A customer asked me, some time ago, to check the color of the objective lenses on several binoculars, all of which were listed as having fully multi-coated lenses. When I asked why, he said that the color of the objective lenses was how you tested to see if a binocular was really multi-coated, compared to only standard (fully-coated). What kind of expert was I?

Okay, fact or myth?

First, I told him to follow up our conversation with my article on the basics of binoculars, How to Understand Binoculars, for a full explanation on binocular lens coatings. I then mentioned that the color you see reflected off the lenses of a binocular can change, depending on the type of light present, the intensity of light present, and especially the angle of light present. All this from one, individual binocular. I invited him to try it for himself.

He was still not convinced, so I told him to visit a local store that had some high end binoculars on display, then compare the colors of the objective lenses, right there in the store. Specifically, I told him to check the color on a Swarovski binocular a Zeiss binocular and a Leica binocular. I told him that I had done this many times and assured him that he would find that each brand had a different color or, at least, a different color tone. Why? High end binoculars use proprietary lens coatings - coatings of each manufacturers own chemical formula. The chemical formulas are different, so the colors vary, though each technically qualifies as multi-coating.

He grumbled that he would try it. I told him to call me back if he could prove me wrong. That was last year. Haven't heard from him since.

Myth busted.