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» Film-Tech Forum   » Operations   » Digital Cinema Forum   » Digital 3D Systems (DLP), Pros and Cons

Author Topic: Digital 3D Systems (DLP), Pros and Cons
Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12295
From: Annapolis, MD
Registered: Dec 1999

 - posted 06-19-2010 12:59 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
Okay...somewhere, there is a DCinema pro/con thread and Tech 3D really belongs in the Film forum (it is film) lets talk about the DIGITAL 3Ds out there for the DLP systems. I've installed three, and not surprisingly, have formed an opinion of them! (and have a forth system in one of my screening rooms)

Let this be a discussion of the TECHNICAL merits/problems of the systems, not the financial side as those are covered in other threads or should have their own thread.

Dolby 3D

The first for me is also my favorite: Dolby 3D

Not not because it is Dolby (or Infitec) but because it allows 3D on a non-silver screen. It is a system that allows excellent 3D reproduction anywhere in the auditorium. And, to my eyes, the images look better than those on a silver screen.

Dolby is the only system that color corrects for each eye too. Now the polarized 3D system should not have color issues since they should be neutral in density but still, the Dolby calibration has one color balance each eye as well as set the light level for each eye.

The chief downside of the Dolby 3D system is the light...or lack there of! When things are going your way, you get a 10% through put with the system. That is, if you have 50fL on your screen in will likely only have 5fL by the time you color correct/drop the color wheel in/ and measure through the glasses (what one really sees). I have one system that only achieved 6% so even starting with 50fL only would yield 3fL (too low...thankfully I have headroom built into my systems). This may make one want to install a gain screen of 1.4 - 1.8 but try to resist you go up in gain, you will loose the even illumination and optimal viewing from all seats. Remember too...if you put in a gain screen, you only get that gain at ONE POINT of the will likely have lower illumination from over half the screen...unless you curve it.

I STRONGLY recommend that with Dolby 3D, IF YOU HAVE SIDE MASKING movable, use an Anamorphic lens. Yes it costs a boat load of money but that is a one-time purchase. It will yield you 20-25% more light (depending on the system and which lens you use). Anyone with a typical cinema with side movable masking that isn't using an Anamorphic is "doing it wrong." The light needed for that Scope image versus the Flat image is far too big a spread

A big plus to Dolby too is its "automatic." That is, you can have your server/player turn it on/off as part of your show without operator intervention. It is the only 3D system that does that, out of the box.

Dolby's disc sits just before the integrating rod and is part of the "clean" light path so minimal to no maintenance is required.

Some manufacturers also offer the Dolby 3D system pre-installed.

Dolby has a manual for there system though the actual color wheel installation isn't very well documented, except for the Barco integrated wheels (Barco documentation). That said, the concept of where the color wheel goes and how it mounts shouldn't mystify one too much, if are competent at such things.

Master Image

Master Image uses a spinning disc infront of the projection lens. And boy does it spin... 4320 RPM

On the up side, its 3D quality is the best I've seen on a Silver screen (and yes, it requires a silver screen). No ghosting and the through put is about 18% on the light. So, to hit 5fL in 3D, you need about 28fL on 2D.

There are a couple of down sides to it.
It is a dirt magnet and requires cleaning on a regular basis (your booth conditions will dictate the frequency).

It is NOISY. Nosier than most any film projector I've heard. You best have double-glazed port frames and good sound isolation on your walls or you WILL hear it in the theatre.

The factory doesn't seem to provide any means (or none that have been documented to me) for controlling it externally...though I'm sure one can "rig" it). Thus this thing will be spinning, in a typical booth, all day. It "idles" at 2880 RPM...slower but still a pretty good clip.

In the event that 3D dies out (we can only hope)...Master Image should have no trouble getting into the Anvil business! This thing is HEAVY...which is good due to its location (in front of the projector) and the vibration/speed it runs.

Since one doesn't spend a lot of time calibrating this system and interfacing is a VERY fast installation. Set the raise/lower limits, position it in front of the lens, connect the supplied cable...done. It just works.

Documentation is more than wanting...especially for the price that is charged for the system.

Real D

Real D should really be broken into two sub categories...Z-screen and XL.

If at all possible, always get the z-screen and not the XL (more on that later).

