I just bought a 16mm lens. I noticed that the iris seems offset to one side. Also, at a full F2.8 I can still see the iris on one side. That only happens if I set the aperature manually. If I put it into full auto mode, the iris does complete disappear. Is this a known "feature" on the 16mm? I checked my 18-55mm and it isn't this way. Here's what it looks like at various settings. Wide open, notice the part of the iris is still there. Partially open, notice how it's offset to one side. Closed.