Metabones Nikon G Lens to Sony NEX Camera Speed Booster Increase maximum aperture by 1 stop Increase MTF. Makes lens 0.71x wider. Optics designed by Caldwell Photographic in the USA (patent pending). Industry's best aperture ring covers a 8-stop range with half-stop clicks. Markings show actual number of f-stops. No more guesswork! (Patent pending)