EXCERPT page containing first few paragraphs. 2023-12-06 16:44:10
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MTF: 90mm f/2.4 (2.5) Summarit-M
MTF of the Leica 90mm f/2.5 Summarit-M is notably less good than the MTF of the 75mm f/2.4 Summarit-M, suggesting a field curvature as indicated by the dip from center until frame edge is reached.
Stopping down, the 90mm f/2.5 Summarit shows somewhat lower contrast than the 75/2.5 Summarit, along with increased astigmatism. Initial field shooting of the 90/2.5 Summarit-M suggests that this astigmatism is due to lateral chromatic aberration.
The 90/2 APO-Summicron-M ASPH easily outperforms the 90/2.5 Summarit-M at f/5.6, and shows much less astigmatism. And at f/2, the Summicron is nearly a match for the Summarit at f/4!
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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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