Add, Do Not Subtract

Add, Do Not Subtract

Although software may one day be developed to resolve
a blurred image, it is much, much harder to sharpen a
blurred image elegantly than it is to add blur to a sharp
image. Motion Blur comes for free when you keyframe
motion in After Effects; what about when there is motion
but no blur and no keyframes, as can be the case in preexising
footage?
If you have imported a 3D element with insuffi cient blur,
or footage shot with too high a shutter speed, you have the
options to add the effect of motion blur using
. Directional Blur, which can mimic the blur of layers
moving in some uniform X and Y direction
. Zoom Blur, which can mimic motion in Z depth
(or spin)
. Timewarp, which can add motion blur without retiming
footage
Yes, you read that last one correctly. There’s a full section
on Timewarp later in this chapter, but to use it to add procedural
motion blur, just set Speed to 100 and toggle Enable
Motion Blur, then raise Shutter Angle and Shutter Samples
(being aware that the higher you raise them, the longer the

render time). The methodology is similar to that of Reel
Smart Motion Blur (RE:Vision Effects); try the demo on the
book’s disc and compare quality and render time.
Don’t forget motion blur when matching foreground and
background elements (Chapter 5). An element perfectly
matched for color and lighting will look wrong until its
motion blur also matches that of the surrounding scene.