How to Use the Lens Distortion Tool in GIMP

GIMP provides a number of ways to alter the perspective on an image. However, there may be times when you want to significantly alter an image to achieve an effect like a fisheye lens or distort vertical lines. GIMP has a tool under FILTERS called lens distortion, which provides a number of ways to distort your image using one simple tool. Read below to discover the basics of using the lens distortion feature and then search your archives for a suitable image to practice with.

Difficulty: Moderately Easy

Instructions

Things You'll Need:

• GIMP running on a MAC or PC Platform
• Image for experimentation

1. 
   Open Image

   The first step is to open the original image in GIMP. Once the image is opened navigate to FILTERS/DISTORTS/LENS DISTORTION to open the tool panel.

2. 
   Tool Box

   The tool panel offers the familiar GIMP preview feature. Enlarge the tool panel so you can easily see the results in the preview window. There are five ways to apply a distortion and a brighten tool. I am not sure why the brighten tool is included since it is not really a distortion.

3. 
   Main Image Distortion

   The MAIN control distorts the entire image. Notice the man on the walkway is distorted as well as the castle. The main distortion actually provides almost a fish-eye effect on the image. Minus number stretches the image and plus numbers compact the image. Experiment with the sliders to see the sort of distortion it creates.

4. 
   Edge Control

   The EDGE control is used to distort the edge of the image. Notice the man and the castle have nearly a normal perspective and the distortion is only to the edges of the image. If you go too far you will create a white border as is shown in this case.

5. 
   Zoom Distortion

   The ZOOM function allows you to zoom in and thus crop out part of the image or zoom out to minimize the image. You can easily save portions of the images this way and it is easier then using the resizing feature.

6. 
   Combinations

   You can use these settings in combination. Notice everything on the left side of the image is fairly undistorted while the rest of the image is wildly distorted. This could help in altering perspective to only one part of the image rather then the whole image. Keep in mind I am demonstrating large changes so you can view the impact, normal changes would be smaller than these in most cases.

7. 
   Final Image

   This is the final image I created where the man walking and the left side remains normal. It almost seems as if the fountain is spewing out the building. Like any effect or distortion you can use bold changes to create artistic images or fine-tuning changes to make small changes to the image. This tool allows you to make most of these changes from a single toolbox making it easy to distort images.

Tips & Warnings

• Experiment with the sliders to understand their impact, there are a lot of distortion capabilities and combination.
• Remember to enlarge the toolbox so you can see the changes in the preview window.

Resources

• GIMP

[mechelle003]

on 11/12/2009 very detailed.

[mechelle003]

on 11/12/2009 very detailed.