Of all the cameras in the world, very few are small enough to fit on a humble keychain. Pentax has addressed this problem with their cute Pentax Q interchangeable lens camera. The camera so petite it fits on your keychain.
Obviously, this is the world’s smallest interchangeable lens camera. It only weights 7 ounces! How adorable! Size-wise, it clocks in at 3.9 x 2.3 x 1.2-inches. It has features aplenty, including a 12.4-megapixel CMOS sensor, an accessory shoe mount, pop-up flash, 3.0-inch display and a stock 47mm f/1.9 lens. Additional lenses can be purchased. The camera also does 1080p HD video. Not bad for something so small.
All of this tinyness does not come cheap, however. The Pentax Q will set you back $900. Who cares about the price, though, it fits on your keychain!