EXCERPT page containing first few paragraphs. 2021-12-08 20:33:54
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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 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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Diglloyd DAP is DSLR-oriented, but also contains workflow and other topics. Much of the focus is on Canon and Nikon but also Pentax and Pentax medium format.
Special emphasis is placed on lens evaluation, focusing on Canon and Nikon and Sigma lenses, but with a few others like Rokinon/Samyang.
- Make better images by learning how to get the best results right away.
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- Workflow discusses image organization, raw conversion and post processing. Many examples show processing parameters for direct insight into how the image was converted.
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- Aperture series from wide open through stopped down, showing the full range of lens performance and bokeh.
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(the blob at lower left is “finger distortion”!)