Sigma 500mm f/2.8 APO EX DG HSM for Sigma Digital and Film SLR Camera

Two ELD glass elements in the front lens elements reduce chromatic aberration to a minimum and also ensure sharp, quality images of high contrast. New coating reduces ghost and flare. The new multi layer lens coating and lens design reduce flare and ghost, which is a common problem with digital cameras and also creates an optimum color balance. It also features a rotatable drop-in filter It also features a drop-in 46mm filter holder in the rear part of the lens barrel, which can be rotated to facilitate the use of filters, including a polarizing filter. Inner focus retains external dimensions for ease of handling. Accepts both 1.4x and 2x APO EX teleconverters. By adding an APO teleconverter (optional extra), you can use this lens as a 700mm f/6.3 MF ultra-telephoto lens with a 1.4x EX teleconverter or as a 1000mm f/9 MF ultra-telephoto lens with a 2x teleconverter.