Thread: ED glass in Scopes & Binos

Originally Posted by Ultimitsu

HD in glass is supposed to mean High density. glass that is of high density has lower refraction, yoi basically get a sharper image. But since the advent hd tv, which means high definition, a lot of acopes uses this term without necesaarily using high density glass.

ed has always had a specifc meaning , extra low dispersion, usually ed glass is used to correct ca. But on cheap scopes, when all other pieces, of glass are of low quality, having a ed lens cannot save it from being bad.

I always thought that 'HD' meant high definition glass, not high density. It was Vortex which termed 'HD' as high-density glass which is simply a Vortex marketing gimmick.
Consumers have already been conditioned to associate the term HD with excellent picture quality as we see in high-definition TVs, so that's why it’s being attached to binoculars.

As has been said, not everyone's "ED," "HD," "XD," etc. is created equal, and there are no industry standards for defining what exactly makes any particular optic an "HD" or "ED" model, nor what performance level the optic must achieve before it can be so labeled.
About the only thing the consumer can go by is the so-called ED / HD optics are usually optically superior to the non-ED/non-HD versions from the same brand... but even then not always by a significant degree.

Summary: It's mostly marketing hype.