Lens Correcting an Image
Photoshop CS3 Tutorial
How to Use the Lens Correction Feature in Photoshop
Using wider angle lenses can introduce image distortion. One effective way to correct the problem is the Lens Correction Filter.
Open an image with lens distortion issues in Photoshop (File > Open...).
With the image layer selected, choose Filter > Distort > Len Correction. Your image appears with a grid overlay.
If your image is slightly rotated, correct by changing the Angle setting. Plus is counter-clockwise and Minus is clockwise.
The other sliders in the Transform section change the Vertical and Horizontal Perspective.
The Remove Distortion slider at the top is helpful to remove a concave or convex pillow effect in the image.
With the Vignette section you can draw the viewer to the center of the image by adjusting the slider to Darken. This technique is common in portraits.
Click OK to accept your settings. Use the Crop tool to trim the image.