Visible crew/equipment: When Mark first meets the Winklevoss twins, just as they are about to leave, right after one of the twins says, "We row crew," Armie Hammer's face hasn't been added properly and you can see that it's a different actor. (00:22:10)
Upvote valid corrections to help move entries into the corrections section.
Visible crew/equipment: When Valerie is crying in front of her dresser, look at the corner mirror as the camera pans to the right. You can see a blurred shot of the cameraman in the reflection.