At the press event today, Leica announced three new SL lenses. Slated to be released in 2020, these new optics will add fast, wide-angle primes to the system. With focal lengths of 21, 24 and 28mm, all lenses feature an f/2 maximum aperture. Also, while unusual for wide angles, all three designs will be APO lenses, or Apochromatically corrected. Usually reserved for 50mm and longer, APO designations usually indicate the highest level of optical quality.
Additionally, and not really a surprise, all three rely on aspherical technology, or ASPH in Leica's naming, to achieve maximum performance. Like all the Summicron-SL lenses, barrel size is consistent across the entire range, with a 67mm front filter thread. So, these wides will have the same measurements as the 75 and 90 APO-Summicron-SL.
If the other lenses in the SL line-up are any indication, this new range of wide angle Summicrons could set the standard for these focal lengths. I'm looking forward to discussing the upcoming optics tomorrow at the show. Stay tuned for more info.