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Message: <blockquote data-quote="henry link" data-source="post: 3168558" data-attributes="member: 6806">Steve,I just ran across this very interesting Bausch & Lomb material from 1950. <a href="http://mcnygenealogy.com/book/binoculars.pdf" target="_blank">http://mcnygenealogy.com/book/binoculars.pdf</a>The explanation of "Balcote" on page 13 is certainly describing what we would now recognize as normal single layer MgFl coating. The descriptions of the individual models at the end includes "average" light transmission specs. For models with 3 element, 2 group eyepieces the spec is 78%. For the two models with 5/6 element, 3 group eyepieces it's 72%.So far I haven't seen any convincing evidence that there were any commercially available binoculars with multi-coating before Zeiss models with T* coating were introduced about 1978.Henry</blockquote>