Corrected entry: Platform Nine and Three Quarters is supposed to be a secret platform that only magical people can access. However when Harry, Ron and Hermione have boarded the train and are looking for a cabin we can see out of the window a GNER (Great North-Eastern Railway) train visible on the next platform. The train is most noticeable for its blue colour with a single red stripe running the length of the train.
Corrected entry: At the Leaky Cauldron a guy picks up a bottle and wraps a rag around it. A second later the bottle is gone.
Correction: It's magic. Not a mistake, the bartender was using magic to clean up.
Corrected entry: When the entire school is banqueting after their arrival, D. Malfoy says: "Potter. Is it true you fainted. I mean you actually fainted?" In the book, he found out because Neville was in the compartment as well, and he told "nearly everyone." But, in the film, only Harry, Hermione, Ron, and Professor Lupin are in the compartment. The three friends wouldn't have told them, and a schoolteacher doesn't go around telling such things to students. So, as Harry himself asked, how did Malfoy find out?
Correction: There are large windows on the compartment facing the hallway, which showed considerable traffic previously and in the other movies because the snack cart was located farther up the train. It is reasonable that someone saw what had happened during the time that Harry was unconscious or was alerted to the scene by Harry's screams, that Ron discussed.
Corrected entry: In the scene where Hermione is about to punch Malfoy, the wand Hermione sticks at him is in her right hand. It cuts to the next scene, and Hermione punches Draco with her right hand. You never see her wand switch hands in between.
Correction: Hermione would have plenty of time (off-camera) to switch hands.
Corrected entry: On the Hogwarts Express, when Ron says, "Let me get this straight," he glances into the camera.
Correction: When Mr. Weasley originally explained this to Harry, he took him away from everyone else. This tells us that he didn't want anyone else to know, so Ron was also checking that there was nobody outside the compartment who could overhear their conversation - he is looking past the camera, as if the camera is not there.
Corrected entry: When Harry and Hermione are back in time and watching Dumbledore knock on Hagrid's door, Harry glances into the camera briefly.
Correction: Perhaps the character briefly looked in that direction by chance. For the purposes of the movie we are assuming that the camera isn't there, so anyone looking at the camera is simply looking at something in that direction.
Corrected entry: When Neville has the Boggart explained to him, he switches positions between shots. (00:40:10)
Correction: Because of the camera angles there is NO way to tell if he change position whatsoever. He is standing perfectly still.
Corrected entry: In the scene where the Wesley twins are teasing Ron about the newspaper clipping. Harry says "and that wizard from Belgium" His mouth doesn't move, and he shows no indication of saying anything.
Corrected entry: During the DADA lesson with Snape, the students' books are open to different pages. Some are near the front; others towards the back. Snape's book is more towards the middle, but he turned Ron's book closer to the back.
Correction: In any normal class environment many students have their textbooks open to pages other than the assigned lesson, as is seen in Ron's case. Then Snape takes quick notice of Ron's textbook, because of his severe dislike of him and his friends, so he opens it to the proper place. As for Snape's book, the teacher's textbooks are often distinctly different than the students' books, so that difference is quite plausible as well.
Corrected entry: During the DADA lesson with Snape, Hermione's hairstyle keeps changing. In some shots, she's wearing it partially up, and in some shots, it's completely down.
Correction: During the DADA class with substitute Snape, Hermione's hair is partially swept up only on her right side, in one large barrette at the back of her head - though she still has loose hair framing the right side of her face. In the thirteen shots where Hermione's hair is seen, there are five shots of the right side of her face and the barrette visibly holds her hair. In the two shots of the left side of her face her hair is always down, as it should be, and in the six shots facing the front of her face the hair on her right is pulled towards the back of her head, where her barrette is.
Corrected entry: During the Whomping Willow scene, Hermione is swung around on one of the branches. When the branch hits her, she is facing outwards, away from the tree. But from the above shot, when she's being pulled into the tree, she's facing inwards, towards the tree.
Correction: Once Hermione is grabbed by the branch, she throws her legs over and climbs on, so when she comes about to scream into the camera, she faces out. In the next shot she passes over Harry as he ducks, and it's only her arms that are grasping the branch, her legs are dangling off as the branch hurtles past at ground level. Then at the start of the next overhead shot, we can't see Hermione, however because of the quick momentum of the branch, as the branch goes from ground level to high above, her legs and body position would shift down and all she would have to do is throw her legs over the branch, so she faces the other way by the time the branch flies up, towards the screen.
