Have you ever wished that your lens could focus closer than it does? Imagine that you could put a magnifying glass in front of your camera's lens. Close-up lenses work in this fashion and are the simplest and least expensive method of close-up photography. They are available in different "powers" (diopters). A +0 close-up lens will allow you to focus your lens somewhat closer than it already does. A +1 close-up lens will allow you to focus closer than the +0. A +2 lens will allow you to focus even closer than a +1, and so on. These lenses can be used individually or in any combination to achieve ultra-close focus. The maximum magnification achieved with these attachments will depend on the focal length of your lens as well as the actual close focusing capability of that particular lens.
NOTE: A +1 combined with a +2 will equal a +3.