Originally posted by krypticide I don't have exactly the same "problem" as you do, but I also noticed an area inside the front element that seems to have spots on it, like if one had misted the lens with hard water. It covers roughly a circle with a diameter somewhat smaller than the actual lens. Doesn't seem to be fungus.
That's interesting. Is it on the INSIDE of the front element?
I have a Sigma 24-60mm lens with something that sounds almost identical to what you describe. Lots of tiny little spots on the coating (maybe pin-head sized), more or less circular if you look closely, that don't come off with a cloth or lenspen. I was thinking the coating might be flaking off. I have treated this lens very carefully, so I don't think it's anything I did physically.
But they do almost look like water spots.
My spots are on the outside of the front element. I'll see if I can get a photo that shows them.