This is a review of the adapter that attaches a Canon-FD mount lens to Sony NEX (E-mount) body.A Canon 50mm F1.8 lens attaches cleanly and firmly to the adapter, and the adapter attaches cleanly and firmly to the camera. When the release button is pressed on the lens, the lens and adapter separate easily, as expected.If the adapter has a drawback it is that it is easy to rotate the "lock-open" ring by accident. This doesn't release the lens but in the "open" position the aperture doesn't close down when the aperture dial is rotated. The worst case situation is that the "lock-open" ring is partially rotated and then the aperture will close partially but not fully. On the other hand this same "lock-open" ring is useful because when used properly it provides, in essence, a binary control for the aperture: In the open position the aperture is wide open giving minimum depth of field and the image is bright and this is ideal for using the Sony NEX focus highlight feature. Then, once the focus position is set, and the aperture will close to whatever position has been set on the lens's aperture ring.I have two adapters to attach Canon FD lenses to Sony NEX bodies. One adapter is branded "K&F" and the other is branded "Beschoi". Apart from the brand texts, the adapters appear to be identical and perform equally.A 35-105mm Vivitar lens does not mount properly onto the adapter, or at least not in a way that gives me confidence it will stay attached. However after much faffing and investigation I found that I had exactly the same struggles attaching the lens to a Canon body, and therefore the adapter cannot be blamed. It is possible that the Vivitar lens is defective in some way but I do not have the experience that would let me be sure. The Vivitar lens has its own mounting lock ring and therefore the mounting operation is a little different to the Canon lens. I mention this only in case somebody else is struggling similarly and wondering which bit, if any, is at fault.