Perspective Photo Distortion Explained
©2009 Darel Rex Finley. This complete article, unmodified, may be freely distributed for educational purposes.
If you take a lot of pictures, you’ve probably noticed this effect. If an object is in the middle of the picture, it is relatively small and undistorted. But if it is near the edge of the picture — especially if it’s in the corner of the picture — the object is relatively large, and kind-of stretched looking.
These two screen captures from Google Street View (one location) illustrate the effect nicely:
Even though these pictures are run through a QuickTime-VR-like algorithm, and are not actually unmodified photos taken with an ordinary camera — still, they accurately represent what a photo would look like if taken in a particular direction from the spot where Google’s van was when it captured this street-view location.
The Longaberger basket building seems to be quite different in these two pictures. The reason for this is that you are not viewing the photo from the same position that the camera was in, relative to the field of view represented by the picture, which creates the distortion. To correctly view this photo, I need to position my head about four or five inches from the center of my display. Here are two photos of my display taken from that position, of the above pictures:
Hey! Now the buildings look almost identical. And these two photos weren’t resized or distorted in any way; just cropped to show only the building.
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