I was about to return a lens for haze when I started looking at my other lenses, which I regard highly and found out that several, if closely inspected, do indeed have similar, if slightly less quantities of who-knows-exactly-what if inspected with a flashlight or held up to a light. Of course none of them show it unless you are specifically looking for it. But it is there none of the less. Has anyone found a good benchmark for when to not get a lens because of haze?