These are not binoculars for travel. Once you adjust the two diopter settings for your specific eyes, they will not focus optimally for other users. Make a note of the settings and if they've changed you can easily go back. I'm slightly farsighted and have two slightly different settings I use depending on whether I wear glasses or not. I don't want to complicate this sound; it is not. You only have to do this ONCE and everything from 20 meters is in focus for you forever. You can find a friend with perfect vision and ask him or her to adjust them and note the two settings, and then use those settings to pass them on to friends with good vision, but they won't be "perfectly" focused for everyone unless they make their own adjustments. They will NOT focus on close objects. Do not attempt to spot birds at a backyard feeding station unless it is at least 50 to 60 feet away. far away, but they're great for spotting a swift eagle in the distance since you don't have to waste time focusing on them. All other reviews praising the optical quality, light gathering ability and solid construction of these fine instruments are true.
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