Kubah IMAX / OMNIMAX

Sekitar pengakhiran 1960s, San Diego Hall of Science (sekarang ini dikenali sebagai Reuben H. Fleet Science Center) memulakan pencarian bagi filem format tinggi di Amerika Utara untuk dipaparkan/diprojekkan/diwayangkan di kubah yang dirancang 76 ka (23 m) tilted dome planetarium. Satu daripada front-running formats ialah menggunakan sistem rangka-berkembar iaitu 35 mm sebelum mereka mengenali IMAX. Projektor IMAX tidak sesuai dipasang di kubah itu kerana dalaman kubah itu adanya 12 ka (3.7 m) lampu rumah yang tinggi di atas. However, IMAX Corporation was quick to cooperate dan was willing to redesign its system. IMAX designed an elevator to lift the projector to the center of the dome from the projection booth below. Spectra Physics designed a suitable lamphouse that took smaller lamps (about 18 inches long) dan placed the bulb behind the lens instead of above the projector. In 1970,[14] Ernst Leitz Canada, Ltd. (now ELCAN Optical Technologies) won a contract to develop dan manufacture a fisheye lens projection system optimized to project an image onto a dome instead of a flat screen.

The dome system, which the San Diego Hall of Science called OMNIMAX, uses films shot with a camera equipped with a fisheye lens on the camera that squeezes a highly distorted 180° field of view onto the 65 mm IMAX film. The lens is aligned below the center of the frame dan most of the bottom half of the circular field falls beyond the edge of the film. The part of the field that would fall below the edge of the dome is masked off. When filming, the camera is aimed upward at an angle that matches the tilt of the dome. When projected through a matching fisheye lens onto a dome, the original panoramic view is recreated. OMNIMAX wraps 180° horizontally, 100° above the horizon dan 22° below the horizon for a viewer at the center of the dome. OMNIMAX premiered in 1973 at the Reuben H. Fleet Space Theater dan Science Center showing two OMNIMAX features, Voyage to the Outer Planets (produced by Graphic Films) dan Garden Isle (by Roger Tilton Films) on a double bill.

IMAX has since renamed the system IMAX Dome. However, some theaters may continue to call it OMNIMAX.

OMNIMAX theatres are now in place at a number of major North American museums, particularly those with a scientific focus, where the technical aspects of the system may be highlighted as part of the theme interest. The projection room is often windowed to allow public viewing dan accompanied by informational placards like any exhibit. Inside the theatre, the screen may be a permanent fixture, such as at the St. Louis Science Center (which also plays a short educational video about the OMNIMAX system just before the feature film) dan Boston's Museum of Science; or lowered dan raised as needed, such as at the Science Museum of Minnesota (where it shares an auditorium with a standard IMAX screen). Before the feature begins, the screen is backlit to show the speakers dan girders behind the screen. IMAX Dome screens may also be found at several major theme parks.[15] While the majority of OMNIMAX theatres in museums focus on educational dan documentary films, on special occasions, as with the release of Charlie dan the Chocolate Factory at the Oregon Museum of Science dan Industry, major studio releases are also shown. The largest IMAX Dome Theatres in North America are at Liberty Science Center in Jersey City, NJ dan the Telus World of Science in Vancouver, BC, both of which have dome screens that are 88 feet in diameter.

IMAX 3D

Untuk menghasilkan illusi kedalaman tiga dimensi, proses IMAX 3D menggunakan dua kanta kamera untuk mewakili mata kiri dan kanan. Kedua-dua kanta ini diasingkan dengan jarak antaramata 64 mm (2.5 in), purata jarak antara kedua-dua mata manusia. By recording on two separate rolls of film for the left dan right eyes, dan mempaparkan mereka serentak, penonton experience seeing a 3D image on a 2D screen. Kamera IMAX 3D is cumbersome, dengan berat melebihi 113 kg (249 lb). This makes it difficult to film on-location documentaries.

Terdapat dua cara menghasilkan illusi 3D dalam pawagam. Pertamanya melibatkan pempolarisasi. Semasa penayangan, gambar mata kiri dan kanan linearly polarized as they are projected onto the IMAX screen.[16] By wearing special eyeglasses with lenses polarized in their respective directions to match the projection, each eye can only see the image intended for that eye since the lens's polarization will cancel out the other eye's image.

Cara lain untuk 3D projection involves the use of LCD shutter glasses. The projectors display each frame of film alternately for each eye (while one projector's image is displayed, the other is blocked), pada kadar 48 gambar sesaat. The glasses contain LCD panels that alternately block the light in one eye while allowing the other to see the image. The shutters flash back dan forth in sync with the projector, such that each eye only sees the image intended for it.

Several films produced in the RealD 3D process for release in conventional theatres have also been presented in IMAX 3D, termasuk karya DreamWorks Monsters vs. Aliens, U2 3D, Avatar, dan Toy Story 3.

Sesetengah pawagam IMAX further enhance the illusion of immersion in the movie dengan menggunakan gerakan tempat duduk dan getaran pada titik-titik tertentu dalam filem.

IMAX HD (48 gambar sesaat)

Variations on IMAX included the 48 gambar sesaat IMAX HD process, which sought to reduce strobing dan offer a more high definition image by filming dan projecting at twice the normal film rate.

Sejarah

The IMAX HD system was tested in 1992 at the Canada Pavilion of the Seville Expo '92 with the film Momentum. It was deemed too costly dan abandoned but not before many theatres were retrofitted to project at 48 frames, especially in Canada, in order to play Momentum.[17] In the 1990s theme parks in Thailand, Germany, dan Las Vegas used IMAX HD for their Motion Simulator rides.[18] The Disney parks attraction Soarin' Over California features a modification of both IMAX HD dan IMAX Dome, projecting in 48 frames per second.

Production issues

The doubled IMAX HD frame rate means that each IMAX HD reel lasts half as long, dan the logistical implications of this reach all the way up the film production chain. IMAX production by default is at least 3 to 5 times more expensive against common 35 mm production. The increased production costs make IMAX HD problematic regardless of overall production funding issues, dan the format has not seen significant adoption.