Lens Correcting an Image
Photoshop CS6 Tutorial
How to Use the Lens Correction Filter 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 > Len Correction.
Make sure that the Preview and Grid checkboxes are selected.
Click the Custom tab on the right side of the panel.
If your image is slightly rotated, correct by changing the Angle setting. Minus is counter-clockwise and Plus 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.