I have never used this in actual practice. Would anyone like to have it? Here's the description: An extension tube for close-up photography that can be used with almost all EF lenses, including EF-S lenses. Simply attach it between the camera body and the lens to easily take high-magnification photos. It has 8 electronic contacts, and the AE function works the same as in normal shooting. The magnification varies depending on the lens. Also, some lenses cannot be used, so please refer to the extension tube attachment magnification table below and the EF lens catalog for details.