Canon offers its factory-refurbished Canon EF 17-40 f/4L USM Lens, model no. 8806A00, for $539.99 with free shipping. That's tied with our mention from December and $209 under the lowest total price we could find for a new one. This ultra-wide-angle lens fits all Canon EF mount SLRs and has a 77mm filter. A 1-year Canon warranty applies.