Randfee,
I have tested just about all the top binoculars over the last nearly twenty years, as well as the premium spotting scopes. From what I've seen, you are not going to find any binoculars that would be free of CA to your eyes if you consider the Zeiss SF to have too much. The top-of-the-line Kowa might be closest, as some have suggested, but on the flip side it is heavy for its specs, has a narrower field of view, and is not as bright (has lower transmission) than the Zeiss SF or any of the Swarovisions. Among the Zeiss models, the SF has less CA than the HT series, and it also has a bit less than the Swarovski 10x42 and 10x50 SV's.
Primarily, CA in these binoculars is lateral, and the centerfield is almost free of it. But, if you really look for CA, you can see a little bit as soon as you move the target off-center at all. A trained and sharp eye is really good at seeing aberrations, that's just the way it is.
For a reference as to what is possible with premium birding optics, look through the Kowa 883 scope with a 25-60x Zoom. You will see CA, but the levels are lower than in any other piece of birding optics I have ever tried. That scope also trails the best Swaro and Zeiss models when it comes to transmission characteristics, but in a good sample the optics are truly well corrected.
Since you are a physicist, I'll remind you of the eternal sample variation issue. With daylight adjusted pupils (2-3mm), a human with sharp vision is capable of seeing the effects of aberrations in the image of a non-diffraction-limited set of optics, and therefore the unavoidable sample differences between actual production units come to play. You said you tested four pairs, so the CA issue was probably not down to that, but true cherries are rare, and you may still find a pair that performs significantly better than the ones you tried.
As for rolling ball, to my eyes the SF has more of it and in more bothersome ways than the Swarovskis. However, how we experience rolling ball seems to be highly individual, so you really need to try them yourself. Many people do get used to whatever distortions their binocular has, but not all do. Therefore, if you buy a model that initially bothers you, you are taking a bit of a bet. Personally, I found the 8x42 SF more bothersome than the 10x42 SF, and with the latter I was mostly rather comfortable after a while. However, I did and do prefer using the Canon 10x42 L IS, which has traditional pincushion, no rolling ball, wide enough field of view at 6.5 degrees, edge sharpness about equal to the 10x42 SV and better than the SF, and CA levels on par with the Swarovisions. In addition, there is image stabilization, but that is another story.
On RB, check out the following BF thread:
http://www.birdforum.net/showthread.php?t=313034
Hope this helps you some.
Kimmo
