Legendary Canon FD500 mm 4.5 L lens. Purchased 7 years ago from a freelance photographer that used this for many photos in National Geographic. This lens has been around the globe. It has very clean optics and is quite a hefty lens. It has the brass Canon EF mount so it's been adapted to Canon EF lens from FD. https://500px.com/photo/121418533/heron-2-by-jason-kelly Sample of what this lens is capable of on the original EOS M camera. Selling as I have a 500mm 4.0 Sigma Sport. This is a tank and take amazing shots.