Abstract: A focus position control apparatus includes a lens for forming an image from light from a subject, an imaging element and an imaging controller for performing photoelectric conversion on the subject image, lights having at least two different wavelengths or wavelength bands, on an imaging plane to generate at least a visible-region image signal and an infrared-region image signal, a focus-position movement mechanism for moving the lens in a direction along an optical axis relative to the imaging plane, a focusing state evaluator for evaluating a focusing state in each wavelength or wavelength band based on the generated visible-region image signal and infrared-region image signal, and a movement controller for driving the focus-position movement mechanism based on the evaluation result from the focusing state evaluator.

Abstract: An optical system has a positive lens group, a negative lens group, and an aperture stop. The negative lens group is disposed at an object side of the aperture stop and has a cemented lens, and in a rectangular coordinate system in which a horizontal axis is Nd and a vertical axis is ?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 are included in both an area determined by a line when a lower limit value is in a range of expression (1a) and a line when an upper limit value is in a range of the expression (1a), and an area determined by expressions (2a) and (3a): 1.45<?<2.15 (1a); 1.30<Nd<2.20 (2a); and 3<?d<12 (3a); where Nd denotes a refractive index, and ?d denotes an Abbe's number.

Abstract: It is preferable that for an image forming optical system a basic structure which includes a first lens group having a negative refracting power, which is made of one cemented lens component, a second lens group having a positive refracting power, a third lens group having a positive refracting power, which is made of one lens component, and is movable for focusing, and a fourth lens group which is made of one lens component having an aspheric surface, and at the time of zooming from a wide angle end to a telephoto end, the second lens group moves only toward the object side, and the first lens group and the third lens group move while following a trajectory of movement different from a trajectory of movement of the second lens group is adopted, and that the image forming optical system satisfies predetermined conditional expressions.

Abstract: In an image forming optical system having a positive lens group, a negative lens group, and an aperture stop, the negative lens group is disposed at an image side of the of the aperture stop, the negative lens group has a cemented lens which is formed by cementing a plurality of lenses, and 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 are 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 (1), and a line when an upper limit value is in a range of the following conditional expression (1), and an area determined by following conditional expressions (2) and (3). 1.45<?<2.15??(1) 1.30<Nd<2.20??(2) 3<?d<12??(3) Here, Nd denotes a refractive index, and ?d denotes an Abbe's number.

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 negative lens group is disposed at an object side of the aperture stop, the negative lens group has a cemented lens which is formed by cementing a plurality of lenses, and 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 are 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 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 negative lens group is disposed at an image side of the of the aperture stop, the negative lens group has a cemented lens which is formed by cementing a plurality of lenses, and 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 are 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 (1), and a line when an upper limit value is in a range of the following conditional expression (1), and an area determined by following conditional expressions (2) and (3). 1.45<??2.15??(1) 1.30<Nd<2.20??(2) 3<?d<12??(3) Here, Nd denotes a refractive index, and ?d denotes an Abbe's number.

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 image-plane 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 are 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 (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.

Abstract: The invention relates to a zoom optical system that makes it possible to offer a sensible tradeoff between cost savings and size reductions and an electronic system that incorporates it. The zoom optical system comprises a lens group having negative refracting power and a lens group having positive refracting power. At least one lens is formed by molding of a first lens blank (11) that provides a surface including at least an optical function surface after molding, and a second lens blank (12) that provides a surface other than said surface including at least an optical function surface after molding, wherein the first lens blank (11) and the second lens blank (12) are integrated into a one-piece lens (10).

Abstract: The invention relates to a zoom optical system that makes it possible to offer a sensible tradeoff between cost savings and size reductions and an electronic system that incorporates it. The zoom optical system comprises a lens group having negative refracting power and a lens group having positive refracting power. At least one lens is formed by molding of a first lens blank (11) that provides a surface including at least an optical function surface after molding, and a second lens blank (12) that provides a surface other than said surface including at least an optical function surface after molding, wherein the first lens blank (11) and the second lens blank (12) are integrated into a one-piece lens (10).

Abstract: The invention relates to a zoom optical system that makes it possible to offer a sensible tradeoff between cost savings and size reductions and an electronic system that incorporates it. The zoom optical system comprises a lens group having negative refracting power and a lens group having positive refracting power. At least one lens is formed by molding of a first lens blank (11) that provides a surface including at least an optical function surface after molding, and a second lens blank (12) that provides a surface other than said surface including at least an optical function surface after molding, wherein the first lens blank (11) and the second lens blank (12) are integrated into a one-piece lens (10).

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: The invention relates to a zoom optical system that makes it possible to offer a sensible tradeoff between cost savings and size reductions and an electronic system that incorporates it. The zoom optical system comprises a lens group having negative refracting power and a lens group having positive refracting power. At least one lens is formed by molding of a first lens blank (11) that provides a surface including at least an optical function surface after molding, and a second lens blank (12) that provides a surface other than said surface including at least an optical function surface after molding, wherein the first lens blank (11) and the second lens blank (12) are integrated into a one-piece lens (10).

Abstract: The invention relates to a zoom optical system that makes it possible to offer a sensible tradeoff between cost savings and size reductions and an electronic system that incorporates it. The zoom optical system comprises a lens group having negative refracting power and a lens group having positive refracting power. At least one lens is formed by molding of a first lens blank (11) that provides a surface including at least an optical function surface after molding, and a second lens blank (12) that provides a surface other than said surface including at least an optical function surface after molding, wherein the first lens blank (11) and the second lens blank (12) are integrated into a one-piece lens (10).

Abstract: The invention relates to a zoom optical system that makes it possible to offer a sensible tradeoff between cost savings and size reductions and an electronic system that incorporates it. The zoom optical system comprises a lens group having negative refracting power and a lens group having positive refracting power. At least one lens is formed by molding of a first lens blank (11) that provides a surface including at least an optical function surface after molding, and a second lens blank (12) that provides a surface other than said surface including at least an optical function surface after molding, wherein the first lens blank (11) and the second lens blank (12) are integrated into a one-piece lens (10).

Abstract: The invention relates to a zoom optical system that makes it possible to offer a sensible tradeoff between cost savings and size reductions and an electronic system that incorporates it. The zoom optical system comprises a lens group having negative refracting power and a lens group having positive refracting power. At least one lens is formed by molding of a first lens blank (11) that provides a surface including at least an optical function surface after molding, and a second lens blank (12) that provides a surface other than said surface including at least an optical function surface after molding, wherein the first lens blank (11) and the second lens blank (12) are integrated into a one-piece lens (10).

Abstract: The invention relates to a zoom optical system that makes it possible to offer a sensible tradeoff between cost savings and size reductions and an electronic system that incorporates it. The zoom optical system comprises a lens group having negative refracting power and a lens group having positive refracting power. At least one lens is formed by molding of a first lens blank (11) that provides a surface including at least an optical function surface after molding, and a second lens blank (12) that provides a surface other than said surface including at least an optical function surface after molding, wherein the first lens blank (11) and the second lens blank (12) are integrated into a one-piece lens (10).