Stop broadening a very specific term to describe which type of modern camera lens a manufacture is selling to cover the tricks that advertisers use. Now adding the word MACRO to a lens is a much more grey area because there's no accepted single definition of what macro actually means, and yes some manufacturers do add it to the name to make it sound more attractive. I don't deny they do. But to think that lens manufacturers use the term PRIME to sell more lenses is, quite frankly, crackers. Manufacturers make and sell prime lenses and zoom lenses. A very simple either/or division that everyone understands. They also make secondary lenses. A TC is one of the many types you can get, but no-one uses the term because it's very broad and non-specific. No-one in their right mind is going to go into a camera shop and ask for a Secondary lens please. Nope, sorry, I wouldn't. Wrong again.