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Nr. 11 615): Leica made a small run of these modern optics in the same style as the rigid 1956 SUMMICRON, but with the modern squared font, to commemorate the 50th anniversary of the 1952 SUMMICRON. Leica didn't bother to copy the mechanics of the more appropriate collapsible 1952 SUMMICRON because it cost too much to duplicate, and instead settled on copying the later, cheapest rigid design. Leica also goofed in making this commemorative in M-mount, which did not exist in 1952, but would have allowed universal compatibility with all LEICAs.
Apple Digital Camera Raw update extends compatibility to Sony RX100 IV, Leica.