LensRentals.com has completed their first MTF comparison between the Canon 35mm f/1.4L II, Sigma 35mm Art & Canon 35mm f/1.4L. The MTF does show a slight advatange for the new Canon over the Sigma Art series lens, but based on the MTF alone, that may not make it worth the price. However, there are a lot more things to consider than just MTF charts. There's build quality & AF performance, both of which are going to be better from the new Canon. Other things like color rendition, CA control, and overall “look” of the images the lens is capable of producing will also matter to a lot of buyers.
We're still waiting for our copy of the new Canon, and we're really looking forward to it.
From LensRentals.com
Everyone always asks me if I would buy this lens. Honestly, I'm not sure that I would just on the basis of the MTF charts. It's the best 35mm by just a whisker over the Sigma 35mm f/1.4, but at nearly twice the price. As more reviewers weigh in there may well show other things that make it worth the price difference. A lot of people only consider Canon lenses, though, and I expect many of them will be upgrading from the Canon 35mm f/1.4 for the increased resolution the new lens gives them. Read the full article
Preorder EF 35 f/1.4L II $1799: B&H Photo | Adorama | Amazon | Canon Store (in stock)