| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a zoom lens and an image pickup apparatus by which both of increase in magnification and angle are achieved and besides reduction in diameter is achieved. <P>SOLUTION: A zoom lens includes, from the object side to the image side, a positionally-fixed first lens group having positive refracting power, a second lens group having negative refracting power and movable in an optical axis direction for zooming, a third lens group having positive refracting power, and a fourth lens group movable in the optical axis direction for correction of a focal position by zooming and for focusing. The first lens group consists of three lenses including a negative lens, a positive lens and another positive lens disposed in order from the object side to the image side, satisfying the following conditional expressions (1), (2) and (3): (1) 15.0<ft/fw<31.0; (2) 7.0<f1/fw<13.0; and (3) -8.5<fL1/fw<-4.0, where fw and ft are the focal lengths of the entire lens system in a wide angle end state and a telephoto end state, respectively, f1 is the focal length of the first lens group, and fL1 is the focal length of the negative lens of the first lens group. <P>COPYRIGHT: (C)2013,JPO&INPIT |
