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Message: <blockquote data-quote="Surveyor" data-source="post: 1347059" data-attributes="member: 50720">Kimmo, jcbouget; I have star tested a few binoculars and, so far, have had no trouble picking the best of the two tubes of any of the sets tested. I concur that this is an easy and fast test that any binohaulic should try. Kimmo, regarding the focusing element. Some time ago I took my 12x50 BN and put them on a straightness-of-line collimator, an instrument that presents a angular target at multiple focus distances, and can confirm that on this instrument there is some vertical and/or lateral movement away from the optical axis during the travel from close focus to infinity. Although the bino was mounted rather rigidly I could see movement just by resting my finger on the focusing knob so I am not sure how much of the movement was in the focus travel itself or how much was caused by the manipulating forces i.e. pressure exerted to turn the knob etc. Also, the direction of focus travel had an effect on the direction of displacement. This was done with a 6x booster. BTW, it was less error than I expected and did not concern me enough to do the test on other binos. Best,Ron</blockquote>