^ Everything jepanic and TheRodent have said, absolutely spot on. Usually it wouldn't bother me because there is a choice but some cinemas now near me are only offering the 3D version and that's extremely unfair.
Anyways, like Nolan said, film photography is ALREADY 3-dimensional. You're not seeing flat images on the screen a la video games like Alex The Kid and Sonic The Hedgehog and suff like that. You're getting a huge depth of field on not only 70mm, but also 35mm as well.