Hi well extention tubes will allow you to get greater than 1/1 but are not a substitute for a good macro lens rather as an aid to it.. They allow closer focus when placed on most lenses, but be aware that they will not work at the longer focal length. As there is no glass it is worth considering a set of Kenko ones when a set of 3 can be obtained for the price of the EF25 the Canon is much better built but nothing in it from the optical point of view..

Danny O'Byrne  http://www.digitalartzone.co.uk/

"All the technique in the world doesn't compensate for the inability to notice" Eliott Erwitt