| 摘要 |
<P>PROBLEM TO BE SOLVED: To provide a zoom lens obtaining good image quality, which is small sized and having little deterioration in optical performance due to a manufacturing error such as relative shifting of shafts in respective lenses and even when vibration insulation is carried out. <P>SOLUTION: The zoom lens is composed of lens groups which are: a positive first lens group L1; a negative second lens group L2; a positive third lens group L3; a positive fourth lens group L4; and a positive fifth lens group L5 in this order from an object side. In this case, when zooming from a wide angle end to a telephoto end, the image forming position is varied by having the second lens group L2 moved to an image surface IP side as well as having the spacing between respective lens groups varied and the third lens group L3 is moved in the direction having the same perpendicular component as the optical axis. The third lens group L3 is composed of: a 3a lens group L3a having positive refractive power; an aperture diaphragm SP; and a 3b lens group L3b in this order from the object side. The 3a lens group L3a is composed of one lens component having positive refractive power. The 3b lens group L3b includes a negative lens. When the focal distances for the 3a lens group L3a and the 3b lens group L3b are respectively f3a and f3b, the relation: -0.1<f3a/f3b<0.1 is satisfied. <P>COPYRIGHT: (C)2013,JPO&INPIT |
