EXCERPT page containing first few paragraphs. 2021-12-05 15:06:54
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This page shows results and examples from 50mm lenses. The 21-megapixel Canon EOS 1Ds Mark III was used to allow the maximum number of lenses to be tested, including Olympus and Nikon.
The amount of focus shift varies by lens. These examples were shot at a distance of 42 inches (1.07 meter). This is a distance that frames a head-and-shoulders portrait, which means that focus shift has the potential to throw the eyes into blur if focusing wide open (f/1.2 or f/1.4) and shooting in the f/2 - f/4 range. In short, it’s not an academic issue at all, but a very real challenge if shooting in this distance range.
In addition to the ~1m tests of the test target, tests were also conducted at the ~6 meter range. Test results showed improvement of detail and contrast at the focus target, indicating that any focus shift was more than compensated for by depth of field gained by stopping down. In addition front/rear sharpness both improved. In short, at the ~6m mark, none of the lenses appear to have a focus shift issue as a practical matter. Further tests could be done, focusing at various apertures, but the results were judged to not warrant it.
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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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- Aperture series from wide open through stopped down, showing the full range of lens performance and bokeh.
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Focused at f/1.4: mouse over for f/2.8 (actual pixels)