You’ve probably experienced lens distortion in your images in one form or another. If you snapped a photo of a building and edges that should be straight lines appear curved or distorted, that’s it.
This is common, but most objectionable in certain genres of photography such as architecture. Also, it is more pronounced in some lenses than others. There are several variations of lens distortion. Examples include barrel distortion, pincushion distortion, and mustache distortion, aka wave distortion. In addition, chromatic aberration and perspective distortion should be included.
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Read this article carefully to gain an understanding of the various lens distortions. A priority for photographers is image quality. Be aware of the different types of lens distortion, then anticipate and minimize the effects in-camera or correct them in post-processing. Or in some situations, you may want to use lens distortion as a creative effect.
The What and Why of Lens Distortion
When light passes through the elements of a lens, the varying shapes and angles lead to geometric distortions in the final image. This distortion manifests in different ways, depending on the curvature of the lens elements. The distortion results from how light is refracted and focused onto the camera sensor. And for the most part, this distortion increases towards the edges of the frame. The center of the image will have the least amount of distortion.
The quality of the glass used, the precision of manufacturing, and the overall construction and optical design of the lens impact the level of distortion present in photos. Prime lenses with focal lengths in the range of 50mm to 85mm are generally the least susceptible to this type of distortion. A lens with a focal length in this range has a more natural field of view that closely resembles that of the human eye. Very often, these types of lenses are preferred by photographers who specialize in portraiture and architecture, where distortion is a major concern.
The image below shows a grid with no distortion, how the human eye sees it.
What is Barrel Distortion?
This type of image distortion causes straight lines to appear curved outward towards the edges and corners of the image. Its shape is similar to a barrel. This effect can be quite noticeable, especially in images with a lot of straight lines or geometric shapes.
Barrel distortion is most commonly seen in wide-angle lenses, particularly those with a focal length of 35mm or less. Lenses with a wider field of view exaggerate the distortion effect.
The image below shows the grid with barrel distortion.
What is Pincushion Distortion?
This type of geometric distortion results in straight lines that bend inward towards the center of the image. Pincushion distortion gives the image a compressed look.
Lenses with longer focal lengths are most susceptible to pincushion distortion. For example, telephoto lenses of 200 mm or more tend to squeeze the image, leading to the bending of straight lines towards the center.
The picture below shows an example of pincushion distortion.
In both barrel and pincushion distortion, the effects are most apparent near the edges of the frame. At the center of the image, the distortion may be so slight as to be unobjectionable.
Wave Distortion, AKA Mustache Distortion, is a Complex Distortion
A combination of barrel and pincushion distortion, wave distortion causes the lines to curve away from the center near the top edge and bottom edge and dip upward at the sides. The effect resembles a wave or a mustache shape.
This complex form of geometric distortion can be difficult to fix and may require specialized processing software. Note however, that trying to correct distortion of this type as if it were the barrel or pincushion variety could make the distortions even more objectionable.
Ultra wide-angle lenses, such as 12-24 mm zoom lenses or fisheye lenses, are most susceptible to wave distortion due to their wider field of view and unique optical construction. These lenses tend to exhibit more pronounced wide-angle distortion towards the edges of the image plane, especially when shooting at close distances.
Perspective Distortion
This is a consequence of the camera’s proximity or angle to the subject, not the result of optical systems.
When the camera is very close to the subject, we get a distorted or skewed appearance. A wide-angle lens exaggerates the effect of this distortion. Adjusting the angle and position of the camera and lens may reduce the impact of perspective distortion.
The image below illustrates this type of distortion. The combination of a low angle, the camera close to the subject, and an 18-mm lens makes the front fender appear abnormally large. Meanwhile, the side of the car seems small and out of proportion, especially toward the rear.
Chromatic Aberration
A common optical issue, chromatic aberration occurs when different colors of light are not focused at the same point on the camera sensor. This results in colored fringes appearing along the edge of objects in an image, particularly noticeable in high-contrast areas. These aberrations are common to some degree in most lenses, more so in zoom lenses that have more elements and moving parts than in prime lenses.
We have an article on chromatic aberration that you may find helpful.
How to Fix Lens Distortion
Now that we understand the various forms of lens distortion, what can we do? This distortion appears as distorted or curved lives. It is most obvious and objectionable in genres of photography that require precise and accurate representation of subjects.
