shoot4fun
Gold $$ Contributor
Although that exit pupil factor can easily be calculated for any optical device it can't make adjustments for how the coating inside of the optic is done. Also, every makers HD glass is of different quality even if it comes from the same glass producer. All optics manufacturers use coatings but not all coatings are the same. Just saying "fully multi-coated HD glass" is not enough. With top quality optics the last, and most important, factor is the peepers looking thru them. My older Leica 10x50 BA binoculars allowed me for many years to sit on a stand and view deer out past 100 yards in pitch-dark if there was just a little moonlight. The last year or two that isn't the case. Same with some very nice scopes I own. Did they go bad? Of course not! It's my EYES!