There are provided a first lens group having a negative optical power as a whole, second and third lens groups having positive optical powers as a whole, which are located in this order from the object side. These lens groups are all configured to be movable in the optical axis direction during magnification. The first lens group is constituted by a bi-concave lens having a negative optical power and a positive meniscus lens which is convex at the object side thereof, which are located in this order from the object side. The second lens group is constituted by a bi-convex lens having a positive optical power and a bi-concave power having a negative optical power, which are located in this order from the object side and bonded to each other to constitute a cemented lens. The third lens group is constituted by a bi-convex lens having a positive optical power. The first and fifth lenses are double-aspherical lenses formed from resin and the third and fourth lenses are single-aspherical lenses.

 
Web www.patentalert.com

> Zoom lens system and image pickup apparatus having the same

~ 00345