If you're looking for a good stocking stuffer for any photographers you know, you may want to consider the Luxi Light Meter.
Light meters are usually dedicated hand-held devices used by photographers to measure the amount of available light in the room. When the light hits a dome on the reader, a number is generated that allows the pros to adjust their photography equipment accordingly to capture the best possible picture. Normally light meters can cost hundreds or thousands of dollars, but the Luxi Light Meter is US$29.99. When combined with an iPhone, it gives photographers an affordable option to the pricey devices.
Extrasensory Devices, the company behind the Luxi Light Meter, raised more than $100,000 on Kickstarter earlier this year. The Luxi Light Meter attaches to your iPhone 5 or 5s by slipping over the top, where its diffusion dome covers the front-facing camera. The dome captures the light that is read by the companion Luxi app. Photographers can then use the reader's output to set their DSLR or other pro equipment.
The Luxi Light Meter isn't a gift for everyone. It's pretty pointless if you're just taking snaps with your iPhone. However, if you know any photographers that work with more professional equipment, the Luxi Light Meter may be just for them.