See also expert version: ExpertCam

v3 and v3b

WASD and Shift WS work normally, allowing you to go almost completely vertical.
IJKL pan the camera, Shift IK raises and lowers the camera.

Version 3 introduces automatic camera control path making.
Q captures a key frame, Shift Q removes all keyframes.
E toggles automation mode. Press once to enter, press again to exit.
U controls air friction/springiness. The higher it is, the more it is constrained to the path. The lesser, the more it tends to bounce. U increases, Shift U decreases.
O controls acceleration gain. The higher it is, the faster it tries to approach the next key frame. The lower, the slower it approaches. O increases, Shift O decreases.

To fully understand how to take command of the auto path, you need to know how it works. The further the next point is, the faster it accelerates, adding velocity. Air friction cuts this speed by a certain percentage. Certain values and paths will tend to cause the camera to overshoot and swing past the keyframe. Useful at some points, not so much in others. PLAN ACCORDINGLY. Also, this only applies to the camera, not it's look point. The look point runs on a basic tween, moving directly/linear from one keyframes location to another.

In some cases, the acceleration controlled camera does not work (e.g. smooth and long panning). In this case, use v3b, where both camera and look point are controlled by a basic tween.

If you still don't get the sequence of how to use the auto pathing. I made a tutorial.
http://www.youtube.com/watch?v=1FhXFQsCOwQ

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Change Log
v1_0: Panning Only
v1_1: Added up/down. Beware shift A,D.
v1_2: More stable.
v1_3: Airplane Flight Mode. DOES NOT replace v1_2.
v2: Complete control, except maximum/minimum pitch.
v2_1: Complete control.
v3: Complete AND automated control.