Home Forums Hunting & Shooting Hunting Optics Please explain eye box and non critical eye relief.

I was under the impression that larger oculars were to allow for a brighter image.
The biggest eyeboxes I've ever seen were on Scout Scopes with 9-14 inch eye relief. After that, the fixed magnification Leupolds like their FXII, 4X. None of these designs have large oculars. E