I love my DSLR, but it stays home about 95% of the time now thanks to the convenience and quality of smartphone cameras for the average snapshot (the last two models I've used, the Samsung Galaxy SIII and iPhone 5 are both fantastic). What I do miss on occasion is the flexibility of switching out a lens for a wider shot, or to zoom in closer from afar, and most often, a macro for detailed shots while hiking or exploring tide pools here in SoCal. No longer, as now I've got the option to magnetically snap on a wide angle, telephoto, fisheye, and even a macro lens (sample below).
Each lens is made from solid aluminum and sticks to almost any phone's back camera with an adaptor ring applied with adhesive. Give it a half hour or so, and the metal ring then works with the magnetic ring on each lens to work in a miniaturized DSLR-style setup.
Photojojo includes two extra-strong rings specially designed for the iPhone 4/4S and iPhone 5 designed to adhere to the glass back and won't block the flash or back mic. But I'd also note if you've got a protective appliqué from the likes of ZAGG or Wrapsol applied onto the back of your device, you may find the adhesive slipping in certain conditions (we had a heat wave here and it peeled off a few days later). But even under strenuous conditions, the lenses worked great, especially the macro attachment which I took up nearly 9,000 feet on a recent hike and snapped some trail finds like these acorn tops close up. Pretty nice depth of field, right? I feel like I've yet to tap into all the creative uses of these lenses, and so they've found a permanent space in my backpack (and without all the weight of my Nikon setup!).