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Optoma H78 - rainbowing

Discussion in 'Projectors, Screens & Video Processors' started by chriswhiteuk, Jun 14, 2005.

  1. chriswhiteuk

    chriswhiteuk
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    Hi guys

    I've just changed from an AE700 to Optoma H78.

    However, rainbowing is an issue !!

    Do DLP projectors need time to settle down or is it personal visual performance ?

    The PQ is amazing - but I would hope so for the amount I forked out (I chose this over the H58 to make sure to eliminate problems, oh well).

    The shop I bought it from has told me to bring it back to compare to their demo projector (which I demoed for an hour), but alas they are unsure on giving a refund - is there any argument on my side ?

    Cheers for any replies.

    Chris
     
  2. Gary Lightfoot

    Gary Lightfoot
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    I have often heard of people getting used to the rainbows to such a degree that they don't see them anymore, so that might happen to you. It is a personal thing though so there's no guarentee unfortunatley.

    Sometimes having a brighter more contrasty image will make rainbows more obvious, so is it possible that your image is smaller than the one you demo'd? It would then be brighter and make the rainbows more obvious to you.

    I don't know how you stand with a refund for rainbows, as there's not actualy anything wrong with the product itself. I wonder what the retailers on the forum would do or suggest?

    Gary.
     
  3. chriswhiteuk

    chriswhiteuk
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    Yes, I have read that it can be caused by brightness of the bulb.

    I'm using a 69" image, so it will be bright.

    I'll take it back and compare - then I'll try the sympathy act.

    In the meantime, Sevenoaks said it was ok to put hours on the bulb.

    Else, alas, it'll be on Ebay and I'll get the pj I probably should of got - the Sony HS50 (although there is no where I can demo it).

    Chris
     
  4. Paul D

    Paul D
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    Hi Chris
    The "rainbow" effect will be more prominent with a new bulb.

    As the bulb settles in, and becomes less bright. The rainbow effect should become less obvious.

    You may also be noticing the effect more because you are scrutinising your "new" image.

    I rarely see the effect on my S3 DLP.
    In fact it took white on black text for it to appear etc.

    However that changed the other week, when "EdgyBoy" brought a H78 round for a demo.
    I suddenly started seeing rainbows on both machines!
    I think the reason, was the fact that we were "scanning" the picture checking for artifacts.

    It took a couple of days before i stopped looking for the rainbow effect.

    Give it a couple of weeks and see how you go. :)
     
  5. TopMeTom

    TopMeTom
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    I used to see rainbows bad,even suffered severe headaches.But then after time with my 200dm I got used to it,no more headaches,and I never notice them.

    good luck,

    Phil
     
  6. Gary Lightfoot

    Gary Lightfoot
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    Chris,

    Have you got something like an ND2 filter or similar (speaker grill cloth??) you could place in front of the lens? If you could dim the image brightness by half, that would give you an idea of how things might look as the lamp dims. It won't take into account you geting used to the effect (or not) over time though.

    Gary.
     
  7. TopMeTom

    TopMeTom
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    swap my sim2 with you if you like :D :smashin:
     
  8. chriswhiteuk

    chriswhiteuk
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    Swap with Sim 2 . . . tempting ! Why's that then ? hehe.

    I've ordered a circular polarising filter to try - had one on my AE500 with good effect.

    The PJ is awesome, even with rainbows - clear, sharp and possibly too bright, so the filter will help here as well.

    I'll keep you posted !

    Chris

    PS. DVD player is louder than PJ, hehe !
     
  9. ian_guinan

    ian_guinan
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    I find with the dlp projectors I've owned the rainbows are always worse when I first get them as I'm not content to sit still and relax and just watch the movie. I'm usually getting up, fiddling with the focus and settings etc. and darting my eyes over the screen getting it all set up.

    Once I'm happy and start relaxing I'm moving my eyes around less and can only bring on rainbows by darting my eyes around the screen. I'm so sensistive to rainbows I even see them on CRT setups!!

    My H77 (soon to be H78 if Optoma get their finger out) is easily the best dlp I've had so far....and I just love being able to hear ALL of my 5.1.

    Ian Guinan
     
  10. chriswhiteuk

    chriswhiteuk
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    the biggest luxury, is being able to have a bit more ambient light (ie. not pitch black) to enjoy a film !

    I've only had it since 4pm !

    Chris
     
  11. venezolano

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    You should update your signature. Congrats for the new pj ;)

    Cheers

    Juan
     
  12. cyberheater

    cyberheater
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    Your brain will unlearn how to see em.

    My wife and I both saw rainbows on our DLP machine. After a couple of weeks we were struggling to see them.

    Just make sure it's well calibrated.
     
