Apple Shake 4 New Features - Manual (Page 69)

Chapter 2 Major Features and New Nodes 69
Note: If necessary, you can preprocess images connected to the AutoAlign node with
other color correction nodes to even out differences in gamma and contrast that aren’t
addressed by the matchIllum parameter.
The LensWarp Node
This node lets you make subtle or large adjustments to an image to either correct for,
or simulate, different types of film and video lenses. As a corrective measure, you can
use this node to remove barrel distortion in an image. You can also use this node to
simulate the lens used in one image, in order to warp another image you’re
compositing over it so that they appear to have been shot using the same lens. This
node affords more appropriate control over the result than the PinCushion node.
There are two ways you can use the LensWarp node.
Manual Adjustments
You can manually adjust the factor and Kappa values to create the desired effect. If
you’re making a simple correction, this may be the fastest way to proceed.
Automatic Calibration
You can also draw shapes along the edge of any distorted features within the image
that are supposed to be straight, and use the calibrate button to automatically correct
the image. This provides the most accurate result, especially for moving images.
To automatically calibrate the LensWarp node:
1 Attach the LensWarp node to an image with wide-angle distortion.
By default, the LensWarp node is in Add Shapes mode.
2 In the Viewer, identify one or more curved features that should be straight, then trace
each curve with an open shape.
Important: Make sure the LensWarp node is turned off in the Parameters tab before
adding calibration shapes.
Before After LensWarp undistort