47th Street Photo via Amazon offers the Opteka 6.5mm f/3.5 HD Aspherical Fisheye Lens for Canon EOS, Nikon, or Sony Alpha Cameras for $149.95 with free shipping. That's the lowest total price we could find for the lens with any mount by $30. It features a removable hood, full 180° views, and is constructed with 10 elements in seven groups (one spherical lens).