they work fine but have a much different feel to focusing than the AI &AI's lenses do. I put the older 35-70 2.8D on my FE2 and it had some nice resistance to the focus ring, not unlike some of my manual lenses. but then I put a newer 50 1.8D and it had, like was mentioned above a plasticy, thinner, cheaper feel to it. Hard to describe it, but there is little resistance to the focus ring and it feels kinda hurky jerky if that makes any sense. Not to say it won't work. I've taken many wonderful pictures with the newer style D lenses. I just prefer the older over the newer D lenses on my manual focus bodies.