| 摘要 |
PROBLEM TO BE SOLVED: To provide an optical system in which a converter lens system can be easily mounted on a main lens system, the optical performance of the optical system when the converter lens system is mounted can be maintained in a good state, and a focal length of the whole system can be easily shifted to be longer.SOLUTION: The optical system includes a main lens system having a focus lens system that moves upon focusing and a converter lens system that enlarges the focal length of the whole system. The converter lens system can be detachably attached to a space formed when the focus lens system moves upon focusing. The converter lens system includes, sequentially from an object side to an image side, a lens part Gn having a negative refractive power and a lens part Gp having a positive refractive power, which are separated by the largest air gap in the optical axis direction of the converter lens system. A focal length fN of the lens part Gn and a focal length fP of the lens part Gp are each appropriately set.SELECTED DRAWING: Figure 1 |
