Originally Posted by Jovanx
I think that any time you take a picture through a circular lens, the distance/pixel relationship will be different in the center than at the edges. Even high-end airphotos have to be digitally "warped" before they can be used by surveyors and planners.
Not true. All camera lenses are circular (round) but most conventional lenses are optically corrected to produce an image that does not have visible distortion of straight lines. In conventional lenses only specialty lenses called fish-eyes produce images with visible spherical distortion.