Matsushita Electric Industrial Co., Ltd.

Panasonic Intellectual Property Management Co., Ltd.

Hisayuki Ii

Shusuke Ono

Hiroaki Okayama

Yasuo Nakajima

Keizo Ishiguro

Takehiro Nishioka

Tsuyoshi Kakimoto

Rieko Hiramoto

A zoom lens system includes: a first lens group having positive power; a second lens group having negative power; and following lens groups. The following lens groups include: a first focus lens group having negative power; and a second focus lens group having positive power, arranged adjacent to, and closer to the image than, the first focus lens group. The first and second focus lens groups move along an optical axis during focusing from an infinity focus point on a close focus point. During zooming from a wide-angle end toward a telephoto end, intervals between lens groups change with the first lens group fixed with respect to an image plane. The zoom lens system satisfies the Inequality &#x2212;0.23&#x3c;f2/TTL&#x3c;&#x2212;0.15, where TTL is an optical total length at the telephoto end and f2 is a focal length of the second lens group.

Zoom lens system, and lens barrel, image capture device, and camera system including the zoom lens system

Zoom lens system

A compact zoom lens comprising a small number of lenses, providing an aperture of about F1.4 and a zoom ration of about 14, with a full angle of view at the wide angle end of 64.degree. or wider. The zoom lens of the present invention comprises, aligned respectively from the object side, a fixed first lens group, comprising a lens with a negative refracting power, a lens with a positive refracting power, and a meniscus lens with a positive refracting power; a movable second lens group to provide zooming effect, comprising a lens with a negative refracting power, a biconcave lens with a negative refracting power, and a lens with a positive refracting power, with at least one surface of these lenses aspheric; a fixed third lens group with a positive refracting power, with at least one surface of these lenses aspheric; a fourth lens group, movable for compensating the position of the focal plane, with a positive refracting power, with at least one surface of the lenses aspheric. The below mentioned formula (1) is satisfied,

Zoom lens and video camera comprising the same

A zoom lens assembly includes, in succession order from the object side, a first fixed lens group of a positive refractive power including a negative lens, a positive lens and a positive meniscus lens; a second movable lens group of a negative refractive power including a negative meniscus lens, a positive lens and a positive lens for effecting a variation of image magnification by moving along an optical axis of the zoom lens assembly; a third fixed lens group of a positive refractive power having at least one aspherical face and including a positive lens and a negative lens; and a fourth movable lens group of a positive refractive power including having at least one aspherical surface and also including negative and positive lenses cemented together.

Zoom lens assembly

A zoom lens comprises sequentially from a side of an object: a fixed first lens group constituted by a convex lens, a double convex lens and a meniscus convex lens; a movable second lens group constituted by a meniscus convex lens, a double concave lens and a convex lens; a fixed third lens group constituted by a single lens having at least one aspherical surface; and a movable fourth lens group constituted by a concave lens and two convex lenses at least one of which has at least one aspherical surface.

Zoom lens

A zoom lens of this invention comprises in successive order from the object side a first group having a positive refractive power and fixed, a second group having a negative refracting power for effecting a variation of image magnification by moving on the optical axis, a third group having a positive power for effecting a light condensing action and fixed, and a fourth group moving on the optical axis so as to keep an image surface position to be changed in response to a move of the second group and a move of the object in a constant positional relation with the reference surface. Comparatively large air space is provided between the third and fourth groups of the zoom lens.

Growing community of inventors

Katano, Japan

Hisayuki Ii