At about twice the diagonal of the 6x7cm format, the 180mm is the preferred focal length when the RZ is used for portrait photography. This lens features an optically correct center, allowing traditional use (no soft focus) at apertures of f/8 or smaller. Soft focus is acheived through the use of three supplementary disks (included)- each one has a large hole in the middle surrounded by smaller holes. The desired soft focus effect is acheived through aperture and disk selection. The discs can also be combined for additional effects and creative control.