Abstract: A projector system including a projector unit and a control device. The projector unit includes: a projector; a change mechanism that changes a projection direction; a plurality of optical systems having different optical properties; and a switch mechanism that selects one of the optical systems. The control device includes: a change unit that controls the change mechanism; and a switch unit that causes the switch mechanism to place one of the optical systems to be used for the projector in conjunction with the changing of the projection direction of the projector which is caused by the change unit.

Abstract: A projection optical system, in order from a magnification side to a demagnification side, comprising a negative first lens unit, a positive second lens unit, a positive third lens unit, a fourth lens unit, a fifth lens unit, and a sixth lens unit, wherein the second and third lens units move along an optical axis in zooming, the first lens unit moves along the optical axis in focusing, and the conditions: ?0.55<fW/f1<?0.30 and 1.9<f123T/f123W<fT/fW (f1: focal length of first lens unit, f123W: composite focal length of first, second and third lens units at wide-angle limit, f123T: composite focal length of first, second and third lens units at telephoto limit, fW: focal length of entire system at wide-angle limit, fT: focal length of entire system at telephoto limit) are satisfied.

Abstract: A projector system including a projector unit and a control device. The projector unit includes: a projector; a change mechanism that changes a projection direction; a plurality of optical systems having different optical properties; and a switch mechanism that selects one of the optical systems. The control device includes: a change unit that controls the change mechanism; and a switch unit that causes the switch mechanism to place one of the optical systems to be used for the projector in conjunction with the changing of the projection direction of the projector which is caused by the change unit.

Abstract: A single focal length lens system comprising at least a positive first lens unit and a second lens unit, wherein the first lens unit includes a first sub lens unit E which successively comprises a negative lens element A, a positive lens element B, a negative lens element C and a positive lens element D, a second sub lens unit comprising at least one lens element is a focusing lens unit in the second lens unit, and the conditions: 1.0<|fW/fA|<2.2, 0.5<fW/fB<2.0, 0.5<|fW/fC|<1.7, and 0.5<fW/fD<1.8 (fW: focal length of the lens system, fA: focal length of the lens element A, fB: focal length of the lens element B, fC: focal length of the lens element C, fD: focal length of the lens element D) are satisfied.

Abstract: A zoom lens system comprising a plurality of lens units, wherein a lens unit located closest to an object side and a lens unit located closest to an image side are fixed with respect to an image surface in zooming from a wide-angle limit to a telephoto limit at a time of image taking, and at least three lens units among all the lens units are moving lens units that move along an optical axis in the zooming, at least one lens unit among the moving lens units is a focusing lens unit that moves along the optical axis in focusing from an infinity in-focus condition to a close-object in-focus condition, and the following condition: ?(Tn)/H?2.1 (?(Tn): the total of axial thicknesses of all the moving lens units, H: the maximum image height) is satisfied.

Abstract: A plastic lens, comprising: a first edge section having a first outer circumferential edge surface formed substantially parallel to an optical axis of the plastic lens; and a second edge section having a second outer circumferential edge surface formed so as to have a step with respect to the first outer circumferential edge surface, wherein the first outer circumferential edge surface is not coated with a black coating material that suppresses internal reflection of light, and at least a portion of the second outer circumferential edge surface is coated with the black coating material that suppresses internal reflection of light.

Abstract: A projection optical system, in order from a magnification side to a demagnification side, comprising a negative first lens unit, a positive second lens unit, a positive third lens unit, a fourth lens unit, a fifth lens unit, and a sixth lens unit, wherein the second and third lens units move along an optical axis in zooming, the first lens unit moves along the optical axis in focusing, and the conditions: ?0.55<fW/f1<?0.30 and 1.9<f123T/f123W<fT/fW (f1: focal length of first lens unit, f123W: composite focal length of first, second and third lens units at wide-angle limit, f123T: composite focal length of first, second and third lens units at telephoto limit, fW: focal length of entire system at wide-angle limit, fT: focal length of entire system at telephoto limit) are satisfied.

