Originally posted by phoebus Not quite sure what you mean by astigmatism, my copy seems to be giving macro like flat field performance with virtually no distortion. Coma wide open - not sure I've seen that either. Longitudinal colour aberration; that does exist wide open. Show me any 50 1.4 that doesn't...
Please, for the sake of fair and unbiased reporting, explain your findings.
I just posted a link to a image of it's distortions wide open. It's bad enough for stars that I think you would have to stop down to use it on a crop sensor. Which is fine, it's still a great lens, I never said it wasn't, but for astro I don't think it would be good wide open for sure. I haven't seen any posts of it at f2.8 or f3, until then I'll wait. The 15-30 for example is really good performer, and I use that lens, but looking for one around 50-85mm.