Real D is a silver screen system (boo!) like Master Image. However it is the weakest, in terms of 3D. It requires some form of ghost busting or you will see shadow images of the wrong eye. The studios will no longer distribute ghost busted images so now, the servers/players must do it real time. My experience has shown that it doesn't work phenomenally well. That said, I have not seen the real time ghost busting on enough systems to know if it was the particular servers or just the process is flawed and is being passed off as "good enough"

Installation is pretty much a breeze on most projectors though the support can be a bit flimsy, depending on the projector model. The mount may restrict opening the projector for service or require removal of the brackets to open the projector.

The system does not automatically insert/remove itself but it can be done quickly...still I prefer that these systems be able to automatically, by virtue of the show build up, move into place or remove themselves. There are some manufacturers that are using their anamorphic attachment mechanisms to "swing/move" them into place.

Light throughput is about 15% (50% more than Dolby but 17% less than Master Image. One should remember though...these are silver screen systems where the gain is typically 2.2-2.4 and the light is typically read at the center of the screen so there is a 2X boost to the light there.

Real D XL

The XL version came out to bring more light for big theatres and that is the ONLY time it should be used! It does get one more light. It has a 28% throughput. Making it the most efficient single-projector 3D system.

This contraption mounts in front of the projector and is HEAVY (something like 40lbs). It has a single inlet but a dual outlet (over/under). There will be two images coming out of it so you will need a TALL port. If you are curious if your port is big enough...measure the height of your existing image, and then add TWO more images of the same size on TOP of that...if you can get that top most image out of your existing port, you'll need to get a bigger/taller port.

Installation can be slow going, depending on your booth/theatre layout. One has to match the upper image to the lower image so that just a single image is presented on screen (they are from the same eye. After all, the second image is the reclaimed light. You have to match in vertical horizontal and in magnification. The more orthograph your system is, the easier it will be to accomplish. If you have a curved've lost the battle already. Getting two starting points to curve a line identically just isn't going to happen (at least not with this system). Remember, these to images are not Left Eye/Right Eye...they are the SAME eye!

The better you get the two images to converge, the higher the resolution the picture will be. Thats right, you can expect the image to have less resolution when you are done...if you get it perfect (and you can get it pretty darn close, everywhere) then you are, theoretically, back to the full resolution. I suspect that most people match the center up pretty well but have a hard time in the corners getting them to match too.

One thing I'm impressed with is the alignment gauge. It is slicker-n-snot. Don't be foolish and use a bright target to align with (the gauge is white)...use a nice simple cross hair pattern...the "tennis court" pattern will do if yours has the center cross hair. You can get that crosshair to easily show up on the gauge and have you set height/tilt perfectly.

The brackets for the XL are cumbersome at best on a Barco installation. They mount to the pedestal and block you from removing the front cover of the projector for service.

You will more than likely need separate "screen" and "lens" files for the 3D formats if you have an XL as it does alter magnification some.

So, my STRONG recommendation is...if you don't "need" the extra light that the XL offers (you are at the max of your projector's lamp and still can't hit 5fL) pass on the XL and insist on the Z-screen, if you are going the Real D route.

There are documents for both the Z-screen and XL...not great documents but enough to get you through...they don't ship with the need to download from the Real D site (passworded FTP site). Real D also has targets on that site for the pre-full-frame triple flash (1920 based) projectors (EFIB boards).


I have not installed this system but have one client that has it. The 3D effect is excellent and installation couldn't be easier...just a transmitter for the battery powered glasses to receive. It, like Dolby, works on any screen, including white.

All systems

One should optimize as well as possible the settings in the "3D" file of the projector you are using. Normally there is a starting point that is documented/provided. Use a good 3D target (like Dolby's Sync Delay) to ensure you are seeing the correct eye and that you are centered on your delay/dark time.

Double/triple check your "Eye Dominance" setting (and it changed between series 1 and series 2 projectors). On series 2, I've found that "LEFT" is correct for Dolby and Real D...whereas "Right" is correct for Master Image. Having this set wrong will cause an odd jittery effect only to the moving objects while the stationary objects look fine. Try it in both settings and you will see the the wrong setting...aside from the twitching, you will feel MUCH more eye strain.


