I'm not exactly sure where to post this but I was wondering if anyone can explain the arcs that appear in this photo and other photos I've taken with my 500mm f/4 (w/1.4 TC) on my 30D. I see them most prominently in photos with open sky and water but I think they may be in all the photos but just more visible in the aforementioned? I have not seen them in photos taken with other lenses. They are always oriented in the same direction with the same 3 vertically oriented arcs right in the middle of the photo.
They are also most noticeable in underexposed shots such as this one.
