The Perspective filter can be used to either correct converging perspective lines caused by lens distortion, or to apply perspective for a creative effect.
Lens distortion can often cause the perspective of a photo to be out, creating the appearance that lines are not vertical or horizontal when they should be.
About the Perspective filter
The Perspective filter can be adjusted in single or dual plane mode, if applied destructively. If using the non-destructive, live filter, only single plane mode is available.
Settings
The following settings can be adjusted on the context toolbar:
Mode—presents the grid as either a single or dual plane.
Source / Destination—offers two preview options.
Source—the image remains static as the perspective box is positioned. When the perspective filter is applied, the image is stretched and cropped to the original canvas size.
Destination—the image is directly linked to the perspective box and transforms (in real time) with the box as the anchor points are dragged.
Show Grid—when selected (default), a grid is displayed between anchor points and lines. If this option is off, only anchor points and lines display.
Autoclip—(Available in Dual Plane mode) Specifies whether or not to alter the image beyond the boundaries of the perspective grid points. If disabled, the image will look continuous; if enabled, the image will have visible seams where the perspective tool has been applied that can then be retouched.
Before/After—if this option is off (default), your page displays your image with the current perspective applied. When selected, your page displays the adjusted and original images simultaneously.