According to Sigma USA website, some older models of Sigma lenses may require upgrading to be used with the newer Canon EOS cameras (EOS 30/33). Has anybody done this before or knows where to get it done in S'pore (eg. is there a Sigma centre here?)? The Sigma USA website provides this info on which lenses need upgrading.
http://www.sigma-photo.com/html/news/Elan7.htm
http://www.sigma-photo.com/html/news/Elan7.htm