RealD vs. Imax Digital 3D: What’s the difference?
| Imax Digital 3D | RealD 3D | |
| 3D technology | Linear polarizing | Circular polarizing |
| Projector | Dual projectors | Single projector (with 3D lens) |
| Screen | Silver coated | Silver coated |
| 3D glasses | Large format (for larger screen) | Standard size |
| Audio | Uncompressed | Varies by theater |
Imax Digital 3D is an evolutionary improvement of the analog Imax 3D theaters that have been around since 1986. Its long history is evident even in the much newer Imax Digital 3D theaters since they still utilize the linear polarizing technology of its analog predecessors. Unlike RealD, Imax 3D movies are less tolerant of head movements. Viewers have to avoid tilting their heads, though some turning--probably unavoidable due to the massive Imax screen format--is possible. Also, Imax screens are curved to fill an audience member's FOV, which enhances immersion while giving those sitting at the sides a better view of the action. Imax Digital auditoriums also use two 2K projectors for 3D shows, which leads to a visibly brighter image through the glasses.
While many Imax theaters these days are digital, there are still auditoriums with the analog Imax 3D format in the US and some other countries. These auditoriums typically have a larger screen and correspondingly large projection equipment and tend to be used for documentaries instead of feature films, too. Omnimax theaters (recently renamed as Imax Dome) are a variation of this analog format, but have a dome-shaped screen.
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