Abstract: There is provided a zoom lens having, in an order of an object-to-image direction, a first lens group having a positive refractive power and fixed with respect to an image plane; a second lens group having a negative refractive power; a third lens group having a positive refractive power and fixed with respect to an optical axis direction; a fourth lens group having a positive refractive power; and a fifth lens group having a positive refractive power and fixed with respect to the optical axis direction. The fifth lens group is composed of a fifth-a lens group having a negative refractive power; a fifth-b lens group having a positive refractive power; and a fifth-c lens group having a positive refractive power, arranged in the order of the object-to-image direction.

Abstract: A zoom lens with a reduced overall length having a color separating prism therein and a telecentric property with a first lens group (GI) having a positive refractive power and having a fixed position, a second lens group (GII) of the variable magnification type having a negative refractive power and having a position movable for magnification variation, a third lens group (GIII) having a positive refractive power and having a fixed position and a fourth lens group (GIV) having a positive refractive power and having a position variable for adjustment of a focal position upon magnification variation and upon focusing are disposed in order from an object side. At least one face of the two convex lenses in the fourth lens group is formed from an aspheric face.

Abstract: An image pickup apparatus having a plurality of image pickup modes and a zoom lens for use with the image pickup apparatus is configured such that, even if the dimension of an effective screen region of an image pickup element changes as a result of changeover of the image pickup mode, the change of the angle of view is moderated and good aberration correction can be achieved in any of the image pickup modes. In an image pickup apparatus (1), an additional lens set (G5) having a positive refractive power is positioned most adjacent the image side with respect to a zoom lens (2) for movement to and from a position on an optical axis of the zoom lens.

Abstract: A zoom lens includes in order and from the side of an object, a first lens group having a positive refractive power and fixed in position, a second lens group having a negative refractive power and movable in position for providing mainly zooming, a third lens group having a positive refractive power and fixed in position, a fourth lens group having a positive refractive power and movable in position for performing a focal position correction due to the zooming and for focusing, and a fifth lens group including a single lens fixed in position.

Abstract: A light amount adjuster includes two filter members, each having a gradation ND region where the transmittance continuously changes, disposed such that the two filter members face each other and the direction in which the gradation of one of the filter members changes differs from the direction in which the gradation of the other one of the filter members changes and configured such that the filter members can move in a symmetrical manner with respect to each other.

Abstract: An image capture apparatus includes: a zoom lens arranged in a housing and including fixed lens groups, movable lens groups and at least three prisms; and an imager device arranged in the housing. The zoom lens includes: a fixed first lens group including a negative lens group having a first optical axis, a first prism approximately perpendicularly folding an optical axis, and a positive lens group having a second optical axis folded by the first prism; movable lens groups and at least one fixed lens group arranged along the second optical axis to perform a zooming action, an image plane position correcting action and a focusing action; and a second prism arranged on an image side relative to a movable lens group that is a closest to the image side among the plurality of movable lens groups for approximately perpendicularly folding the optical axis.

Abstract: A zoom lens with a reduced overall length having a color separating prism therein and a telecentric property with a first lens group (GI) having a positive refractive power and having a fixed position, a second lens group (GII) of the variable magnification type having a negative refractive power and having a position movable for magnification variation, a third lens group (GIII) having a positive refractive power and having a fixed position and a fourth lens group (GIV) having a positive refractive power and having a position variable for adjustment of a focal position upon magnification variation and upon focusing are disposed in order from an object side. At least one face of the two convex lenses in the fourth lens group is formed from an aspheric face.

Abstract: A zoom lens made up of a first lens group having positive refracting power, a second lens group having negative refracting power, a third lens group having positive refracting power, and a fourth lens group having positive refracting power, which are disposed in order from an object side, in which the first lens group and the third lens groups are stationary, and the zoom lens performs mainly variable power by shifting the second lens group in an optical axis direction, and performs correction for image position fluctuations and focusing by shifting the fourth lens group in the optical axis direction, is characterized in that the first lens group is composed of five lenses: a concave lens; a convex lens with a strong convexity facing to an image side; a cemented lens made up of a concave lens with a strong concavity facing to the image side, and a convex lens; and a convex lens with a strong convexity facing to the object side, which are disposed in order from the object side, and by satisfying each of the fo

Abstract: The present invention provides a camera system which comprises: a zoom lens; phototaking means converting an image captured by the zoom lens into an electric image signal; and image control means, in which the zoom lens is made up of a first lens group having positive refracting power, a second lens group having negative refracting power, a third lens group having positive refracting power, a fourth lens group having negative refracting power, and a fifth lens group having positive refracting power, which are disposed in this order from an object side, and is configured so that the first lens group, the third lens group, and the fifth lens group are stationary; the second lens group is shifted in an optical axis direction to mainly perform variable power; and the fourth lens group is shifted in the optical axis direction to perform correction for image position fluctuations and focusing.

Abstract: When a brightness level of an object is below a predetermined level, an ND filter is removed from an iris opening to fully open the iris opening, and when the brightness level of the object is above a predetermined level, the ND filter is placed to the iris opening to fully close the iris opening. When the ND filter is moved between the fully-opened state and the fully-closed state, an exposure change amount corresponding to an amount offsetting the exposure change amount due to a state transition is generated by controlling iris blades.

Abstract: An image pickup apparatus having a plurality of image pickup modes and a zoom lens for use with the image pickup apparatus is configured such that, even if the dimension of an effective screen region of an image pickup element changes as a result of changeover of the image pickup mode, the change of the angle of view is moderated and good aberration correction can be achieved in any of the image pickup modes.

