Sony Corporation

Hideki Kai

Hiroyuki Matsumoto

Motoyuki Ohtake

Makoto Kanai

Syuuji Maki

A variable focal length lens system including: a first lens group having positive power; a second lens group having negative power; a third lens group having positive power; and a fourth lens group having positive power sequentially arranged from a side where an object is present. An aperture stop is disposed between the second and third lens groups. The first to fourth lens groups are so moved that the distance between the first and second lens groups increases, the distance between the second and third lens groups decreases, and the distance between the third and fourth lens groups decreases when a lens position setting is changed from a wide angle end state to a telescopic end state. The third lens group includes a negative lens and a positive lens disposed on the image side thereof. The variable focal length lens system satisfies the conditional expression, 0.35&#x3c;f3/|f3a|&#x3c;0.8.

Variable focal length lens system and imaging apparatus

A zoom lens includes: a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power, the first to fourth lens groups being arranged in order from an object side, in which zooming is performed through varying a distance between adjacent lens groups of the first to fourth lens groups, and the fourth lens group includes a first positive lens, a first negative meniscus lens, and a cemented lens which are arranged in order from the object side, the cemented lens being configured of a second negative meniscus lens with a convex surface facing the object side and a second positive lens.

Zoom lens and image pickup unit

A zoom lens includes a first lens group having positive refractive power, a second lens group having negative refractive power, a third lens group having positive refractive power, and a fourth lens group having positive refractive power, the first, second, third, and fourth lens groups being arranged in order from an object side, and satisfies conditional expression (1) and conditional expression (2) below, (1) 0.95&#x3c;|fw12|/fw&#x3c;1.2 and (2) 140&#x3c;f1/&#x3b2;t234&#x3c;150, where, fw12 denotes a synthetic focal length of the first lens group and the second lens group at a wide-angle end, fw denotes a focal length of a whole lens system at the wide-angle end, f1 denotes the focal length of the first lens group, and &#x3b2;t234 denotes the synthetic magnification of the second lens group, the third lens group, and the fourth lens group at a telephoto end.

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Kanagawa, Japan

Hideki Kai