Thanks anyway! Even the vignetting information is useful. Unfortunately there is no such thing as a "free lunch". I' ll check vignetting in photozone.de and the-digital-picture.com
Can you please get a picture of the night sky with the lens fully open and see how the stars show at the corners? If the lens has coma (which even Canon L lenses have fully open) they will look like ... seagulls!
I can but I have to be motivated enough to drag it out after dark lol. I should have tested it for that before when I was testing all the other lenses. I think I can chalk that up to not counting on this to be much of a night sky lens due to all the light fall off/vignetting. I suspect there's enough vignetting at f2.8 with this lens that it will be hard to get bad coma issues with stars. But now I am curious what the distortion would do to a star trail lol. Anyway, I just kinda doubt the issue will be coma on a night sky with it F2.8 and as much vignetting as there is there(it's more than the 14L II...which also has winged stars/coma I guess). I have to send my 5D II in to fix the mount to sensor plane issue, which might happen today, so it'd likely be after that returns.