John Dracon
John Dracon
Obviously, binoculars have a fixed pupil. The human pupil is variable. Of what significance is that to the binocular user? I've never paid much attention to this fact until recently when I had my eye dilated to check for diabetic neuropathy,(none present) but since I had read that our iris loses its capacity to open and shut within a certain range as we age, and hence controls the diameter of our pupils, I decided to see if my dilated pupils could make use of a 7x50 binocular at late dusk. I'm 74.
That same day I waited until the sun had set and then began to use the 7x50. And sure enough I could see quite well, even when it was quite dark. The next day I repeated this process. But of course my pupils were now back to normal and the 7x50 didn't reveal the significant detail it had the night before. In fact it was a whole lot less detail.
I'm not sure what my pupils are in darkness, but they sure aren't 7 mm to 9 mm. Which leads me to believe that all that extra diameter of objectives lens and hence weight of binoculars is somewhat unnecessary for a birding binocular. While the 7.1 pupil of the 7x50 is useful in eye placement, I wonder if seniors like me ought to accept the limitations we bring to binoculars, period. John
That same day I waited until the sun had set and then began to use the 7x50. And sure enough I could see quite well, even when it was quite dark. The next day I repeated this process. But of course my pupils were now back to normal and the 7x50 didn't reveal the significant detail it had the night before. In fact it was a whole lot less detail.
I'm not sure what my pupils are in darkness, but they sure aren't 7 mm to 9 mm. Which leads me to believe that all that extra diameter of objectives lens and hence weight of binoculars is somewhat unnecessary for a birding binocular. While the 7.1 pupil of the 7x50 is useful in eye placement, I wonder if seniors like me ought to accept the limitations we bring to binoculars, period. John