Even then, the top five binoculars tied in their resolution scores, showing no consistent, repeatable differences over multiple trials. However, when we magnified the images to 32x, using two stacked doublers, differences in resolution became clearer. The binoculars in our survey showed similar resolution at 8x. We kept testing until we agreed upon a consistent relative score.
We compared each binocular to a reference binocular to confirm that what we were seeing was not influenced by eye fatigue or other temporary issues. We controlled the lighting conditions carefully. We mounted binoculars side by side on a stable, vibration-free platform. We quantified each binocular's ability to resolve fine detail, using an USAF-1951 optics resolution chart. People come in all sizes, and many hands are needed when evaluating binoculars. Their impressions were especially valuable for ergonomic issues. We invited local birders for a test day to broaden our perspective. We tested and rated them on resolution, focus knob, eyecups, diopter adjustment, and fit and feel. They split naturally into two groups: models priced $1500 and up and another group priced around $1000.
Even if one of these babies is not in one's budget right now, it's likely to be in one's sights. A binocular that incorporates the pinnacle of human technology has a special ambience about it. Zeiss, Swarowski, and Leica now offer high-quality binoculars priced a notch below their top-end models, and we especially wanted a chance to compare them. This time, we asked manufacturers to send us their high-end models, selling for $600 and up. In our previous review, we tested 8x42 binoculars in the $200 to $600 price range.
The following review also appears in the May, 2012, Bird Watcher's Digest. Binoculars Review For Bird Watcher's Digest, May, 2012