As far as I recall the only times you get a truly unimpeded view of the landscape is when you trigger the cinematic sequences associated with activating a vista point (I have a lot of screenshots from those vistas).
After the patch is released zooming in fully while playing will switch the camera to first-person view. It's not intended as a special option for a particular scenario, just an alternative view. This is pleasing news to me and will necessitate my return to Tyria for the equivalent of a tourist trip. I will take a sandwich and explore some areas and take all the screenshots.
There are a number of other camera changes included in the update too. A field of view slider will let you alter how much of the game world you see on screen while position sliders let you tinker with the horizontal and vertical camera positioning so you can create custom over-the-shoulder perspectives.
Another tweak is that the camera will now focus on your character's head by default. The reason this is interesting is that it sounds like it's intended to bring out the height characteristics of the game's races. A Norn (those nine-foot-tall hunters), for example, will feel taller to play than one of the Asura (the formerly-underground race with the sad ears). If you find that ballsing up your jumping puzzles you can toggle back to having the camera a fixed height from the ground instead.
ArenaNet will be having a livestreamed demo on Twitch of the features on 27 Feb (that's Friday) at 8pm GMT if you're curious about how it'll work.