Mirror Lenses are another piece of old technology that's slowly making it's way back to the mainstream. It's a different design in lenses that allows for super telephoto in a super compact form factor (not to mention cheap). We're talking getting 500mm for $100.00 and 1000mm lenses for $200 dollars. << that's no typo. That's cheaper than just basic Kit lenses. Many photographers have been using Mirror Lenses for Wildlife photography to get those distant shots. Now that HD Video seems to have taken a turn to DSLR's, these lenses are growing in popularity by Film Makers. The price can't be beat and you can take some awesome stealth footage without being up in someone's face. Great if you're planning on using video as a Papparazi or Stalker? Check out the Rokinon 500mm Mirror Lens.