If your image has a fisheye distortion, it looks as though it has been pasted onto a sphere or blown up like a balloon. Lines that should be straight are curved and the edges of the image look compressed.
Important: This effect works on greyscale and 16 million color (24-bit) images only. To increase the color depth of an image, see Increasing the Color Depth of an Image.
To correct a fisheye distortion:
Choose Adjust > Photo Fix > Fisheye Distortion Correction.
Adjust the image using the following options:
Field of View The strength of the correction. Adjust this value until the distortion disappears.
Preserve central scale Whether the scale of the center of the picture remains the same or is adjusted. If you mark this check box, pixels are either added to, or removed from the image. Clear this check box if you do not want to change the size of the image or layer.
Note: Notice the Result size group box. If the Preserve central scale check box is marked, the changes to the original image in the width and height display for the adjusted image.
Correcting Pincushion Distortions