Hi Frank you may wish to review this site ( I have this lens and it is an absolute gem of a lens use it on my 350D and 40D bodies, very sharp and good results in low light image IS also very useful also use with x 2 extender again good results for high speed racing cars/bikes)
http://www.the-digital-picture.com/R...ns-Review.aspx
and:
http://www.dpreview.com/lensreviews/...p8_is_usm_c16/