QUOTE=commasense;16742573]Sorry to contradict you, Chronos, but it’s not that simple. You are right about two things: 1) the screens in most multiplex IMAX theaters are smaller than the true giant screens in museums that most of us think of as IMAX, and 2) RealD’s circular polarizers are better than the IMAX linear ones. In IMAX, if you tilt your head from the vertical, you get ghosting, which doesn’t happen with RealD’s glasses.
But apart from that, it’s not true that RealD’s technology is generally superior to IMAX.
First, there are several RealD systems: the original system, known as Z-Screen; the XL system, intended for larger screens; and the XLW (not shown on the linked page), which is for the largest screens.
Most multiplex theaters have the Z-Screen, which is less efficient than the other RealD systems. On top of that, many theater operators turn down the brightness on projector lamps to save power and lamp life. The result is that the images on many, if not most, RealD screens are quite dark. Hollywood’s official standard for screen brightness in 2D is 16 foot-Lamberts, and the industry’s unofficial “goal” for 3D is 6 fL, but most standard 3D screens are 3 fL or lower. (To make it worse, operators don’t always remove the polarizers when they show 2D films, so a movie in a RealD theater may be darker than it should be even when it’s not a 3D show!)
In contrast, IMAX digital theaters use two high-power projectors that are automatically aligned and calibrated every day. Image quality in an average IMAX digital theater will almost always be significantly better than that of an average RealD theater.
RealD’s XL and XLW systems are much better than the Z-Screen, and can begin to rival the quality of IMAX, but since most RealD installations are single-projector, and all IMAX systems have two, IMAX still has better brightness, resolution, and contrast than most RealD XL installations. Furthermore, I can pretty much guarantee that you will not be able to find out if a given RealD auditorium has Z-Screen or XL. The theater staff probably doesn’t know, and AFAIK, neither the theater chains nor RealD provide this info on their Web sites.
The only exception is what are called “Premium Large Format” (PLF) theaters. These are the chains’ in-house IMAX-like brands, and most use the RealD XL system. Regal has RPX, Cinemark has XD, Carmike has Big3D. Like IMAX, these are usually the largest screens in the location, and have brighter projectors, better sound, and other amenities like plush chairs. There is a up-charge for tickets, but it is usually smaller than for IMAX.
So if you want the best image, look for IMAX or your local chain’s PLF theater.
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Most of your information is close, but not quite right.
Real D:
Real D systems: Z-screen, XL, XLW, and XLS
The z-screen is the first digital 3D system developed, and was incredibly popular. The Development of this technology went hand in hand with pioneering the digital 3D revolution and established Real D as the name in Digital 3D after 3 years of working with Digital projector manufactures and scrambling to meet Disney mark for 100 digital 3D screens for the release of “Chicken Little” (Feb 2006)… Imax announced their venture into digital cinema in later that year (Nov 2006) meaning that Real D had a 3 year R & D head start.
The XL uses an optical system designed to recycle some of the light lost in the polarization effect. This step forward effectively double the light output of the 3D image. Due to the optics the two images need to be converged on screen and therefore places a lower end limit on the size of the room it can be placed into… if your throw from projector lens to screen is less than 35 ft. and insuring a throw ration greater that 1.44 for a side masking auditorium and 1.26 for a side masked Auditorium. Generally speaking that means it will work in any regular sized auditorium and most of your larger auditoriums… if you are going for a Premium large format those screens tend to have a lower aspect ration so you would need a systems designed to handle the shorter throw and larger screen… enter the XLW.
The XLW is an XL with a specialty lens designed to handle the Premium Large format specialty screens that are competing with IMAX (as mentioned earlier… Regal has RPX, Cinemark has XD, Carmike has Big3D) The XLW has an optical lens that goes throw a 9 month manufacturing process that is geared toward efficiently spreading the light at a greater angle to deal with the shorter throw and larger screen.
The XLS… this was a lens designed by Sony to work with only Sony projectors… the only cinema projector not to use DLP… and not originally intended for 3D. If your watching 3D on a Sony Projector you really don’t care about 3D anyway so I’ll skip a detailed explanation and say that the quality is similar to the Z-screen… when the projector is new. Generally the only chains that are using these are AMC and Regal… in their smaller houses as they have found that Sony can’t produce the light need for a large the mid size house for 3D.
Real D Products in the field:
It was mentioned that “Most Multiplexes use Z-Screens”… that is just not true most multiplexes have a mix of Z-screens and XL-XLW’s. Upon developing the XL Real D launched a program to place the XL, and later the XLW, into all of the houses that met the specs. At this time there are around 4 times as many XL/XLW in active use as the Z-screens. Generally when I walk through a projections booth (as I do 8-20 times a month for work) there are generally only one or two in a multiplex and on average 6-8 XL/XLWs.
“…the industry’s unofficial “goal” for 3D is 6 fL, but most standard 3D screens are 3 fL or lower…”
This statement is just outright false. It may have initially been the case when Hollywood’s first unofficial standard was 4.5 fL, but I have personally tested a couple of hundreds screens in a survey that involved around a thousand screens from various chains of various sizes globally and can tell you the average readings on Real D XL’s was around 5.9 fL and the only reason it was that low was due to some smaller chains sticking to the 4.5FtL standard to save costs in power usage and bulb size.
*“… I can pretty much guarantee that you will not be able to find out if a given Real D auditorium has Z-Screen or XL. The theater staff probably doesn’t know.” *
Your right the staff downstairs probably doesn’t know, but most people go to the same theater over and over… look at the porthole glass if you see one box of light it’s a Z-Screen if you see two boxes of light you are looking at an XL or an XLW… another clue is if your auditorium has more than 100 seats its probably an XL/XLW. So while the staff you ask may not know its not that hard to figure out.
IMAX:
Back in those distant days of actual film being projected (you know like 8 years ago) IMAX was defiantly the king of high resolution image and quality with a 70mm film real as opposed to the standard 35mm that the standard projectors use… however if you actually look at what IMAX has to offer today you need to realize the Emperor Wears No Clothes.
“… IMAX digital theaters use two high-power projectors that are automatically aligned and calibrated every day. Image quality in an average IMAX digital theater will almost always be significantly better than that of an average Real D theater.”
The first time I was in a projection booth and saw an Imax digital projector I admit I took an interest. I asked the projectionist how it compared to the other Digital Projectors he had and he laughed and said “check this out.” He then proceeded to pop a few screws lose and open the large impressive IMAX branded shell of the projector and opened it up to reveal the same Christie Digital projector that was just down the hallway. The simple truth of the mater is that an IMAX digital projector is the exact same projector that you’ll find in any theater… when the digital cinema revolution began IMAX didn’t think it would take over the industry as it has, and didn’t make the advancements to stay ahead of the game. Instead they scrambled in the aftermath of the rollout and announced their entrance into the field more than a year after digital projectors were already being installed and quickly partnered with an established company to make the digital transition… then slapped an IMAX branded plastic shell around somebody else’s product claiming it as their own… and if you want to know why they have two projectors for their setup instead of one… its because they can’t do it with one. Do you know why they calibrate their equipment every day,… its because they have to.
The truth is the only IMAX advantage right now is the lingering marketing in the public consciousness from their domination of film world… when it comes to digital I’d rather watch Real D, if for no other reason so that when I tilt my head slightly I don’t lose the 3D Effect.
And as for the difference between the 2K and 4K resolution… if the screen is smaller than 60 Ft. 99.9% of the public doesn’t notice a difference (exceptions being editors, Camera ops, some projection specialists ect…) and if the screen is Larger than 60 Ft. then across the board they have 4K projectors anyway… so once again IMAX has no advantage.