Cheers for that...I get the idea and have known about this ratio business for years, but to be honest, never thought about it, or realised it had anything to do with eye pupil.
7mm pupil is just the average pupil size also the human pupil can be anywhere from 4mm to 7mm depending on the person...............the bigger the ocular size or objective or tube has no impact becaause the human eye cannot procees it, for example infra red its in the spectrum but we simply cannot see it............and not a problem deker..............hope this helped.......