| 摘要 |
PROBLEM TO BE SOLVED: To obtain a zoom lens having excellent optical performance capable of coping with even an imaging device equal to or above a mega-pixel while achieving the miniaturization of an entire lens system, and an imaging apparatus using the same. SOLUTION: The zoom lens has only a first lens group having negative refractive power, a second lens group having positive refractive power and a third lens group having positive refractive power as a lens group in order from an object side to an image side, and is constituted of four lenses as the entire system. When the focal distance of an i-th lens group is denoted as (fi), the focal distance of the entire system at a wide angle end is denoted as (fw) and the focal distance of the entire system at a telephoto end is denoted as (ft) assuming that (i) is order counted from the object side when zooming is performed by changing space between the respective lens groups, the zoom lens satisfies conditions, that is, an expression(1): -0.85<f1/f2<-0.7, an expression (2): 1.6<ft/fw and an expression (3): 0.8<f3/√(fw×ft)<1.5. COPYRIGHT: (C)2007,JPO&INPIT |
