What are the main differences between Canon FD and EF lenses in terms of compatibility and performance?

Canon FD lenses are manual focus lenses that were designed for older Canon film cameras. They are not compatible with modern Canon EF mount cameras without the use of an adapter. EF lenses, on the other hand, are designed for Canon's current line of digital cameras and offer autofocus capabilities. EF lenses are generally considered to have better optical performance and are more versatile in terms of compatibility with Canon cameras.