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Elise Brandt
Expert Film Handler

Posts: 160
From: Kuusankoski, FIN/ Kouvola, Finland
Registered: Dec 2009

 - posted 06-20-2010 03:46 AM      Profile for Elise Brandt   Email Elise Brandt   Send New Private Message       Edit/Delete Post 
Informative, thank you. I haven't yet seen any other 3D system but Xpand, that's what we have in our theater.

I might add a downside to any system with battery-operated glasses, even when you check them after every wash and before use, there will always be times when they stop working in the middle of the show. Usually people notice during the trailers but even if that happens, some numbnuts just sit through the movie with glasses that don't work and only complain after.

I've heard a lot of good things about the Dolby system. Its too bad almost all theaters in this country (that have gone digital so far) opted for the Xpand. I'm pretty sure that in the near future one or two that convert will go the Dolby way.

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Demetris Thoupis
Phenomenal Film Handler

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From: Aradippou, Larnaca, Cyprus
Registered: Apr 2001

 - posted 06-20-2010 04:17 AM      Profile for Demetris Thoupis   Email Demetris Thoupis   Send New Private Message       Edit/Delete Post 
I have witnessed both Dolby and X-Pand system during installation. I have to admit that the fastest to install is the X-Pand system and it is brighter than Dolby. Excellent post Steve. I do concur that when Dolby is correctly callibrated as a 3D system it is unbeatable and yes the MasterImage does give the best 3D effect out of the silver screen solutions. Panavision claims their system is compatible with Digital technology. Since I am not attending Cine expo [Frown] can someone inform us about it?

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12295
From: Annapolis, MD
Registered: Dec 1999

 - posted 06-20-2010 08:50 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
Yes, the XpanD is brighter than Dolby (forgot to mention that). It does not need the severe color correction or eye balance that Dolby does. It should be the brightest 3D out there, on any screen using a single projector.

XpanD is only a single projector solution so if you need a really bright picture with dual projectors, XpanD won't be your solution. The other 3Ds can do dual projector which will yield MORE than double the light because you no longer need a "dark time" to transition between the eyes...both are on at all times.

I would say that XpanD is a good solution for smaller cinemas/screening rooms...especially if you have home-grown 3D content, like Universities. Naturally, one needs to ensure they get the glasses back and keeps the batteries charged/changed.

There is a color processor by Cine-Tal that will allow one to color correct for Dolby 3D on alternative content. You do have to get your signal into an HDSDI form for it though.


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Todd McCracken
Master Film Handler

Posts: 263
From: Northridge, CA, USA
Registered: Mar 2008

 - posted 06-21-2010 10:55 AM      Profile for Todd McCracken     Send New Private Message       Edit/Delete Post 
Strange, the master image unit we have in our lab is very quiet. I cannot hear it running over the exhaust fans.

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Pietro Clarici
Expert Film Handler

Posts: 136
From: Foligno (PG) Italy
Registered: Sep 2008

 - posted 06-21-2010 01:18 PM      Profile for Pietro Clarici   Author's Homepage   Email Pietro Clarici   Send New Private Message       Edit/Delete Post 
quote: Steve Guttag
XpanD is only a single projector solution so if you need a really bright picture with dual projectors, XpanD won't be your solution.
Actually, you can use a dual projector stack with XpanD: one particular theatre I know of has a pair of CP2000Xs projecting on a 30x16,5m Perlux 180 screen.

Of course, there's still dark time involved as the projectors show the same frame at the same time, and correct alignment is critical, as in Real D XL and XLS.

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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12295
From: Annapolis, MD
Registered: Dec 1999

 - posted 06-21-2010 03:30 PM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
Okay...yes you can do it that way, of isn't quite the same as doing it like Dolby or even Real D where each projector carries a separate eye though. If your screen is curved and any displacement in the projectors relative to each other comes off of resolution.


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Paul Linfesty
Phenomenal Film Handler

Posts: 1381
From: Bakersfield, CA, USA
Registered: Nov 1999

 - posted 06-21-2010 05:03 PM      Profile for Paul Linfesty   Email Paul Linfesty   Send New Private Message       Edit/Delete Post 
The Cinerama Dome in Hollywood used the XPAND system with two projectors, and they have a deep screen. While the projection quality was fairly bright (for digital 3-D), I must say the glasses were considerably awkward and uncomfortable for someone who is wearing regular glasses. They kept slipping every few minutes throughout the entire movie!

