Something I discovered trying for critical focus adjustments with the 8x20 Ultravid:
Initially I tried focusing in the daytime at a local park with trees and seating facilities etc., not able to get what I thought was a perfect (or nearly so) focus and diopter adjustment.
Then this morning at dawn when it was still somewhat dark, while I was musing on the subject of Twilight Factor, I had the idea to try the 8x20 on some parked cars and buildings around 75 yards distant. What I discovered surprised me, in that I could focus much more easily and accurately under this dim light.
I get the notion that the combination of high resolution with this binocular, plus the lack of unneeded distractions competing for my attention (less light and simpler objects to focus on), made such an important difference for me in achieving critical focus.
Initially I tried focusing in the daytime at a local park with trees and seating facilities etc., not able to get what I thought was a perfect (or nearly so) focus and diopter adjustment.
Then this morning at dawn when it was still somewhat dark, while I was musing on the subject of Twilight Factor, I had the idea to try the 8x20 on some parked cars and buildings around 75 yards distant. What I discovered surprised me, in that I could focus much more easily and accurately under this dim light.
I get the notion that the combination of high resolution with this binocular, plus the lack of unneeded distractions competing for my attention (less light and simpler objects to focus on), made such an important difference for me in achieving critical focus.