Corrected entry: In the beginning when the Dursley's are sitting at the dinner table and Mr. Dursley says "Can I tempt you, Marge?" you will notice that there is a spoon in the pudding bowl. The very next shot you will notice the spoon is missing from the bowl and the reappears in the next shot. (00:02:35)
Correction: The large silver spoon is in the bowl in every shot. When Marge snaps her fingers at Harry, the spoon's position is only different, the handle now points between Dudley and Petunia, but the position change is already noted in another mistake.
Corrected entry: When the train lurches while picking up the dementors, Ron and Hermione go backwards, and Harry goes backwards into his seat. It can't lurch both ways, and they would fall one way, not two.
Correction: The Hogwarts Express not only stops abruptly, it is stopped by the Dementors. The fact that the train quickly jerks SIDEWAYS (as seen when Harry peeks out of the compartment) and also forwards and backwards on the track, is perfectly believable, since it is the Dementors causing it in the first place.
Corrected entry: In the scene when Harry was holding the shoe by the laces for dropping it on to the floor to get the Monster's book of Monsters, then the shoe turns around completely(in his hand) between the two quick shots.
Correction: It's not in "two quick shots" that the shoe turns. In the first shot the shoe is dangling from the laces that Harry is holding, with the shoe facing him. Then there's a shot of Hedwig. When we see the shoe in the third and fourth shots the shoe, though facing out, is turning while dangling. So it is quite plausible that the shoe turned round while out of view, between the first and third shot.
Corrected entry: In the scene when Ron is holding his rat with Harry and Hermione, his rat bites his index finger. If you look closely, you can see that his finger has a blood mark on it before the rat even bites it.
Correction: Not true. I watched this on DVD frame-by-frame, and there is no blood mark on his finger. Only a dark shadow is visible under the finger that covers the one that is about to be bitten, but it does not look like 'blood.'
Corrected entry: When Harry comes out of the secret passageway, he puts on his cloak, and knocks over a box, after he does, you can see a crew member's shadow moving out of shot.
Correction: No, if you are referring to the shadow on the wall to the right of the box's original location, that is a shadow from the box and it's contents as it falls. There is a light source from the left, as you can see the shadow on the same wall of the person heading up the stairs in the previous shot, just before Harry comes out of the hole in the floor.
Corrected entry: If the Marauder's Map showed Peter Pettigrew, it should have shown Sirius Black and two Harry's and two Hermiones as well.
Correction: This is not a plot hole. How do we know that it didn't? Harry didn't have the map at the time. Lupin did. In fact it was because of the map that he knew to follow them to the Shrieking Shack. He saw Peter coming out of Hagrid's hut and ran to follow. He may have simply not noticed that Sirius was there (or at least he wouldn't care about it since he knew he was innocent at this point) and didn't see the two Harrys and Hermiones.
Corrected entry: When Lupin stops Harry from facing the Boggart, he turns it into a balloon, and forces it back into the wardrobe. However, the wardrobe closes before the balloon reaches the wardrobe.
Correction: No it doesn't. It just looks like it because it's quite low down on the screen.
Corrected entry: In the Great Hall, the teachers all sit up at the top table. However, in the long shots, the filmmakers use quite a few doubles for the more popular characters (e.g. Prof. McGonagall and Hagrid), because they would cost too much if they used the proper actors.
Correction: Principal actors are not paid by the hour. Movie makers film scenes simultaneously using second unit directors. Often stunt doubles or stand-ins are used for shots that do not require close ups, while the primary actors are filming another scene at a different location.
Corrected entry: In the beginning when he is casting the Lumos Maxima spell, he is doing magic outside of school, which is not allowed.
Correction: This has already been explained on this site. Harry apparently had homework to do but his uncle wouldn't allow him to do his homework. In a way, it falls under the 'emergency use of magic' clause in the rules.
Correction: The Hogwarts Express is very much the same as the Knight Bus that Harry takes to the Leaky Cauldron, in the sense that muggles cannot see it, even when in the same vicinity as other cars. The same principle applies for the train sitting on the platform at the station next to the real trains.
Jazetopher