Tokina Acknowledges Pairing Issue with 11-16mm f/2.8 Lens and Canon 7D? Kind of:

Since upgrading to the Canon 7D I have been experiencing repeatable auto-focus problems with my ultra-wide angle Tokina 11-16mm f/2.8 lens. The problems occurred whenever using any of the manually selected AF points outside the center point. Focus would be inconsistent, often resulting in images with soft focus, or totally out of focus. Since the lens originally worked flawlessly on my Canon 40D with manually selected AF points, I decided to send it in to THK Photo Products (Tokina's US servicer) in California for service/repair. About two weeks after shipping my lens out, I received the following email from THK's service representative on June 13, 2011:

In regards to the Tokina 11-16mm lens you sent in for repair, my technician has informed me that it was necessary to send your lens back to the factory in Japan.

We can offer you a replacement lens or arrange for a refund from the place of purchase.
— THK Photo Products

Since the Tokina 11-16mm is one of my favorite lenses (I use it for almost all of my landscape and star-trail photography), I informed the representative that I would prefer a replacement over a refund.  However, since I wanted to avoid a repeat of the AF problems I had experienced, I asked if a replacement would definitely solve my problem.  Here is his response:

Japan has found that when using this lens on the 7D, it works best when used in the Center Focus Mode. In the 19 point AF mode, the camera will automatically focus in on what ever is nearest in the frame, and this can cause soft images. However, when using the Center Focus Mode, the camera will focus in of the center of the subject without any problem.

We will replace the lens for you immediately.
— THK Photo Products

Although not directly stated by the THK representative, I'm assuming the lens I bought was an older version that requires a chip update to make it compatible with the 7D.  Since the 11-16mm was released in February 2008, a full year and a half before the release of the 7D, it was likely not designed to work with the 7D's brand new 19-point AF system.  Thus, when the 7D hit store shelves, there were reports of  auto-focus issues with the Tokina 11-16 when mounted on the Canon 7D.

This is a risk when buying third-party lenses, as lens manufacturers cannot anticipate every new feature a camera maker like Canon may develop.  As such, incompatibility with newly released camera bodies is possible.  Luckily for Tokina owners, it appears (unofficially) that they are willing to replace/update older versions of the 11-16mm f/2.8 lens to make it compatible with the 7D.   I'd assume this update has already made it's way into their manufacturing process, so the newest versions of this lens hitting store shelves don't suffer from this problem.

I'm looking forward to receiving the replacement lens, and will update this post once I receive it and have had time to test it. I also want to thank THK for their prompt and direct response to my service request.

Hopefully other Tokina 11-16mm users will find this information useful.

** UPDATE - October 13, 2011 **

After using the replacement lens for a couple of months now, I can report that the center AF point does acquire focus rather quickly and reliably on my 7D. Just stick with the center AF point and all should be good!

** UPDATE - January 27, 2012 **

Canon Rumors is reporting that Tokina will be releasing an updated MarkII version of their famed 11-16mm ultra-wide lens July of this year. I can't wait!! Read more below:

Tokina AT-X 11-16 f/2.8 PRO DX Ⅱ Lens Announced