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Message: <blockquote data-quote="henry link" data-source="post: 1386413" data-attributes="member: 6806">Kevin,Magnification and horizontal collimation error also affect overlap. Higher magnification causes greater apparent separation between the same object as seen in the left and right fields and forces the eyes to toe in more than lower magnification. If you fail to see perfect overlap of the fields at infinity there is probably some horizontal convergent error in the collimation. That may be done intentionally to be certain to avoid divergence. The eye has no problem with convergence but can't handle any divergence. Of course any extra convergence at infinity will be added to the natural convergence at close distance.John,I remember the B&L Audubon 10x40. I considered it to be an unacceptable binocular for close viewing because of the poor overlap. The 10x Leupold/Opticron/Minox internal focus Porros should be just as bad or worse. Henry</blockquote>