something else to consider
Sigma 17-70mm F2.8-4.5 DC MACRO
http://www.dpreview.com/news/0601/06011802sigma17-70.asp
http://www.sigma-photo.co.jp/english/news/17_70_28_45_dc.htm
Sigma 17-70mm F2.8-4.5 DC MACRO
http://www.dpreview.com/news/0601/06011802sigma17-70.asp
http://www.sigma-photo.co.jp/english/news/17_70_28_45_dc.htm