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MTF: 90mm f/2 APO-Summicron-M ASPH
MTF of the Leica 90mm f/2 Summicron-M ASPH is exceptional across the frame at f/2, offering a uniform image quality with only a modest decline to the edges and corners. In this sense, it seems to be (slightly) superior to the 75/2 Summicron-M ASPH because there is no dip in the middle zones. However, its close range performance suffers in practice from a focus shift and a less good level of correction (no floating element), and there the 75/2 APO performs better.
At distance, the performance of the 90/2 is about as good as one can hope for in its ultra-high contrast and exceptional uniformity across the frame even to the extreme corners. In particular, its field curvature is low.
At f/5.6, the 90/2 Summicron exhibits exceptional contrast to the extreme corners, and for all practical purposes offers the same performance as the 75/2 Summicron-M ASPH.
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Diglloyd Guide to Leica is by yearly subscription. Subscribe now for about 25 cents a day ($90/year).
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Diglloyd Guide to LEICA contains in-depth coverage of Leica M system cameras and lenses, with additional coverage of Leica M Monochrom, Leica Q.
Special emphasis is placed on Leica M lenses and certain Zeiss ZM lenses.
- Make better images by learning how to get the best results right away.
- Save money by choosing the right lens for your needs the first time, particularly the Summilux/Summicron/Elmarit choice and/or Zeiss ZM.
- Make better images, a sort of “cheat sheet” saving yourself months or years of ad-hoc learning. Processing parameters are discussed and shown.
- Jaw-dropping image quality found nowhere else utilizing Retina-grade images up to full camera resolution, plus large crops [past 2 years or so].
- Real world examples with insights found nowhere else. Make sharper images just by understanding lens behavior you won’t read about elsewhere.
- 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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