Abstract: An image pickup apparatus includes an image forming optical system which includes an aperture stop that sets an axial light beam, and a diffracting optical surface disposed at a position different from a position where the aperture stop is disposed, and an imager which is disposed on an image side of the image forming optical system, and has a light-receiving surface which is not flat and is curved to be concave toward the image forming optical system, wherein the diffracting optical surface satisfies the following conditional expression (1). 0.1<|DSD/TL|?1.

Abstract: An image pickup apparatus includes an image forming optical system having an aperture stop, a first lens, and a second lens, and an imager having a light-receiving surface that is curved to be concave toward the image forming optical system, and a relative partial dispersion for a medium of the first lens differs from a relative partial dispersion for a medium of the second lens, and when a straight line indicated by ?gFLA=?×?dLA+?LA (where ?=?0.00163) has been set, ?gFLA and ?dLA for the medium of the first lens are included in both of an area determined by the following conditional expression (1) and an area determined by the following conditional expression (2), and the following conditional expression (3) is satisfied: 0.68<?LA??(1), ?dLA<50??(2), and 0<|f/Rimg|?1.5??(3).

Abstract: The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-bending zoom optical system comprising, in order from its object side, a 1-1st lens group G1-1 comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G1-2 comprising one positive lens and a second lens group G2 having positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group G2 moves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

Abstract: An image pickup apparatus includes an image forming optical system having an aperture stop, a first lens, and a second lens, and an imager having a light-receiving surface that is curved to be concave toward the image forming optical system, and a relative partial dispersion for a medium of the first lens differs from a relative partial dispersion for a medium of the second lens, and when a straight line indicated by ?gFLA=?×?dLA+?LA (where ?=?0.00163) has been set, ?gFLA and ?dLA for the medium of the first lens are included in both of an area determined by the following conditional expression (1) and an area determined by the following conditional expression (2), and the following conditional expression (3) is satisfied: 0.68<?LA ??(1), ?dLA<50 ??(2), and 0<|f/Rimg|?1.5 ??(3).

Abstract: The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-bending zoom optical system comprising, in order from its object side, a 1-1st lens group G1-1 comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G1-2 comprising one positive lens and a second lens group G2 having positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group G2 moves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

Abstract: An image pickup apparatus includes an image forming optical system which includes an aperture stop that sets an axial light beam, and a diffracting optical surface disposed at a position different from a position where the aperture stop is disposed, and an imager which is disposed on an image side of the image forming optical system, and has a light-receiving surface which is not flat and is curved to be concave toward the image forming optical system, wherein the diffracting optical surface satisfies the following conditional expression (1). 0.1<|DSD/TL|?1.

Abstract: The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-banding zoom optical system comprising, in order from its object side, a 1-1st lens group G1-1 comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G1-2 comprising one positive lens and a second lens group G2 having positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group G2 moves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

Abstract: The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-banding zoom optical system comprising, in order from its object side, a 1-1st lens group G1-1 comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G1-2 comprising one positive lens and a second lens group G2 having positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group G2 moves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

Abstract: The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-bending zoom optical system comprising, in order from its object side, a 1-1st lens group G1-1 comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G1-2 comprising one positive lens and a second lens group G2 having positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group G2 moves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

Abstract: The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-bending zoom optical system comprising, in order from its object side, a 1-1st lens group G1-1 comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G1-2 comprising one positive lens and a second lens group G2 having positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group G2 moves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

Abstract: The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-bending zoom optical system comprising, in order from its object side, a 1-1st lens group G1-1 comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G1-2 comprising one positive lens and a second lens group G2 having positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group G2 moves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

Abstract: It is preferable that an image forming optical system includes in order from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, and a subsequent lens group having a positive refractive power as a whole, and that the third lens group includes only a cemented lens having a negative refractive power, which includes a positive lens and a negative lens in order from the object side. Moreover, it is preferable that a cemented surface of the cemented lens in the third lens group has a shape which is convex toward an image side.

