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Yes, my experience is that I get different amount of rainbows from different DLP:s. Not only related to how fast the colorwheel is, but overall brightness and other non charted facts as well (dont really know what gives me more rainbows from some than others even though they have the exact same specifications)


The only way to find out if you are disturbed or not is to check the DLP:s out. Most people dont actually see it, but if you do you really want to take a hard look on the different ones until you find the one which gives you the fewest of them.
 

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Discussion Starter · #4 ·
Well, that's good and bad.


To my disappointment today I saw rainbows that became quite distracting but maybe they were worse on this unit. I'll have to look at some others...


Thanks, I was wondering if they were all this distracting.
 

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It do depend on what unit you saw as well, which one did you see. If I know it and have seen it I can comment if it produces more rainbows than other ive seen or not, just to give you an indication. (if Ive seen it...)
 

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I'm not sure about differences from model to model but I just viewed the Infocus 7205 yesterday and saw about 15 rainbows in 2 minutes time. I had to stop watching.


I've seen older 2x business projectors and even a 4x HT1000 and I don't remember them being anywhere near that bad! If the IF is representative of the latest and greatest DLPs in terms of rainbows, it looks like either another LCD or LCOS will have to be in my future :(


And before someone asks, I was not "trying" to see them. No darting eyes or jerking head movements. It was on The Fifth Element at various chapters. Anytime a scene came on with dark and light areas and had movement... yikes!

-Matt
 

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Matt,


I have a 7200 IF and Screen Research screen and I and no one else has ever seen a rainbow.


Could the type of screen material actually cause a rainbow to form??????


I really don't know.


Larry
 

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don't forget that what you watch (movie) is just as important as anything. Honestly even though we talk about rainbows a lot and have a rudimentary idea of what causes them. I don't think anyone has come up with exactly why they happen, if we did I think we would know how to build projectors that downplay them (i.e. that is why projectors of the same generation have different rainbow results). On the other hand we know how DLP works, it is a spinning disk with many colours, and that white is done when all the colours are on and black when they are off, so a scene with something white zooming on a black background will be the worst while a static image would be the best
 

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Ok, sorry to say is that I have not seen the DWIN TV3. It features a good setup in terms of colorwheel speed so if you saw it on that one you should not buy a DLP projector unseen, my suggestion is that you try to check out more than that one.


Generally it seems like projectors that are very bright, like the Infocus projectors, are giving people more problems with RBE than projectors that are a little bit dimmer. Specified at 1200 ansi lumen its probably quite a brigh projector which could acount for it.
 

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Quote:
Originally posted by lkosova
Matt,


I have a 7200 IF and Screen Research screen and I and no one else has ever seen a rainbow.


Could the type of screen material actually cause a rainbow to form??????


I really don't know.


Larry
I use a Hi-Power with my current LCD so I can't imagine that being a problem... I think the 7205 was on a 92" white screen with a small bit of gain, maybe 1.5? I couldn't tell who made it though.


I don't mean to criticize others setups at all, I just think I might unfortunately be one of those people who sees rainbows :( It really bums me out because I definitely prefer the image they throw over LCDs...

-Matt
 

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Rainbows definitely vary (though I cannot explain why). I cannot even watch most Samsung DLP rear projection TVs. With those, I see intense rainbows almost constantly. On the other hand, I was at a friend's house and he showed me his Marantz 12s2 projector. Watching for 45 minutes, I saw no rainbows.


Then I bought an Optoma H77, thinking that if I saw no rainbows on the older technology (HD2 versus HD2+) Marantz, I would certainly see none on the newer Optoma. Wrong. I do see rainbows on the Optoma, but fortunately they are fairly low intensity and not too frequent. Just to complicate things further, I actually prefer my H77 to that Marantz (paying half the price helps too). The colors are nicer and contrast is better on the Optoma, so I am willing to suffer some minor rainbows to get the otherwise better picture.


About the only way to know what you will see is to audition each of the projectors.


