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Message: <blockquote data-quote="typo" data-source="post: 3429732" data-attributes="member: 83808">Alan, Paddy hasn't got it quite right. <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink    ;)" loading="lazy" data-shortname=";)" />Last autum Paddy and his palls were kind enough to invite me over to join them for some birding. When he and Steve decided it was time to go inside and get a beer their pupils were about 4mm. We did a quick 8x432 vs. 8x42 comparison and decided there was no brightness difference at that light level. So two far more capable birders than I decided a 4mm EP was all they needed. I watched a barn owl hunting for another 15 minutes or so with an 8x42 before the low light finally stopped me. For them, the time beyond a 4mm EP wasn't particularly useful. There wasn't enough light to ID the little brown jobs at a decent range and they've probably seen enough barn owls for several lifetimes. I'm sure their pupils could have dilated further, just 4mm was enough for their needs.There is a lot of individual variation but a 5mm max would be about typical for a 60 year old. Some older members of the forum say they do better than that. David</blockquote>