The optical formula did not change between incarnations I ve heard this several times but not from a definitive source this is why I put a cite needed tag in the article It makes sense that a different type of focus motor shouldn t affect the optics and that Canon or anyone else wouldn t invest R D in developing a new optical formula if it isn t needed Between this and having been told a few times at a pro camera store online it passes my level of probably true Still it needs a citation and if anybody else feels like this doesn t pass the threshold Wikipedia says to act bold and remove it Hopefully somebody has access to diagrams of the glass in both lenses or can settle this somehow