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Mark Gulbrandsen
Resident Trollmaster

Posts: 16269
From: Bountiful, Utah
Registered: Jun 99

 - posted 06-21-2010 05:27 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
I pretty much agree with what Steve says but let’s start with the best of the best.

Two projector three dee is by far the top of the line. It can be done with either Dolby 3-D, Expand, or circular or linear Polarization. I have installed two systems and both were polarized… only because at the time Dolby was not ready to do two projector systems. It’s expensive and alignment is a pain in the ass but the results are superb. Bright, sharp and excellent color. It seems as though all distribution has accepted it although Disney has a ridiculous set of specs they want you to meet.

Dolby gives so far the best results of al the single projector three dee systems but at the cost of more than a lot of light loss. IMHO for any 3-D system to work to it's full capabilities you do need to have a properly curved gain screen... period. Flat screens simply do not work well for any three dee! Do not install Dolby on a matte white screen unless you’re prepared to hand out night vision goggles with each pair of Dolby glasses! Be it a white gain screen or silver a proper curve ratio is going to make the light distribution at least on a 1.4 gain white screen very acceptable. But don't ever expect to get decent light distribution on anything over 1.4 gain and certainly never on a silver screen. This may be one time where the curved compound screen that sucks could come into great use... for any three dee screen. You would stand a chance with a silver screen in a curved compound frame. Where's Glenn Berggren when you need him?

I am not a fan at all of Master Image. Sure it works great but it is way too expensive and too much the goop sucker upper. Any filter that passes an image that requires frequent cleaning isn't going to remain optically perfect for very long! A new filter wheel is around $500. Sure it gives good results but at a ridiculous price... for what it actually is. I still have three for sale if anyone is interested!

Standard Real-D just sits there and works. Content must be Ghost Busted! It is just about as automatic as Dolby is. The Z screen is super reliable and most of the very first units that were installed are still out there working to this day. It is right now the least expensive way to get into 3-D because of the CBG deal. It may however prove to be the most expensive deal for you in the long run since you pay them ~.50 per 3-D ticket sold! I have not dealt with an X-L unit yet but it's use is certainly more limited! Those with early D-cinema projectors such as the BARCO DP-100 would certainly benefit from the use of the X-L adaptor if it can be utilized if you are going to go three dee.

How many more Three Dee systems do we need? Panavision is also about to bring us another three dee system that will also work on a white surface. It apparently uses fixed color comb filters... nothing active in this system. That alone makes it extremely attractive! Reports from people I know that have seen demos say it is better than Dolby 3-D and far more light efficient. It will be used for both Digital Cinema and Film Releases.

Expand... Demos I've seen look good. I will never instal one because I don't like business dealings with any French people, especially French Canadians. I had my fill of them in the broadcast industry! You could generally cut a better deal in much less time with a brick wall! There were Expand glasses for sale recently on E-bay at a surplus place in Salt Lake City. 75 bucks a pair, possibly from the systems Marcus removed from their chain (for good reasons)! The down side is that if you also have USL IR hearing departed transmitters the Expand Transmitter operates on the same IR frequency... I think Expand should change their frequency since they came along second!

I hope three dee goes away or at best at least be utilized on films where it can make a difference. I believe it will at the very least taper off in a year or so as present green lighted productions are released. It seems the public is already growing weary of it.


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Steve Guttag
We forgot the crackers Gromit!!!

Posts: 12295
From: Annapolis, MD
Registered: Dec 1999

 - posted 06-23-2010 02:21 AM      Profile for Steve Guttag   Email Steve Guttag   Send New Private Message       Edit/Delete Post 
As an update to the Master Image. It appears that starting with version 6 of their I/O board they now have an automation connector. It provides optoisolated inputs, complete with V+ and common so you can use relays, Open collector, or even voltage out from your automation (active high or low). Raise, Lower and Start/Stop are available.


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Mark Gulbrandsen
Resident Trollmaster

Posts: 16269
From: Bountiful, Utah
Registered: Jun 99

 - posted 06-23-2010 12:03 PM      Profile for Mark Gulbrandsen   Email Mark Gulbrandsen   Send New Private Message       Edit/Delete Post 
Not necessary, althugh they should be handing those out for free. There are not that many Master Image units out there!

You can just wire right across the start switch in the unit as it sits right now. Just go to an unused set of contacts on your NA-10 or eCNA automation and create a cue for same.


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