Sigma Boosts HSM Lens Range

Sigma have added HSM focusing (AF-S) to their 18-50mm f/2.8 and 17-70mm f/2.8-4.5 lenses, making them compatible with the Nikon D40 and D40x auto-focusing and also have full time manual focusing override.

Considering theses are optically very close to my prized Tamron 17-50mm f/2.8, this is a very good move by Sigma.