Going from a wide shot, then suddenly zooming in on a character or detail is a "crash zoom", "whip zoom", or "snap zoom". Used correctly, its a technique to quickly give the audience an overview of the situation, then rapidly immerse them. When done precisely it can add impact to the action on screen. When done imprecisely, often followed with a close tracking shot as in the question's examples, it can give a documentary feel, like a reporter or home-movie with a hand-held camera choosing to focus on a subject in the heat of the moment.
They've been around for as long as we've had zoom lenses. For example, Stanley Kubrick makes heavy use in The Shining (examples at 57 seconds). They were also heavily used in kung-fu movies and some westerns from which Tarantino takes his inspiration.
Traditional whip zooms are done by changing the focal length (ie. a zoom lens) or in post-production by blowing up a portion of the film. A zoom lens seems to be closer to the action by reducing the field of view, but the camera remains in the same spot. This creates a number of visual distortions. You seem closer, but all the angles remain the same; things appear flat when zoomed in, objects which might be separated by some distance appear to be on the same plane. It also creates a shallow depth-of-field where only a narrow plane is in focus. Whip zooms take advantage of this to suddenly focus the audience on the chosen subject and blur out the background. Computers have added the ability to do it with greater precision and speed.
Blowing up a portion of the film has a similar effect, but it loses fidelity.
A whip zoom can also be done by physically moving the camera closer. This changes the angles, focus, and perspective naturally giving viewer a sense of motion, but is limited by how fast and smooth one can move the camera and keep the subject in focus. With computer graphics now the camera can be completely virtual and moved as fast as the editor wishes. This offers the editor the full range of perspective, speed, depth-of-field, and focus provided by zoom and camera movement when creating a whip zoom. And it can be done in post-production.
A good example of the changes in perspective between zoom and camera movement is the dolly zoom. This moves the camera in while zooming out at the same rate (or vice versa). The angles and perspective change as if you're moving, but the apparent distance to the subject remains the same as if you're standing still. The visual contrast creates a sense of shock or Vertigo.
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