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AVS' Prestigious Rainbow Effect (RBE) Club...

post #1 of 28
5/11/08 at 8:17am
Thread Starter 


This is a thread for fun with a bit of data calculations. It concerns mainly those of us affected by RBE. How you saw it, what equipment did you own that exhibited it, and how did you rectify it (if at all, ie, by changing to LCD/LCOS) etc...

I'd like to try and gather some info on how many of us see RBE, and to what degree. The general consensus is that 1/10 people see it regardless of the speed of the color wheel. Let's see if that's true among us Projector lovers.

I first saw it with my brother's Optoma HD65. On default setting it was terrible. After calibration, it helped but was still frequent. I also owned a HD70 which was better with a filter put on it but it didn't eliminate it.

I would say, I fall into the Average to high category. I don't get sick or eye strain but I see RBE with involuntary eye movement.
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post #2 of 28
5/11/08 at 8:46pm
The only problem with this poll is that it is voluntary - you will get more RBE affected people voting than any other group.

Fun? Maybe. Accurate? No way.
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post #3 of 28
5/11/08 at 9:15pm
I voted that I've never seen it. Not entirely true, but effectively true. I've got an X1, and when I first got it about 5 years ago, I experimented with very contrasty movies trying to see RBE. I could detect it if I went looking, but it certainly didn't affect anything I watched. I've seen lots of more annoying affects on other displays, like comb effects, bad color balance, pixels that are always on, etc. The earliest I remember is when you're watching an old western and the stagecoach wheels went backwards. ...GB
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post #4 of 28
5/12/08 at 10:54am
I've never seen it with my IF4805. I've tried, but never have. I've asked fifteen or twenty friends and none have noticed it either.
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post #5 of 28
5/12/08 at 10:25pm
I think everyone sees RBE at least if trained. I had several friends that didn't see it but then I showed them a particular test shot and I have yet to find a person (OK, I've only tested a few friends) that didn't see it. The test scene is the white circle within the white rectangle at the end of the THX optimizer demo found on any THX certified DVD for testing your setup's aspect ratio. Play that and then tell people to dart their eyes from one edge of the rectangle to the other and the typical response is, " Oh, yeah, I see it now" Once you see it there you see it much more often in common scenes too I think.


I have not tested an LED DLP, but assume they are the same in this regard.
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post #6 of 28
5/12/08 at 11:46pm
WHy would you force or teach people to see it? If they don't, leave them alone.
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post #7 of 28
5/13/08 at 6:07am
Agree.
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post #8 of 28
5/13/08 at 6:57am
I'm not sure if its rainbows, but I sure do get an eyestrain from watching DLP sets. The LED based sets aren't a problem however.
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post #9 of 28
5/13/08 at 7:17am
Quote:
Originally Posted by m. zillch View Post

I think everyone sees RBE at least if trained. I had several friends that didn't see it but then I showed them a particular test shot and I have yet to find a person (OK, I've only tested a few friends) that didn't see it. The test scene is the white circle within the white rectangle at the end of the THX optimizer demo found on any THX certified DVD for testing your setup's aspect ratio. Play that and then tell people to dart their eyes from one edge of the rectangle to the other and the typical response is, " Oh, yeah, I see it now" Once you see it there you see it much more often in common scenes too I think.


I have not tested an LED DLP, but assume they are the same in this regard.

I see RBE in real life if I go to that extreme, geez- who cares.
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post #10 of 28
5/13/08 at 8:38am
Quote:


WHy would you force or teach people to see it? If they don't, leave them alone.

"Ignorance is bliss." Some people enjoy living that way. I don't.

Most average people, not AVS forum types, when asked if an LCD or a DLP projector (front or rear) can show a true black will confidently point to an all black screen and say, "Sure! See?" But if you then demonstrate that it is actually very dark gray, not black like on a CRT for example (which comes close) they will have the same reaction, "Oh yeah, now I see what you mean".

I guess it's wrong to educate/train them in that regard too.
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post #11 of 28
5/13/08 at 9:19am
I used to see it more often than I do now.

