First attempted and performed convincingly in Alfred Hitchcock’s 1958 film entitled Vertigo, the equilibrium-altering dolly zoom, or “Hitchcock zoom,” is an unsettling in-camera effect that is achieved with the help of a zoom lens, changing the focal distances so that the object of focus is kept in the same position while the camera itself is being or moved toward or away from the subject.
For example, in the animated GIF below, French photographer Micaël Reynaud, practiced the technique by first capturing images fully zoomed out while close to the concrete block. He then started to walk away from the object while zooming-in to keep it in frame and at a uniform size. The results, when meshed together, are vertigo-inducing to say the least.
Take a look: