You Don't Need a Neutral Density Filter

摘要

Every couple of months, photo magazines tell photographers that if they want to get good images of landscapes that include the sky and perhaps a lake, they must use graduated neutral-density filters. They are used because the exposure latitude of slide film is only a few stops, and that is not enough to expose the entire scene properly. To use it, one must position the filter in front of the lens, and then, while holding down the depth-of-field preview button, look through the lens and move the filter until the boundary between dark and light is in the right place.