I think I used to "look for it", now I just watch movies to enjoy them, and not evaluate my projector, an X1.
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post #12 of 28
5/13/08 at 9:47am
Quote:
Originally Posted by m. zillch View Post

"Ignorance is bliss." Some people enjoy living that way. I don't.

Most average people, not AVS forum types, when asked if an LCD or a DLP projector (front or rear) can show a true black will confidently point to an all black screen and say, "Sure! See?" But if you then demonstrate that it is actually very dark gray, not black like on a CRT for example (which comes close) they will have the same reaction, "Oh yeah, now I see what you mean".

I guess it's wrong to educate/train them in that regard too.

That's entirely different. After you "educate" them on black levels they're not going to say their image is unwatchable because the blacks look grey. However, if you cause them to start noticing rainbows they may never be able to enjoy watching an image on a DLP again.
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post #13 of 28
5/13/08 at 9:54am
I'm glad I know about it, since I am planning to buy a projector this year.
I was watching a projector image and kept getting bothered by flashes of colour. I realized this must be the rainbow effect I've been reading about. I was unsure why it was happening at random intervals, until I worked out it was when I shifted my eyes across the screen quickly.
I was not looking for the effect - I wasn't even aware I was looking at a DLP projected image.

What I do know is that DLP projectors are not even a consideration for my purchase.
Definitely 3LCD for me.
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post #14 of 28
5/13/08 at 11:15am
Quote:
Originally Posted by TF Ghost View Post

That's entirely different. After you "educate" them on black levels they're not going to say their image is unwatchable because the blacks look grey. However, if you cause them to start noticing rainbows they may never be able to enjoy watching an image on a DLP again.

I can see poor black level, fixed panel noise, vertical banding on LCD projectors, motion smearing with quick motion (sports) on flat panel LCDs, etc., yet I find them all "watchable". I'm not sure why you think RBE is different from these other defects I see additionally to RBE. It's not like I point it out to people and suddenly they grab their heads in pain, "Oh no, I have a headache now, thanks a lot, jerk!"

People who get headaches/nausea/eyestrain from RBE don't need educating, they have these problems from the get go. My "education" using the training session has yet to induce those symptoms in anyone; they merely see the RBE whereas before they would say they didn't. Still watchable for most.
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post #15 of 28
5/13/08 at 11:25am
pj hd72 & hd65, i do not see it when watching movie, but if i move me head to the side - away from screen ... i can notice the RBE.
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post #16 of 28
5/13/08 at 2:24pm
I'm in the market for a DLP projector... or should I say was. Turns out I see the RBE. I was viewing an older Ben Q that was properly calibrated. Does this mean I will be able to see it on 1080p DLP's ? Also I have a slight stigmatism could this be the cause of why I see RBE so easily?
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post #17 of 28
5/13/08 at 2:40pm
Caible, don't judge DLP current technology by an older one. Look at a current one to see if you still see RBE. Each year the makers claim less and less RBE as they increase the number of segments on the spinning color wheel and/or spin it faster. Only you can determine if you still see it.

I don't think the question is "Can I see it?" I think the real question is, "At the frequency that I see it with normal sources (not my test pattern) does it bother me?"

I don't think the resolution (1080p) nor your astigmatism have anything to do with RBE.
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post #18 of 28
5/13/08 at 7:46pm
Quote:
Originally Posted by TF Ghost View Post

That's entirely different. After you "educate" them on black levels they're not going to say their image is unwatchable because the blacks look grey. However, if you cause them to start noticing rainbows they may never be able to enjoy watching an image on a DLP again.

I have to disagree. To some, poor black level is just as bothersome as RBE is to others.
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post #19 of 28
5/13/08 at 7:50pm
Quote:
Originally Posted by caible View Post

I'm in the market for a DLP projector... or should I say was. Turns out I see the RBE. I was viewing an older Ben Q that was properly calibrated. Does this mean I will be able to see it on 1080p DLP's ? Also I have a slight stigmatism could this be the cause of why I see RBE so easily?

