Avatar director James Cameron is quite unhappy with studios that add 3D to films during the post-production process.
Cameron apparently believes that such treatment should be reserved only for "classic" movies, such as Jaws or ET.
"My personal philosophy is that post conversion should be used for one thing and one thing only - which is to take library titles that are favorites that are proven, and convert them into 3D - whether it's Indiana Jones, Close Encounters or Titanic," Cameron said in a keynote speech at Blu-Con quoted by the BBC.
"Unless you have a time machine to go back and shoot it in 3D, you have no other choice. The best alternative is if you want to release a movie in 3D - make it in 3D."
According to Cameron, it is quit difficult, if not impossible to achieve a high-quality conversion of 90 minute movie like "Clash of the Titans" in just two weeks
"[Well], I don't mean to throw that [particular] movie under the bus because my buddy Sam [Worthington of Avatar] is in it, but I think everybody realized that this was a point at which people had gone too far."
Cameron also criticized the latest Harry Potter movie which was produced by the same studio as "Titans."
"They announced it in 3D - threw a bunch of money trying to convert it to 3D in post-production and it simply didn't work. They just didn't get it done."
Cameron added that the relatively nascent standard would become mainstream as soon as glasses-free 3D were a reality.
"Once we get to auto-stereoscopic, that's watching 3-D without glasses, it is going to be the way we watch all of our media.
"[But yes], that's probably [still] eight to 10 years away," he conceded.