Sunday, January 6, 2013

RealD vs. Imax Digital 3D: What’s the Difference?

                Originally published - January 6, 2013
          From CNET Asia by Timothy Fernandez on 1/4/13

3D movies are quite common these days, with many of the latest animated films, action-packed blockbusters and horror flicks being presented with a third-dimension. The passive polarizing technology used to display 3D in most movie theaters is also similar to those found in passive 3D TVs.  However, the fact that some movies are presented  in several 3D formats in the theaters can be somewhat confusing. 

Most of us who’ve caught a 3D movie at the cinemas recently probably experienced the more common RealD 3D technology, while Imax Digital 3D (as well as its analog counterpart) is a format presented at Imax auditoriums. But is there any difference between RealD 3D and Imax Digital 3D?

Here’s what we know.

First, the similarities

RealD 3D and Imax Digital 3D both utilize passive 3D technology, which makes use of relatively lightweight eyewear. These passive 3D glasses use polarizing filters to allow each eye to see a slightly different image. This is why the glasses can sometimes seem darker in one eye than the other–it’s meant to block out certain spectrums of light. The glasses at Imax theaters are larger, to compensate for the larger field-of-view at those auditoriums.
Both these technologies are also digital, which means that you’ll get a clean image and none of the image noise or “cigarette burns” that are visible from regular film projectors.

How they compare

RealD 3D
The prevalent technology in 3D cinemas worldwide comes from RealD, an American company founded in 2003. The RealD 3D format is natively digital. This means that movies have to be produced in a digital 3D format for projection on film-less digital projectors. RealD cinemas also use a passive circular polarizing technique to achieve 3D which allows viewers a clear image even when turning or tilting their heads. Passive 3D TVs use circular polarizing technology, too. The first RealD 3D movie screened was Chicken Little in 2005.

Imax Digital 3D  
This is a competing format that’s been around for a little longer. Imax cinema auditoriums are well known for their massive, curved screens, which fill a larger portion of your field-of-vision (FOV), or how much  much your eyes can see a any one time.

An Imax auditorium in Singapore. (Credit: Shaw Theaters)

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. 

Why do Imax Digital 3D movies cost more?

3D ticket prices vary across Asia but Imax Digital 3D tickets typically cost more than their RealD 3D counterparts. In Singapore, a weekday ticket to a new movie at theLido Cineplex starts at S$19 on Imax Digital 3D while the average cinema with RealD 3D charges S$12 on average. At an AMC cinema in Los Angeles, a typical Imax Digital 3D movie starts at about US$12, while the same movie on RealD 3D would be about US$2 cheaper.

Theater audiences are paying more for Imax 3D movies for a few possible reasons. The first would be the consistent audio and visual quality across Imax auditoriums, the generally larger screen (that’s at a closer proximity to the audience) as well as a brighter image from the dual-projectors.

Of course, certain cinemas that use the RealD format for 3D screenings do have other selling points such as sharper 4K projectors, or better sound. An example of the latter would be auditoriums with Dolby Atmos setups, which can present more believable surround sound effects.

Just the facts

Aside from the larger screen size, there are other notable differences between Imax Digital 3D and RealD 3D. RealD 3D projectors like Sony’s 4K Digital Cinema models use a special lens to project 3D visuals, which can provide viewers with up to four times the resolution of full-HD 1080p. However, not all RealD 3D auditoriums have 4K projectors–many feature 2K digital projectors–so you may have to check with your favorite cinema chain’s Web site to find out which they use.

All Imax Digital 3D theaters, on the other hand, use Christie 2K dual-projector systems, which give twice the resolution of full-HD and a brighter 3D image. What this means is that RealD 3D auditoriums with 4K projectors can provide a visibly sharper image, especially with movies shot on similarly high-resolution cameras.

Imax Digital 3D
RealD 3D
3D technology
Linear polarizing
Circular polarizing
Dual projectors
Single projector (with 3D lens)
Silver coated
Silver coated
3D glasses
Large format (for larger screen)
Standard size
Varies by theater

The 3D effect

A scene from sci-fi movie Prometheus, which was shot in 3D and released on Imax 3D and RealD 3D screens. (Credit: Twentieth Century Fox)

To some, 3D movies should “pop” out of the screen, similar to what audiences experience with 3D rides at theme parks. Others prefer a more subdued 3D effect that stays behind the screen, adding a little more depth to the standard 2D fare.

Those who prefer the reach-out-and-grab-you effect might be partial to Imax Digital 3D, which the company claims to excel at. Executive Vice President (Technology) of the Imax Corporation, Brian Bonnick, says that Imax Digital 3D movies “can appear in front of the screen” which may be more lifelike. He also credits Imax’s “patented theater geometry”, “proprietary wide-angle lenses” and brighter images for this effect.

If you’re not a fan of props being hauled your direction or swords almost touching your nose, then RealD’s 3D effects could be the alternative. While RealD technology is capable of extending beyond the screen, the screens used in these cinemas tend to be flat and positioned further from the viewer, which would minimize the coming-at-you effect. The 3D effect they produce would also be similar to what you’d experience on your 3D TV at home. Some videophiles also prefer the 3D effect to be behind the screen and not protruding from it, so that it does not serve as a distraction from the movie itself.

However, do keep in mind that some movies may be shot with effects coming out of the screen for dramatic effect–the James Cameron epic Avatar would be one example. Other movies, such as Prometheus by Ridley Scott, are shot with a more subtle effect, which can be equally believable. So it really isn’t all about the 3D format, but which movie you’re watching, too.

Is there a superior format?

Honestly, after watching a good number of Imax Digital 3D and RealD 3D movies, we’d say that the 3D effect is very comparable between these two formats. Imax 3D does seem a bit more dramatic, thanks to the larger screen and closer viewing distance, but the way the movie was shot is equally important. There are, however, some notable differences.

Imax screens are massive and curved, which should help improve your view of the screen and minimize ghosting–the appearance of a double-images that’s prevalent on some 3D TVs. Imax Digital 3D screenings should also be consistently brighter. Imax says that its linear polarizing technology provides an “improved signal-to-noise performance over circular polarizers” and “allows more light through”. However, keep in mind that this technology makes 3D movies less tolerant of movements, especially tilting your head sideways.

RealD 3D typically provides better viewing angles that allows viewers to tilt and turn their heads while watching. While 3D movie enthusiasts probably know that keeping their heads still minimizes ghosting or double-images, young children may not. RealD representative Rick Heineman believes that this flexibility is important for moviegoers who should be “free to sit comfortably”.

Another frequently overlooked aspect is consistency. While RealD theaters are far more abundant, the venues only need to sport “compliant digital cinema projectors”. This means that your moviegoing experience would depend on the type of projectors used by the cinema as well as the sound system installed–these can vary significantly depending on the brands of equipment used. Imax theaters, however, have to meet standards for audio and image quality, which means they’ll look and sound more consistent across the board.