You need to try to watch one in a properly calibrated environment for a couple of hours. While other digital artifacts may be bothersome to some, be it black level, dithering, etc., they typically don't cause physical side effects like RBE may, and I emphasize the may, cause such as dizziness, headaches, or nausea in extreme cases. Try some of the forum sponsors that let you return a PJ as long as it has less than 4 hours on the bulb to see how it affects you in your environment.
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post #20 of 28
5/13/08 at 8:43pm
Quote:
Originally Posted by Uther View Post

I have to disagree. To some, poor black level is just as bothersome as RBE is to others.


You are right. I'm one example. I can no longer watch certain dark movies, for example "Seven", because the dark room scenes are just terrible. Black level is just part of the problem; bad shadow detail and black crush make certain scenes totally unwatchable, yet I can usually tolerate the few times I see RBE in a movie (although I have never lived with a DLP, I only see them in stores).
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post #21 of 28
5/13/08 at 8:58pm
Always saw rainbows on my 2x wheel X1...only scenes that were black on white or vice versa.

I see rainbows very rarely on my Optoma HD72 with the faster wheel. Only when very tired and playing Gears of War (very grey/black).
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post #22 of 28
5/13/08 at 10:21pm
Thread Starter 
Quote:
Originally Posted by m. zillch View Post

You are right. I'm one example. I can no longer watch certain dark movies, for example "Seven", because the dark room scenes are just terrible. Black level is just part of the problem; bad shadow detail and black crush make certain scenes totally unwatchable, yet I can usually tolerate the few times I see RBE in a movie (although I have never lived with a DLP, I only see them in stores).

Here's how RBE bothers me. I'm deeply involved in the story and voila, a rainbow pops up and it distracts me from the story. Or a scene with shining objects and the RBE just won't stop. To me, that is more annoying than terrible black and shadow.
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post #23 of 28
5/13/08 at 10:49pm
I was watching a movie that had some black and white scenes. The DLP was properly calibrated, but I do hope I see it less on a newer projector. I just know that I need to see a demo before I buy a DLP.
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post #24 of 28
5/14/08 at 8:36am
Thread Starter 
Here's a list of projectors I've seen rainbows on:

Mitsubishi HC1500 (this one was the worst)
Optoma HD65
Optoma HD70
Infocus IN72
Sharp XVZ2000

I've never seen a 6x DLP, so I don't know if that will help. RBE affects people individually. Some people don't mind it too much. I can't stand it.
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post #25 of 28
5/14/08 at 8:43am
I see RBE, but it doesn't bother me too much; I try not to dart my eyes to fast across the screen. I saw it more when I had SD sources, but now that everything I run in my media room is HD, I see it far less. My wife and son don't see it at all.
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post #26 of 28
5/14/08 at 9:02am
I'm average, but my wife is high....

I'm a weird one, I don't generally initially see them. But once it's starts, I see them a lot the rest of the viewing / night.
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post #27 of 28
5/14/08 at 9:11am
Quote:
Originally Posted by m. zillch View Post

I think everyone sees RBE at least if trained. I had several friends that didn't see it but then I showed them a particular test shot and I have yet to find a person (OK, I've only tested a few friends) that didn't see it. The test scene is the white circle within the white rectangle at the end of the THX optimizer demo found on any THX certified DVD for testing your setup's aspect ratio. Play that and then tell people to dart their eyes from one edge of the rectangle to the other and the typical response is, " Oh, yeah, I see it now" Once you see it there you see it much more often in common scenes too I think.

My experience exactly, EXCEPT I've never "trained' anybody else to see it, and I trained myself, with considerable success, to not see it.
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post #28 of 28
5/15/08 at 9:06pm
OMG the X1 I tried a few years back definitely made me ill. I then had a Sharp XR-10 which was better but Sin City still made me sick. My IN72 that I've had for a year now is MUCH better yet, but alas I think the next one is going to be an LCD.
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