Getty ImagesIn one scene from Alfred Hitchcock’s 1958 thriller Vertigo, lead character John “Scottie” Ferguson (James Stewart) is shown following Madeleine Elster (Kim Novak) up a bell tower. Scottie is afraid of heights. So when he briefly stops and glances down, he experiences a wave of vertigo. The stairwell distorts, seemingly stretching into the distance below him – a potent reflection of his dizzy and panicked state. This scene is the first ever example of the “dolly zoom”, a dynamic visual technique achieved through camera movement and a zoom lens. Also known as the “vertigo effect” or the “contra zoom”, it requires significant skill. The subject must remain the same size within the frame, while the background distorts by either stretching or compressing. CC BY Most of us have a list of our favourite films and TV series of all time. But do you ever wonder how these were made? In this series we go behind the scenes to reveal the ingenious tricks and innovations that have transformed screen production over the course of a century.Another famous example comes from Steven Spielberg’s Jaws (1975), when police chief Martin Brody (Roy Schneider) realises the shark is attacking swimmers in the water.In Peter Jackson’s The Lord of the Rings: Fellowship of the Ring (2001), the technique is used to indicate impending danger, as Frodo (Elijah Wood) realises the Nazgûl are headed towards him and his party. Combining artistic and technical creativityThe dolly zoom is said to have been invented by Irmin Roberts, a camera operator at Paramount, after Alfred Hitchcock requested a visual effect that would encapsulate the feeling of fainting. The technique is named after two pieces of technology: a “dolly”, which is the wheeled platform that moves the camera, and the telephoto “zoom” lens.The change of perspective comes as the camera zooms out while moving towards the subject – or vice-versa, zooms in while moving away from the subject.While other techniques can provide a similar visual effect, such as the crane shot or drone shot, the perspective change that ripples through a dolly zoom stands out as being particularly unique, as it tends to offer more precision and smoothness.Achieving this affect to a high standard takes considerable planning and coordination, even today, as remote technologies are used to manage the focus, frame and the speed of the camera. Thanks to advanced software technologies, the dolly zoom effect can now also be achieved in post-production. This is an attractive option for low-budget filmmakers who can’t afford to buy or hire a zoom lens.A collaborative effortThe dolly zoom requires collaboration between the director, production designer and cinematographer. Usually, all three will work together to decide which scene the effect will appear in, which location will work best for the shot, and the type of slider or length of track required to move the camera. On set, the performance of the camera and grips department demand perfect synchronisation. Many rehearsals may be required to ensure the shot is executed faultlessly.Consider this scene from Martin Scorsese’s Goodfellas (1990) as an example. Seated against a window, Henry (Ray Liotta) and James (Robert De Niro) are chatting and having lunch in a diner. As the camera moves towards them, the telephoto lens zooms out and, gradually, the cars on the street outside rise to prominence. The effect punctuates Henry’s disorientation as he realises he is being framed for murder.This shot is more complex than it looks. The crew must coordinate the camera movement, and manual adjustments to the zoom and focus rings on the lens, to be perfectly timed with the actors’ performance. An iconic visual trickThe dolly zoom has become an iconic visual motif that combines technical innovation with cinematic impact.Almost 70 years on from its first use, it now appears relatively frequently in both film and television. The effect is even simulated in animation. In Ratatouille (2007), for example, it is used to emphasise Remy’s admiration towards his idol, Chef Gusteau. The dolly zoom offers a way to creatively express a psychological experience that connects the viewer with the characters onscreen.Susan Kerrigan does not work for, consult, own shares in or receive funding from any company or organisation that would benefit from this article, and has disclosed no relevant affiliations beyond their academic appointment.