Visible crew/equipment: When the men are pushing the catapult to the gate look at the far left of the screen for a few seconds you can see a crew member in a baseball cap and then a large movie camera. There's also a twig palisade next to him where two more crew members are visible.
Visible crew/equipment: When they are moving the catapult, if you look above Robin and Azeem, you can see a crew member in the window above them. He is wearing all black, but you can tell he is trying to get out of the shot.
Visible crew/equipment: Following the river duel the outlaws, Robin and his men sit around a campfire in the woods. There is a high-angle shot looking down on the men, also showing Little John perched in a tree. Look behind the tree, through the branches, and you can see a piece of camera tracking on the ground.
Chosen answer: The masked men weren't part of a cult, they were the Sheriff's soldiers, the same ones that Robin meets when he first returns home. They are just in hoods and masks to appear intimidating while trying to kill the noblemen, like Locksley.
Bishop73