Abstract: The invention concerns with an exposure control mechanism for use in an image pickup apparatus in which a diaphragm aperture formed by a plurality of diaphragm blades moving straightforward in opposite directions is covered by an ND filter, and intends to prevent deterioration of image quality caused by diffraction even in an image pickup device having a small picture size and a short pixel pitch. The image pickup apparatus comprises an exposure control mechanism for adjusting the quantity of light flux entering a shooting lens system. The exposure control mechanism comprises a diaphragm made up of diaphragm blades movable on a plane perpendicular to an optical axis in opposite directions to define a diaphragm aperture, and an ND filter made up of at least two ND filter elements having different transmittances.

Abstract: The invention concerns with an exposure control mechanism for use in an image pickup apparatus in which a diaphragm aperture formed by a plurality of diaphragm blades moving straightforward in opposite directions is covered by an ND filter, and intends to prevent deterioration of image quality caused by diffraction even in an image pickup device having a small picture size and a short pixel pitch. The image pickup apparatus comprises an exposure control mechanism for adjusting the quantity of light flux entering a shooting lens system. The exposure control mechanism comprises a diaphragm made up of diaphragm blades movable on a plane perpendicular to an optical axis in opposite directions to define a diaphragm aperture, and an ND filter made up of at least two ND filter elements having different transmittances.

Abstract: Provided is an electronic view finder for use in a video camera apparatus that by making the relative position between an LCD and an ocular lens unit proper can decrease the rotatory polarization characteristic and can thereby enhance the contrast of the image. When a liquid crystal image screen surface has the characteristic of Viewing-Angle that this screen surface is seen with its contrast or brightness being different according to the direction in which to see the screen surface, the center of an eye-cup opening portion (6) on the light emission side of an ocular lens unit (2) is shifted from an optical axis (3) of the ocular lens unit (2). Thereby, an observer's eye is guided to a position detached from the position corresponding to the optical axis (3) to see the liquid crystal image screen surface (1) from an oblique direction. It has been thereby arranged to enable the liquid crystal image screen surface to be observed with an excellent contrast.

Abstract: An imaging apparatus with an exposure controlling mechanism being made to define an iris aperture by moving iris blades on surfaces perpendicular to an optical axis, wherein the exposure controlling mechanism includes a first iris blade to which a first ND filter having at least two levels of transmissivity is attached, a second iris blade to which no ND filter is attached, and a third iris blade to which a second ND filter having a single transmissivity is attached, and the first to the third iris blades are made to differ respectively in amounts and phases of their displacements caused by an operation of a driving means.

Abstract: Provided is an electronic view finder for use in a video camera apparatus that by making the relative position between an LCD and an ocular lens unit proper can decrease the rotatory polarization characteristic and can thereby enhance the contrast of the image. When a liquid crystal image screen surface has the characteristic of Viewing-Angle that this screen surface is seen with its contrast or brightness being different according to the direction in which to see the screen surface, the center of an eye-cup opening portion (6) on the light emission side of an ocular lens unit (2) is shifted from an optical axis (3) of the ocular lens unit (2). Thereby, an observer's eye is guided to a position detached from the position corresponding to the optical axis (3) to see the liquid crystal image screen surface (1) from an oblique direction. It has been thereby arranged to enable the liquid crystal image screen surface to be observed with an excellent contrast.

Abstract: A zoom lens comprising a first lens group having a positive refracting power and its position fixed, a second lens group having a negative refracting power and displacable mainly for magnification, a third lens group having a positive refracting power and its position fixed, and a fourth lens group having a positive refracting power and displacable mainly for correction of the focal position for magnification and focusing.

Abstract: A zoom lens of high image quality having various aberrations improved and most suitably used with a still camera is disclosed. A first lens group (Gr1) to a fifth lens group (Gr5) having positive, negative, positive, positive and substantially zero refracting powers, respectively, are arranged in that order from an object side toward an image surface side. The third lens group (Gr3) is configured of a joint lens of a convex lens and a concave lens, while the fifth lens group is configured of a joint lens of a concave lens and a convex lens. The conditions -0.018<1/.upsilon.3<0.018, 10<.vertline..upsilon.5.1-.upsilon.5.2.vertline. and 1<.vertline.r5.2/fW.multidot.tan .omega.W.vertline.<3 are satisfied, where .upsilon.3 is the equivalent Abbe's number of the third lens group, .upsilon.5.1 is the Abbe's number of the lens of the fifth lens group nearer to the object side, .upsilon.5.2 is the Abbe's number of the lens of the fifth lens group nearer to the image surface side, r5.

Abstract: A variable magnification finder wherein a change in magnification is performed by rotating the finder about an axis. According to a first embodiment of this invention, a variable magnification finder has in succession from an object side a first lens component including a four-surface lens, a second lens component having a convex surface facing the object side and a third lens component having a convex surface facing the object side. The four-surface lens includes a first surface opposite a second surface and a third surface opposite a fourth surface. The first and second surfaces have a first optical axis in common and the third and fourth surfaces have a second optical axis in common. The first optical axis is substantially perpendicular to the second optical axis. Magnification of the finder is changed by rotating the four-surface lens on a third optical axis which is substantially perpendicular the first and second optical axes.

Abstract: An inner focus type zoom lens is a nine lens system including third, fourth and seventh lenses which are plastic lenses including aspherical surfaces, and first, second, fifth, sixth, eighth and ninth lenses which are spherical glass lenses. This zoom lens system can reduce the manufacturing cost by employing the plastic lenses and eliminating aspherical glass surfaces. Moreover, this zoom lens system is superior in correction of aberrations and less susceptible to temperature changes.