Visible crew/equipment: At dinner, just after Harry takes the plate from Petunia and as Aunt Marge says, "A bit more," referring to the brandy Vernon pours, in the left glass door of the hutch behind Vernon, there is a nice clear reflection of a crew member lowering his white sleeved arm off screen. (00:02:40)
Visible crew/equipment: When Hermione and Harry go back in time, they duck and hide from Malfoy (after being punched) and his friends as they leave. The bulging rectangular outline of the transmitter (for hidden cordless mic) is visible at her lower back, under her pink jacket. It is visible in a few shots, including when they are at the pumpkin patch. The outline of Harry's transmitter is visible at his back, as he bows to Buckbeak at the pumpkin patch, when they rescue him. (01:45:10)
Visible crew/equipment: At the end of the film when Harry is in Lupin's office, Lupin packs his bags and then he walks past his desk. He then starts saying "If I am proud..." to Harry. As he says this, he walks forwards towards Harry, passing a cabinet of skulls. Reflected ahead of him in the glass panel of the cabinet is a very large boom mic which slowly moves out of sight as Lupin walks forward. It is very visible. (02:02:30)
Visible crew/equipment: When Harry and Hermione are at Hagrid's to rescue Buckbeak, Harry walks toward the hippogriff and bows. In the next shot, when his head is down low, look directly in between the right edge of the screen and the wood post, above the pumpkins. A pair of black pants quickly pass to the left; it's certainly not one of the crows, unless it grew human legs. (Only visible in widescreen.) (01:53:00)
Visible crew/equipment: When Dumbledore, Fudge, and the executioner show up at Hagrid's hut (the first time), Harry, Hermione, and Ron sneak out the back then hide behind the pumpkins, and the mic pack bulge can be seen under Hermione's hoodie, at her side. (01:26:10)
Visible crew/equipment: In many shots throughout the film, there are noticeable reflections of either the reflector screen or studio/set lights, in the lenses of Harry's glasses, as well as Professor Trelawny's. (01:24:00)
Visible crew/equipment: At the end of the film, when Harry enters Lupin's office, he walks past a cabinet full of skulls, saying "You've been sacked?" Reflected in the glass panel of the cabinet is a cameraman with equipment, moving along with the camera, a little above Harry. He's a little hard to see, but he's there! (02:01:30)
Visible crew/equipment: When the student's are looking at the wardrobe while listening to the teacher you can see a crew member on the glass window of the door of the wardrobe.
Chosen answer: It's not known what it is. It is left to the audience's imagination of what exactly is in the room or what some witch or wizard was doing in there. This is only meant to be a humorous bit and is unrelated to the plot. It didn't happen in the book.
raywest ★