Hello, what happened to me - probably never happened to many. I have mounted macro/wide angle lenses on my regular 15-55mm canon lens, which come stock with XTi. And what happened next is trully unbelievable. The macro ring got stuck on the lens. So when I tried to take it off, only the wide angle lens would go, leaving the ring on the lens. And I tried and tried to take the little ring off, but I cant. It is just stuck. This is the .4" part on the bottom of the additional wide angle/macro lenses here: http://www.plus-foto.com/images/prod/m-image/lens-002-a.jpg I appreciate your input... this has driven me crazy, since I had to take photos with wide angle lenses and all that vignetting in making me sick.