Wow, got it today, definitely a steal for the price, I wanted it for the fast af that everyone raved about, coupled with the sharpness and build. Day after I bought it I thought i might regret it, as The focus on the 17-50 was just so slow I thought I might be doing something wrong, but holy shit, the speed is insane, focuses inside at least 3/4x faster than the tamron does in good light, I have a feeling I just won't be able to live with the speed of the 17-50 after this.