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End of the rainbow


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14 replies to this topic

#1 of 15 OFFLINE   SteveCoug

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Posted October 26 2004 - 02:15 PM

I have an InFocus 4805.

It's an excellent PJ for the money, very good picture quality for only $1500.

I love it.

There's just one problem ...

I am one of the people who sees "rainbows." My wife doesn't notice them (or at least she's never said anything and I'm not telling her!) and nobody else has ever said anything about it. I don't want to mention it because I think it's partly a mental thing. I didn't really notice them until I read about the "rainbow" problem on this forum and now I see them all the time.

I love the idea of a front projector because it gives you a true "movie theater" experience. Now that I have a taste, I'd like to eventually upgrade to get rid of the "rainbow" problem.

My question is, what do I need to get to avoid seeing rainbows in the future? I understand that the rainbows are caused by the color wheel, is that correct?

I have looked at the InFocus 7205, but that still uses a color wheel. Do I need to go to a three lens (RGB)projector (if there is such a thing) to avoid the rainbows?

BTW, I still highly recommend the 4805 for anybody who wants to get into FP without spending a lot of money. Excellent projector! But some of us notice the rainbow effect. However, I have no plans to get rid of the projector .. I will keep watching movies and football on it until I can afford to upgrade. I'm just plannig for the future and need to know what I should be looking for.

Thanks!

#2 of 15 OFFLINE   Stephane

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Posted October 26 2004 - 03:54 PM

Steve. I have some very good news for you. First of all your problem is exactly the same as mine. Now that is not the good news.

Here is what you see. The color wheel is your problem true. Now many companies have been trying different things to try and get rid of the rainbow effect. All projectors started of will at least 5 color segments in their color wheel. Now these colors were ( 2 red, 2 blue and at least 1 very large green). And as time evolved in the projector world we have seen compaines try many different things. The first was to try and make the color segments smaller and have more of them.

What I mean by this is that the color wheel is broken into 3 primary colors red green and blue. Some have split this into 6 segments, 2 red 2 green 2 blue. Some companies have even added a white or transparent segmant to get ride of this effect.

Now some companies have tried to have variable speeds to control this problem. But I still see the rainbows on very expensive projectors. IE I look a Runco VX 5000 and no matter what I did to adjust the speed of the color wheel I still saw the rainbows. I do not know how much the Runco VX 5000 is worth in the states and I am not calling it a bad projector, but it does not negate the fact that I still saw color wheels.

Now for the good news. I am not sure if you have been following the technologies offered to the public this year. I am happy to tell you that there is a RP DLP that now uses a true 5 color segment color wheel. Now I know that this is not yet in the front projectors but if you do not plan to buy a new FP this year, who knows you may just have the option of buying that FP next year and have almost ZERO problems with the color wheel. Can you believe that Samsung is the one and only out with this technology this year. I am very impressed.

The new color wheel has a red , green , blue , cyan and a dark green to it. This is the first DLP that I am able to watch without getting a head ache. And for me to say this is A LOT...

Stephane Sauve

#3 of 15 OFFLINE   SteveCoug

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Posted October 26 2004 - 07:40 PM

Stephane,

Thanks for the info! That is encouraging. Do you have a link to that Samsung projector so I can see what you are talking about?

BTW, I just found a Flash animation on the web that illustrates the dreaded "rainbow" effect on DLP projectors that some of us experience.

Take a look:

http://www.placeyour....P_Rainbow.html

Notice the word "Rainbow" on the top has a red-green-blue halo as it moves across the black background. This is what those of us who notice the rainbow effect often see on DLP projectors.

The word "Rainbow" on the bottom is what people see if they do NOT see the rainbow effect.

This is exactly my experience with my 4805 DLP projector .. the rainbow effect typically appears when there is a high contrast between a white and black area moving across the screen. It is more noticeable in some movies than in others and is much worse in dark scenes than in bright daylight scenes.

But the main thing I wanted to do is to demonstrate the effect to people who have never see "rainbows" before so that you can finally understand what we are talking about. As you can tell, it can be pretty annoying.

#4 of 15 OFFLINE   Scott L

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Posted October 26 2004 - 09:35 PM

I see it, it's an annoyance but it doesn't totally run my viewing experience. Any time there's a big shiny sword in a dark area I know it's coming though. Posted Image

You could always go LCD, which have no rainbows at all. They're getting better all the time, but this new Samsung tech sounds interesting.

