Is ED glass more important than Dielectric Coatings on Binoculars?

Deciding on how to choose between binoculars on your shortlist can be difficult, even if you know exactly what all the terms and features mean and do. If you don’t, I can be even trickier, as separating the marketing hype from the important specs and features is a nightmare.

Someone who was trying to make this choice recently asked if ED glass was more important than Dielectric Coatings:

Answer
They do different things, so based on what is more important to you will perhaps help you decide:

ED glass can (but not always) help correct chromatic aberrations, which in turn potentially leads to an image with less color fringing; however, it also depends on the quality of the ED glass and the rest of the optical system as a whole. I have often looked through high-quality or well-made non-ED glass binoculars and seen less color fringing than low-quality (or poorly made) ED glass binoculars – more: Guide to Extra Low Dispersion Glass (ED Glass)

Dielectric coatings: Mirror coatings are put onto the surface of the roof prism that don’t reflect 100% of the incident light. The better the mirror coating, the more light that gets reflected through the prism, and therefore, you potentially end up with a brighter and possibly better quality view.

Dielectric prism coatings have the highest reflectivity index (can be as high as 99.999% or better), whilst the others will probably use a silver mirror coating  (often has a reflectivity of 95% to 98%).

If I had to choose between having one or the other, I would definitely go with a binocular that has Dielectric coatings, as it is expensive and thus a good sign of quality … meaning the rest of the optical system is probably also going to be very good.

Hope this helps.