Samyang 500mm f/6.3 .... got this bad boi in the mail yesterday was pretty stoked to test it out... probably gonna get a ND filter for this guy next using a 92mm
Bower High-Power 500mm f/6.3 Telephoto Mirror Lens (SLY50063) : Digital Slr Camera Lenses : Electronics - Amazon.com
Rokinon High Definition 500mm F/6.3 Telephoto Lens Kit | eBay
Samyang Mirror Lens 500 mm 1:6.3 DX. Comparison with Rubinar 500/5.6. Review of the mirror-lens lens by Rodion Eshmakov | Happy
Samyang Mirror 500mm F/6.3 DX | LENS-DB.COM
500mm f6.3 Telephoto Mirror Lens + T2 Adapter for Canon EF EOS DSLR Camera White | eBay