So I picked up a refurb 8mm during the President's Day sale and took it on a snowshoeing trip last week. When I looked at the shots, I was surprised by the amount of CA, as well as lots of green and purple blobs in many of the pics with the sun in the frame (I was intentionally trying to get the starburst effect). Granted, a bright day in the snow is going to be challenging for any lens, especially something as wide as this. I don't remember having these kinds of issues with the Rokinon 7.5, however. The 8mm also doesn't seem to be as bitingly sharp as the 7.5. This poses kind of a dilemma for me, as I ordered it primarily for underwater. It turns out that I can't use it in the same dome port as my 12-40 without changing extensions, which I don't want to do (the fewer o-rings touched, the less likely I am to flood expensive gear). I was thinking of keeping it anyway both because of the astro possibilities and for just how much fun fisheye shooting can be. Now I'm wondering if I should just return it and get a 7-14. Are my expectations too high? Did I just get a bad sample? Also, I'd be interested in any tips on correcting CA in post, other than clicking the box in LR. Thanks in advance!