TECHART PRO adapter is the world’s first autofocus adapter for your manual focus camera lenses. It is able to turn your manual lens into an autofocus lens and use it under the Sony A7 cameras. Not only does it immediately give lives to all the manual lenses, it also changes the experience we had with these lenses. You can now use your favourite Leica lenses for taking snap shots, motion pictures or candid photos.

Techart PRO adapter is a lens adapter with a motor and a printed circuit board, allowing the camera to measure the focus and communicate with the motor. And the motor will move the lens closer or further away from the camera sensor to reach the focal point. The principle is similar to the Contax AX camera that the flange distance is adjusted to reach the focus. The maximum z-shift is 4.5mm which is sufficient to cover the focusing distance for most of the lenses. And the optical performance will NOT be affected for unit focusing lenses.

Check discussion at http://www.personal-view.com/talks/discussion/14578/techart-pro-leica-m-sony-e-autofocus-adapter