Apple Shake 4 - Manual (Page 889)

Chapter 28 Filters 889
The following example is from a 3D render. Ringing appears around the background
letters of the text when normally passed into a ZBlur. Instead, separate the circle into
foreground and background elements with the 3D render. These are then blurred and
composited in Shake.
Parameters
This node displays the following controls in the Parameters tab:
amount
The maximum amount of blur.
near
The value of distance toward the camera at which maximum blur occurs.
far
The value of distance away from the camera at which maximum blur occurs.
focusCenter
The distance from the camera at which there is no blur. By default this is set to (far-
near)/2+near.