Automatic Iris LCD’S Achilles heel

[foghorn]

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

[DEANO-B]

What are you talking about

[gandley]

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

[gingercat]

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

[foghorn]

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.

Foghorn

[DEANO-B]

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 ) 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!

[Audiofilenoob]

Originally Posted by foghorn

our 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

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.

[PJTX100]

Originally Posted by Audiofilenoob

...and every 720p machine apart from the panny's have screen door problems on largish screens with a decent viewing distance.

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

[Wilt]

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.

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

[Audiofilenoob]

Originally Posted by PJTX100

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

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.

[gandley]

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

[ROne]

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.

[gandley]

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

[PJTX100]

Originally Posted by Wilt

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

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

[UrbanT]

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.