for a walk around lens, you will want the 24-70. Anything wider than 24 on fullframe is way to wide. you get a great set of options in its zoom. If it helps, think about it this way, dont worry about quality of the glass, just focus on what you want to shoot as for walk around. with 24-70 you can give yourself a tighter crop, or loosen it up a little. the 16-35 is just to loose for walk around. Even if was to go to a festival i