- Creating a Tilt-Shift Effect
- Intentional Creative Distortion: A Toy Camera Look
- Final Thoughts
The new Lens Correction feature in Adobe Photoshop CS5, Adobe Camera Raw 6.1 or later, and Adobe Photoshop Lightroom 3 does a great job of removing various forms of distortion that you find in all kinds of lensesfrom phone cameras to $1500 pro lenses. But there’s nothing stopping you from taking Lens Correction a step further: using it as a creative tool that can strengthen your compositions and jazz up your images.
If you haven’t used Lens Correction before, here’s a quick overview. Lens Correction is designed to take care of issues including the following:
- Distortion: While Lens Correction doesn’t correct every type of distortion, it does correct barrel and pincushion distortion (see Figure 1).
- Chromatic aberration: When lens elements aren’t able to focus all colors in the same spot, you see chromatic aberration, which appears as fringes of colors (see Figure 2). There’s also an artifact called color fringing that’s related to the sensor instead of the lens, but I’m not talking about that here.
- Vignetting. Ideally, a lens should produce an image that’s evenly lit from corner to corner. When the corners are darker than the middle, that’s a vignette.
Figure 1 How barrel distortion makes an image appear to bow out.
Lens Correction can also address perspective distortion, where lines that should be parallel converge due to horizontal or vertical linear perspective.
Figure 2 Fringes of color created by chromatic aberration.
When using Lens Correction for creative purposes, chromatic aberration controls aren’t very useful but distortion and vignetting controls are, so I’ll concentrate on those last two.
I’ll show the Lens Correction dialog in Adobe Camera Raw 6, which is also available in a slightly different form in Adobe Photoshop Lightroom 3 as well as in Adobe Photoshop CS5. I won’t cover the conventional lens correction procedure in this article, but it’s a good idea to apply conventional corrections to an image before you start to use lens corrections creatively. This gives your image a solid baseline for further work. The rest of this article assumes you’ve had some conventional experience with using the Lens Correction feature.
Creating a Tilt-Shift Effect
It’s common to use Lens Correction as a software substitute for a tilt-shift lens, which can remove the keystone distortion you see from pointing the camera up at a building. When I use Lens Correction to remove keystone distortion, I often like to make the dominant lines perfectly horizontal and vertical to give an image some of the qualities of a rectilinear abstract painting. I especially like to do this with an image that has strong colors (as shown in Figure 3).
Figure 3 An image with keystone distortion (left), and after I straightened the vertical lines (right).
Next, I’ll use an example of removing distortion to give a Neoclassical building a more monumental feeling. In this case, I also customized the powerful black-and-white conversion features in Adobe Camera Raw to enhance that drama of the image, though I won’t be covering black-and-white conversion in this article.
Shooting for Distortion
When you apply or remove a high amount of distortion, pixels can get pushed out so far that large amounts of the image can end up outside the frame (see Figure 4).
Figure 4 Before correction (left), and with the image occupying the frame unevenly after correction (right).
Notice how much less image area is left to work with on the right side of the original color image after I apply the distortions I wanted. When you shoot an image that you want to appear “flat” as in my examples, you’ll get better results by minimizing the amount of distortion you start out with. As much as is practical, step back as much as you can while filling the center of the frame, and tend towards a longer focal length (zoom in) while still leaving space around the subject. A longer focal length compresses the apparent depth of the image, and shooting farther back reduces the amount of keystone distortion you have to deal with later. In my example, I was already across the street, and I couldn’t back up any further without cars entering the bottom of the scene.
If you don’t leave enough room around the subject, later on you’ll either be limited in the amount of distortion you can apply or you’ll be forced to crop out large areas of your image.
Adjusting Lens Correction Settings
With the image taken, we’re ready to play:
- Open the image in Camera Raw 6, Lightroom 3, or Photoshop CS5, and then do the following:
- In Camera Raw, click the Lens Corrections tab.
- In Lightroom 3, go to the Develop module and display the Lens Corrections panel.
- In Photoshop, choose Filter > Lens Correction.
Figure 5 The Manual Lens Corrections settings that straightened the building in my image.
This is typically an iterative process, so be patient as you zero in on the optimal settings. It’s not always clear which control to move next; it depends on the image and the lens. Keep an eye on the relationship of horizontal and vertical lines all across the grid, watching for when you might have taken a correction too far. Take advantage of the ability to nudge the values by small, precise amounts by clicking in a number field and pressing the Up Arrow or Down Arrow key. The final image is shown in Figure 6.
Figure 6 The final image.
Rotate, Scale, and Customized Warps
The Rotate and Scale options may seem self-explanatory, but there’s more to them that may not be obvious. While you can rotate and scale in Lens Correction, you can also achieve the same effects by using the Crop tool. It’s up to you where you do them, but it can be easier to apply these adjustments in either one place or the other, not both. For example, applying rotation in both the Lens Correction dialog and the Crop tool combines both rotation values, making it harder to reverse the correction or understand which option to change when you want to alter rotation further.
If you need to straighten uneven distortion that can’t be addressed with the Distortion slider, you can take the image into Photoshop and apply the Edit > Transform > Warp command to customize the warp with a mesh. I find this is sometimes necessary when the subject wasn’t in the center of the lens.