>>3203906To answer your question specifically, a simple meter (spot or center-weighted avg) is always going to expose for zone V, or middle gray. If I spot meter the bright part of the scene, it will give me a reading that puts that spot at middle gray, so the rest of the scene will be very dark. If I point it at a dark area, it will make that middle gray so the rest of the scene will be too bright. But if I know my camera has about ten stops of dynamic range, and that 3 stops above middle gray (zone VIII) is the brightest my camera can capture without any loss of detail, I can choose to put the bright area in the water in that zone by spot metering on it (zone V reading) then overexposing by 3 stops to put it in zone VIII. That's a bit of an oversimplification, and the actual numbers depend on the camera or film in question, but that gives you a basic idea of the technique.
Also, a lot of people think the zone system only applies to B&W or film. That's not true. The zones just represent brightness, it doesn't matter what color they are. And exposure for digital is basically the same as for slide film.
