I plan on taking a trip where I'll be taking a lot of outdoor photography, mostly architecture, but landscape as well. I own a sony a100 digital slr and I was wondering if a wide angle lens would be something to invest in, also what focal length should I look for, as i anticipate needing some zoom. And has anyone had experience with a polarizing filter? I've heard that it helps with reducing haze, and reflections from glass? Appreciate the help!