Many iPhoneographers have been looking for a macro lens that will work with the iPhone 4 and 4S to take awesome closeup images. Unfortunately, a lot of those lenses cost a few bucks -- the Olloclip (which also includes a fisheye and wide-angle lens) runs $69.99, and while the magnetic macro lens from Photojojo is only $20, it also leaves a lot to be desired. Now appsman over at Instructables.com has designed a slide-on macro lens holder that can be had for about $15.

His design can be printed out at 3D printing house Shapeways for $11.00, and then equipped with a 12 mm PCX glass lens with a 51 mm focal length from Surplus Shed (part number L4471) for $4.

The design looks good, and can be used with any iPhone 4 or 4S without a case. Of course, if you're really looking for an inexpensive macro lens for your iPhone, you can always try a water drop ...