Automatic Iris LCD’S Achilles heel

Discussion in 'Projectors, Screens & Video Processors' started by foghorn, Oct 14, 2005.

  1. foghorn

    foghorn
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    By constantly striving to equal DLP contrast levels has LCD created their own “rainbow effect” with the automatic iris?

    Allow me to clarify, when I refer to rainbow I am more referring to the distraction caused by rainbows and how its appearance during viewing can remove you from the enjoyment of a what your are watching.

    Over the years LCD manufactures having almost successfully tackled screen door effect and vertical banding, have they now inadvertently created a method of distraction to rival the rainbow effect?

    Foghorn
     
  2. DEANO-B

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    :confused: :confused: What are you talking about :confused: :confused:
     
  3. gandley

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    I guess he means How the brightness goes up and down a bit when the iris is open and closing, it can be a bit annoying. Also the iris does not always get a scence to its correct darkness/brightness, more so if there are subtitles on the screen, seems to confuse the iris.

    This is the case with the sony LCD, more expensive models like the Ruby may work just fine. Have not seen a Z4 or AE900 in action yet but i would still prefere high contrast with no iris if the sony is anything to go by
     
  4. gingercat

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    Do you mean that you actually notice the image changing as the iris opens/closes? That could be a pain!
     
  5. foghorn

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    Deano-B

    Gandley has understood what i was saying, i am referring to the distraction caused by the iris opening and closing. I was not trying to suggest that the automatic iris caused rainbows. :thumbsup:

    Foghorn
     
  6. DEANO-B

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    I agree that the Sony HS50 iris is too strong, and have stated this before in this forum. When I demoed it I found the picture to be dull on certain scences and the overall picture seemed to be affected by the iris in a very negative way. Not all irises have this effect though as my AE700 (when its working :mad: ) has a 2000:1 contrast ratio and the iris doesn't overally dominate the picture quality, which gives in my opinion, a much more punchy and vived image. It is going to be interesting to see if the new LCD PJs have adopted Sony's marketing ploy of a good looking spec sheet, or if they have got around the 'dull image' problem!
     
  7. Audiofilenoob

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    You are having a laugh aren't you?

    The D5 panels still suffer from VB and again its a lottery if your machine has it or not and every 720p machine apart from the panny's have screen door problems on largish screens with a decent viewing distance.

    The iris I agree with. I've never seen Sanyo or Panasonics interpretation but Sony's is aweful. It cuts the lumens then compensates for the brightness by pushing the contrast way out and tweaking the gamma curve resulting in anything but realistic hue's, shading and tonality. Faces in a dark scene look completely unnatural and then when it flicks from dark to light, you get a moment where all the colours are messed up because the contrast and gamma are out of whack.

    Sure it may get you 4000:1 contrast but what's that worth if it doesn't look natural? Nothing IMO.
     
  8. PJTX100

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    Erm, no. From "decent" viewing distance SDE isn't an issue, from close-up it is. 1.5x screen width or more SDE usually isn't an issue.

    Early accounts of D5 panels are that SDE is reduced further...PJ
     
  9. Wilt

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    Sorry if this sounds thick. So if I decide to have a 2m wide screen i should be seated 3m away if I buy D5 panel? Or can get a little closer, say about 2.7m as the shape of my room permits.

    Thanks
     
  10. Audiofilenoob

    Audiofilenoob
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    Since decent is vague at best I should have been more specific. Depending on where folks are sitting in the room it could be anything from 1.2x - 2x the distance from a 110" screen.

    The HS50 was dissappointing here and took you right out of the experience. Only really when you sat in the seat at 2x did it dissappear.

    I expect the only time SDE will become completely moot is when the 1080p machines arrive.
     
  11. gandley

    gandley
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    a mini review on the avsforum has the new sony HS60 with worse SDE than the old HS50, which is a bit of a surprise.

    some of his words anyhow

    Last night I watched the HS60 in CKL's setup for more than 2 hours. Tried many familiar clips.

