In my recent research (and shopping) for a good mate for my new Canon P, I've noticed that there seem to be variations within certain lens models. For example, the unpainted, polished aluminum Jupiter-8 lens is older than the one finished in black (though I've seen examples that were all "chrome" and some that were chrome and black that were both supposedly from 1961.) I've also read that the build quality on the older lenses tends to be better and more consistent than on the newer ones. I haven't been able to dig up any information about the variations within the Industar 61 line of lenses. When, exactly, did the Soviets begin producing the L/D version? I've seen some that are all black, and some that are black and chrome (referred to as "zebra" lenses, presumably after the Pentax lenses that were also called "zebra".) Are the chrome and black ones older, or were they simply cosmetically different from the black ones and produced around the same time?