| 摘要 |
A variable-power optical system has: a first lens group (G1) having a positive refractive power, the first lens group (G1) being arranged furthest toward the object side; a negative lens group (G2) having a negative refractive power, the negative lens group (G2) being arranged on the image side relative to the first lens group; a positive lens group (G4) having a positive refractive power, the positive lens group (G4) being arranged on the image side relative to the negative lens group and including at least one lens for moving integrally with an aperture diaphragm; and a focusing group (G3) arranged between the negative lens group and the positive lens group; the first lens group moving with respect to an image surface, the interval between the first lens group and the negative lens group changing, and the interval between the negative lens group and the positive lens group changing during power variation, the interval between the focusing group and the lens disposed in a position facing the object side in the focusing group changing, and the interval between the focusing group and the lens disposed in a position facing the image side in the focusing group changing during focusing, the focusing group being configured from a single lens component, the positive lens group comprising a front group having a positive refractive power and a rear group having a negative refractive power, the interval between the front group and the rear group being the largest air interval among the air intervals in the positive lens group, and the rear group comprising two lens components. |
