Wisdom and Inspiration
Adobe Photoshop's Lens Correction Filter
By John Paul Caponigro
Nov 1, 2007

Adobe Photoshop's Lens Correction Filter (Filter: Distort) is an extremely useful filter that can be used to fix common lens distortion artifacts.

Its large preview displays a customizable grid that can be activated and reactivated to help guide you while making adjustments.

Several of the adjustment types can be found in RAW converters such as Adobe Camera RAW and Lightroom. These features can be used on other types of files, including TIFF files from scanned film.

Chromatic Aberration provides two sliders (Red/Cyan Fringe and Fix Blue/Yellow Fringe) that can be used to correct color fringing, most pronounced along high contrast contours and at the edges of images.

Vignette provides two sliders; Amount darkens or lightens corners while Midpoint adjusts gradient transitions to the center.

The Straighten Tool can be used to trace a contour and snap it perfectly vertical or horizontal, rotating the image to correct camera tilt.

There also are additional distortion features not currently found in RAW converters.

Antartica © John Paul Caponigro

The Remove Distortion slider (and the Move Grid Tool) correct barrel and pincushion distortion. This is excellent for straightening bowed lines. (For instance, straighten a horizon bowed by a wide angle lens.)

Transform offers two sliders that can be used to fine tune linear perspective; Vertical Perspective (simulates adjusting eye level, correcting for high or low exposure angles) and Horizontal Perspective (simulates shifting left or right to adjust angle of view) and Angle (rotation)

Finally, Edge fills in empty space at the border, typically produced by the distortions during correction; Edge Extension replicates pixels at the edge of the image, Transparency leaves space unfilled, Background Color fills space with a solid color. Each has specific but limited use.

Typically, corrected images need subsequent cropping (or cloning). Scale can be used to rescale an image during distortion. It can be used to crop, but unlike the Crop tool, it resamples an image.

Click Set Lens Default to save the current settings as the default for a camera model/lens/focal length combination. Click the Options button to the right of the Settings menu to Save Settings for reuse. Click the Settings menu to Load Settings that have been previously saved.

The Lens Correction Filter is one filter well worth becoming acquainted with. Used judiciously, it can improve a great many images.