The PhotoX is a clear, waterproof case that fits an iPhone 5 or 5th generation iPod Touch. The case has a soft membrane front so you can swipe and click when the phone is sealed inside.
The backside has a threaded connection that accepts a tiny lens. It also has a mounting bracket for one of the many accessories that Optrix sells. They include suction cup and handlebar bike mounts, a tripod connector and a monopod.
Optrix even sells a chest strap, presumably for skydiving, snowboarding or kayaking. That sounds a lot more practical than my approach: skiing downhill while holding my Sony Handycam up to my face.
The PhotoX cost about $100 at Optrix.com. It comes with a flat lens and a macro. A step up is the PhotoProX, which costs $150 and comes with two additional lenses, a fisheye and a telephone.
I wanted to illustrate the PhotoX by shooting a beach video, but as you can see from the clip below, the surf wasn't up.