EXCERPT page containing first few paragraphs. 2019-02-23 22:16:29
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The MTF tells a helpful story: lens performance is at its peak at infinity and quality is maintained across the full focusing range from 1:1 to infinity focus.
The consistent performance makes the Touit 50/2.8 a versatile all-around short telephoto lens (75mm equivalent field of view) for general purpose photography to tight head shots (portraits) to closeups of flowers and insects.
MTF at taking distance of infinity
The dip in mid-zone MTF is due to a field curvature. Stopping down raises the MTF in the mid zones. Probably the lens is near optimal wide open, just not in an exact geometric plane.
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Diglloyd Guide to Mirrorless offers comprehensive integrated coverage of most APS-C and full frame mirrorless cameras and lenses.
Special emphasis is placed on Sony full-frame, including Sony lenses and the high performance Zeiss Batis and Zeiss Loxia lenses plus Rokinon/Samyang and others. Fujifilm X, Olympus and Panasonic M4/3, Sigma dp Merrill and dp/sd Quattro are also covered in depth. Years in the making, it offers a wealth of material for choosing and using a mirrorless camera.
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- Aperture series from wide open through stopped down, showing the full range of lens performance and bokeh.
- Optical quality analysis of field curvature, focus shift, sharpness, flare, distortion, and performance in the field.
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