Sigma 300mm f/2.8 EX DG IF APO Telephoto Lens for Nikon SLR Cameras Fast maximum aperture F2.8 telephoto lens optimized for digital SLR cameras. Fully compatible with all Nikon Digital SLR cameras Multi layer lens coating minimizes flare and ghost. Two ELD (extraordinary low dispersion) glass elements produce excellent imaging capability Accepts both 1.4x and 2.0x EX Teleconverters to produce 420mm F4 and 600mm F5.6 Autofocus ultra telephoto optics.