Hot on the heels of the optic launched yesterday Sigma has announced the ultra-telephoto 50-500mm F4-6.3 EX DG/HSM lens, which is also optimized for digital SLRs. It has a new lens coating which reduces flare and ghost and also creates an optimum color balance. It also features HSM (Hyper Sonic Motor)which provides a quiet high speed AF function, a zoom lock switch and has four pieces of SLD (Special Low Dispersion) glass for correcting color aberration.
