Lee Filters can work with adapters but the 14mm doesnt have a filter thread. But there are adapters available!
I know it a really different price point but the samyang 14mm is also a very nice lens and af on super-wide angles isnt that important.
That Samyang looks like quite a bargain considering what you get.
Does anyone have any experience with the Nikon 14-24 with 16-9 Novoflex adapter? I've read great things about this combination and even Lee offers a filter system specifically for this lens (unfortunately the Big Stopper doesn't fit, though).