It was the movie Jaws which brought downtown Edgartown, State Beach and the Vineyard’s breathtaking South Shore to audiences nationwide for the first time.

But Island newcomers be warned -- Amity Island isn’t any more realistic than the great white shark that terrorized it.

In a slide show compiled from candid photos taken in the summer of 1974, Edgartown resident Joe Hazen explained how the Vineyard was modified for movies and recalled the friendliness and the fun generated 20 years ago by visiting Hollywood crews. His slide show -- last seen in ’75, the year the movie opened -- was presented to about 300 people this weekend at the Old Whaling Church in an event benefiting the Martha’s Vineyard Preservation Trust and the Martha’s Vineyard Art Association. It includes the work of about eight other amateur photographers who, with Mr. Hazen, caught scenes of a plastic shark in a crate and 26-year-old Steven Spielberg getting advice from his parents. The entire movie, except for live Australian shark footage, was filmed on the Island.

“I was retired and I have a house out here overlooking Katama Bay,” explained Mr. Hazen, who trailed movie crews during their six months of work here. “Out of the house I have a widow’s walk, and I could go out there and take pictures.

“They didn’t know what I was doing. I was doing it mostly for my own amusement but then it occurred to me that this would make an interesting show.”

Of course, it’s pretty easy to spot some of the movie’s differences -- like Roy Scheider’s truck parked the wrong way on Main street. And any Islander knows you didn’t go to Tashtego to buy poster board and paint. But Mr. Hazen’s photographs -- some taken from his boat -- show some of the less obvious differences too.

For one thing, some of the show’s buildings -- including the Menemsha shack owned by Quint, the slightly off-kilter shark hunter -- were built specifically for the film and then torn down later.

And what about that shark killing scene?

“We’ve got to get a bigger boat,” Roy Schieder declares after his first encounter with the 25-foot great white.

But producers had actually gone to a great deal of trouble to create Orca, Quint’s boat. In fact, they used two, one that was sailable and a duplicate that was designed to sink in the film’s finale.

Mr. Scheider -- known among his troubled townspeople as police chief Martin Brody -- is supposedly out at sea when he kills the shark.

Of course, he was really in Katama Bay, not too far from Mr. Hazen’s house.

But filmmakers were able to create the effect of being in high seas. Here’s how: They placed two boats -- well out of camera view -- on each side of Quint’s boat. Using a rope strung between the two boats and through the top of Quint’s, they moved the boat back and forth so it appeared to be caught in the active ocean waves.

Movie makers at the time were pretty up-front about those tricks. They were less open, however, with Bruce, the Hollywood-made shark. The makers of Jaws tried to shield the public from their three fake sharks, made of foam rubber, plastic and sand. After all, if people saw too much of Bruce, those dull lifeless eyes, “just like a doll’s,” might not have been as impressive. The shark was controlled by more than 30 pipes and an elaborate system of air compressors kept on a floating workshop that was always nearby but out of camera view.

Of course, there was little Mr. Spielberg could do about the red spongy pieces of fake shark that washed up on the shore for weeks after filming the finale. The debris was generated when the crews blew up a plastic shark head loaded with fish guts and blood. The fish guts were used in order to attract sea gulls.

Mr. Hazen’s show was originally presented to benefit the Art Association, which operates the old Sculpin Gallery.

The association will benefit again, but this time the event was organized by the preservation trust, which owns and maintains eight historic Island buildings: the Old Whaling Church, the Flying Horses Carousel building, the Dr. Daniel Fisher House, the Vincent House Museum, Alley’s General Store, the Old Schoolhouse Museum and two buildings in Edgartown’s commercial district.

Special events like this weekend’s generate roughly 20 per cent of the organization’s revenue, executive director Christopher Scott said. The group also draws income from events held at its buildings and from donations. Government grants are not part of the equation because, Mr. Scott said, money for preservation of buildings is scarce.

“We really do rely on the generosity of Islanders who come to our special events, use our properties and contribute to us philanthropically,” he said this week, noting that Jaws “had a tremendous impact on the Vineyard. It was one of the beginnings of Martha’s Vineyard being broadly portrayed to the general public. I’m sure it had an effect on increasing visitation.”

Mr. Hazen, a board member of the preservation trust, adds that the movie was “very good and very well done.”