The K&F Concept Canon FD Sony E-mount adapter is easy to mount. The instructions are simple enough : turn the « Open - Lock » ring towards the « Open » position, mount the lens, and turn the adapter’s ring towards the « Lock » position, a nFD lens will click in just like on a camera. Lenses feel very securely mounted. You can check that it is properly mounted by turning its aperture ring, and you should see the diaphragm stopping down.As for use, it’s important to know that the adapter allows the lens to focus beyond infinity (which is not a real problem, as not reaching infinity would be). So, if you turn the lens’s focusing ring to its infinity mechanical stop, the image will be blurred, and it would take a tremendous amount of stopping-down to regain some focus. Instead, just pull back slightly from the infinity stop, and use any means on the camera to assist in focusing, like « peaking level » and having « focus magnifier » set on one of the custom buttons.Finally, just one weak point of the adapter : the « Open - Lock » ring is close to the lens’s aperture ring, and I find it’s easy to move it between the Open and Lock position, which could potentially upset the lens’s proper stopping-down. Something to keep an eye on. Maybe I’ll put a piece of tape on that ring when I do some intensive shooting…Altogether, a very fine piece of equipment, that gives a second life to those good old FD lenses. I’m very happy with it, highly recommended!