In architecture, landscape, and product photography, where straight lines, geometric shapes, and level horizons are essential to the composition, even small amounts of lens distortion are unacceptable.
Other genres, such as macro-photography, portrait, and wildlife, the absence of straight lines makes lens distortion difficult to detect. In these instances, lens distortion may be present, but not objectionable. That is, the emphasis is on the overall composition and mood of the picture rather than accuracy of horizontal and vertical lines.
Correcting Lens Distortion in Lightroom
Adobe Lightroom contains built-in profiles for thousands of lenses. These profiles are calculated to correct most types of lens distortion. And stop me if you’ve heard this before: you’ll get the best results working with RAW files.
After the image is imported, go to the Develop module and locate the Lens Corrections panel. Select the Profile tab and check the Enable Profile Corrections box. Based on the metadata in the image file, Lightroom detects the lens used to capture the photo and applies the appropriate action to correct image distortion. Also, you can check the Remove Chromatic Aberration box.
This is a quick and easy method to address lens distortion and works very well in most cases.
Using Lightroom’s Manual Lens Correction
If Lightroom doesn’t have your lens profile or if you want full control for correcting lens distortion, choose the Manual mode on the Lens Corrections panel. Move the Distortion slider to the left or right to remedy barrel distortion or pincushion distortion.
This panel also features Defringe sliders to minimize chromatic aberration and Vignetting sliders to mitigate darkening at the corners.
The options in the Manual tab give you an effective way to address lens distortion. Please note that even though it’s a more cumbersome process than using the built-in profile, you have greater control of the outcome.
Photoshop has a similar feature: Lens Correction under the Filter tab.
Use Lightroom Transform to Adjust the Perspective
A powerful tool, Transform easily straightens vertical and horizontal lines in photos. The Auto button turns the process over to Lightroom. Other functions allow for full manual adjustment of Vertical lean and Horizontal shift. In addition, sliders for Rotate, Aspect, Scale, and axis Offset fine tune the image to ensure accurate representation of the scene.
Transform is especially useful when photographing buildings. In the two examples below, the first photo exhibits a backward lean. The second photo shows the corrected perspective rendered by Lightroom. The difference is substantial. And, as you can see, it’s a good idea to leave plenty of room to crop after the perspective change.
Other Lens Distortion Correction Software
Lightroom and Photoshop are the gold standard for image processing; however, alternatives are available.
Evoto AI, Gimp, InPixio, LuminarNeo, and Photoshop Express employ artificial intelligence and built-in lens profiles to analyze images and remove distortions. Some are free; others offer a free trial.
Other platforms are available for correcting lens distortion in images and enhancing the quality of your photography.
Have a Little Fun with Lens Distortion
Usually, we aim to minimize it, but lens distortion offers creative opportunities. Photographers explore and experiment with the visual effects, normally called defects of the optical systems, to add a creative touch to their images.
A telephoto lens compresses the image and makes the subject appear thinner. This may give you a positive outcome for some portraits. A wide angle lens exaggerates features, especially at the image center and at a close distance to the subject.
By utilizing the geometric distortion of a lens and taking a unique perspective, photographers creatively manipulate the composition of their shots to achieve a desired result. So, we can use lens distortion as a tool to enhance the overall creativity and impact of our work.
Conclusion
In most cases, lens distortion is a negative. It is most objectionable in architectural photography, for example, where straight lines and angles are crucial for capturing buildings and structures accurately. Additionally, landscape photography can also be affected, as the distortion can alter the natural shapes and distort the horizon.
To correct lens distortion in post-processing, photographers utilize software tools with built-in lens profiles to reduce or eliminate the distortion. Sometimes, we find a creative use for it, turning a negative into a positive.
I hope this article gives you an understanding of lens distortion and how to minimize it or incorporate it into your own photography world. If you have any questions or comments, please submit them in the space below.
Take Away
- Lens distortion in photography refers to aberrations in optical systems that result in the warping or bending of images. It can have a significant impact on the quality and accuracy of a photograph, distorting the subject and creating an out-of-proportion look. Powerful image processing software is available to correct the most common forms of lens distortion.
