I wasn’t quite so lucky with the serial number this time, getting a 1991 sample. Those who know Soviet history will recall that the USSR collapsed in 1991 & as the rumours of this collapse circulated there was an understandable drop in the quality of output from state-subsidised optical plants like KMZ & its satellite plant LZOS. Still, whilst this particular sample may not be optically as good as some of the earlier, chromed samples, the build quality is still superb & the rings are some of the smoothest I have felt. Incidentally, this is the first pre-set aperture lens I have used; there are two aperture rings, one to set what aperture you want & a second to actually stop down. So you set the aperture you want with the first ring, focus wide open & then stop down with the second ring before taking the shot.