Now lets take a look at the 3D formats themselves from the perspective of the moviegoer:
Dolby 3D is the newest of the 3D technologies currently on the market, using specific wavelengths of red, green, and blue for the right eye, and different wavelengths of red, green, and blue for the left eye. 3D professionals we’ve talked with consider this format because it provides more vivid and accurate colors while keeping a sharper image with no ghosting (the phenomenon of seeing a distracting shadow image behind or next to the 3D image).
Dolby 3D is typically much darker than RealD due to the Color Wheel in the projector and the glasses. If the movie theatre has a higher wattage lamp in the projector than normally used for 2D (which is recommended, but often not followed as it is more costly), the brightness can be even better than that produced by RealD’s technology and a silver screen. Dolby presents actual depth, acting more as a window to a 3D world than in-your-face spectacle. I have found the lenses are more reflective, which can cause trouble if there is any light behind you (I sometimes see movies in small screening rooms where the projector is very visible not far behind your head). Also, I’ve been to theaters in the past that have the subtitles for the deaf being projected from the back, which could be reflected inside the glasses. The glasses are washed in between screenings — often resulting in distracting splotches and water marks on the lens.
RealD uses circular polarized glasses instead of linear polarization, which is considered to be better because viewers are able to tilt their head without any loss of 3D. The RealD 3D technology delivers twice the light of other 3D technologies, and with 3D projection, the more light the better.
The technology specializes in perception of actual depth, acting more as a window to a 3D world. (In comparison, IMAX provides more immersive pop-out experience, which packs a WOW-factor but can be tiring on the eyes.) The format has less ghosting than others, and audiences consider it easier to keep track of quick action sequences. RealD is said to suffer from uneven illumination issues as the silver screen reflects the light stronger in the middle than it does at the sides of the silver screen. The issue is less evident when you sit in the middle of the theater, but is said to be more noticeable when sitting on the sides of a cinema. The glasses are considered the most comfortable of the bunch, and also the most reliable in terms of lens cleanliness as each pair is new and disposable.
Photo via Wired
IMAX 3D is the oldest of the current 3D technologies found in movie theaters. The technology uses linear polarized glasses, which means that if viewers tilt their head off off the normal 90 degree axis, the 3D effect will be lost. Moviegoers who are unable to keep still or stay straight during a film could experience headaches or eyestrain. The technology results in a lower contrast in dark scenes, some ghosting artifacts and audiences sometimes experience problems refocusing their eyes quickly enough in fast-moving action sequences. The large screen is seen to be more immersive, giving audiences more pop-out foreground 3D than the other formats.
But this intense 3D experience can be tiring on your eyes, especially in longer films. Remember, The original IMAX 70mm huge screen theaters were created for 60-80 minute 1.44:1 aspect ratio nature documentaries, not 3-hour Hollywood sci-fi tentpole movies. In fact, James Cameron requested that 1.87:1 aspect ratio version of Avatar be projected smaller, in the middle of the IMAX screen, to allow for optimal presentation. I have also found that you must be near the center in the last five rows of a traditional IMAX theatre for an optimum experience with a widescreen movie.
The glasses are cleaned between screenings, but many of the reusable glasses often feature visual faults, like scratches or visible marks. The Digital IMAX theatres uses two 2K-resolution Christie projectors (pictured above) to project two 2K images over each other, producing an image that is potentially twice as bright as a normal movie theater. Most of the IMAX screens curve inward at the edges which helps retain light, resulting in a brighter presentation.
Xpand doesn’t suffer from uneven illumination issues due to not having a silver screen. The glasses are bulky and considered the least comfortable of the bunch. I once attended a screening at the Arclight in Hollywood where the glasses ran out of batteries, forcing me to exchange my glasses with the attendant outside the theater. Luckily it wasn’t during the actual movie. But this issue is slight as the issue should not occur if the movie theater is conducting proper handling of the glasses and recharging when required.