Since it's not cost-prohibitive like Showscan was, distributors could get it into theaters and allow us time to adapt to the new format -- just as Peter Jackson has requested.

ENGADGET: Editorial: Despite shaky 48 fps Hobbit preview, high frame rates will take off

This might have had something to do with the unfinished nature of the preview, but after a 2D Showscan test in the 80's Trumbull said -- based on audience reaction -- he wouldn't use HFR cinema for period or dialogue driven films.

ENGADGET: Editorial: Despite shaky 48 fps Hobbit preview, high frame rates will take off

In fact, there's no known upper limit since the human eye sees a continuous stream of movement, not individual frames. 60 fps was tried in the 70's by Douglas Trumbull with his 70mm film process called Showscan (see the More Coverage link below for its comeback tour), but studios and theaters of the era couldn't stomach the cost of the celluloid it required and the company went bust.

ENGADGET: Editorial: Despite shaky 48 fps Hobbit preview, high frame rates will take off