Patent ID: 7715110
Filing Date: 2010-05-11
Classification: G02B

Abstract:
1. A zoom lens system consisting, in order from an object side thereof to an image-forming side thereof, a first lens group with negative refractive power, a second lens group with positive refractive power, and a third lens group with positive refractive power, wherein zooming is carried out by moving the first lens group, the second lens group, and the third lens group and focusing is carried out by moving the third lens group, the first lens group consists of one negative lens and one positive lens disposed in that order from the object side, wherein at least one surface out of surfaces of the negative lens and the positive lens is aspherical, the second lens group consists, in order from the object side, of a cemented lens composed of a positive lens and a negative lens, and one meniscus lens that is concave on the image-forming side, wherein one surface of the meniscus lens is aspherical and at least one surface out of a surface of the object side of the cemented lens, a surface of the image-forming side of the cemented lens, and another surface of the meniscus lens is aspherical, the third lens group consists of a single positive lens, and a combined focal length f