I had chance to compare a friend's 500 f/4L IS and his showed the same characteristics. The right word I should have used is "sparkly" when a bright light is shined on them. Lens performed flawlessly. I missed an opportunity to buy a 70-200 f/2.8L IS II for $800 two weeks ago because that lens sat unused for years and the AF stopped working so I became paranoid with all my unused gears.