| 摘要 |
PROBLEM TO BE SOLVED: To provide a zoom lens that achieves optical quality which is stable even in course of manufacture. SOLUTION: The zoom lens includes, in order from an object side, a first lens group G1 having positive refractive power, a second lens group G2 having negative refractive power, a third lens group G3 having positive refractive power, and a fourth lens group G4 having positive refractive power. When a lens position changes from a wide-angle end state to a telephoto end state, the first lens group G1 and third lens group G3 are fixed, the second lens group G2 is moved to an image side, a change in the position of an image plane is compensated for by the movement of the fourth lens group G4. The third lens group G3 includes, in order from the object side, a first positive lens L31 the convex face of which is oriented on the object side, a negative lens L32 the concave face of which is oriented on the image side, and a second positive lens L33. An aperture stop S is disposed near the first positive lens L31 disposed in the third lens group G3. The zoom lens satisfies conditional expressions which are appropriately set. COPYRIGHT: (C)2011,JPO&INPIT
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