This Photojojo lens mount($240) turns your iPhone into a silly SLR lenses. It is ridiculous strapping a zoom or L-lens to an iPhone 4, but at least you’ll have the large (for a DSLR) 3.5-inch Retina Display touchscreen
“This case-adapter combo lets you mount your Canon EOS or Nikon SLR lenses to your iPhone 4 giving your phone powerful depth of field and manual focus. “
Source: Likecool