rmorrison1116 wrote:
So, which L series lens is this Sigma better than? If you honestly believe a $350 Sigma lens is built better than even an inexpensive $1000 L series, you obviously don't own any. I do own the Sigma 17-50 f/2.8 in Nikon mount and yes, it is a really nice lens but, I also own several Canon lenses, both black and off white with the sexy crimson band, and the Sigma lens is not as well made as any of them.
My statement is for picture quality, the Sigma is that good.
Your statement concerns build quality, for the price I would expect the Canon to be better. How much so is objective since neither of us can test that. Both Sigma and Canon build a quality, well made lens. The OP will do well to get the Sigma.