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Message: <blockquote data-quote="613Orm" data-source="post: 3218173" data-attributes="member: 107876">A friend contacted me tonight. He went out with his Swarovski 8x30 SLC Mark III today to see if he could repeat my observation. He has optician papers on not having astigmatism. He was astonished of what he saw. He looked at street signs with black text and noticed it got blacker towards the edge of the field, which made it stand out as sharper to the eye. His opinion is that it must be a contrast thing. I have also suspected something linked to contrast. I tested my Granites in the afternoon, and somehow depending on the light (sun to right or left) the zone of increased sharpness was to the right or left (3 or 9 o'clock) of the center. I have hard to see that astigmatism would change with the light. Anyway, my friends observation seems to exclude astigmatism and point towards something else. Maybe someone knows if binoculars show more contrast towards the edge?His suggestion on why it seems to be varying along a horizontal plane is that maybe the image processing of our brains is trimmed to that plane.</blockquote>