IMAX theater tickets are more expensive than regular theater tickets because the technology is more expensive to own and run, in addition to the IMAX company's surcharges for using their products. The IMAX name is also associated with a premium experience, allowing theater owners to charge extra.
IMAX is not just a name for a film format -- it is also a company that sells special cameras, film stock and the technology to show films made with its proprietary technique. IMAX equipment is difficult to film with and difficult to use in theaters, and it requires special upkeep. IMAX offers surcharges to theater owners for maintenance and re-mastering older films made in other formats, as well as licensing fees for using the IMAX name on their advertising.
Finally, due to the premium experience associated with the brand, some unscrupulous theater owners charge high prices for films viewed in the smaller and less maintenance-heavy IMAX Digital format. While IMAX claims that IMAX Digital is just as high a quality as its biggest formats, IMAX Digital screens can be as small as a sixth of the size of regular IMAX screens.