'You're gonna need a bigger boat.'

Hard to think of the late Roy Scheider, who was born on this day in 1932, without thinking of Jaws, and the scene (above) where Police Chief Martin Brody sees the shark for the first time. Interestingly, the famous line, 'You're gonna need a bigger boat', wasn't in Carl Gottlieb's script – it was improvised by Scheider.

Everyone remembers the body-in-the-submerged-wreck scene, which produced such a scream from the audience in pre-screening that director Stephen Spielberg re-shot it to draw out the moment for maximum effect. But for me, the most memorable shot was the so-called 'Jaws shot', when Brody is sitting on a deckchair on the beach and realises that young Alex Kintner has been killed by the shark. It was a cinematic first, a 'forward-tracking, zoom out' shot where the camera tracks in to Scheider's face and simultaneously zooms out, creating a visually unsettling but highly effective blurring-in-motion of the background. A similar effect, but in reverse – 'forward-zoom, reverse tracking' – was used by Irmin Roberts in the movie Vertigo, with Jimmy Stewart.