Tamron Company, Ltd.

Lai Wei

Akio Arakawa

Toshiya Segawa

A variable magnification optical system according to the present invention includes, in order from an object side: a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, a fourth lens group having positive refractive power, and a following lens group, wherein at least the second lens group is moved so that a gap between the first lens group and the second lens group increases and a gap between the second lens group and the third lens group decreases when zooming from a wide angle end to a telephoto end, and a predetermined conditional expression is satisfied.

Variable magnification optical system and image pickup apparatus

A zoom lens includes sequentially 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 positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a negative refractive power. The zoom lens satisfies given conditions to implement a compact, wide angle, large aperture ratio zoom lens having excellent optical performance and compatible with solid state image sensors capable of recording full high vision images.

Zoom lens

A zoom lens includes sequentially 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 positive refractive power, a fourth lens group having a positive refractive power, and a fifth lens group having a negative refractive power. The zoom lens satisfies given conditions to implement a compact, large aperture ratio zoom lens having excellent optical performance and compatible with solid state image sensors capable of recording full high vision images.

A zoom lens includes sequentially from an object side a first lens group having a negative refractive power; a diaphragm; and a second lens group having a positive refractive power. Zoom from a wide angle edge to a telephoto edge is performed by displacement of the second lens group along an optical axis, toward the object side. Correction of imaging plane variation accompanying the zoom, is performed by displacement of the first lens group along the optical axis. The second lens group includes sequentially from the object side, a positive first lens having at least on aspheric surface and a positive second lens. Furthermore, a first condition &#x3c5;d&#x3e;63 and a second condition &#x3c5;d&#x3e;70 are satisfied, &#x3c5;dbeing the Abbe number for a d-line in the first lens of the second lens group and &#x3c5;dbeing the Abbe number for a d-line in the second lens of the second lens group.

Anti-vibration zoom lens optics of four lens groups where a unit associated with an aperture stop and an anti-vibration unit can be spaced apart from each other without interference between their driving mechanisms. The four groups include a leading, first lens group of positive refractivity, a succeeding second lens group of negative refractivity, a third lens group of positive refractivity, and a trailing, fourth lens group of positive refractivity all arranged in this order from the front end closest to the object to the rearmost. The fourth lens group include three subsets of lens pieces, a leading, first subset, a succeeding, second subset, and a trailing, third subset all arranged in this order from the front end closest to the object to the rearmost, and the second subset of lens pieces are moved perpendicular to the optical axis to compensate for blur in the imaging plane.

Anti-vibration zoom lens optics

A zoom lens includes sequentially from an object side a first lens group having a negative refractive power; a diaphragm; and a second lens group having a positive refractive power. Zoom from a wide angle edge to a telephoto edge is performed by displacement of the second lens group along an optical axis, toward the object side. Correction of imaging plane variation accompanying zoom, is performed by displacement of the first lens group along the optical axis. The second lens group includes a positive first lens disposed farthest on the object side and having at least one aspheric surface, and a cemented lens that includes a negative lens, a positive lens, and a negative lens. Furthermore, a first condition &#x3c5;dp&#x3e;75 is satisfied, &#x3c5;dp being the Abbe number for a d-line in the positive lens included in the cemented lens of the second lens group.

A zoom lens includes, sequentially from an object side, a first lens group having a negative refractive power; and a second lens group having a positive refractive power, where focal length is varied by changing a distance between the first lens group and the second lens group, and a first conditional expression 0.8&#x3c;|f/f|&#x3c;1.0 is satisfied, fbeing the focal length of the first lens group and fbeing the focal length of the second lens group.

A zoom lens includes, sequentially from an object side, a first lens group that is negative; and a second lens group that is positive, where focal length is varied by varying a distance between the first lens group and the second lens group. The first lens group includes, from the object side, a first lens that is a negative biconcave lens having at least one aspherical surface, and a second lens that is a positive meniscus lens having a convex surface facing toward the object side and at least one aspherical surface, and a first condition 0.8&#x3c;|f/f|&#x3c;1.0 and a second condition 0.5&#x3c;|r/f|&#x3c;0.8 are satisfied, where fis the focal length of the first lens group, fis the focal length of the second lens group, ris radius of curvature of a surface of the first lens in the first lens group, the surface facing toward an image.

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Saitama, Japan

Lai Wei