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Message: <blockquote data-quote="typo" data-source="post: 3534927" data-attributes="member: 83808">CJ,SeemS your minimum requirement for available ER is 14.5mm but you find 16-17mm more comfortable. Unfortunately from my little survey knowing the true ER figure isn't going to help you much. Now, if only they put available ER on the spec sheet.:-OThe ISO is a comittee agreed minimum specification. All of these binoculars are made to a company specific optical specification. Besides the true ER it also has parameters for resolution, collimation, dioptre accuracy, rotational error, magnification differential, transmission, contrast and no doubt many other metrics as well. I'd love to see that info, (as I'm sure would their competitors), but it's primary value is for those in the workshop. In practice this information would be disseminated very selectively. It means we currently have to settle for what some wooly tradition decides they will allow us to know. Length, width, FoV, weight, and some random value for which might or might not be ER. Not even that is specified in the ISO marketing requirement. You probably guessed already that one of those sets of results was for the ZenRay Prime 10x42. I rechecked the maximum available ER a couple more times just for you. 14.3mm! Of course that is masses of ER for me and results in very easy eye positioning. Might have saved you time and money if they had put that on the spec sheet.<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink    ;)" loading="lazy" data-shortname=";)" />David</blockquote>

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