This telephoto zoom lens has a large aperture of F2.8 that is constant throughout the zoom range. The angle of view of the 120-300mmF2.8 varies from 20.4degree to 8.2degree and offers great versatility of composition from a fixed position. Two Special Low Dispersion (SLD) glass elements in the front lens group and two in the rear group offer effective compensation of color aberration. Since focusing and zooming do not change its overall length, this lens offers ease of handling. HSM ensures a quiet, high-speed, AF as well as full-time manual focus. A removable tripod collar is provided with the lens. As the front of the lens does not rotate, circular polarizing filters can easily be used. When this lens is used with the 1.4x EX or 2x EX Apo Tele Converters (optional), it becomes a 168-420mmF4 AF telephoto lens or a 240-600mm F5.6 AF ultra-telephoto lens respectively.