Presented in 1976 and sold till 1981, it’s a very modern well-done lens. UC was meant for “ultra coated” and “ULTRA COMPACT” but this lens is not so small. It’s very well manufactured, feels dense and everything you touch feels quality.
On Konicafiles an article says there should be one previous version of this lens, “It would seem that the first version was produced for only a few months. It has 9 elements in 6 groups, weighs 395g, and is extremely rare.”
Konica UC Fish-eye Hexanon AR 15mm f2.8
the rare and elusive Konica UC Hexanon fisheye