Photography is best in the morning and evening when low light produces interesting shadows and colors. Photographing dunes can be difficult. White dunes usually come out gray if exposed as indicated by your camera's internal meter. For manual cameras, if the picture includes mostly dunes, overexpose the shot by one or two stops to bring out the sand's whiteness. It the subject is a person or a plant, meter off the subject for a proper reading. A polarizing filter will enhance contrast.