Follwoimg yesterday's release, Sigma has announced another set of 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. It costs £899 and will fit SLRs with Sigma, Canon and Nikon-D mounts.
Focal Length: 50-500mm
Minimum Aperture: F22
Lens Construction: 20 Elements in 16 Groups
Angle of View: 46.8°- 5°
Number of Diaphragm Blades: 9pcs
Minimum Focusing Distance: 100cm -300cm(39.3?-118.1)
Maximum Magnification: 1:5.2
Filter Size: 86mm
Lens Hood: Petal Hood
Dimensions: Diameter 95mm (3.7) x Length 218.5mm (8.6)
Fittings: Sigma, Canon and Nikon-D, (Konica Minolta and Pentax TBA)