doesnt get any response from canon support to my Mails.
Maybe someone knows the answer?
Manual tells me about flashing nd warning in Tv or Av Modes that it happens when:
The gain value is to high
The arpeture is too closed
Ok, and what is too high and to closed in Numbers?
Correct in that the manual doesn't state what those gain or aperture values are.
However, to make a guess, I think it would be anything beyond f/8 and say 18 dB.
You can always just try it and see at what point the warning shows up.