If you're paying an extra $5 to see the new "Star Trek" movie on an IMAX screen, you're getting ripped off if it's not the huge IMAX screen you're used to.

Some theaters that claim to have an IMAX screen, and charge $5 more to get in, are showing the movie on a screen that is slightly larger than a regular movie screen, but not as big as the 76 feet by 97 feet screen that IMAX customers have come to expect, according to a blog by Los Angeles actor Aziz Ansari.

Ansari went to see the "Star Trek" movie at a theater in Burbank, CA, on Monday and found that the $5 surcharge didn't get him into a big-screen theater, but to one that is slightly larger than normal. AMC and Regal theaters across the country are doing this, he found. According to the LF Examiner, a web site that bills itself as the "Independent Journal of the Large Format Motion Picture Industry," the co-CEO of Imax Corp., Richard Gelfond, told members of the Giant Screen Cinema Association in September 2008 that "we don't think of (IMAX) as the giant screen." Rather, he said, "it is the best immersive experience on the planet."

Despite that its two major digital partners, AMC and Regal, wanted to call the new digital projection system "IMAX Digital" to differentiate the new system, IMAX chose not to, according to the LF Examiner.

Ansari didn't realize he was duped until his ticket was torn and he was inside the theater. Now that you know, ask before buying your ticket what size the screen is.