Tokina 11-16mm f/2.8 vs. Canon 10-18 f/4.5-5.6
I have a Canon 7D Mark II camera, and am planning to buy an ultrawide lens for architectural photography (and landscape photos, to some extent). I like to shoot interiors of buildings (e.g. old libraries, theaters, etc), so light is somewhat of an issue. Therefore I am leaning toward buying a Tokina lens, with a constant f/2.8 aperture. However, I'm wondering if the Canon would be a better buy for the following reasons: 1. I'd probably stop down anyway when shooting architecture; 2. I'm not sure I trust third party lenses; 3. (this is more of a general photography question): since I'll be shooting anteriors or landscapes with fairly little motion to worry about, I am wondering if I could use a slower shutter speed with the Canon, thus letting in enough light to compensate for the smaller aperture. I'll be using a tripod.
Thanks for your thoughts!
--Wendy