Canon last had an EF-M camera and lenses in 1991 (inset, LCD screen pic) The Canon EOS M mirrorless camera with new EF-M mount and lenses is due to be officially announced on Monday. The EOS M seems to be closest to the Sony NEX C3. The lack of physical controls hint that it is too basic to compete with the NEX 5N or NEX 7. Because it is designed…