In my opinion, videographer can call himself anything in the industry...
It's not a trade or profession like Doctors or Architects where only if you've got the qualifications, then you can be called Doctor and perform surgery.
If you dare to call yourself a Cinematographer in the industry, I think you'd better have experience in handling at least 16mm motion picture cameras....have good knowledge in science (physics) especially in the areas of optics & light.
I have a Dip. in Film, a Degree in Recording Arts, and shot 2 short films with 16mm Arri cameras....even so, I still don't think I am qualified to call myself a Cinematographer.