----------------------------------- nobody 28 Sep 2017 00:36 ----------------------------------- @Herr_Alien The Minefield: Advertising Hype in Binoculars I would far rather have full-sized, precisely polished BK7 prisms with blackened sides, grooved hypotenuses and shielded reflective surfaces, that are held in a proper cage than under-sized "naked" ungrooved BaK4 prisms, that have been made with minimal quality control and are glued into the housing and held in place with a spring-clip.