One of the biggest problems with camera phones is that they’re too small to allow for truly focussing lenses. To focus a picture, two lenses have to be able to move — to slide closer or further together. And given how teensy most phones are, they don’t even have the leeway you find in the smallest digital cameras. Given all the circuitry that has to fit inside the phone, there’s no room left over to allow for several lenses.

The eye, in contrast, works in a very different way. Rather than change the distance between two lenses, the eye simply uses one lens that can alter its own shape — thus changing its focus. Now a couple of scientists in Singapore claim they’ve created a cameraphone lens that does precisely this. It’s got a flexible polycarbonate lens which is hollow inside, and filled with water. The cameraphone can pump water in or out in tiny amounts, to subtly change the shape of the lens. It allows a cameraphone to do something hitherto impossible, which is to get a true close-up shot (that’s an example above). There’s a story on an Asian web site about it here.

It reminds me of Adaptive Eyecare, the company that developed the world’s cheapest eyeglasses. They too have flexible plastic lenses, which are filled with clear oil. You snap an oil pump onto it, then pump oil in or out until it achieves the perfect focus for your eyes. The idea was developed by an Oxford professor and is currently being rolled out in several African countries, where many farmers suffer from poor eyesight brought on by malnutrition.

(Thanks to Ratchet Up for this one!)