Point of view is a rule about information, not a camera position. Restrict the audience to one character’s knowledge and every revelation lands with that character, which makes surprise available and dramatic irony impossible. Give the audience more than any character has and the reverse is true. Both work; drifting between them without a reason is what makes a piece feel unmoored.
The most common error is the accidental switch: a piece that has been rigorously inside one perspective cuts to information that character could not have, and the audience quietly stops trusting the rules. They will not name it, but the tension drops.
In visual work the discipline is enforced by what the camera is allowed to see. Deciding early "we never see anything she does not see" is a constraint that solves dozens of later questions, and it is worth writing at the top of the treatment.
What is point of view in storytelling?
The rule governing whose knowledge the audience shares. It determines what can be withheld, and therefore whether the piece runs on surprise or on dramatic irony.
Can you change point of view mid-story?
Yes, if the change is structured and consistent. What damages a piece is the accidental switch — a single moment of information the point-of-view character could not have — because it quietly tells the audience the rules are not real.