(at around 24 mins) When Nina returns home after being assigned a role, she stands at her front door to go in. She is wearing her white scarf around her neck. She then puts her key in the lock and other hand on the door knob as she walks through the door to the other side, her hands are still on the door but her scarf is now over her arm.
(at around 31 mins) In the gala scene when Thomas is speaking with Nina by his side on the staircase, the level of champagne in Nina's glass changes. In the shot from her point of view showing her finger and champagne flute, the glass is less than half-full and near her fingers. In the close up of Nina and Thomas, her glass is nearly full.
(at around 47 mins) When Thomas asks David if he can ask him a question, David is standing with arms akimbo. When Thomas asks him whether he would have sex with Nina, the mirror behind Thomas shows David standing with his arms crossed. But when the camera cuts to David scoffing at the idea, he is standing with arms akimbo again. Then when Thomas stands up, the mirror behind him shows David standing with arms akimbo but when the camera cuts to Nina, the mirror behind her shows David with his arms crossed again.
(at around 1h 8 mins) When Nina and Lily barricade themselves in Nina's bedroom after their night-out and Nina's mother is trying to come inside the room, Lily puts her hands on Nina's shoulders and leans herself on Nina. In the very next shot when Nina says to her mother to leave her alone, Lily is no longer visible in the shot.
(at around 1h 35 mins) When Nina is transforming to a black swan in the final dance act, and the camera pans to her left arm, and then to the right, a black bar appears to the left of the screen for a couple of seconds.
(at around 24 mins) When Nina returns home and looks for her mother, after being assigned a role, a camera operator is visible in a mirror.