Thanks. I'm in Canada, so shipping and duty might be too much on these if I have to send them back. It makes me think twice about them. I've never tried any binos with field-flatteners, so I'm not sure how sensitive I'll be to it. That's what it comes from, right?You might want to try them out before buying. I tried them at Scheels and the rolling ball effect/barrel distortion really bothered me. But I might be more susceptible to that since I notice it some on the Meostar S2 scope (20-70x) at low zooms, while many people only see a minor effect if at all with that eyepiece.
Scheels does offer free returns for a year window, so they'd be great for testing out optics.
I know what pincushion distortion is, but what's barrel distortion?Yep, thanks for the clarification. Just because there are field flatteners doesn't mean there's an automatic rolling ball effect. For the effect to exist, and how severe it is, depend on both the individual viewer's eye structure and perception, as well as the specific amount of pincushion distortion (k value) the manufacturer adds.
Quite a few people have mentioned the rolling ball effect for the Meostar S2 30-60 eyepiece - it must have less pincushion distortion than otherwise to correct for this effect at lower zooms. (I personally bought the 20-70 to avoid this effect, though I still see it some at 20-25x).
Spiral Horn - When you compared the S2 30-60x vs the Cronus 10x42: since there was noticeable barrel distortion with the 30-60 but not with the Cronus, maybe it's safe to say the Cronus lenses have less barrel distortion and might be a safer bet (at least than the 30-60) for the average user with regard to the rolling ball effect. I agree that they are very sharp optics and I might have been tempted to buy them had they agreed with my eyes more.
Dmcp - that's an interesting experiment! I'd say either C or D was the straightest. Could definitely see the pincushion effect with E, and slight barrel distortion with B.
I see. Thanks!It’s basically the globe or rolling ball effect. If lenses have field flatteners that include 0 pincushion distortion, the natural distortion of our eyes makes the image look convex and slightly rolling while panning. The severity would depend on the individual, as well as how much pincushion distortion is added to the lenses. That’s what I got from the article at least. http://holgermerlitz.de/globe/distortion.html
If the individual had almost no rolling ball distortion from his own eyes, or if the pincushion distortion added to the lenses effectively canceled out the rolling ball distortion from his eyes, then the image would pan well and look natural. But if the mix and match of the whole system yields more rolling ball distortion than otherwise, there would be a noticeable convex-looking image that appears to rotate as the glass is panned. Depending on the individual, the end result could be hardly noticeable if at all, noticeable but not annoying, annoying, or at worst nauseating.