This is the official statement from Nikon USA on the Nikon 24-70mm f/2.8 light leak problem, previously described here:
“We have received indications that when extremely bright light strikes the lens while shooting at high sensitivities, light other than that passing through the front of the lens may be reflected. This is not a problem with normal shooting and occurs very rarely under very specific conditions.
We value our customer feedback, and if a user is inconvenienced by this issue, they may request an inspection of their lens. If deemed necessary Nikon will take the appropriate steps to address the issue.”
