| 摘要 |
PROBLEM TO BE SOLVED: To achieve both performance improvement and compactness of a lens. SOLUTION: A variable focal length lens system constituting a lens barrel includes at least in the order from an object side: a first lens group having a positive refractive power; a second lens group having a negative refractive power, and a third lens group having a positive refractive power. A guide means includes: a fixing barrel; a rotation frame which moves forward/backward in the optical axis direction in relation to the fixing barrel by rotation around the optical axis in relation to the fixed barrel; a direct advancing frame which is arranged inside the rotation frame and which does not rotate but displaces in the optical axis direction as a whole when the rotation frame rotates; a first guide frame which moves forward/backward the first lens group in the optical axis direction in relation to the direct advancing guide frame; and a second guide frame which moves forward/backward the third lens group in the optical axis direction in relation to the direct advancing guide frame. When the second lens group is fixed to the direct advancing guide frame as a whole and the lens position state changes from a wide angle end state to a telephoto end state, the direct advancing guide frame is fixed in the optical axis direction. COPYRIGHT: (C)2011,JPO&INPIT
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