wide angle sigma

I am getting my first wide angle lens and need some advice. Most of what I shoot is landscape photography, however, my only lenses are the Sigma 50 1.4 A, and the Canon 70-200 2.8. I am about to purchase a new wide angel lens and I want to go with a prime, Sigma Lens. When I saw the...

Hey all, I'm a bit confused by these two lenses. A friend asked me why was one double the other, and at first glance I was going to give her the "oh, well, one is variable aperture and the other isn't, the latter being better quality, yadda yadda yadda"... but then when I clicked the links, the...