Pentax SP coating protects the exposed lens elements
ED elements compensate for chromatic aberration
Focal length equivalent to 450mm in the 35mm format
Super telephoto lens equivalent to 460mm in the 35mm film format. The second and fifth lenses use ED glass, and the optical system uses an inner focus system for correcting thoroughly the various types of aberrations that reduce image quality.
Ultrasonic motor is used in the lens for providing an "SDM" mechanism that enables quiet and smooth autofocus operation. (AF driven by the internal camera motor is also supported.) The lens components are sealed for enabling a dust-resistant and drip-proof construction that prevents the entry of water and dust into the lens. An inner focus optical system is used for correcting various types of aberrations over the entire shooting range. SP (super protect) coating for protecting the lens front surface from water and dirt Quick-Shift Focus System for enabling manual focus operation after focusing by AF without any switching operation.