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Message: <blockquote data-quote="ronh" data-source="post: 1580223" data-attributes="member: 55514">Bob, thanks for sharing all these excellent, and no doubt fun, observations.Bob has said that his eyes that will open up to 6mm+, I think 6.5mm, right Bob?  So, in very low light, the surface brightness seen in the 7x50 will be greater than that shown by the 16x70 by the square of the ratio of the effective exit pupil diameters, or 2.2 times brighter in the 7x50. That is really noticeable! When it gets so dark that it's just flat hard to see, "resolution" is not the game, seeing something is. Under such conditions the view is lousy at best. But that would be, in the 7x50. Bob, you said this exactly right early in this thread. My comparisons concur. It's just a matter of how dark it has to get, and how much of the 7x50's light output your eyes can accept, before the "night glass" wins.Ron</blockquote>