
A close-up lens is an easy and affordable solution for close-up/macro photography. You can get a macro lens from a telephoto lens with a longer working distance.
Joni Niemelä's review of the NiSi Close-Up Lens Kit
The NiSi Close-up Lens set is suitable for both zoom and prime lenses with focal lengths between 70 and 300mm. The magnification you get depends on the focal length available. You get about 1:1 magnification at about 200mm focal length.
The close-up lens attaches directly to lenses with a 77mm thread, but with the included adapters you can also use the Nis with lenses with a 72mm and 67mm filter thread.
The package includes the Nisi Close-up Lens, 67mm and 72mm adapters, and a protective case.