In my mind at least, point of view can be discussed in two sets of terminology. Specifically, there's internalized or "tight" POV, and externalized or "loose" POV. Call it a range from "objective" to "omniscient," which is to say, a point of view can range from an external POV, which can speak to what it knows and observes at that very instant, to one that can tangent off into anything and everything in the universe because it knows all.
There's another set of criteria, which revolves around *who* the narrator is. There are three options there--first, second, and third person. Simply, "I," "you," or "she."
For these purposes, we'll do 'em all in third person. To get a feel for the difference without confusing the issue with who's talking.
Let's start first with one of the two real oddballs, objective POV (the other real oddball is first person omniscient, which I have seen used twice.). The classic point of view of Dashiell Hammett's THE MALTESE FALCON, this POV *never* offers us internalizations. It observes the characters from the outside, and it's an unwinking camera eye. Like so:
Robert James was a gray-haired, beetle-browed man in his forties, with a square chin, square shoulders, and a perpetually quizzical expression. One Saturday at the office, he spent fifteen minutes organizing his files, and didn't finish. Halfway through the Js, his unhappy secretary Maryanne brought him coffee, a doughnut, and a revolver, which she squared on his blotter without comment.
He set the files aside after she left the office and checked to be sure the revolver was loaded. One bullet, as was traditional. He closed his eyes as he slid the barrel into his mouth.
Okay. The entire scene is told from a camera's-eye view, and we're not privy to the character's thoughts. The difference between this and the other end of the scale--omniscient--is that, while omniscient still allows that external picture of the character--the narrator's voice to emerge, in other words--it also allows us to flit sylphlike into anything within the scene we choose. We can see from the point of view of the narrator, any of the characters, any observer. Anywhere.
It's tremendously difficult to manage, and done poorly, it can be very jarring. The writer needs at all times to be aware of the POV choices he's making, why he's making them, and how he's transitioning between POVs. He has to lead the reader smoothly from one perspective to the next, without confusing her. WATERSHIP DOWN is a good example of omniscient. (All of these POVs can also have intrusive or invisible narrators. That's a different lecture.)
This is the same scene in omniscient:
Robert James was a gray-haired, beetle-browed man in his forties, with a square chin, square shoulders, and a perpetually quizzical expression that reflected what he would have called a deep curiousity about the world, though some might have considered it a sort of wariness. One Saturday at the office, when he'd spent fifteen minutes organizing his files and only made it to the Js, his secretary Maryanne entered his office.
She saw him hunched over a pile of manilla folders, sorting through them with a distracted expression. The tray in her hands was heavier than other mornings; in addition to his usual coffee and doughnut, it held a revolver loaded with a single bullet. She couldn't stand to look at it, and had draped a napkin over the gun after she readied it.
She set it on his desk without speaking, and he pushed the papers aside and checked the gun before she left. It's about time, he thought. Then his lips closed, warm around the barrel, and he fired.
See? I can even go into the POV of the revolver, if I like. The trick is to maintain the narrative thread, and always be aware of the transitions and smoothing them out, so the reader is never jarred or confused. ("head-hopping.")
There's also cinematic omniscient, so called best-seller omniscient, which is an often clumsy use of omni that does not partake of that narrative discipline, and often suffers line of direction problems. DUNE is one example of this kind of omni. I'm told that whassisname Brown book I haven't read is also in this POV.
In between these two lies limited omniscient, what we frequently--and sloppily--refer to as "third person limited."
In this POV, we are privy to the thoughts of only one character. It can be written on a sliding scale--from so firmly in the head of that character that we never see or think anything he doesn't see or think first (this is the POV recommended by many for beginning writers (and considered de rigeur by some, in genre, though I think that's amatter of fashion and I'll bloody well wear bell bottoms if I want), because it teaches the discipline one needs to handle other POVs firmly) to what I like to call telepathic steadicam POV, which is to say, you see the scene as if from over the shoulder of the POV character, and can read his mind. ("Loose" third person limited.) (Difficult to do well.)
Here's a very tight limited third person:
It was a Saturday. James was bent over files at his desk, brow furrowed as he sorted papers into the J folders, intent enough that he jumped when Maryanne bumped the door open with her hip. He didn't look up until she set the tray down, and then the napkin-covered outline of a revolver beside the coffee and doughnut caught his eye.
She turned on a pointed shoe and left him staring at the thing. Slowly, he reached out and brushed the napkin aside, then checked the load. One bullet.
He closed his eyes as he slid the room-temperature barrel into his mouth, tasting gun oil. It's about time, he thought, and fired.