I just placed this up here for everyone who says "there's a scratch on my front element and its ruining my pictures". This is a Sigma 150-500 that was dropped, the front element nearly shattered, and photos taken with the lens as you see it. In the interest of full disclosure, it was a bit slow to autofocus :-)
The last two pictures show the real effect of the damage - shot into the sun the lens decompensates fully.