Vertigo
The moments in which Scottie is experiencing vertigo are shot in very specific ways. Alfred Hitchcock used a dolly zoom—in which the camera is steadily zooming in, while also moving physically backward—to achieve this POV shot of Scottie's fear of heights, a disorienting image that puts us in Scottie's frame of mind.
Green light
When Judy is finally transformed into the spitting image of Madeleine, she emerges from the bathroom with her recently dyed bleach-blond hair pulled back perfectly, wearing a gray suit that Scottie has bought for her. The green light of the sign outside her hotel room illuminates the room as she emerges, in a slightly blurry shot that suggests the ghostliness of the transformation. This surreal image of Judy as a half-ghost suggests that she is a dead woman coming back to life, crossing the border between the living and the dead.
Disembodied Head
At one point, the film goes inside one of Scottie's nightmares. We see his visions of all of the horrors that Madeleine told him about. He visits the empty grave of Carlotta Valdes and sees Carlotta come to life and walk around. Then, at one point, we see Scottie's disembodied head at the center of the screen, floating, with a look of horror and disorientation. We get a central and close-up view of Scottie's all-consuming dread and fear.
Scottie escaping the bell tower
After "Madeleine" falls to her death from the bell tower, Scottie is worried about being implicated in the death and runs away. Hitchcock puts the camera at a bird's-eye view, and we see him scurry out of the building, no larger than an ant on the screen. Meanwhile, we see a group of people running to examine Madeleine's body on the roof. It is a shot that adds to the confusion of the moment, in which it is unclear exactly what has happened, and who is to blame.
