Barrel distortion is a real bother, most often seen when working with wide-angle lenses. Barrel distortion is the curvature that often shows in vertical lines in an image as they bend subtly around the center of a scene. This manifests itself in architectural interior photographs especially. It’s not so much that interior scenes create any more distortion than other types of photographs, it’s just that our eyes are used to seeing doors, walls and ceilings remaining relatively straight, parallel and perpendicular.
First, to check for distortion, I turn on the grid view in Photoshop’s View menu. This will provide the physical proof to see just how distorted a scene may be. Evidence in hand, open Lens Correction in the Filter menu. From here, you’re just a few mouse clicks from a straightened image. Slide the distortion adjustment slider until the lines become parallel—checking them against the grid to be sure you don’t go too far.
In this menu you also can save a preset for a particular lens, making it easier to make the same adjustment for barrel distortions in future images. Click OK and Photoshop will render the changes onto the image file, but you’re not quite done. Notice the edges of the frame are now devoid of image detail? To eliminate this, I often simply crop into the scene until the frame is filled again. Another option would be to duplicate the original image file onto a new layer, apply the lens correction to the top layer, and then use your retouching skills to blend the transition between the corrected and original layers. This is the preferred approach if you absolutely have to have every inch of the original image and can’t afford to crop into the scene at all.
If you really want to tackle barrel distortion most precisely, download Adobe’s new Lens Profile Creator to make a custom profile for each of your lenses so that with one click you can precisely correct every new exposure.
Barrel distortion is both an insidious aberration and an easy fix. So now you’ve got no excuse for those distracting distortions in your wide-angle images.