Correcting Barrel Distortion
Barrel distortion is defined as a geometric distortion most common in wide angle lenses, which causes an image to distort spherically outwards. It is most visible in pictures that have straight lines close to the edge of an image. These distortions tend to be lens specific, and in the past, it required very technical calculations to correct them. However, with the current software technology available on the market, they can be repaired very easily no matter what type of camera you use. This article will focus on how to correct barrel distortion in digital images using Adobe Photoshop.
Step 1: Identifying Barrel Distortion
No matter what camera you use, if you apply wide angle lens or adapters (those in regular small digital cameras), there will always be some amount of distortion. The most important thing to focus on is the straight lines present in your image. If they seem to bend away from the center of the image, then most probably, your image is distorted.
Step 2: Correcting Barrel Distortion
Go to the Filter Menu in the Menu Bar and Choose Lens Correction. In Adobe Photoshop CS5, the Lens Correction Interface has received a major overhaul. On the top left corner of your screen, you will see the lens correction tool, which allows users to click on the image and drag towards or away from its center to correct the distortion. If you don’t want to correct the barrel correction in your image with this tool, you have the option of choosing the automated and custom correction tools on the right hand side of your screen.
Step 3: Using Automated Distortion Correction Tools in Photo Shop CS5
The automated correction tool is simple to use, if you have the right data. Nowadays, image files come with their metadata, which basically provides some basic information about your image, such as the size of the image, the color depth, image resolution, when the image was taken and the type of camera used to create it. This metadata is now crucial for the automated lens distortion correcting tool in Adobe Photoshop. Adobe Photoshop automated lens correction comes with an inbuilt library of different lens information, and the distortion they cause in each and every camera sold in the market (and they keep updating it). What this means is that once Photoshop knows what camera took the picture, it will automatically be able to correct the Barrel distortion that has taken place.
Step 4: Using Custom Distortion Correction Tools in Photo Shop CS5
If you are not satisfied with the results of the automated option, you can click on the Customize tab next to the Auto Correction Tab, and this will take you to a section where you can again manually correct the barrel distortion in your image with the help of a slider. The key to correcting this distortion properly is to not over-correct, otherwise you induce an effect known as the pin cushion distortion effect, which is the opposite of barrel distortion effect.