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Author Topic: Real D & Dolby 3-D - What is the difference? Jack Ondracek Film God Posts: 2348 From: Port Orchard, WA, USA Registered: Oct 2002 posted 12-19-2008 08:32 PM                        Well, I'm mainly concerned about the screen. Silvering something like that is hardly practical. Barco specifies their light levels with gain screens. I don't remember how much, but I don't think it was all that excessive. So, yah... I'm pretty sure my main screen would need more than one projector. It's 86 feet. My smaller ones are 60. I was mainly wondering if anyone saw a problem with the concept.  |  IP: Logged Julio Roberto Jedi Master Film Handler Posts: 938 From: Madrid, Madrid, Spain Registered: Oct 2008 posted 12-19-2008 09:52 PM                    Well, you can silver (or purchase) a silver screen that size, that's not a problem. See all the IMAX 3D screens installed ... all of them silver, of course. And such screen with dual linear polarized projection would yield the highest brightness for 3D systems as it stands. It would also work quite well (better extinction than circular), but there are the issues with the directionability and gain. People way off center would start to see more ghosting, which doesn't happen on Dolby, plus everybody needs to keep their heads leveled with the screen. Also, I wouldn't be surprised if some windshields depolarized the light a bit. And those outside the preferred cone of gain from the silver screen would also see a darker picture. So Dolby would be best and no problems on having it work. Except that right now it would need the light of 4 projectors plus a gain screen to reach really good levels. A set of Barco DP-3000 (7Kw lamp) with passive Dolby 3D should give you on a 1.0 gain between 3 and 5 fl on your 60'. For your 86' it would be between 1.5fl and 2.4fl. A bit less on Christie's CP2000-SB (6Kw) or NEC's NC2500S (6Kw). The margin of error in my calculation is because I don't know the exact claimed light loss of passive (dual) Dolby 3D, so I calculated the best theoretical possible and the worse I have measured from passive Infitec. On a 2.0 gain screen, you get twice that much for those within the cone of preferred illumination, of course. So with a 1.8 gain slightly (perhaps 5%) curved screen and two projectors and a passive Dolby system (if Dolby properly supports it, which they should have no problems doing if they so wished), I think it's doable for the bare minimun supported 3D light level (3.5ft) on 85 feet screens on a pair of 7Kw lamp. Barely If you want to do it right, would need to use 4 projectors (28kw of xenon ... ... at least it's better than Imax's 15kw x 2 for some of their polarized+silver 3D sites). Not sure 4 projectors operation is properly supported in the industry . Yet. But technically should be a no brainer. In spite of what the industry might say, there have been open complains from patrons of too-low light levels with 3D films. I personally think that anything below 5fl shouldn't be considered acceptable. Certainly not 3.5fl. I'm fine with 6fl for 3D. Current 3D films are "timed" to resolve all the contrast they can from 3.5fl to 5.5fl light levels. [ 12-20-2008, 06:03 AM: Message edited by: Julio Roberto ]  |  IP: Logged Ron Funderburg Jedi Master Film Handler Posts: 814 From: Chickasha, Oklahoma, USA Registered: Nov 2007 posted 12-19-2008 10:35 PM                        I have a question is there a specific reason that no 3d films have ever been scope? Is the ratio to wide for the eye or for the camera to use the 3d? I mean if I was making a 3d I would want the widest picture I could get! Or has a film been in both scope and 3d?  |  IP: Logged Tristan Lane Master Film Handler Posts: 444 From: Nampa, Idaho Registered: Feb 2002 posted 12-20-2008 01:07 AM                     quote: Ron Funderburg I have a question is there a specific reason that no 3d films have ever been scope? The most recent Scope 3D film that I've seen was Beowulf. Avatar will be Scope as well.  |  IP: Logged Darryl Spicer Film God Posts: 3250 From: Lexington, KY, USA Registered: Dec 2000 posted 12-20-2008 01:42 AM                    Monster House was scope  |  IP: Logged Julio Roberto Jedi Master Film Handler Posts: 938 From: Madrid, Madrid, Spain Registered: Oct 2008 posted 12-20-2008 01:47 AM                    I forgot to mention that low gain polarization preserving materials also exist for front projection, so there could be an use there for drive-ins. http://www.dalite.com/whats_hot/index.php?wID=176 Well, doing films in Scope, as we all know, adds its own set of production problems. But no real reason why they are not more common in 3D other than it's probably a bit more expensive and Scope lenses (if filmed true scope as oppossed to spherical, say Super 35) could render some additional artifacts on 3D. Nothing like a showstopper, though. And, of course, a non-issue on CGI animated films. In the projection side of things, scope has its own set of problems. TI DLP's for digital cinema are 2048x1080. They render a 1.85 (flat) ratio picture at 1998x1080, so only a bit of the chip surface is lost in this format (2.5%). Therefore, almost all the light available is reflected out to the lens. But to fit a Scope picture, the best you can do is constant height, at 2048x871 pixels, where roughly 19% of the chip's area is not used, and therefore its resolution and light is lost. Actually, the real best you can do is an anamorphic image, which would yield 100% of the chip area (resolution and light, but DCI doesn't like it). You would need of course an anamorphic lens (or adapter) on your projector, which would suck a bit more light than a spheric one, neglecting a bit of the brightness advantage, but still worth it for very large Scope screens. Here are some of the numbers: 2048x1080=100% resolution and light (scope, anamorphic) 2048x871=81% - scope contant height 1612x871=63.5% - flat constant height 1998x850=76.8% - scope constant width 1998x1080=97.5% - flat constant width Note that if you zoom in or out you can change some of the results (i.e. fitting a larger image into a smaller screen, using the best of both worlds), but you get the picture. A zoom lens or a focal length adapter would usually also suck up more light than a fixed prime. Not related, but am I the only one enjoying the trailer for the Bloody Valentine 3D movie? http://www.youtube.com/watch?v=bsRbqpiqkKU LOL. It's 3D of the 80's all over again. Crappy horror movies galore (any1 remembers this year's Scar 3D's anymore?). Except that now, CGI kid's movies join the batch. If Avatar 3D bombs next year, I say 3D is almost the 80's all over again. Soon we'll see re-issues on digital cinema of Jaws 3D and Friday the 13th. Except in brand new expensive HD projectors [ 12-20-2008, 04:18 PM: Message edited by: Julio Roberto ]  |  IP: Logged Ron Funderburg Jedi Master Film Handler Posts: 814 From: Chickasha, Oklahoma, USA Registered: Nov 2007 posted 12-20-2008 03:23 PM                        So Beowulf was in 3D (at those digital theaters that can do that)! Were their others? I don't remember them if their were but their could have been. I was just curious why not, 3D (film or other wise) is expensive and you would just think if you went to that expense you would do it in scope because wider is better!  |  IP: Logged Julie Lucero Film Handler Posts: 37 From: Valencia, California, USA Registered: Sep 2008 posted 12-20-2008 05:32 PM                     quote: Ron Funderburg is there a specific reason that no 3d films have ever been scope? Weren't most of the 3-D movies during the 1980s done in scope? My recollection is that JAWS 3-D and SPACEHUNTER (and a couple others whose titles I can't think of) were in scope.  |  IP: Logged Claude S. Ayakawa Film God Posts: 2738 From: Waipahu, Hawaii, USA Registered: Aug 2002 posted 12-20-2008 09:28 PM                        In my opinion, the best 3-D films were made in the 50's in dual film projection with HOUSE OF WAX being among the best. Although I did see KISS ME KATE, HONDO and DIAL M FOR MURDER in theatres, these pictures did not play in 3-D in Hawaii because people at that time seem to have lost interest in the format and that was unfortunate. As far as I can remember, all 3-D films during in the fifties were flat and none were in scope. CinemaScope was just being introduced at this time and the Liberty Theatre in Honolulu was set up as the first of two venues in the city to show dual projection 3-D with a brand new flat silver screen. So far, as good as Real D is and perhaps Dolby 3-D, I do not think the effect of the modern digital process is as realistic as dual film projection 3-D was in the early fifties. -Claude  |  IP: Logged Steve Guttag We forgot the crackers Gromit!!! Posts: 