EXCERPT page containing first few paragraphs. 2024-04-18 19:22:35
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Distortion
Distortion is exceptionally well corrected given the 114° angle of view. However, distortion should be understood as consisting of three distinct phenomena:
- Perspective “distortion” caused by varying distance of subject matter to lens;
- Geometric “distortion” caused by projecting a three-dimensional subject onto the flat imaging plane.
- Curvilinear distortion is caused by the lens; straight lines do not render as straight lines. This is the “real” distortion.
Perspective distortion
Perspective distortion is not really distortion at all; an object imaged at a distance of 1/2 meter is four times as large (twice linearly) as the same object imaged at a distance of one meter. The same object is imaged 16 times larger at a distance of 1/2 meter as at 2 meters!
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Geometric distortion
(the blob at lower left is “finger distortion”!)