To investigate camera tilt motion:

The left canvas shows the relative location of the scene objects and the camera. The right canvas shows the scene from the camera's vantage point.
Please use a browser that supports "canvas" Please use a browser that supports "canvas"
Manipulate the function lookAt(M, eye_x, eye_y, eye_z, center_x, center_y, center_z, up_dx, up_dy, up_dz)

eye (0.0, 0.0, 5.0) center (0.0, 0.0, 0.0) up <0.0, 1.0, 0.0>
X: -5.0 +5.0 X: -5.0 +5.0 X: -1.0 +1.0
Y: -5.0 +5.0 Y: -5.0 +5.0 Y: -1.0 +1.0
Z: -5.0 +5.0 Z: -5.0 +5.0 Z: -1.0 +1.0

Each click of the tilt button rotates 1 degree about the u axis.