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Message: <blockquote data-quote="Jack Speer" data-source="post: 3666653" data-attributes="member: 143695">I am new to the technical side of things, but I don't think that's quite right. Henry or someone please correct me if I'm wrong, but angular magnification distortion is caused by the lack of pincushion distortion (though maybe it can be caused by barrel distortion as well?). By keeping the lines straight, AMD is introduced.For me, looking through my Swarovision 8.5x42 it looks like objects brought to the top or bottom edge shrink relative to their normal size when seen through the center (for some odd reason I don't see this on the left or right, even when I look through one eye with the binocular turned sideways). This distortion is what causes rolling ball for some people. I think the only way to correct AMD is to introduce a certain amount of pincushion. Thus it is not possible to have a binocular free of both rectilinear distortion and AMD.</blockquote>