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DLP Rainbow Effect - Is It Noticeable On 4x Colour Wheels?

cataferal

Standard Member
Unfortunately, it took me 4 days to realise that my eyes were susceptible to the "Rainbow Effect" on my new Optoma DW318. I'd heard all about the phenomenon in my research, but this being my first foray into the world of projection, I naively ignored the warnings that surrounded business-class models like this and just decided to buy it. At first, I was enamoured with the principle of playing games and movies on a 80" screen that took up no extra space in my bedroom, but its limitations did start to sink in when I saw a few black and white movies. My decision to send it back was hammered home during a test of GoW3 on PS3, during which the many panning shots of dark caverns came out as a nauseating exhibition of flickering colours. And so, I'm left £10 shorter for the return P+P, a little wiser for the experience, and a little hungrier for a projector that'll ideally deliver the same image quality, only minus the rainbows.

It seems that this model is regarded as a variation of Optoma's Pro350, which uses the same 2x colour wheel format that causes this problem. Meanwhile, I've heard that the more Home-Cinema-centric HD600x uses a 4x wheel, but even here some people still notice the effect occasionally.

I've often heard that perception of the RBE varies in intensity from person to person, which makes this judegement all the harder to make. I'm looking for a home-theatre Projector at around the £450-500 price range. Would other RBE sufferers consider the 4x colour wheel projectors worthwhile? Or would 3LCD or 6x colour wheel DLPs be my only options?
 

kbfern

Distinguished Member
A lower lumen output dlp or one with a faster or different colour wheel combination will help but as to whether it will eliminate it for you is debatable.

LCD would be the only guarantee of not seeing them but this is not possible with a new projector in your price range.

You will either need to up your budget to at least £650 for an Epson TW450 which I think is the cheapest new LCD out there or go second hand which opens up your choice to other makes.
 

TurksMeister

Active Member
I havent got anything to add other than the original post was a very interesting read!

Good luck - and if you go with the HD600x, please let me know what you think, as I plan on getting this projector.

Cheers!
 

JUICE690

Active Member
I suffered on both x4 (HD65) & x5 speed (Infocus IN80).

It was worse on the Optoma but still annoyingly noticeable on the Infocus:(

6x is my only option now (other than LCD) but my goodness does that get expensive. :eek:
 

Clarner

Active Member
I am susceptable to RBE, I see it on ALL DLP projectors whatever the speed, Sim2, Projection design, Infocus, Optoma, etc, Including top end models. However general opinion is that it is only a minority that see RBE, and with use you get used to it. As I love DLP in every other way I decided to do an experiment, I bought an Optoma HD65 when it first came out for £416 and gave it a spin. Straight out of the box it was rainbow city, the high lumens, new bulb and 4 speed RGBCYM wheel took no prisoners. After a couple of hundred hours to tame the bulb, a grey screen, (home made) and low lamp mode, I hardley notice the rainbows. They are still there but don't bother me! However my wife, both my daughters, their boyfriends my cousin and brother in law ALL saw rainbows. I made the point of showing them some demanding material and asking them what they thought of the picture quality, all were impressed. I then asked them if there was any thing unusual about it, and it was then that the various descriptions of RBE came out. For your budget and for gaming there is nothing else out there, the HD600X is 4 speed but RGBRGB which in theory is twice as fast as the HD65 as the eye only sees in RGB so for each revolution the HD600X refresh's twice. If you do decide to give it a go persevere with it as there is nothing to compare bang for buck wise. Also make sure you calibrate the PJ, you can usually get some baseline adjustments from others on the forums. Good luck!
 

cataferal

Standard Member
Thanks for the responses. I've been searching far and wide, and it really does seem like the HD600X is the only option for my budget (unless I hit the used market, which can be a dubious proposition in terms of value). Anything less, and I'm in Business-PJ land.

I'll report back once I've picked it up, and hopefully I won't find myself pining for a 6x wheel model. I'll be sure to take Clarner's advice, and give it a little time to sink in (as well as to calibrate it properly). Fingers crossed :)
 
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Dave163

Active Member
In theory certain LED projectors with DLP engine like the LG HS102 should be able to offer extremely rapid colour cycling, like fifty times faster than a colour wheel or something of that order. That's way way way too fast for the human eye to behold any rainbows. I haven't seen the LG demo'd, though it's probably a bit lacking in brightness and is "only" 800x600.

