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Message: <blockquote data-quote="ronh" data-source="post: 1279641" data-attributes="member: 55514">Thanks, Henry and Kevin, that was helpful. I hope you guys will bear with me through one more issue I'm trying to grasp here.In a 42mm f/4 binocular operating at 8x, 40 lines per mm works out to about 4 arcmin at the eye. That does not sound hard to see. So, the plotted (to 40 lpi for the glass types, but only to 20 lpi for the phase coating comparisons) differences might be quite noticeable. The disturbing impression I am left with is that the differences between uncoated junk glass and the finest roof prism binos made by Swaro in 1991 would be small, compared to the great dimunition in quality imposed by any binocular, compared to the naked eye. Shouldn't a binocular's MTF be flat at near 100%, to look essentially perfect to the eye? Down to 10% at easily-resolved wavelengths sounds completely horrible.But, that's not how it seems. Binoculars of top quality give views that seem excellent, thrilling, spectacular, or we wouldn't be here! So, either I'm not very critical, legally blind more like it, or I have misinterpreted or been misled somehow by the results of Konrad's paper.To help put it into perspective, the MTFs of the naked eye and Porro prisms should also be used, but I haven't easily wandered up on either, unfortunately.End of rambling, bottom line question: At what contrast dropoff does the eye start to notice a loss?Ron</blockquote>