed in such a way that the direction of incidence of light beams incident thereon is restricted, the pixels other than the pixels for focus detection are pixels for image picking-up that are designed in such a way that the degree of restriction placed on light beams incident thereon is smaller than that placed on light beams incident on the pixels for focus detection, the pixels for focus detection output at least a signal for ranging, the pixels for image picking-up output at least a signal for an image, and there are at least three pixels for focus detection in an area defined between a circle having its center at the center of any one of the pixels for focus detection and having a radius equal to 3.

Abstract: An image forming optical system of the present invention includes at least one cemented lens which includes a first lens element (e1), a second lens element (e2), and a third lens element (e3). The first lens element e1 is cemented to a surface on one side of the second lens element e2, and the third lens element e3 is cemented to the other surface of the second lens element e2. The first lens element e1 is a positive lens, and a combined refracting power of the second lens element e2 and the third lens element e3 is negative. The cemented lens satisfies a predetermined conditional expression.

Abstract: An image pickup apparatus,includes a computing section which computes a defocus amount which has been estimated,a calculating section which calculates an accuracy of defocus detection, a setting section which sets a correction value from a result of the calculating section, a correcting section which corrects the correction value obtained from the result of the setting section, to reduce an absolute value of the defocus amount which has been estimated, a lens-drive amount calculating section which calculates a lens-drive amount based on a result from the correcting section, and a control section which, at the time of video photography, carries out focusing successively by using the defocus amount and the lens drive amount obtained from the computing section, the calculating section, the setting section, and the correcting section.

Abstract: An image forming optical system characterized by comprising a positive first lens group, a negative second lens group, and third and subsequent lens groups having a positive composite refracting power, wherein the first lens group is composed of a cemented lens made up of one positive lens and one negative lens arranged in order from the object side, and the image forming optical system satisfies the following conditional expressions (1-1) and (2-1): 0.05<T1g/Flt<0.10??(1-1) 0.50<?gF<0.75??(2-1) where T1g is the thickness of the first lens group on the optical axis, Flt is the focal length of the entire image forming optical system at the telephoto end, and ?gF is the partial dispersion ratio (ng1?nF1)/(nF1?nC1) of the negative lens, where nd1, nC1, nF1, and ng1 are refractive indices of the negative lens respectively for the d-line, C-line, F-line, and g-line.

Abstract: An image pickup apparatus in which, a taking lens is installable or fixed, includes an image pickup element in which, pixels having a photoelectric conversion portion are arranged two dimensionally. The pixels include focal-point detection pixels which are arranged to restrict a direction of incidence of a light beam which is incident, and image-pickup pixels which are arranged such that, the direction of incidence of the light beam which is incident is not restricted more than the direction of incidence restricted by the focal-point detection pixel. The focal-point detection pixel outputs at least a signal for ranging, and the image-pickup pixel outputs at least a signal for an image. The image pickup apparatus includes an overflow judging section which judges whether or not the photoelectric conversion portion has overflowed, and a calculating section which calculates an amount of defocus based on a judgment result of the overflow judging section and the signal for ranging.

Abstract: An image pickup apparatus of the invention includes: an optical imaging system; an image pickup device; a defocus quantity calculation section for calculating a defocus quantity based on a phase difference between signals for focus detection obtained from pixels for focus detection; a high-frequency component quantity detection section for detecting a quantity of high-frequency component contained in a pixel signal outputted from a pixel other than the pixels for focus detection; a region determination section for determining in accordance with which of the defocus quantity and the high-frequency component quantity the optical imaging system is to be driven, according to a detection result of detecting in which of a plurality of divided blocks of the image pickup device an object of interest is present; and a focusing section for driving the optical imaging system in accordance with a determination result of the region determination section.

Abstract: The image pickup apparatus of the present invention includes: an optical imaging system for forming an object image; an image pickup device including a plurality of pixels that photoelectrically converts the object image; a defocus quantity calculation section for calculating a defocus quantity based on a phase difference between a plurality of signals for focus detection obtained from a plurality of pixels for focus detection that respectively receive a light flux that passes through a different pupil region of the optical imaging system; a focusing section for driving the optical imaging system so as to achieve an in-focus state, in accordance with the defocus quantity calculated at the defocus quantity calculation section; an addition practicability determination section for determining a practicability of performing inter-frame addition on a plurality of signals for focus detection before calculating the defocus quantity, based on an analysis result of a signal component of the object image; and an inter-

Abstract: An image pickup apparatus includes: an optical imaging system; an image pickup device; a defocus quantity calculation circuit for calculating a defocus quantity based on a phase difference between a plurality of signals for focus detection obtained from a plurality of pixels for focus detection that respectively receive a light flux that has passed through a different pupil region of the optical imaging system; a focusing section for driving the optical imaging system so as to achieve an in-focus state in accordance with the calculated defocus quantity; and a thinning-out circuit for thinning out a plurality of signals for focus detection that are not used for calculating the defocus quantity, based on an analysis result of a signal component of an object image.

Abstract: At least some of the pixels on which color filters that give the largest weight to a brightness signal or color filters that have the highest transmittance among the plurality of color filters are provided are pixels for focus detection that are designed in such a way that the direction of incidence of light beams incident thereon is restricted, the pixels other than the pixels for focus detection are pixels for image picking-up that are designed in such a way that the degree of restriction placed on light beams incident thereon is smaller than that placed on light beams incident on the pixels for focus detection, the pixels for focus detection output at least a signal for ranging, the pixels for image picking-up output at least a signal for an image, and there are at least three pixels for focus detection in an area defined between a circle having its center at the center of any one of the pixels for focus detection and having a radius equal to 3.

Abstract: An image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop, the positive lens group is disposed at an object side of the aperture stop, the positive lens group has a cemented lens which is formed by cementing a plurality of lenses, in a rectangular coordinate system in which a horizontal axis is let to be Nd and a vertical axis is let to be ?d, when a straight line indicated by Nd=?×?d+? (where, ?=?0.017) is set, Nd and ?d of at least one lens forming the cemented lens is included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and of an area determined by following conditional expressions (2a) and (3a). 1.45<?<2.15??(1a) 1.30<Nd<2.

Abstract: An image forming optical system according to the present invention is characterized in that, in an image forming optical system having a positive lens group, a negative lens group, and an aperture stop, the positive lens group is disposed at an object side of the aperture stop, the positive lens group has a cemented lens which is formed by cementing a plurality of lenses, in a rectangular coordinate system in which a horizontal axis is let to be Nd and a vertical axis is let to be ?d, when a straight line indicated by Nd=?×?d+? (where, ?=?0.017) is set, Nd and ?d of at least one lens forming the cemented lens is included in both of areas namely, an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1a), and a line when an upper limit value is in a range of the following conditional expression (1a), and of an area determined by following conditional expressions (2a) and (3a). 1.45<?<2.15??(1a) 1.30<Nd<2.

Abstract: In an image forming optical system having a positive lens group, a negative lens group, and an aperture stop, the positive lens group being disposed at an image-plane side of the aperture stop and having a cemented lens, and when a straight line indicated by Nd=?×?d+? (where, ?=?0.017) is set, Nd and ?d of at least one lens forming the cemented lens are included in both an area which is determined by a line when a lower limit value is in a range of a following conditional expression (1), and a line when an upper limit value is in a range of the following conditional expression (1), and in an area determined by following conditional expressions (2) and (3) 1.45<?<2.15??(1) 1.30<Nd<2.20??(2) 3<?d<25??(3) Here, Nd denotes a refractive index, and ?d denotes an Abbe's number.