I did see a pocket pico projector with DLP and was surprised that it had a very noticable rainbow effect. In fact I bought a picoprojector and have been reaosnably satisfied with it despite its low brightness (ideal for bringing round to friends for impromptu video nights here in Africa as it has it's own battery for when the power goes off) but it doesn't use a DLP chip. Since I don't show it more than about four feet wide as it's bright enough for that but no more, its resolution of 800x600 isn't such a restriction. I wrote a review a few months ago that yoj'll find if you search my posts - it cost around £300.

In your price range, or while you wait until HD projectors with LED bulbs and DLP engines come down in price by a few tens of thousands of pounds, how about a second hand hidef LCD projector?
 

YamahaClavinova

Active Member
Hi, i'd say go for the DLP PJ.

I have a HD65 and I was also worried about rainbows when I bought it. Being a glasses wearer, it's meant to worsen the effect too.

When I first used the PJ, the RBE was quite noticeable, especially with certain movies scenes, such as the opening sequence of Casino Royal.

In a similar way to Clarner who posted above, I showed these scenes to friends, none of them described seeing rainbows. Only when I pushed them to tell me if there was something odd about the image, such as the RBE, did they say they had noticed it. So I think unless you are looking for it, it's generally not a problem.

Also, as other people have mentioned, the effect does reduce drastically with time. Now I virtually never see rainbows, even when watching black and white material. I think just about the only time I see them now is when I'm watching a film and suddenly the thought of 'rainbows' might pop into my head, where i'll think "ohh, I haven't seen rainbows for ages..." then I'll scan my eyes across the image, and rainbows will be visible. But this is just forcing them for the sake of it.

So I guess what I'm saying is when you get the PJ, you'll see rainbows, especially since you'll be looking for them! But quite quickly you'll forget about them and won't see them any more.
 

Peter Parker

Distinguished Member
As kbern said, image brightness plays a part in how visible rainbows can be if you're susceptible to them, and your original pj was very bright - the image brightness you were getting had the potential to be around 10 times greater than you would find in the cinema, and three times greater than an average direct view display.

If you find your new DLP pj still has rainbows, you can use an ND (neutral density) filter to reduce the image brightness. An ND2 will reduce the brightness by half, though because we don't perceive brightness in a linear fashion, the reduction appears less than that, so it won't appear as dim as it sounds (ND will reduce by 75%). If you do decide you like the image but still see rainbows,, then try the lens of some sunglasses in front of the lens to see if that helps. Ignore the initial reaction of the image being dimmer as your eyes will adapt, but if the sunglasses works in reducing rainbows, an ND4 will reduce the brightness to something close to that of the cinema. You might prefer a brighter image for games and TV stuff like sports though, but removal of the filter will allow that (with the downside of rainbows becoming visible again).

If you can find the pj on demo somewhere and have a look, you'll know for sure if you see rainbows with it.

If you decide to go the ND filter route, try to get a Hoya glass one, as they have little effect on the image compared to a plastic or resin version.

Gary
 

cataferal

Standard Member
I did see a pocket pico projector with DLP and was surprised that it had a very noticable rainbow effect. In fact I bought a picoprojector and have been reaosnably satisfied with it despite its low brightness (ideal for bringing round to friends for impromptu video nights here in Africa as it has it's own battery for when the power goes off) but it doesn't use a DLP chip. Since I don't show it more than about four feet wide as it's bright enough for that but no more, its resolution of 800x600 isn't such a restriction. I wrote a review a few months ago that yoj'll find if you search my posts - it cost around £300.
I've read your review of the Adapt 305 (thanks for that), and I'm quite impressed by the lumens it seems to pack. Plus, the lack of perceptible Rainbow Effect, and the 20,000 hour lamp life definitely help the argument that LED backlighting will be the future of projection. Quick questions: do you know how it'd handle a 640x480 image via VGA - does it scale well? Also, does it give you aspect ratio options (stretch, 1:1 or maintained)? And finally, does it charge via USB at all?

Thanks very much if you can answer these.
 

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