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Message: <blockquote data-quote="Kevin Purcell" data-source="post: 1404788" data-attributes="member: 68323">I find with both the Legend and the Cascades eye position on the EP axis makes a big difference. Both can give a lot of CA off-axis. But for me they're close enough when on axis but both show more CA. But I think you are more impressed with the Cascades than I am <img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite2" alt=";)" title="Wink    ;)" loading="lazy" data-shortname=";)" />I think we get the overall ordering close enough though.Same with the off-axis image quality.I posted a paper from the UA optomech collection about specifying optics and this has a interesting section on this. Worth reading if you review bins. This is easily the most difficult area to characterize or specify of any optical system as it ends up with so many personal preferences.<a href="http://www.birdforum.net/showthread.php?t=133880" target="_blank">http://www.birdforum.net/showthread.php?t=133880</a>For me off-axis image quality has never been a huge issue so long as it's not terrible and the ZRS (and ED) are certainly far from that. But for others it's a big issue and calling it "edge to edge sharp" seem to be setting some people up for a fall.I think this sort of parameter ends up as being "try it and see". It may be close enough to edge to edge for some people and "just a decent sized sweet spot" to others.Personally I think it's fine and without checking to closely it looks the same across the field. I didn't notice the field curvature until I went hunting for it. So we may be obsessing a bit too much.</blockquote>

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