| 摘要 |
PROBLEM TO BE SOLVED: To enhance the imaging performance of a small-sized zoom lens having a zooming ratio of about 3, suitable to equipment that uses a high pixel solid-state imaging device. SOLUTION: The zoom lens 1 includes in the order starting from an object along an optical axis O1, a 1st lens group 10 having positive refractive power and positioned fixedly at all times along the optical axis O1 when a power of the zoom lens is varied or the zoom lens is focused, a 2nd lens group 20 having negative refractive power, a 3rd lens group 30 having positive refractive power, a 4th lens group 40 having positive refractive power and a 5th lens group 50. The 2nd lens group 20 and the 4th lens group 40 are moved for varying the power of the zoom lens, and the 4th lens group 40 is further moved for focusing the zoom lens. The 1st lens group 10 includes a prism 13 as a reflecting optical element. The 2nd lens group 20 includes, in the order starting from the object along the optical axis O1, a negative lens 12 and a bonded lens, including a negative lens 22 and a positive lens 23, and the 4th lens group 40 includes two positive lenses 41 and 42. COPYRIGHT: (C)2006,JPO&NCIPI
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