| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens capable of attaining stable optical quality also in manufacturing. SOLUTION: When a lens position state is changed from a wide angle end state to a telephoto end state, a 1st lens group G1 and a 3rd lens group G3 are fixed in a fixed position in an optical axis direction, and a 2nd lens group G2 is shifted to an image side, and the fluctuation of an image field position caused by the shift of the 2nd lens group G2 is compensated by the shift of a 4th lens group G4, and the 3rd lens group G3 is constituted of a 1st positive lens L31 having a convex face on the object side, a negative lens L32 having a concave face on the image side, and a 2nd positive lens L33 arranged in this order from the object side, and provided that a distance from the object side lens face of the 1st positive lens constituting the 3rd lens group G3 up to the image side lens face of the negative lens is expressed by D3a, a focal distance in the wide angle end state is expressed by fw, the zoom lens satisfies the following conditional inequality (1); D3a/fw>0.5. COPYRIGHT: (C)2005,JPO&NCIPI
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