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Message: <blockquote data-quote="Chosun Juan" data-source="post: 3534872" data-attributes="member: 92780">David,Hahah  :-O  Just the standard shoe size will do (although between AUS, US, UK, and European sizes that is not always straightforward! <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile    :)" loading="lazy" data-shortname=":)" />  :-OI honestly think that the Standard ISO specified ER measurement is such an important metric that I would not like to see it lost in fog.Apart from that you could argue that it's six of one half a dozen of the other between that and (if I understand you correctly), the 'available' ER which would be the total ER minus the eye cup rim depth. The issue I have with that is that then we lose that important total ER metric, and there's still going to be several mm discrepancy based on your glasses script, curvature, offset, facial characteristics (importantly including symmetry) etc, etc, etc. I just don't see any real advantage to it, especially when it's going to be so modified by ocular diameter. It's a bit like quoting the inside length measurement of a shoe as so many cm ..... but what about the width, form profile, and height??  :cat:So all in all I much prefer the total ER measurement.  I would like to see the ISO measurement tolerance tightened to +/-0.5mm and become the universal figure quoted.My vision is fairly myopic, so the short-sighted script helps somewhat. The best bins I have found for fit for my current glasses are the Swarovski 10x50 SV, and the Zeiss 8x42 HT (also the best views I have seen so far - still a few newies to try like the Leica NV). The SV quotes 20mm ER, and the HT 16mm. It is interesting that I have to back the eye cups out the exact same smidge on both of them (guessing ~1.5-2mm).I did have the quoted 20mm Zen-Ray Prime HD 10x42 for a while with its huge square profile oculars. I actually measured these to be 19mm (perhaps +/- nearly 1mm) ER (I think you would need a micrometer equipped calibrated railed jig and precise light source and perpendicular screen with sensitive minima measurement to do it really properly). These were just sufficient to see its full Fov with eye cups screwed all the way in, but I found them way too critical for alignment and positioning - possibly among the hardest bins to use that I have tried. Ease of view was like chalk and cheese between it and the aforementioned SV, and HT.My goto Zen ED3 8x43 have a quoted 16.8mm ER and are barely sufficient (the ED3 has redesigned eye cups to offer absolutely minimal eye cup rim standoff from the ocular lens). The ease of view is not as luxurious as the SV, and HT, though I do prefer them (in many ways! <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite1" alt=":)" title="Smile    :)" loading="lazy" data-shortname=":)" /> to the 18mm ER Zeiss Conquest HD.So it seems I need around 16-20mm total ER along with regular type eye cup design, but there are so many esoteric factors involved that it really is a try it and see situation. Something like the generous randpupille design of the SV, but with leading glare control would be awesome.The 17mm ER of the 10x42 MHG might be marginal (especially given Vespo's comments), but honestly I am more concerned about centre levels of CA (never mind at the edge too), and sharpness, resolution levels. The transmission graph also doesn't bode too well for colour 'pop' at the extremities of the spectrum, and hence neutrality, and overall brightness (having being spoilt by my Swift Audubon 8.5x44 ED).Time will tell whether it is worth ~a grand to me or not ....  :cat:Hopefully it spurs other manufacturers on to make quality 70° AFov 10x bins .... :t:Chosun  :gh:</blockquote>

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