This deal is back: Roberts Camera via eBay has the optically-stabilized Sigma 17-50mm F2.8 EX DC OS HSM for Canon for $429.99. They’re an authorized Sigma retailer, and this ties for the cheapest price from an authorized dealer that we’ve seen since tracking this lens in 2011.
Compare with other authorized retailers who are currently asking $569 for this lens. This lens was due for a price-drop as the Canon equivalent EF-S 17-55mm f/2.8 IS saw a price drop from $1059 to $829 over the last few months. At a little more than half the price, this Sigma version is a fantastic deal.
Does this lens fits my 5d mk ii?
No, unfortunately not. It’s a “DC” lens and thus only works with crop-sensor camera bodies.