It's funny how many people who bashed canon for having some external zoom lenses are now fine with it with the sigma 28-105. Seen a lot of "this lens is the reason to switch from canon" posts Also no IS which I've seen so many people say is required but now I guess is fine without I'm sure it's a great lens. If someone is already invested in canon though it'd probably make more sense to get the 24-105 2.8 than switch all your gear to Sony just for that lens.