Continuity mistake: When Robin and his men steal the cart of brew and Friar Tuck, the Friar's trousers (that he is wearing under his brown robe) change colour repeatedly between shots. When he is singing, and when he is trying to sit up after the men have opened the chest of money, the are flesh coloured (cream). But when he has been hit on the head by the branch and falls from the cart, they are brown. (01:05:40 - 01:06:45)
Continuity mistake: During the confrontation with Guy of Guisborne, over the issue of Wolf's poaching, Guy's teeth during the short conversation ("Well, well - Robin, welcome home") are coloured to look brown. But shortly after when Robin has him prone at his sword's end, and Guy identifies himself ("Guy of Guisborne, the Sheriff's cousin") you can see his teeth have not been made up for that shot - they are white.
Continuity mistake: When Robin is talking to the Bishop in his private chambers, they're sitting by the window. They're both lit on the side of their faces that are near the window, but for some reason in the Bishop's closeups, he has harsh white light on the other side of his face as well. Not only is there no source for this light, but in the wide shot that side of his face isn't lit.
Continuity mistake: When John starts to cross the burning bridge to rescue his wife and baby, he steps onto the bridge and almost into the fire, which is just inches from him. But when the bridge breaks, the fire has suddenly moved several feet below him (so it doesn't burn him up as he climbs to safety, I presume.).
Continuity mistake: As Marion begins to distract Robin from aiming the arrow you will notice that at the wide angle shot she picks up a brown fletched arrow. As the shot tightens it is a white fletched arrow.