Look at this site and the introduction section. The original photo shows an uncorrected picture taken with a fisheye lens. If you roll your cursor over the photo, the software application is applied to the photo and it corrects the image so that it makes sense to the human eye and perception.
After seeing this, you can see how a defense attorney could argue 'altered evidence' if a true fisheye lens were used on a still or video image. A wide angle lens will show as a normal wide image, similar to a person's binocular vision.