| 摘要 |
PROBLEM TO BE SOLVED: To obtain an optical system whose optical element driven to correct camera shake is light in weight, where aberration is excellently corrected even in an ordinary state or a corrected state and which is made as compact as an optical system having no camera shake correcting function by providing a decentered lens with a diffraction optical surface. SOLUTION: The telephotographic system zooming lens is constituted of a 1st group Gr1 having positive refractive power, a 2nd group Gr2 having negative refractive power, a 3rd group Gr3 provided with a diaphragm S and having the positive refractive power, and a 4th group Gr4 having the negative refractive power; and zooming is performed by changing a distance between respective groups. In such constitution, the decentered lens is provided with the diffraction optical surface. In such a case, it is desirable to constitute the decentered lens of a single lens. Furthermore, the single lens satisfies following conditions; 0.005<ϕd<ϕr<0.10 andνdr>50. In expressions,ϕd expresses the power of the diffraction optical surface,ϕr expresses the synthetic power of the refractive optical surface of the lens having the diffraction optical surface, andνdr expresses the Abbe number of the lens having the diffraction optical surface.
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