Gareth A Posted May 15, 2013 Share Posted May 15, 2013 Does anyone know where to purchase Polarized 3D glass that goes in front of the projector for use with 3D Linear glasses. We know where to get the glasses from, but not the glass that goes in front of the projectors!! Also if anyone in the BR actually sells it, please PM me. Thanks. Link to comment Share on other sites More sharing options...
deepvisual Posted May 15, 2013 Share Posted May 15, 2013 you could DIY by using photographic polarising filters.get linear not circular. Cokin Link to comment Share on other sites More sharing options...
timtheenchanteruk Posted May 15, 2013 Share Posted May 15, 2013 Rosco? #073001720 Sheet: 17" x 20" more a film than glass though, don't know if its suitable for what you want now I think about it. Link to comment Share on other sites More sharing options...
gyro_gearloose Posted May 16, 2013 Share Posted May 16, 2013 I really wouldn't want to look at a linear-polarising 3d system for too long. You have to keep your head perfectly aligned with the screen or you lose the 3d effect. There is a reason that 3d digital cinema systems use circular polarising systems. Have you tried just taking the filters off a pair of glasses and using them in front of your projectors? Link to comment Share on other sites More sharing options...
dwright2104 Posted May 16, 2013 Share Posted May 16, 2013 I really wouldn't want to look at a linear-polarising 3d system for too long. You have to keep your head perfectly aligned with the screen or you lose the 3d effect. There is a reason that 3d digital cinema systems use circular polarising systems. Have you tried just taking the filters off a pair of glasses and using them in front of your projectors? Been there done that with a 1200 lumen projector, it lasted about 10 mins and started to melt. but I totally agree that you need to look at circular polarising, as the linear is a nightmare unless your head is perfectly straight. Link to comment Share on other sites More sharing options...
AHYoung Posted May 16, 2013 Share Posted May 16, 2013 american polarizers {in America} make filters { and glasses} for projection, they make both linear and circular, and im sure could guide you towards what would suit your application. remember that you need a high gain screen that retains the polarization if its to work properly... Link to comment Share on other sites More sharing options...
paulears Posted May 16, 2013 Share Posted May 16, 2013 We always use linear polarisation for theatrical 3D projection because of the better extinction, which improves the wow factor for effects. Circular polarisation is more gentle, but has the visual version of audio crosstalk - robbing the image of the best 3 dimensional effect. The turning head issue hasn't proven an issue. It only misbehaves when the person viewing moves too quickly. Running across an empty circle front row is a very strange experience - I fell over!The ones we use are in square frames, and we mount them about 100mm in front of the lens on a magic arm. Circular polarisers are also more expensive - which is perhaps worth considering. Ours usually are supplied by XL - along with Barco projectors. Link to comment Share on other sites More sharing options...
dbuckley Posted May 16, 2013 Share Posted May 16, 2013 Interesting; there are several 3D systems commonly and widely used for cinema exhibition, none of which use linear polarisation... Link to comment Share on other sites More sharing options...
Gareth A Posted May 17, 2013 Author Share Posted May 17, 2013 Thats Paul. Will contact XL then. Yes - we dont have much issue with the head turning either and mount them the same way. We already have the screens and 2 other sets of filters, but were bought 3rd party with no information supplied as to where to get further ones. Along with a few hundred thousand pairs of glasses. !! Thanks all . Link to comment Share on other sites More sharing options...
paulears Posted May 17, 2013 Share Posted May 17, 2013 glasses housekeeping is horrible if you intend reusing them. People stick them in their ears and chew them - so dunking each set in sanitiser is important, then rinsing and drying. You obviously get breakages and theft - so even if you intend recovering them, the shrinkage rate is shocking. Link to comment Share on other sites More sharing options...
dbuckley Posted May 17, 2013 Share Posted May 17, 2013 Glasses cleaning, about 3:00 in... http://www.youtube.com/watch?v=14oAs6W5DQ8 Link to comment Share on other sites More sharing options...
Gareth A Posted May 17, 2013 Author Share Posted May 17, 2013 Yucky.! Thankfully no. Cardboard giveaways.! Link to comment Share on other sites More sharing options...
gyro_gearloose Posted May 17, 2013 Share Posted May 17, 2013 The cost for the 3D component of our forthcoming digital cinema system is around £20,000. Nearly half of this is for the glasses, with the rest paying for the active filter that sits in front of the projector. The projector itself has to be much more powerful, as the polarising filters throw away about 60-70% of the light. By way of comparison, our current 35mm projector uses a 1.6k Xenon while our new digital projector will need a 4-5k Xenon :o Link to comment Share on other sites More sharing options...
deepvisual Posted May 17, 2013 Share Posted May 17, 2013 I;ve never heard of passive 3D with circular polarisers.how does it work? Link to comment Share on other sites More sharing options...
dbuckley Posted May 17, 2013 Share Posted May 17, 2013 Passive 3D with circular polarization is the most popular of the current 3D technologies, the market leader being RealD (corporate website), and there is a description of the technology on Wikipedia. RealD won the 3D wars by having a zero capital investment for the projection technology (rental $20K per year) and disposable glasses, which makes life very easy for the exhibitor. More than that, originally the distributors paid for and supplied the glasses, which meant that the exhibitor was in it for just that $20K per annum. Now, hoewever, the exhibitors have to pay for the glasses themselves, so they are often surcharged; once upon a time they were free. The only hard bit is requiring the right type of screen which is a capital investment for the screen upgrade. The Dolby system which I linked to the glasses handling video above has a capital cost of not much more than $20K, but you then have to manage the glasses as they are not disposable, roughly $20 a pair. So you have to have a glasses handling opperation, and purchase a commercial grade dishwasher. And, worst of all, one has to have staff to collect the glasses, try to stop them being nicked, and then do the wash processing. Exhibitors hate staff costs that don't contribute directly to the top line. Link to comment Share on other sites More sharing options...
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