The Sigma 2.0 x Teleconverter EX APO DG means that you can increase the focal distance of your lens without compromising on the minimum focusing distance. For example, this would convert a 70-200 mm f/2.8 lens to a 140-400 mm f/5.6 telephoto lens, or a 300 mm f/2.8 lens as a 600 mm f/5.6 ultra telephoto lens. Adding greater versatility to your current kit, this Teleconverter is a great alternative to carrying additional lenses.