I've been researching on the web for a wide angle lens and thought I'd ask you folks for some opinions. So, long story short, I recently traded some equipment and now have a D7000 with the following lenses: 35 1.8, 50 1.8, 105 2.8 and a 80-200 2.8. I'm considering the Nikon 10-24, Tokina 12-24 or maybe a 17-50 2.8? I have only briefly owned a 3rd party lens, but, have been considering it; constant aperture is preferred. I have not done must landscape work, but I would like to have the ability to do so. Any thoughts?