Tru3D Active-to-Passive 3D Polarizer Add-on Review
Lets say you into 3D. Lets also say you think active shutter glasses are the work of the devil.
Well Tru3D has a solution for you: a converter that turns any 3D projector requiring active shutter glasses into a 3D that only requires cheap passive 3D glasses, plus all the brightness benefits that go along with that.
All 3D projectors under $15k for the home market currently use “active” 3D technology. This means they require active shutter glasses, battery operated LCD lenses shutter in sync with the image to allow/not allow light to enter your left or right eye. In addition to the cumbersome nature if these glasses, they reduce the apparent light output of the projector. Even a bright projector will be dimmer in 3D mode while wearing the glasses. A bright 3D projector, in 3D mode, will offer marginal-to-mediocre brightness. A marginally bright projector, will be outright dim in 3D mode.
Most movie theaters use a different method, called passive 3D. The glasses required for this method have simple circular polarized lenses. These let far more light through to the eyes. Passive 3D puts some of the heavy lifting on the projector (instead of splitting the burden with the glasses, as with active). It also requires the use of a screen that maintains the polarization of the light, which most don’t. These two factors are why you don’t see more passive 3D projectors for the home.
Enter Tru3D, with their “Polarization Modulator,” a device to convert an active 3D projector into a passive 3D projector.
The core of the Tru3D system is a single-plane polarizer. Mounted in front of a projector lens, it twists the light depending on which eyes information is displayed. On your face all you need are cheap circular polarized glasses like you
steal borrow get at most 3D movie theaters. The only trick is you need a silver screen that keeps the polarization of the incoming light. This, of course, is an added cost.
If you have a big family or have big movie parties requiring a lot of glasses, this could be cost effective. Also, if you’ve got a huge screen, the extra brightness possible with non-active glasses 3D will be extremely welcome.
My review sample was an Optoma HD33 with Tru3D rig attached. They sell this setup, for $3,300. Separately, the Tru3D Polarizer is $1,499 and will work with any “single-lens stereoscopic 3D projector (up to 6K Lumens) “. The polarizer hooks up to a small box that itself plugs into the service port on the back of the projector.
My review sample also came with a Da-Lite silver screen, though it was a small portable unit that isn’t fair to review on its own. As far as screens that maintain the polarization, this silver Da-Lite fits the bill. Stewart makes a screen that is said to work well with both 2D and polarized 3D.
Firing up the projector, I can see a potential issue right away. The polarizer acts as a mirror, reflecting a bright image exactly backwards. I calculated about 10% of the brightness of your projector is now lopped off and shot backwards. So tabletop placement is out of the question, as is any placement that would put the polarizer in your line of sight. Depending on your room, this reflected image will make your back wall a second screen. At least mostly, the bottom part of the reflected image hits the projector itself.
The fix for this would be fairly easy, some sort of black matte cloth acting as a sort of shroud between the lens and the polarizer (but not much more, you don’t want to cover any of the projector’s vents).
Even in home theater we not immune to the laws of physics, so all that light bouncing backwards is light not going on the screen. So right away some of the advantage of a passive 3D system is being lost (i.e., the added brightness). It didn’t seem to matter much.
The 3D effect is quite good, with a lot of depth. There’s also a naturalness to it I find lacking in most active shutter systems. Maybe it’s a subconscious revulsion of the shutters. As far as 3D goes, it’s more relaxing to watch than many other 3D projectors, though how much of this is the extreme brightness of the small silver screen in my review sample, I honestly can’t say. I did get the mild eye strain I’ve gotten with some active shutter glasses though, so that’s something. There was some slight cross-talk, but not any more than I’ve seen on some other 3D displays. It had a slight red tint, but it wasn’t that overly noticeble. If you move off to the side, the 3D effect flattens a little, but not badly. Overall Irate the 3D as “very good.
How much light is lost with this system is debatable. The passive glasses themselves certainly seem to pass more light, compared to active shutter glasses. Putting them on doesn’t have the intense sunglasses at night feeling you get with actives. When you add in the light lost to the reflection, plus what’s lost in the polarizer itself, I’dsay that there’s still an advantage in brightness going for passive, but not as much as it may seem at first.
The most notable difference between active and passive, though, is there’s always light going to your eyes with passive. That seems to have an effect on perceived brightness, though whether this is psychosomatic or physical, I can’t say.
Being such an odd product, I feel I have to qualify this review slightly. The small silver screen used in this review created an extremely bright image. Brighter is always better, even to trained eyes. On a normal sized screen, with normal projector brightness, I bet the difference between active and passive would be less severe. That said, the lightweight glasses and added perceived brightness are definite and worth considering.
So overall, the Tru3D is an interesting, if niche, product. It’s a bit pricy in my eyes, but then again I’m not keeping a family of 5 in $100 3D glasses. If you watch a lot of 3D and are tired of replacing batteries or recharging, or you like to have big movie nights and don’t feel like buying $1,000 worth of 3D glasses, the Tru3D certainly looks a lot more appealing. Also, and it may seem trivial, but wearing passive glasses is way less annoying than active. Lastly, the extra brightness of the 3D image is very welcome. If this seems like something you’d be interested in, I can say that it works exactly as advertised (placement concerns aside).
The Tru3D Active-to-Passive 3D Polarizer is priced $1,499.99 at Tru3d.com. HDGuru.com awards the Polarizer a ♥♥♥.5 out of ♥♥♥♥♥ heart rating.
Geoff Morrison @TechWriterGeoff
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