User Guide

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ADOBE AFTER EFFECTS 5.0
User Guide
Simulating a zoom lens
You can simulate a more realistic accelerating effect of a zoom lens when working with 2D
layers by using Exponential Scale, which converts linear scaling of a layer to exponential
scaling. This is useful for creating a cosmic zoom, for example. Zooming optically with a
lens is not linear—the rate of change of scaling accelerates as you zoom. To simulate this
acceleration, Exponential Scale converts the velocity of the scaling to an exponential curve.
To apply Exponential Scale:
1 In the Timeline window, hold down the Shift key and select starting and ending
keyframes for the scale property.
2 Choose Animation > Keyframe Assistant > Exponential Scale.
Note: Exponential Scale replaces any existing keyframes between the selected starting and
ending keyframes.
About tracking motion
The Tracker/Stabilizer tracks motion by matching pixels from a selected area in the first frame
to pixels in each succeeding frame, thereby following that motion. For example, suppose you
have footage of a bareheaded person walking, and you’d like to add a hat to this person’s
head. Use the Tracker controls to isolate the top of the head and track its motion in the
first layer, and apply the tracked motion to an image of a hat in a second layer.
UG.book Page 393 Wednesday, February 21, 2001 12:05 PM