I have a T2i and am planning to rent a telephoto lens for my upcoming cruise to Alaska. I was originally planning to rent the 70-200 f2.8L, but now I'm wondering about the 28-300 f/3.5-5.6L. I'll mainly be looking for wildlife photo ops, some scenery, etc. The 70-200 costs less to rent, but would this be a case of 'bigger' actually being better? The only other lens I have is the 15-85. so I have the wide angle covered, I'm mainly looking for reach.