The Summarit-M is essentially a coated Xenon 5cm F1.5, designed during the 1930s. The optics were changed slightly, one of the elements had the surface curvature revised. Leica's first-superspeed lens. This lens has a reputation for being soft wide-open, improves by F4. I've taken 5 of these apart, currently own 2 and a "half". All of them were marked 51.1mm, slightly shorter than the Leica standard. They were also optimized for F2.8 for close-up, and were in focus at F1.5 at infinity.
So I changed this one, moved the rear group back 0.2mm. This optimized the lens for F1.5 close-up, and increased the focal length ever-so-slightly.
before_mod_f15 by fiftyonepointsix, on Flickr
before_mod_f15_crop by fiftyonepointsix, on Flickr
close_test_f15 by fiftyonepointsix, on Flickr
close_test_f15_crop by fiftyonepointsix, on Flickr
Before and after applying this modification, all at F1.5.
So I changed this one, moved the rear group back 0.2mm. This optimized the lens for F1.5 close-up, and increased the focal length ever-so-slightly.
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Before and after applying this modification, all at F1.5.
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