#5 of 15 OFFLINE   cabreau

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Posted October 27 2004 - 01:17 AM

Steve,
I have some even better news for you. The rainbows will go away. Most people who see them (I am one of them) don't give it enough time for their eyes to adjust to watching the screen. I have a BenQ PB6200, which only has a 3x color wheel, while yours has a 4x (harder to see rainbows on yours). I saw rainbows all the time in dark movies, like Matrix Reloaded, Underworld, etc. NOW, I just don't see the rainbows anymore...and I'm really not looking. If you give it some time, and just let your eyes adjust to watching movies on that projector, I'm very confident you'll stop seeing them.

And yes, there are still CRT "gun" projectors that you can buy, but they are usually over $15k, they are dim, so you need complete light control. The good side to these, is that usually, the max resolution is above and beyond 1080i, so they deliver the best picture you will get.

For LCD projectors, Panasonic should have the AE 700 on shelves within the month. This is a 1280x720 projector for TRUE HD. It alst has 2000:1 contrast ratio, which puts it in the league of DLPs. Sony has a new LCD projector that does 6000:1 contrast ratio at 1280x720! The price is just under $3500 for that one. There are some others too, Infocus has the SP5000, which is LCD and does 1280x720. So not only will you NOT see rainbows, but HD on these will blow away HD on your 4805 because they have over twice as many pixels! There's the Sanyo PLV-Z3 which is another good performer. My choice, right now, for the price, is the AE700 by Panasonic. Though, the Infocus SP5000 has a Faroudja DCDi chip in it that works on the component interface.
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#6 of 15 OFFLINE   Leo Kerr

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Posted October 27 2004 - 03:03 AM

Unfortunately, if you want to stay with DLP, rainbows will probably remain visible to some people, even with those interesting sounding odd-color wheels.

The way around it, of course, is to use three imaging chips - three LCD panels, 3 DLP panels, 3 D-ILA panels, or 3 CRTs.

3 LCD projectors are cheap. They also have the liabilities of LCDs.

Single DLP projectors are also cheap to expensive, and have varying degrees of rainbows.

3-DLP projectors are uniformly expensive - or perhaps, another way to put it, expensive to obscenely expensive.

3-chip D-ILA projectors... are also expensive. And expensive to operate (lamp costs.) And it's probably the only thing to seriously compete with 3-chip DLP in terms of picture quality.

Leo Kerr

#7 of 15 OFFLINE   tom j r

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Posted October 27 2004 - 04:55 AM

SteveCoug,
Have you calculated the brightness of your screen/pj setup? If it is overly bright (20+ ft-lamberts) then you are more likely to see the rainbows. The brightness is a function of lumen output, 600 (assume you are on low power due to the extremely loud fan on hi), screen gain and screen size. For example, I am displaying a 92" diagonal image on a 1.1 gain screen which comes out to 26.2 ft-lamberts. I then cut it in half with a Hoya HMC ND-2 filter. Once the lamp dims to a certain level I will take the filter off and continue to use the pj as it dims further.
I have heard what Cabreau states that over time your brain will adjust to filter out the rainbows. May be hard getting to that point (thinking of massive headaches)...
Interestingly enough, when I first saw some pj's at Ultimate Electronics, I noticed rainbows right off but didn't know that's what they were. This was with +6K machines, Sharp if I remember right! So far haven't seen a single one on my 4805 at home.
Another thought, if you are displaying a massive image and sitting too close, that could contribute as well. If you find yourself contstantly moving your eyes back and forth watching the action you may need to either move back further or display a smaller image.
Hope you find a way for it to work for you! The 4805 is a fantastic pj for the money!

#8 of 15 OFFLINE   Leo Kerr

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Posted October 27 2004 - 06:34 AM

At work we're running a couple of programs on Christie DS-30s - 4 color wheels (RGB-White). In addition to what Tom says about brightness affecting rainbows, so does the source material. Black and white programming seems worse than color, for example (sometimes even when it's still.) Fast motion doesn't help, either.

Leo Kerr

#9 of 15 OFFLINE   SteveCoug

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Posted October 27 2004 - 10:03 AM

cabreau,

Thanks for the input.

Again, that sounds very encouraging. It sounds like
I just have to wait until next year to get a real good quality upgrade. I have always heard that LCD projectors were not as good as DLP (although I am not sure why) but it sounds like LCD is gaining on DLP in terms of picture quality. That sounds like the way to go to escape the dreaded color wheel problem.

As you mentioned, it's also possible that I may "get over it." I watched a few video scenes on my 4805 last night to see how bad the "rainbows" were and I didn't notice any! I watched scenes from an old 1970's movie "Little Big Man" and a new movie "Pirates of the Caribbean" both are bright, colorful movies with very good video transfers.

But just a few days ago, I watched "Network" which is an old 1976 movie that is very dark (figuratively and literally) with a fairly poor quality, grainy video transfer. I saw LOTS of rainbows in that movie!

