Abes of Maine has the Sigma 17-50mm F2.8 EX DC OS HSM Lens (Canon or Nikon) for $594 - $15 off with coupon code LOYALTY15 = $579 with free shipping. Features Sigma's Optical Stabilization System, Hyper-Sonic Motor, and is for smaller chip APS-c or 4/3 digital cameras only. [Compare]