The iris diaphragm has 9 diaphragm blades to obtain beautiful out of focus image. It incorporates the floating focus system and the use of two aspheri

The iris diaphragm has 9 diaphragm blades to obtain beautiful out of focus image. It incorporates the floating focus system and the use of two aspherical lens elements to minimize distortion, spherical aberration and astigmatism. Internal focus system of the lens eliminates front lens rotation, thus allowing the use of a Perfect Hood and easy use of polarizing filters. The lens also incorporates a dual-focus mechanism.