The Sony Alpha to Sony NEX body mount adapter provides compatibility to a whole new selection of lenses at a fraction of the cost. This adapter allows for Sony Alpha lenses to be mounted onto a Sony NEX-3 or NEX-5 camera body. Though the lens fits and works seamlessly as an adapter, the automatic diaphragm (AE metering) and other autofocus functions do not work with this adapter. You can use the lens in fully manual exposure mode or in aperture-priority mode. It contains no optics and guarantees infinity focus.