Just before Chrissie surfaces there is a cut to a low-angled shot of the ocean with the land in the distance. The setting sun is clearly visible just above the horizon under a thin bank of cloud. The use of a wide angle lens creates an effect known as perspective distortion and makes the girl seem impossibly far from the shore. She breaks the surface facing the camera and we briefly glimpse her bare shoulders before she sinks back until her mouth is almost level with the water. She is smiling and gives a couple of excited breaths before she turns her head towards shore and cries out 'Come on in the water.' Susan Backlinie gives a wonderfully nuanced reading of the line, suggesting the girl's puzzlement and frustration that the boy has not followed her. There is a cut to the boy on the shore struggling to remove a shoe. He mutters 'Take it easy' to himself and then loses his balance, collapsing drunkenly onto the wet sand. In the distance there is a mass of low-lying cumulus, illuminated from behind by the setting sun, and -by pure natural coincidence- its shape suggests the dorsal fin of a shark.
Changing cloud patterns from shot to shot are an inevitable result of location shooting and are likely only to be spotted by meteorologists. The fact that the sun moves position can be put down to artistic licence: there was a need to illuminate the beach from Chrissie's perspective and to provide a backlight effect as the boy passes out. Strictly speaking, there should be no sun at all. When Brody types up the report he records the time of death as 11.50 p.m - even on the longest day of the year (June 20th) daylight hours on Marthas Vineyard are from about 4.30 a.m to 7.30 p.m. To add to the confusion the underwater shots of Chrissie swimming on the surface include a bright source of white light, clearly intended to be a full moon.
Clearly some individual shots were captured at sunset during what cinematographers call 'the magic hour', but most of the scene was filmed day for night. Night filming can be both difficult and expensive as it requires powerful lighting and special rates for the crew.