Abstract: A zoom optical system in which: a positive first lens group, a negative second lens group, a positive third lens group, and a positive fourth lens group are arranged in that order from the object side and magnification is changed by properly changing distances between these lens groups; the first lens group consists of only one lens element and the most object-side surface of the first lens group has a convex shape which faces toward the object side; the second lens group includes, in order from the object side, a negative single lens, a negative cemented lens, and a positive single lens; and the following condition (1) or (2) is satisfied: 0.2??Dw-w10/Lt?0.

Abstract: A zoom lens according to the present invention includes, in order from the object side to the image side, a first lens unit having a positive refracting power, a second lens unit having a negative refracting power, a third lens unit having a negative refracting power, and a fourth lens unit having a positive refracting power, wherein during zooming from the wide angle end to the telephoto end, the first lens unit, the second lens unit, the third lens unit, and the fourth lens unit move in such a way that they are located closer the object side at the telephoto end than at the wide angle end, the distance between the first lens unit and the second lens unit is larger at the telephoto end than at the wide angle end, the distance between the second lens unit and the third lens unit is larger at the telephoto end than at the wide angle end, and the distance between the third lens unit and the fourth lens unit is smaller at the telephoto end than at the wide angle end.

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: The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-bending zoom optical system comprising, in order from its object side, a 1-1st lens group G1-1 comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G1-2 comprising one positive lens and a second lens group G2 having positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group G2 moves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

Abstract: The invention relates to an electronic image pickup system whose depth dimension is extremely reduced, taking advantage of an optical system type that can overcome conditions imposed on the movement, of a zooming movable lens group while high specifications and performance are kept. The electronic image pickup system comprises an optical path-bending zoom optical system comprising, in order from its object side, a 1-1st lens group G1-1 comprising a negative lens group and a reflecting optical element P for bending an optical path, a 1-2nd lens group G1-2 comprising one positive lens and a second lens group G2 having positive refracting power. For zooming from the wide-angle end to the telephoto end, the second lens group G2 moves only toward the object side. The electronic image pickup system also comprises an electronic image pickup device I located on the image side of the zoom optical system.

Abstract: It is preferable that an image forming optical system includes in order from an object side, a first lens group having a positive refractive power, a second lens group having a negative refractive power, a third lens group having a negative refractive power, and a subsequent lens group having a positive refractive power as a whole, and that the third lens group includes only a cemented lens having a negative refractive power, which includes a positive lens and a negative lens in order from the object side. Moreover, it is preferable that a cemented surface of the cemented lens in the third lens group has a shape which is convex toward an image side.

Abstract: A zoom optical system in which: a positive first lens group, a negative second lens group, a positive third lens group, and a positive fourth lens group are arranged in that order from the object side and magnification is changed by properly changing distances between these lens groups; the first lens group consists of only one lens element and the most object-side surface of the first lens group has a convex shape which faces toward the object side; the second lens group includes, in order from the object side, a negative single lens, a negative cemented lens, and a positive single lens; and the following condition (1) or (2) is satisfied: 0.2??Dw-w10/Lt?0.

Abstract: A zoom lens according to the present invention includes, in order from the object side to the image side, a first lens unit having a positive refracting power, a second lens unit having a negative refracting power, a third lens unit having a negative refracting power, and a fourth lens unit having a positive refracting power, wherein during zooming from the wide angle end to the telephoto end, the first lens unit, the second lens unit, the third lens unit, and the fourth lens unit move in such a way that they are located closer the object side at the telephoto end than at the wide angle end, the distance between the first lens unit and the second lens unit is larger at the telephoto end than at the wide angle end, the distance between the second lens unit and the third lens unit is larger at the telephoto end than at the wide angle end, and the distance between the third lens unit and the fourth lens unit is smaller at the telephoto end than at the wide angle end.