Macro lens system

摘要

A macro lens system includes a positive first lens group, an aperture and a negative second lens group arranged in the order from an object side. The driving mechanism drives the lens groups and the aperture to move independently along an optical axis for focusing. When the lens groups are moved toward the object side, the aperture is also moved to the object side. The moving amount of the aperture is determined to control increasing of an effective F-number. The moving amount of the aperture is smaller than that of the first lens group and is larger than that of the second lens group.