  13. psflynn

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    Hi,

    im in a similar situation with my new 4805, didnt see rainbows in demos - but as soon at home in a pitch black room - i see lots!

    I think too much scrutiny and not relaxing is a big issue - i also found having some ambient light seems to help - based on the advice in here hopefully when i chill and after a few weeks they will be minimised.

    Chris,

    where did you buy your filter from?

    Paul
     
  14. Bristol Pete

    Bristol Pete
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    Go HDMI and the rainbows may go away...
     
  15. psflynn

    psflynn
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    interesting - is that from your personal experience? and with what PJ/DVD combination?
     
  16. Bristol Pete

    Bristol Pete
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    SIM2 30H - Pioneer 868 all via HDMI - zero rainbows. None, nada, zilch....:)
     
  17. jmbrailsford

    jmbrailsford
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    I see the occasional rainbow, but luckily I seem to have gotten used to it and it doesn't bother me.

    Glad really as I feel the DLP picture is better for me than LCD so delighted that I am the only one out of 5 people that watch the projector that suffer slightly from the rainbow effect.

    :smashin:
     
  18. Grumble

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    I have a new H78, and have not seen any rainbows.
    Maybe I'm just to much in awe at the big screen, DRH 203x114, to notice them. :cool:
    I use a PC running MCE2005 and connected via the DVI output of the graphics card.
    I've not found it necessary have the bulb on full power, as I have a good blackout blind.

    Cheers
    Graham
     
  19. chriswhiteuk

    chriswhiteuk
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    I'm getting used to it - when I get the install finalised (ceiling mounting) I'll be able to relax and enjoy a bit more.

    I'm getting the filter from EBay, as Jessops didn't have any in stock.

    Chris
     
  20. Nick_UK

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    That could be the answer - don't view in a pitch black room - try a little dim lighting behind the screen.
     
  21. Penfold73

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    Personally I think the odd rainbow is not a problem, especially as the picture from DLPs is so much better than LCDs (IMHO), but if you are getting eye strain and headaches that's another matter entirely. In that case I wouldn't hesitate to go LCD or LCOS (I had to pay a hefty re-stocking fee on an X1 to get a Z2, because the X1 was giving me serious headaches).
     
  22. chriswhiteuk

    chriswhiteuk
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    I've been watching and watching, and the long term outlook for me and this pj relationship is not looking good.

    I can see lots of rainbows at the moment, I must be one of the more sensitive people to this :(

    It's a real kick in the butt, as the picture is so sharp and awesome, but I find my eyes hurting - could the Sony HS50 compare ?

    Chris
     
  23. LV426

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    I sympathise. If you are one of the "unfortunate" few - then regretfully, I suspect you have made an easy mistake with your choice.

    Based solely on reviews (not personal experience) I gather the HS50 comes as close as currently available to DLP performance, without the flicker.

    Unless you want to spring 20k on a 3-chip DLP, or wait and spend 10k (?) on a Sony Qualia.
     
  24. Geordie Bry

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    chris i have a screenplay 7205 3 weeks old at first myself and the wife were seeing rainbows i fitted nd filter to achieve correct foot lamberts and wow no more rainbows
     
  25. chriswhiteuk

    chriswhiteuk
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    Hi there

    Which ND filter did you get, as they come in different stengths.

    Thanks

    Chris
     
  26. LV426

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    If you need to reduce brightness (which is all an ND filter will do) then, actually a better way to do it is to use a grey screen*. I'm unconvinced that reducing brightness solves it - but it may, so stay open minded.

    But, before you go to any expense at all - try watching wearing sunglasses. This will have virtually the same effect as an ND filter (of a given intensity). This may give you an indication of how effective reducing the brightnress is going to be.

    (*) A grey screen is more effective at maintaining or improving contrast in less than perfect ambient conditions, because, as well as reducing overall brightness of the projected image, it also reduces brightness from extraneous light in your room - reflections and/or less than perfect blackout. An ND filter only reduces brightness of the projected image, and any stray light thus becomes more visible.
     
  27. chriswhiteuk

    chriswhiteuk
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    Just recieved and tried a circular poleriser - no joy, I can still see rainbows.

    I wouldn't be upset if the rainbows were associated with bright objects moving, but I can see them most of the time - it must be how my eyes move (I have good eyesight).

    I've listed it on EBay, see how I fare.

    I can't return it, as the pj is fine, just me making a bad selection.

    Chris
     
  28. Gary Lightfoot

    Gary Lightfoot
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    The H78 has an 8 segment 5 speed colour wheel so I doubt the Benq will be any better for him. :(

    Gary.
     
  29. chriswhiteuk

    chriswhiteuk
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    sooo . . . Sony HS50 or Yamaha DPX510 ?

    is there much in it (apart from price) ?

    Not much on the internet about it !

    Chris
     

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