Ira
 

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Rainbows are easier to see with brighter images. Many people never see them no matter what. But for those who are sensitive, a brighter image makes them more prevalent.


The Infocus 7205 is the brightest FP mentioned in this thread. At a given screen size, it will be much brighter than the other projectors mentioned, and therefore rainbows will be easier to see if you are sensitive to them. That doesn't mean the projector won't work for you. You can dim it down with a ND filter, or a low gain screen. If you see fewer rainbows with a different HD2+ such as the Marantz, reduce the 7205 image ft. lamberts to equal the dimmer image, you will probably see an equivalent number of rainbows.


A screen material can't cause rainbows, but a higher gain screen can make them more visible to those who are sensitive.


Pip
 

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Quote:
Originally posted by AnthonyP
Honestly even though we talk about rainbows a lot and have a rudimentary idea of what causes them. I don't think anyone has come up with exactly why they happen, if we did I think we would know how to build projectors that downplay them...
Let me know if I am wrong but I thought the cause was well understood. As the eye slews across a bright white part of an image, the RGB components of the bright spot fall on adjacent parts of the retina rather than overlaid, thus the colors where we expect white. The length of the trail depends on the slew rate of the eye. Those with more sensitive (to low exposure levels) and rapidly responsive (to quick changes in color) eyes can detect the colors that are only there for a small period of time, for one sector.
 

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Hai,


To make it more complex i have also found that we somehow adapt to the rainbox effect i could see them at the first but have to force myself now. This would be bulb related (less output after a while) but replacing the bulb didn't bring them back.


Over the years ive heared about more people who over the course of about 2 weeks stopped seeing them on their projectors. This makes rainbows a very weird and complex problem and means any buy of a dlp stays with a little risk :(


Daniel.
 

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DLPs are different regardless having the same specs, and it is true that people adapt (at least I do) to a particular machine. This weekend I played around with a 5x Domino20 and a 2x Infocus X1. I could see more rainbows with the former, but that is just because I am not familiarised with the Sim2. The first time I saw an X1, two years ago, I thought it was a rainbow-making machine. Simmilarly, I can hardly spot any rainbows in my own PJ, but I could not stop seeing them when I just bought it.
 

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Mark, I don't disagree, and that what makes it puzzling. Your explanation is the accepted fact, and why the faster the sped the less likely that you will be affected by them. On the other hand there is a lot of empirical evidence that shows that there is more to it. You can take two machines from two different manufacturers and same specs on the rest and one of the machines will create a pick that has more rainbows. If it was only what you said then the two machines should show the same rainbows. That is why I said rudimentary, obviously the sequential ness of colours is the primary factor and that the different colours hitting different parts of the retina is a major factor, but there is definitely more than that.
 

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Pip,


I use a Screen Research white .95 gain screen. I use the 7200 on the low bulb setting , usually, but play around with the gamma settings. Even at its brightess I do not see any rainbows. I am in a dedicated room also.


I find this thread interesting. Trust Me, I am not complaining that I do not see any rainbows....I just wonder why so many see them.


Larry
 

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I can see rainbows if I try. I only see them on dark sceens with a bright light. i just got a new Sim2 HT 300 E-Link and I have not yet sceen any rainbows. At the local HT store they have a HT 300 Link (non E modle Texas Inst Dark chip3) and I could not see any rainbows on it either. This was the major selling point and long with the black level and color with the Sim2 HT 300's
 

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AnthonyP -


I do agree on the different machines, but I know from my experience that brightness of the image and the ANSI CR (ambient light changes this) are major factors. My rainbow sightings increased when I changed from white wall to Hi-Power or when all lights are off.


I would think it's hard to get 2 different machines that have the same wheel speed, same sector arrangement on the wheel, same brightness, same ANSI CR, in the same room.


The RPTV DLP's are terrible for rainbows. They are simply too bright.


________________________


For those who have not seen rainbows, just look at the PJ lens from outside of the screen area, dart your eyes back and forth, you'll see them.
 
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