Is this the "rainbow effect?"

Discussion in 'Displays' started by jim.vaccaro, Jul 12, 2005.

  1. jim.vaccaro

    jim.vaccaro Second Unit

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    Today when someone was giving a presentation, I could see the lens of the projector out the corner of my eye (it was rear projecting onto a screen), and I could see a distinctive color band of red, green, and blue emanating from the lens. When I looked directly at the lens though, it disappeared....but when I blinked or viewed the lens through peripheral vision, I could see it again.

    Is this the "rainbow effect" that everyone talks about? Because if it is, so much for my future plans to by a 4805...
     
  2. Michael TLV

    Michael TLV THX Video Instructor/Calibrator

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    Greetings

    Yes that is the rainbow effect ... but I prefer to watch the program on the screen and not the projector.

    Doctor, doctor, it hurts when I hit myself like this ...

    Each technology has its issues. Rainbows for DLP and vertical banding and discoloration issues for LCD. I personally find vertical banding on LCD to be even more bothersome than a DLP with a fast color wheel.

    Regards
     
  3. jim.vaccaro

    jim.vaccaro Second Unit

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    Um, obviously. Haha.

    The reason I ask the question (thank you for responding by the way) is because I understand the rainbow effect can also be seen on the screen itself. I just wanted to verify that was what I was seeing and not something else.

    Other than bulk and weight, CRTs are still the best thing out there IMO, but CRT projectors are not an option for me.
     
  4. Leo Kerr

    Leo Kerr Screenwriter

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    Yes, the dreaded rainbows. It's easier to see it in the lens than the screen. It's easier to see out of the corner of your eye than when you're staring at it - or especially when you blink.

    Different projectors have varying degrees of it, depending on the filter-wheel combinations, combined with the wheel speed.

    We've got, (for example,) a Christie DS+60 that looks very nice. The DS+25 also looks nice, but the DS-30 and DS-30W are horrid for RBE.

    My preference, though, was the X5 or S6...

    Leo
     
  5. Paul D G

    Paul D G Screenwriter

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    If you can see it when looking at the lens, would that mean you could see it when watching the screen? Seeing as the lens is the source, I would think it would be very easy to see as opposed to the projected image.

    If you flick your eyes across the screen rapidly you should be able to see them. However, if you don't that doesnt necessarily mean you won't see them at all. It took about 90m of watching a movie on my DLP before I started noticing them and it just got worse after that.

    -paul
     
  6. Alf S

    Alf S Cinematographer

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  7. Ron Boster

    Ron Boster Screenwriter

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    What particular scenes in movies tend to show the rainbow effect. I'm on my second LCD projector...I didn't go the DLP route for fear of someone in my family being suspectable to rainbows and then not being able to enjoy the HT room. I may take some discs to local dealer and check out with an extended demo. Buying local should allow for some benefits [​IMG]

    thanks
    Ron
     
  8. Gavin_mi

    Gavin_mi Stunt Coordinator

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    i have a mits WB-62327 DLP TV and i have never seen a rainbow, but i will ask the question above again....can anyone name a movie/scene that display the rainbows?

    Gavin
     
  9. Paul D G

    Paul D G Screenwriter

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    I can't say any particular movie or scene itself would best represent the effect. It's just... there. However, I did notice it less during certain TV programs. Specifically Third Watch reruns on A&E which I am currently addicted to.

    But if you were twisting my arm to say something I'd would suggest testing out something with a sharp image and a lot of action (like a battle scene), or something with sharply contrasting objects - black vs white. Like a space sequence.

    BTW - after telling my brother about my RBE troubles he started shying away from DLPs in his search. The link above nicely demonstrates what I saw. Now I can ask my wife if she could put up with that for a two hour movie. [​IMG]

    -paul
     
  10. Gavin_mi

    Gavin_mi Stunt Coordinator

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    not sure what projector you saw this on, or if projectors are more susceptible but I have never seen this on my DLP 62 inch TV. however my TV has the TI DLP2 chip in it which I hear is like 500 times better/faster than the original DLP chip. If you are worried about RBE, then just get a quality DLP setup [​IMG]
     
  11. aaron campbell

    aaron campbell Second Unit

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    I didn't see rainbows at the stores when shopping for my Samsung 61". But after I got it home, I see them all the time, if I look down away from the screen real fast. I don't see them when watching the tv, just when turning my head away from the screen.
     
  12. Gavin_mi

    Gavin_mi Stunt Coordinator

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    well after reading this thread I tried everything I could think of, blinking quickly, looking around, looking at it at an angle on all kinds of different material.....still havnt seen any rainbows and ive had the TV for almost 2 months now.

    Gavin
     
  13. jim.vaccaro

    jim.vaccaro Second Unit

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    That's good to know, Gavin. What type of TV is it? I'm considering LCOS as an option right now.
     
  14. Gavin_mi

    Gavin_mi Stunt Coordinator

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    its a Mits WD-62327

    however no TV is perfect. some complains I have about the TV include: that it does not accept 720p inputs, which is retarded because that is its natural resolution....go figure....therefore EVERYTHING that comes into the TV is either upconverted or downconverted (if using 1080i) also the power cord is like freaking 5 foot long so you either have to use an extension cord or get lucky and have an outlet where you want the TV. I also wish the TV had HDMI input...other than that I couldnt be happier.

    I didnt want you thinking that this TV was some kind of gift from the A/V gods and was flawless.

    GL in finding something that makes you happy, thats what its really all about.

    Gavin
     
  15. jim.vaccaro

    jim.vaccaro Second Unit

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    Despite the other shortcomings, no HDMI definitely makes that a deal breaker for me.

    Still haven't seen much that competes with JVCs LCOS (DILA) TVs yet.
     

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