Abstract: A single focal length lens system comprising at least a positive first lens unit and a second lens unit, wherein the first lens unit includes a first sub lens unit E which successively comprises a negative lens element A, a positive lens element B, a negative lens element C and a positive lens element D, a second sub lens unit comprising at least one lens element is a focusing lens unit in the second lens unit, and the conditions: 1.0<|fW/fA|<2.2, 0.5<fW/fB<2.0, 0.5<|fW/fC|<1.7, and 0.5<fW/fD<1.8 (fW: focal length of the lens system, fA: focal length of the lens element A, fB: focal length of the lens element B, fC: focal length of the lens element C, fD: focal length of the lens element D) are satisfied.

Abstract: Compact and lightweight zoom lens systems having less aberration fluctuation in association with focusing, lens barrels, interchangeable lens apparatuses, and camera systems are provided. The zoom lens system comprises: a first lens unit having positive optical power; a first focusing lens unit which is located on an image side relative to the first lens unit, has negative optical power, and moves along an optical axis in zooming and focusing; and a second focusing lens unit which is located on the image side relative to the first focusing lens unit, has positive optical power, and moves along the optical axis in the zooming and the focusing, and satisfies the condition: |d2T/d1T|<1.0 (d1T: an amount of movement of the first focusing lens unit in focusing at a telephoto limit, d2T: an amount of movement of the second focusing lens unit in focusing at a telephoto limit).

Abstract: A zoom lens system wherein a positive lens unit located closest to an object side is fixed with respect to an image surface in zooming, a negative lens unit, among lens units located on an image side relative to an aperture diaphragm, is a focusing lens unit which moves along an optical axis in focusing, and the conditions: ?1.8<fn/fW<?0.3 and 0.1<T1/fW<1.5 (fn: a composite focal length of the negative lens unit, T1: an axial thickness of the positive lens unit located closest to the object side, fW: a focal length of the entire system at a wide-angle limit) are satisfied.

Abstract: A compact and lightweight zoom lens system having excellent imaging performance, which is favorably applicable to an interchangeable-lens type digital camera system, is provided. The zoom lens system of the present invention includes, in order from an object side to an image side, a first lens unit having positive optical power and composed of not more than two lens elements, a second lens unit having negative optical power, a third lens unit having negative optical power, and a fourth lens unit having positive optical power. In zooming from a wide-angle limit to a telephoto limit, the fourth lens unit moves along an optical axis. Further, the following conditions are satisfied: 1.50<nd1<1.72, 50<vd1<75 (nd1: a refractive index to the d line of a positive lens element constituting the first lens unit, vd1: an Abbe number of a positive lens element constituting the first lens unit).

Abstract: A zoom lens system comprising a plurality of movable lens units which individually move along an optical axis at the time of zooming, wherein a lens unit located closest to an object side is fixed relative to an image surface at the time of zooming, at least two of the movable lens units are focusing lens units which move along the optical axis at the time of focusing in at least one zooming position, and the condition: 0.1<T1/fW<1.5 (T1: an axial thickness of the lens unit located closest to the object side, fW: a focal length of the entire system at a wide-angle limit) is satisfied; an interchangeable lens apparatus; and a camera system are provided.

Abstract: A plastic lens, comprising: a first edge section having a first outer circumferential edge surface formed substantially parallel to an optical axis of the plastic lens; and a second edge section having a second outer circumferential edge surface formed so as to have a step with respect to the first outer circumferential edge surface, wherein the first outer circumferential edge surface is not coated with a black coating material that suppresses internal reflection of light, and at least a portion of the second outer circumferential edge surface is coated with the black coating material that suppresses internal reflection of light.

Abstract: A zoom lens system comprising a plurality of lens units, wherein a lens unit located closest to an object side and a lens unit located closest to an image side are fixed with respect to an image surface in zooming from a wide-angle limit to a telephoto limit at a time of image taking, and at least three lens units among all the lens units are moving lens units that move along an optical axis in the zooming, at least one lens unit among the moving lens units is a focusing lens unit that moves along the optical axis in focusing from an infinity in-focus condition to a close-object in-focus condition, and the following condition: ?(Tn)/H?2.1 (?(Tn): the total of axial thicknesses of all the moving lens units, H: the maximum image height) is satisfied.

