So... is HD or ED glass a significant advantage over "regular" glass for the increase in cost? Specifically, I am looking at Kowa spotters. The Prominars are twice what the standard scopes are. If there are advantages, where are they? mtmuley

Nobody? OK, let's argue about it then. mtmuley

HD Glass or Flourite glass is worth the expense.

Actually, ED usually refers to fluorite glass, and is short for "extra-low dispersion," and does have advantages for binoculars. It used to be used only in high-end binoculars, but appears in many less-expensive models today.

HD is a marketing term, usually intended to stand for "high definition," but doesn't really mean anything specific.

John nailed it. The HD moniker has been bastardized to the point of being meaningless.

ED or Flourite glass does help to reduce color fringing. It is worth paying extra for, in my opinion, in a spotter.

My experience is in comparing Leupold and Swarovski spotters, both the same models in HD and non HD and in a Swarovski SLC HD bino compared to a Leica non HD (maybe not as fair a comparison). I used these side by side and my take is that in the spotters it is very hard to tell a difference-I certainly don't think it could be worth twice as much in the Kowa but would have to see for myself. In the bino comparison the SLC HD has better color transmission, especially in the gold and yellow spectrum.

I know every one is different and it may be a huge upgrade to some eyes. It is said to be more noticeable if you are using one with a camera.

Thanks guys. Sorry I lost track of this as I got too damn busy with work. So, I guess the Prominar is ED glass not the HD designation that means nothing. Now I have to decide if the Prominar is worth the extra cost over the standard 66mm. Thanks again. mtmuley

HD by itself is a marketing term, but a lot of manufacturers are using it to designate presence of ED glass in the design. It is a pretty silly way of going around this, but that's what we've got.

With spotters, in my opinion, there is no execuse for not getting ED/fluorite glass, be it Kowa or anything else. For high magnification, it makes significant difference.

For what it is worth, I would take Vortex Razor HD 16-48x65 over a non-ED Kowa any day.

All that having been said, now that I think about, I do not think Kowa makes a non-ED 66mm spotter any more. Or am I confusing them with someone else?

If memory serves me right, 66mm and 77mm Kowas both use extra-low dispersion glass, while the larger 88mm uses a pure fluorite element in its optical system.

In the past, I recall seeing a non-ED version of a 66mm Kowa, but it has been a while. The only non-ED spotter Kowa currently makes is the 82mm SV.

ILya

Good info clarifying the diff!!!