Chromatic Aberration
Description
Chromatic aberration is caused by a lens having a different refractive index for different wavelengths of light and is seen as fringes of color around the edges of the image. This fringing is removed by un-distorting the individual color channels.
There are some new types of color fringes that are not chromatic aberration. These effects might be visible as purple or blue fringes and are visible around overexposed areas in most cases. If the following conditions apply, your image most likely has true chromatic aberration as opposed to color fringing caused by sensor overloading:
• Corners should show most color fringes whereas the center should show none.
• Color fringes should be not only at the edges of overexposed areas but at lower contrast edges, too.
• Color fringes should be of complementary color (red-cyan, green/magenta, and blue-yellow) on opposite sides of a dark or bright area.
• Color fringes should be in all corners with the same direction and pointing out from the center.
Note: Chromatic Aberration must be applied as the first layer (bottom of the layer stack) when multiple layers are used. Otherwise, all filters below will not be rendered.
Category
Lens.
Controls
Red/Cyan, Green/Magenta, Blue/Yellow
Use the appropriate color group to remove the chromatic aberration. For instance, if you see red/cyan fringing, use the Red/Cyan group. Start by adjusting the Distortion parameter.
Distortion
Pulls the corners of the image in or out. Negative values pull the corners of the image inward while positive values pull the corners of the image outward.
Anamorphic Squeeze
Anamorphic Squeeze corrects for the squeeze found in anamorphic motion picture lenses.
Curvature X and Y
Curvature X and Y correct for non-radial, asymmetric distortions found in anamorphic motion picture lenses.
Note: Anamorphic Squeeze and Curvature X and Y only work once the Distortion parameter has been adjusted.
Center X and Y
Determines the center point for the distortion.