Amazing sunset behind Driftwood at Tamarin beach. The interest of a long exposure is to blur the elements that are in motion. The longer it is, the more the movements will be blurred, even if they are small. The surface of the water will have a characteristic dreamy, wispy look, and clouds will form trails. Similarly, fast-moving subjects will eventually disappear from the final image. A side effect is that you will also maximize the quality of the final image. It can also have a purely technical interest: if you really don't have enough light, a long exposure will be the only way to make a properly exposed picture.