Groupon offers the Rokinon 8mm f/3.5 Aspherical Fisheye Lens for Canon or Nikon, model no. FE8M-C, for $249 with free shipping. That's at least $20 under the lowest total price we could find for either lens elsewhere, although we saw the Canon option for $20 less in July. Sales tax is added where applicable. It features an ultra-wide 180° diagonal field-of-view. Deal ends September 20.