The extra long boom (actually, that's fairly standard for experienced boom-ops) keeps him out of frame. He is also extraordinarily good at aiming correctly; that's why he's so well paid and working on big-budget projects. They are probably also using a long shotgun mic, which is even more directional than a standard shotgun mic.
They are also doing all of the other proper production sound procedures for big-budget films. The actors are most probably wired with lavs as well. The new Lectrosonics transmitters are completely water/sweat proof, and very, very small.
It's most likely paired with a CountryMan B6 lav or equivalent.
(As the man said, if you have to ask, you can't afford it....)
In addition to the great gear they are probably capturing dialog wilds. Then, in audio post, the dialog editor works his magic with alts and wilds. And, of course, ADR is always an option, and having a pilot/guide track, whether the DX editor uses alts, wilds or ADR, makes sync one hell of a lot easier.