Abstract: A single focal length lens system comprising: at least a front lens unit having positive or negative power, and being fixed in focusing; a focusing lens unit having positive power, and moving along an optical axis in focusing; and a rear lens unit having negative power, and being fixed in focusing, wherein the focusing lens unit includes: a cemented lens of a negative lens and a positive lens; and a positive single lens located on the image side relative to the cemented lens and having an aspheric surface, the rear lens unit is composed of one single lens, and the condition: ?0.5<fW/fGR<?0.1 (fW, fGR: focal lengths of the entire single focal length lens system, the rear lens unit) is satisfied.

Abstract: Compact and lightweight zoom lens systems having less aberration fluctuation in association with focusing, lens barrels, interchangeable lens apparatuses, and camera systems are provided. The zoom lens system comprises: a first lens unit having positive optical power; a first focusing lens unit which is located on an image side relative to the first lens unit, has negative optical power, and moves along an optical axis in zooming and focusing; and a second focusing lens unit which is located on the image side relative to the first focusing lens unit, has positive optical power, and moves along the optical axis in the zooming and the focusing, and satisfies the condition: |d2T/d1T|<1.0 (d1T: an amount of movement of the first focusing lens unit in focusing at a telephoto limit, d2T: an amount of movement of the second focusing lens unit in focusing at a telephoto limit).

Abstract: A single focal length lens system comprising a front lens unit, an aperture diaphragm, and a rear lens unit, wherein the front lens unit is composed of three or less lenses including a negative lens located closest to the object side and a positive lens located on the image side relative to the negative lens, and does not move along an axis in focusing, the rear lens unit includes a focusing lens unit moving along the axis and a fixed lens unit not moving along the axis in focusing, and the conditions: 0.4<fW/fGF<1.5, 0.9<fW/T1<4.5, and ?0.3<fW/fG1<0.3 (fW, fGF, fG1: focal lengths of the entire single focal length lens system, the focusing lens unit, the front lens unit, T1: an axial distance from an object side lens surface of the negative lens to the aperture diaphragm) are satisfied.

Abstract: Compact and lightweight zoom lens systems having less aberration fluctuation in association with focusing, lens barrels, interchangeable lens apparatuses, and camera systems are provided. The zoom lens system comprises: a first lens unit having positive optical power; a first focusing lens unit which is located on an image side relative to the first lens unit, has negative optical power, and moves along an optical axis in zooming and focusing; and a second focusing lens unit which is located on the image side relative to the first focusing lens unit, has positive optical power, and moves along the optical axis in the zooming and the focusing, and satisfies the condition: |d2T/d1T|<1.0 (d1T: an amount of movement of the first focusing lens unit in focusing at a telephoto limit, d2T: an amount of movement of the second focusing lens unit in focusing at a telephoto limit).

Abstract: A zoom lens system comprising a plurality of movable lens units which individually move along an optical axis at the time of zooming from a wide-angle limit to a telephoto limit during image taking, wherein at least two of the movable lens units are focusing lens units which move along the optical axis at the time of focusing from an infinity in-focus condition to a close-object in-focus condition in at least one zooming position, and among the focusing lens units, a lens unit having the absolute value, which is not the greatest absolute value, of a wobbling value at a wide-angle limit is a wobbling lens unit which senses a moving direction of the focusing lens units at the time of focusing by wobbling itself in a direction along the optical axis; an interchangeable lens apparatus; and a camera system are provided.

Abstract: A zoom lens system of lens units, the system including, in object-side-to-image-side order: a first lens unit having positive optical power; a second lens unit; an aperture diaphragm; one or more additional lens units, with a first of the additional lens units being a first focusing-lens unit having negative optical power and moving along the optical axis in the zoom lens system focusing; an image blur compensating lens unit, adjacent the first focusing-lens unit and movable in a direction perpendicular to the optical axis in order to optically compensate image blur; with the lens system satisfying: 0.1<(T1+T2)/H<2.0 (T1 being the axial thickness of the first lens unit, T2 being the axial thickness of the second lens unit, and H being the height of an image the zoom lens system forms on an image surface on the image-side end of the zoom lens system).