    Well, this time around I finally saw many minor flaws. Such as:

    - DTS sampler 9, Master and Commander clip, some minor VB and minor color uniformity (left reddish and right greenish) in the fog scene
    - seeing the DI goes brighter and dimmer in scene change
    - DVD subtitle confusing DI
    - 4:3 with left/right pillarbars confusing DI
    - not so great ANSI contrast in bright scene
    - screendoor annonying
    - vertical motion scan line effect
     
  12. ROne

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    I agree with the comments about auto Iris on here.

    I had a sneaking suspicion before I saw it - it doesn't make any sense for intra-frame contrast at all, and this has been re-enforced with the Z4.
     
  13. gandley

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    yet some review sites dont even mention any issues with the Z4`s auto iris.
    and i can only base my opinion on what i saw with the sony, but i am in no way surprised an auto iris has issues, its just a trick to push contrast numbers. Afterall 7000:1 does sound alot better than the panel on its own doing maybe 2000:1. I would be happy with a steped iris that can be set givin the type of source viewed but anytime you let a electronic component decide what should or should not be for a givin image i think you will get problems more so at the pricepoint of these LCDs. I guess when an iris moves as quick as our own we wont notice the brightness changes.

    But i for one could not live with it, too flippin distracting.
    (i was hoping these LCDs would carry me over till a decent 1080p unit nest year but after the sony demo i i thought this would be the case)

    I suppose not everybody will mind it though, much in the same way as RBE
     
  14. PJTX100

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    It's all personal preference, you may find it suits you no problem. It is a fact that the closer you get to screens (of whatever sort) the more artefacts you see. The 1.5x - 2.0x screen width "rule" seems to suit most people...PJ
     
  15. UrbanT

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    I would add for balance, that in 10 months of ownership, I have only ever noticed the auto iris on a very few occasions when watching a film. If you are flicking chapters through a film, its a different matter (I hope no-one is commenting that it was obvious when doing this, as its not relevant).

    I can't possibly see how someone can compare the rainbow effect to the Sony auto-iris in terms of distraction.
     
  16. gandley

    gandley
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    Perhaps we are just sensitive to different things. i see no RBE yet i can easily see the iris in action and i mean easily. it does my head in.( not in a headache eyestrain kinda way like rainbows)
     
  17. MikeK

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    I can't possibly see how someone can compare the rainbow effect to the Sony auto-iris in terms of distraction.


    Well people who can't see rainbows but who CAN see the iris in action, might well say the iris is more distracting.
    Really depends on your personal viewpoint and what you are sensistive to!
     
  18. UrbanT

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    I meant more in line with the physical effect. If you do suffer rainbows, you can be subject to headaches, and at worst nausea. Not something an auto-iris will do :)
     
  19. PJTX100

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    I'm disappointed everyone's focussing on the auto iris, when these machines are the first implementation of the new D5 panels. The pics of the Epson 600 made it look like D5's were going to be something special. The fact that everyone's focussing on technology that's already been implemented on the HS50 means that perhaps the D5's aren't a big leap after all...PJ
     
  20. inzaman

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    in relation to what UrbanT has stated above re chapter skipping, when you were trying some scenes were you chapter skipping or watching scenes spread over chapters.
     
  21. Jonny1973

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    But can't you turn off the dynamic iris if you don't like it???

    Show me a DLP that has the option to turn off rainbows.
     
  22. sainthalo

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    luckily i dont have rainbows but when i put the tv on today found this...

    [​IMG]

    I quite like it but if anyone has any ideas what the hell it is please let me know!
    :lease:
     
  23. clancol

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    correct me if im wrong but you can switch off the auto iris.

    If you don't like it then switch it off.
    you simply have a lcd projecter with a fixed contrast ratio or a higher contrast ratio that is adjustable via an iris but can be noticed when changing.
    it's your choice.
    you can't compare A-iris to rainbow,
    Wouldn't it be nice if we could switch of the rainbow effect.
     
