| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical system which is used for large aperture photographic lenses suitable for image capturing devices and which, among other things, is equipped with an inner focusing mechanism that corrects well for distortion aberration over an entire focusing range while suppressing other aberrations and offers good image quality, a large aperture ratio, and a wide view angle.SOLUTION: An optical system comprises a first lens group G1 having positive or negative refractive power, a second lens group G2 having positive refractive power, an aperture stop S, and a third lens group G3 having positive refractive power arranged in order from the object side to the image side. Among lenses having negative refractive power in the third lens group G3, 3A lens L3A positioned on the most object side has a concave surface on the object side. When shifting focus from an object at infinity to an object at a close distance, the second lens group G2 and the third lens group G3 moves toward the object side. The optical system satisfies predefined conditional expressions. |
