IMHO, as always, if you are looking at any 5 series Canon, you certainly want a much better lens than that Tamron anyway. The 5 series is way too good of a camera to hamper it with a poor lens. Avoid any zoom with a huge zoom range. If you do want that type of zoom photography look at the Powershot P&S line up. Again, MHO.
The Sigma MC-11 can easily be modified to accept EF-S lenses. All that has to be done is a removal of the internal plastic cover, which sits under the outside ring. It's removal does not effect the function of the adapter in any way.
This is commonly done and takes just a few minutes to do.