New lens technology could lead to lighter and smarter cameras.

Photography by Rensselaer/Carlos A Lopez.  This series of time-lapse photos shows how the lens moves in and out of focus.

Researchers at the Rensselaer Polytechnic Institute in New York have built and  tested a liquid lens that captures 250 pictures a second.

The lens is made of water droplets that vibrate when exposed to high-frequency sounds. This vibration allows the focus of the lens to be altered.

"The lens is easy to manipulate, with very little energy, and it's almost always in focus - no matter how close or far away it is from an object," said project leader Amir H. Hirsa, professor and associate department head for graduate studies in the Department of Mechanical, Aerospace and Nuclear Engineering at Rensselaer. "There is no need for high voltages or other exotic activation mechanisms, which means this new lens may be used and integrated into any number of different applications and devices." 

When light is passed through the water droplets the new device can be used as a camera lens. The images are captured electronically and any out of focus frames can be removed automatically by software.

This is the first time researchers have changed the focal length of an image by using two water droplets and a sound wave set at a specific frequency.

Amir believes the technology will allow miniaturised cameras to be built into small surveillance equipment and mobile phones. Batteries would also last longer with this type of lens as it uses less power than a conventional lens.

The project began in 2004 and the researchers are hoping to develop better liquid lenses than those of Varioptic, S.A. who according to PC Magazine in 2005 made a lens that sandwiches drops of water and oil between glass or plastic.

Amir and his team are hoping further funding will help them study the movements of the liquid further.

This isn't the first time scientists have developed new lens ideas  as ePHOTOzine have previously reported that researchers have also built a lens based on the human eye.