| 摘要 |
<p><P>PROBLEM TO BE SOLVED: To provide an imaging optical system equipped with an anti-vibration mechanism which can cope with a large-sized imaging device, achieves higher performance and downsizing, suppresses beam exit angle, and has small aberration variation in entire photographing region while focusing by lightweight lens groups. <P>SOLUTION: An imaging optical system includes in order from an object side: a first lens group G1 having positive refractive power; an aperture diaphragm S; a second lens group G2 having positive refractive power; and a third lens group G3 having a negative refractive power. When focusing from an infinity object to a short-distance object, the second lens group G2 moves to the object side along an optical axis, the third lens group G3 have at least one positive lens and one negative lens, and a part or all of the third lens group G3 are made to move in a direction orthogonal to the optical axis to perform vibration isolation and moreover to satisfy a predetermined conditional expression. <P>COPYRIGHT: (C)2013,JPO&INPIT</p> |
