BAK-4 vs BK-7 Prisms in Binoculars: The 10-Second Field Test That Tells You Which You Have
You do not need a spec sheet to figure out what kind of prism glass is inside your optics. By holding them at arm’s length and looking at the exit pupil, you can immediately tell what you are working with. I am going to walk you through this ten-second field test and explain why the … Read more