So it seems to depend on not only the darkness of the movie, but also the quality of the transfer. Rainbows seem to be worse on low quality video transfers, especially if there are lots of dark scenes.

I also agree that rainbows may go away with time. Since I tend to be obsessed with them lately, I have been looking for them. But if I try to relax my eyes and just watch the movie, they don't seem as obvious.

Also, I'm sitting a little too close to the screen. I have a 92" diag screen and I am sitting only 13 feet away. I would like to be farther away, but the way my room is configured, that's as far back as I can move the couch. I have zoomed in the picture so that there is a aobut 2" of white space visible around the edge of the video images on the screen in an effort to make the picture a little smaller and reduce visible pixels.

One important piece of advice for people buying a PJ is make sure you have enough room to sit at least 2X the screen width away for best picture quality. In my case, with a 92" screen, I should be at least 15 feet away from the screen for optimum picture quality. Any closer than that and you start to see the pixels in the screen, especially on white areas and text.

#10 of 15 OFFLINE   Stephane

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Posted October 28 2004 - 02:11 AM

Good Morning Steve.

Stephane again. I would not be so quick to judge the LCD front prjectors. Wit the proper screen, they look amising. I own an LCD front projector because of the obvious reason of rainbows. I bout a Sony VPL 10 HT a few years back. I also bought at the time a Steward grey hawk screen. Graw hawk screen was the best available to me at the time. What is does since the screen material is light grey s to boost my dark greys more towards black. Now I admit that it is not black. But it beats the hell out of watching a movie with rainbows.

These days the Sony projectors are very good. you do have to spend a little more on a good screen to enhance it but it is well worth it. I am going to wait another few years before I even think of an upgrade to my system. With the advent of this new DPL 5 segment color wheel I want to see how this pans out.

Stephane

#11 of 15 OFFLINE   SteveCoug

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Posted October 28 2004 - 09:48 AM

I've been reading up on the new Panasonic AE700U and it sure looks good based on the reviews I have seen so far.

In fact, I have decided to buy one!

Anybody want to buy my 4805 for $1,200?

I just posted a thread in the hardware for sale forum:

http://www.hometheat....hreadid=215478

The 4805 is really an excellent projector for the price. And I would keep it if I wasn't one of the unlucky few who experience "rainbows."

But with the Pansonic AE700U avialable for about $2200, I can upgrade to a higher resolution AND get LCD technology to avoid the rainbows. So I'm gonna bite the bullet and do it.

#12 of 15 OFFLINE   Stephane

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Posted October 29 2004 - 01:35 AM

Congrats Steve, very nice choice. You now travel on the path to the dark side LMAO. I hope that you enjoy your movies without the rainbow effects. Do not forget that it may take you a little while to adjust to the color difference on the screen and the lack of black levels.

If you want to improve your grey scall and get darker grays ( closer to black), I would suggest that you look into Stewart screen FIRE HAWK. This screen came out after I had bought my Gray hawk.

I know, the screen is not cheap, but it makes on hell of a difference if you are running LCD technology.

Maybe that could be your next upgrade.

Regards

Stephane

#13 of 15 OFFLINE   SteveCoug

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Posted October 29 2004 - 07:33 AM

Stephane,

If you check the specs on the Pansonic AE700U it is about the same as the 4805, which is why I decided to make the move. Contrast ratio is the same, color is supposed to be excellent and I think blacks should be fine. From what I have read, the Pansonic AE700U is a MAJOR step forward for LCD projectors compared to previous models -- they are finally catching up to DLP quality picture, which is great news for those of us who suffer from "rainbows."

I will post my experiences with the Pansonic AE700U as soon as I get it set up, which should be some time next week.

#14 of 15 OFFLINE   SteveCoug

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Posted November 05 2004 - 09:17 AM

Folllow up ...

I got my AE700 yesterday.

It's a great projector, much easier on my eyes due to lack of "rainbow effect." I used to get sore eyes, dizzy and/or headaches from watching the 4805.

I will say that the colors seemed a bit brigher on the 4805 compared to the AE700, but they are both great projectors.

If you are NOT sensitve to "rainbows" the 4805 is the best PJ on the market for the money. Amazing quality for only $1500.

But if you are like me and see rainbows, the AE700 is an excellent option. It costs a bit more, about $2200, but well worth it for me.

#15 of 15 OFFLINE   Fernando Saa

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Posted November 05 2004 - 11:06 AM

Hi, I'm about to purchase my first projector and I was wandering, SteveCoug, are you saying that the colors look better on the 4805?, are you using the same screen?, how are the blacks?, and resolution wise do you notice any difference? thanks a lot.
Fer