12814 From: Annapolis, MD Registered: Dec 1999 posted 12-20-2008 09:44 PM                     Yes, the over/under process of the '80s basically necessitated "scope" aspect ratios. In fact, Drive-In prints were printed as Scope prints. Steve  |  IP: Logged Julio Roberto Jedi Master Film Handler Posts: 938 From: Madrid, Madrid, Spain Registered: Oct 2008 posted 12-20-2008 10:34 PM                    Any1 said 80's over/under? http://img257.imageshack.us/img257/6595/screenshot02rp9.jpg [Hint: it's Sony's new over/under lens for their digital cinema projector single-projector 3D system, where half the pixels would be used for each image. ] At least the whole chip is used and each image is a "better aspect ratio" full 2k 4:4:4 12 bits instead of 4:2:2 10bits in current TI DLP 3D (either Reald or Dolby ). And no 144hz temporal disparities, for those that are bothered by it, as either Reald or Dolby. http://www.dcinematoday.com/dc/pr.aspx?newsID=1211 [ 12-21-2008, 01:40 AM: Message edited by: Julio Roberto ]  |  IP: Logged Mark J. Marshall Film God Posts: 3188 From: New Castle, DE, USA Registered: Aug 2002 posted 12-21-2008 01:35 AM                    THAT is something I'd like to see.  |  IP: Logged Monte L Fullmer Film God Posts: 8367 From: Nampa, Idaho, USA Registered: Nov 2004 posted 12-21-2008 03:06 AM                     quote: Julie Lucero SPACEHUNTER "Spacehunter" looked on the screen as if it was in Scope, but it was actually shown through a flat lens. The frame had a dbl image (top image was left eye and the bottom image was the right eye) that was shown through a split flat lens that put the two images slightly side by side and you used polarized glasses. If the operator didn't watch his framing, it was easy to thread this 180* out and it still looked okey on the screen. But then to view this off-frame presentation correctly, you would have to wear the glasses upside down. Otherwise, you definitely felt your eyeballs being yanked out of your head. The leaders were definitely marked for frame and if this print was built up on any transport (the cinema I watched this in had the Cine 4x Towers), the framelines were a bit heavier than the split line in the frame..and the note in the cans specifically noted this special condition. Otherwise, this was an excellent 3D film presentation when using the polarized glasses. Anaglyph is just something to get used to since it alters the color and lowers the brightness. -Monte  |  IP: Logged Julio Roberto Jedi Master Film Handler Posts: 938 From: Madrid, Madrid, Spain Registered: Oct 2008 posted 12-21-2008 06:35 AM                    Yeah, virtually all 3D films of the 80's were shot in what is called the over/under format, in which you took a normal 35mm full frame and splitted it in half, printing one image on the top half and another in the bottom. Looked like this: http://img101.imageshack.us/img101/1070/historyformatsjj3.gif They weren't filmed in Scope, but in the 3D systems used at the time that produced that result (stereovision, spacevision, etc). You could almost call it (incorrectly) 48fps 2-perf 35mm When projected through a 3D lens (or a spherical lens+3D adapter), the aspect ratio on the screen was similar to 2.40 scope. There were a couple of films around that era that were exceptions. I remember projecting a risqué american one that was side/side anamorphic (Stewardesses) and another swedish on that was over/under but cropped to something like 1.66:1 (Champagnegalopp). I remember I kept a frame of it somewhere from a splice. I remember Spacehunter. I don't recall exactly what was the problem with it but I remember it having the worst ghosting of all the ones we showed in that round. I think it was shot with a dual system and then converted to the over/under, but the aligment or perhaps the interaxial weren't all there.  |  IP: Logged Mark J. Marshall Film God Posts: 3188 From: New Castle, DE, USA Registered: Aug 2002 posted 12-21-2008 08:58 AM                    I've wondered about temporal problems with the over/under format similar to the ones found with single projector digital 3D since the mechanical 35mm shutter blade opens up one frame before opening the other. I've never actually seen anything in the over/under format, so I can't say if it's a problem or not. Also, what is that over/under frame from?  |  IP: Logged

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