If you’re using Photoshop, you could start with Edit > Transform and use Distort, Skew and other Transform tools to reshape your image and eliminate converging lines at the edges of the frame. But this won’t work for the most insidious kind of distortion, which is called barrel distortion. This type of distortion is cylindrical and causes the images to appear to curve out from the center of the frame. To correct this distortion, you need to work a little harder.
Open the image in Photoshop, and duplicate the image onto a new layer (CTRL + J), then under the Filters menu choose Distort > Spherize. You’ll see your image open into a new preview window where it probably looks extra-distorted—like it has been mapped onto a globe. By default, the Spherize filter is maxed out at 100% and has made the image look perfectly round. You can drag the slider into negative values, however, and this will make that sphere appear convex. This is a great and simple way to eliminate barrel distortion from photos.
But this still isn’t the most powerful wide-angle distortion repair option that Photoshop offers. For that, turn to the Lens Correction filter. Photoshop’s Lens Correction capability is found under the Filters menu. It launches a separate window in which the photo will load and presents you with two primary choices: auto correction or custom. Auto correction is certainly worth a try, as it’s easy enough to implement with a click. But to really get in and fine-tune barrel distortion—along with other distortions such as chromatic aberration and vignetting—you’ll want to choose the custom option.
Once in the Custom panel, before you go any further, look to the checkboxes at the bottom of the screen, and be sure "Show Grid" is selected. This will provide a perfect reference for the lines you’re straightening with the filter.
The top slider in the Custom control panel is for repairing geometric distortion, and you’ll notice that this slider looks familiar—it works exactly the same way as the Spherize filter does, where negative values create a concave look and positive values create a convex shape in your photos. But that’s not all the Lens Correction filter can do. At the bottom of the panel, you’ll see the Transform controls, including adjustments for vertical perspective and horizontal perspective. These adjustments are great for wide-angle image distortions, particularly if you’ve gotten a little too close to the subject while shooting or if you weren’t standing in just the right spot. With the vertical perspective controls, you actually can correct for keystoning, the most common distortion that occurs when you point your camera up at a structure. Vertical lines appear to converge, rather than remaining parallel, and this vertical perspective slider will correct for that. (The horizontal perspective slider, as you can imagine, creates a similar fix in the horizontal plane. I’ve used this control to adjust the weighting of a building in the frame, making it look like I had actually moved significantly from my actual shooting position.)
ADOBE LENS PROFILE CREATOR
|For the most customized lens distortion fixes available, consider investing in Adobe’s free download of Lens Profile Creator. The program helps you first map, and then eliminate, the specific barrel distortions, vignetting and chromatic aberrations that lens will create in various shooting situations.
Because the process starts with downloading and printing a black-and-white grid that you then photograph and process within the Lens Profile Creator software, you’re able to map everything from subtle color fringing to distinct edge distortions that occur when you use your lenses—whether they’re extreme wide-angles or telephoto zooms.
In fact, one of the best things about Lens Profile Creator is that you can develop custom distortion profiles for the same lens when used at different focal lengths, at different apertures and at different focus points.
Maybe the best part about Lens Profile Creator is that it can be applied manually or automatically to photos via multiple software interfaces—whether you prefer to use Lightroom, Photoshop or Adobe Camera Raw. Because information such as lens model, focal length, focus point and aperture are all stored in the metadata of digital image files, distortion can be automatically removed without even a single click of the mouse.
In between these two controls you’ll see a few more sliders for a few other types of wide-angle distortions mentioned above: chromatic aberration and vignetting. Chromatic aberration is particular to individual lenses and occurs when different colors of light are focused at different points. This can cause color fringing, and these sliders allow you to eliminate a fringe in any color. Vignetting occurs at the edges of the frame when an image gets darker due to light falling off as it travels from the center of the lens. The Amount slider adjusts just how bright (or dark) the vignetting correction will be, and the Midpoint slider lets you control how close to the center it will begin. (You also can use this control to add vignetting to images in order to drive a viewer’s eyes toward the center of the frame.)
The Lens Correction tool just might be the most powerful—yet still quite straightforward—approach to remedying wide-angle distortion in any form. You can save distortion presets to come back to when you use the same lens in the future. But there’s another option Photoshop provides that lets you create custom presets that map and eliminate the precise distortions created by your specific lenses—not the models of your lenses, mind you, but the actual lenses you own. It’s Adobe’s Lens Profile creator, and it can be used in Photoshop, Lightroom and Adobe Camera Raw to remove the specific distortions from the lenses in your bag. If you’re desperate to eliminate all traces of distortion from your images, this custom profile creator is the ideal way to go.