Ewan McGregor on 'Revenge of the Sith' in Vanity Fair: "It was all green screen: they had us on green disks on a green floor with a green background, and a guy on the floor rotating us like chickens, as we lunged at each other with lightsabers.
What keeps you emotionally grounded is the other actor. Ep. II, I was on my own, speaking to thin air. But this scene was harrowing for Obi-Wan. I lose Anakin, and we see the danger if what it might lead to in Eps. IV, V, and VI.
For all my moaning about green screen, I did enjoy playing Obi-Wan and this link to Alec Guinness.
It was upsetting when people would laugh and joke about [the prequels]. Now, many years later, they mean a lot to the generation that were kids then. So from smirking, cynical opinions, now I'm getting feedback from the kids they were made for. I'm really happy about that." (x)