OPTICAL SYSTEM AND IMAGING DEVICE PROVIDED WITH OPTICAL SYSTEM

Provided are: an optical system provided with 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 negative refractive power, which are arranged in order from the object side, the second lens group moving along the optical axis during focusing, and the third lens group moving along the optical axis during focusing; the first lens group and the third lens group are fixed with respect to the image plane, and when the distance from the object-most side surface of the second lens group to the image-most side surface is OAL2 and the distance from the object-most side surface of the entire optical system to the image plane is OAL, 0.06 < = OAL2/OAL is satisfied. 提供一种光学系统、以及具备光学系统的拍摄装置，上述光学系统具备：从物体侧依次排列的、具有正屈光力的第一透镜组、具有负屈光力的第二透镜组、以及具有负屈光力的第三透镜组，在对焦时，第二透镜组沿着光轴移动，第一透镜组以及第三透镜组相对于成像面固定，在将从第二透镜组的最靠物体侧面到最靠像侧面的距离设为OAL2，将从整个光学系统的最靠物体侧面到像面的距离设为OAL时，满足0.06≤OAL2/OAL。