| 摘要 |
PROBLEM TO BE SOLVED: To provide an inner-focus type optical system performing focusing with a small number of lenses and having high imaging performance, an imaging apparatus including the optical system, and a manufacturing method for the optical method.SOLUTION: An optical system comprises, in order from an object side along an optical axis, a first negative lens, a second negative lens, and a third positive lens, and performs focusing from an infinite object to a short distance object by moving the third positive lens in an optical axis direction. The optical system satisfies the following conditional expression: 0.01<(-Fln)/Fl3<1.00, where Fln represents a composite focal length of the first lens and the second lens and Fl3 represents a focal length of the third lens.SELECTED DRAWING: Figure 1 |
