You can put the optical quality and magnifying power of a binocular to use as a telephoto lens for your iPhone with the HookUpz Digiscoping Adapter for iPhone 4/4s/5/5s/SE from Carson. The adapter is designed for full-sized binoculars (those with objective lenses from 32mm to 50mm). Simply slip the phone into the included case and place the ring around the phone's camera lens over either of your binocular's eyepieces. The adapter comes with two rings and fits most eyepieces with an outside diameter between 40mm and 44mm.
Compatibility
Fits most binoculars with 40-44 mm diameter eyepieces