Following yet more queries stemming from this morning's article, here's a video on how binocular lenses are made and assembled. I hasten to add that the craftsmen at Carl Zeiss, who work by hand, are one of the reasons why high-end binoculars cost at least ten times more than automated-assembly equivalents!
Zeiss, Swarovski and other top-end binoculars are made that way. Lower-cost units are assembled by machine, but at much lower prices. I doubt I'll ever be able to afford a top-tier unit, but I've handled them, and I have to say they make my mouth water . . .