This lens enables gradual changes to the amount of soft focus from the normal setting in general shooting. As the amount of soft focus is adjusted after focusing is achieved in the normal setting, the difficulty involved in focusing is alleviated, making the lens more user friendly through the adoption of 1 focusing ring system where focusing is achieved by turning the helicoid ring and soft focus is performed by sliding the ring linearly.
Functionally, by changing the space between the front and rear lens groups, the spherical aberration is created on the underside while other aberration changes are reduced, and the effective aperture is maximized to increase the marginal illumination, providing well-balanced soft focus throughout the entire frame.
In the normal setting, sharp definition with high contrast is also obtained through good aberration compensation, making the lens useful for general shooting.