  24. clancol

    clancol
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    think someone just said that didn't they.

    I should read the enitire thred before posting shouldn't I?
     
  25. Audiofilenoob

    Audiofilenoob
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    You can!

    Buy a 3 chipper :hiya:
     
  26. UrbanT

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    I wonder how many people who bought HS50's have sold them because they didn't like the auto-iris? I can't remember reading of anyone who has. The majority of demo's are held with poorly setup units, do not last long enough, and are from clips, rather than sitting and watching a film.

    Its sounds like I am simply defending my purchase. But I want to assure you, I am a fussy bugger. The Sony was my 4th projector in 5 months, and since owning it, have never felt the need to change it yet, 10 months on.

    But, anyone demoing this, would notivce the iris ALOT, when flicking around a film. Its interesting that in this whole thread, no-one has yet given any examples?
     
  27. DEANO-B

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    Agree with your point about the contrast ratio figures and think that Sonys poor effect with the HS50s auto iris was a marketing ploy/mistake. Although pepole here seem to be jumping the gun and I think need to wait for ALL the new high contrast ratio PJs to be seen, as who knows Hitatchi,Epson, or Panys PJs may work well.

    [/QUOTE]I suppose not everybody will mind it though, much in the same way as RBE[/QUOTE]

    People should'nt see this as a major disastor as RBE is. As you've put earlier the auto iris (AI) is 'a bit annoying' whereas with RBE your buying into a system that can make a picture unwatchable. Many people on these forums have bought DLP machines and not seen RBE when demoed in the shop only to find 1 week later that they start to see RBE, and others buy a DLP to find they have to return their machines due to friends/family seeing RBE.
     
  28. DEANO-B

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    Hiya Urban - I demoed the HS50 in a very good demo room with 2 friends for about 1 hour, messing with settings and watching film clips which usually lasted around 5 minutes. I found the picture to be very poor giving a dull look to most scences when there was some dark part in the image, and don't think you had to specifically pick any single example out of a film to notice it looked bad. We've stated this a million times on these forums though that setup is the key to any PJs PQ, and as you've stated people who buy the HS50 don't seem to complain or exchange them. Maybe it was a setting/screen problem! Its just a pity we all can't take our own setups with the best screen/settings etc. for our own indivual PJs and compare them to others.
     
  29. Demon

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    As mentioned, it is inevitable that using a slight 'smoke and mirrors' will have an effect..

    I can see it on the AE700, it is almost instantaneous, but the contrast jumps on some scenes, which is 'noticeable'... the Z4 is much slower in an attempt to not make it so obvious'.. but it seems they've boobed a bit on top of this by making its operation quite complex to suss out, since it depends on picture mode etc..

    Just watching a movie, and in some places you will see it effect.. I am in two minds as to whether this is acceptable or not...


    I am probably going to send mine back and look at the AE900 reviews, but none of the Z4 reviews mentions much about the auto-iris, so I am not sure if I can trust the reviews of the AE900... Thats why I love these forums, uber-techies who can weed out the wheat from the chaff, to them we owe a lot..
     
  30. gandley

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    Im not seeing it as a critical issue, its just somthing i dont like. And from what i have seen the benefit isnt that great either. Now cine2fine tech will be most interesting and hopefully the iris wont have to work as hard as the panel contrast should be higher in the first place.

    I still would like to see the Z4 in action for myself, but i doubt Rone was not seeing what he was seeing.

    Oh and didnt shinobiwan descibe his HS50 as a PoS (for the reasons being stated here), just thought i mention that for urbanT

    But also there is 65% of the market that do not see RBE. according to some sources RBE effected is a very low minority and judging by DLPs market dominance i guess it holds some truth. also the reverse can happen, you can see RBE then (for some unexplained reason) adjust and not see rainbows, which is what happened to me.
     

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