For the money, the Olloclip can't be beat
Alexander George from Wirecutter ( about 1 year ago )
The Olloclip slips on over the iPhone’s corner and, depending on which direction it’s turned, gives a fish-eye, macro, or wide-angle effect to your shots. The simplicity and sturdiness of its design trumps other lens options that are obtrusive, flimsy and inconvenient by comparison.