Panasonic TH-L42E3Z luminance/instability breathing at low light levels

Forums › Home Theatre (including HTPC and EPG Collector) › Panasonic TH-L42E3Z luminance/instability breathing at low light levels - any ideas?

ageorge

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#93084 14-Nov-2011 08:13

Brand new product which shows fantastic picture when luminance levels mid to high, but watching Harry Potter which has lots of dark scenes its awful because in these scenes its constantly changing its brightness level, almost like breathing eg one part you can see the dark scene next part its hardly visible.
Eco mode is off, brightness is 55, backlight is 50, contrast 65 (none of these settings alter the problem) latest firmware, tried reset to factory (am ex TV serviceman)
Pause the video and operate menu button/picture, then the dark picture shows how it should be until menu is closed and source is running, then the brightness falls off again.
EG you can adjust the picture controls in that mode and its fine until you exit the menu!
I am suspecting a logic is looking at the overall luminance and when menu is onscreen its not clamping the picture down. EG like a dynamic filter effect.
Have tried the same program source on DVD and USB source and its the same.
Have tried the same program source on my PC and brightness is stable.

Here is the scenes (MKV) I am talking about there is a brief start piece which is low light, then it gets quite dark and thats where it starts hunting the luminance levels:
http://dl.dropbox.com/u/1541849/downloads/Hp7darksceneNew.mkv

Last night I was watching a freeview movie and the effect was the same its really disconcerting, and I hope not a bug in the model firmware.
Any ideas please? Hopefully its specifically this set. Have put a service request in with Panasonic. Will advise how it turns out. If its sorted, I will highly recommend this model as it really is impressive apart from that trait. What Im hoping is its not part of a spec boosting exercise they are using to get maximum contrast ratio, at the cost of picture quality.
Thanks,
Alistair.

gcorgnet

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#544951 14-Nov-2011 08:29

I know some TVs have some auto brightness "feature" which tries to adapt the brightness to what you are watching.

I tried this "feature" on my Samsung LED for whole of 12 seconds until I realised that the whole concept was flawed!

Have a dig around the menus to try and see if you can spot something like this...

Guillaume

ageorge

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#544966 14-Nov-2011 09:04

gcorgnet: I know some TVs have some auto brightness "feature" which tries to adapt the brightness to what you are watching.

I tried this "feature" on my Samsung LED for whole of 12 seconds until I realised that the whole concept was flawed!

Have a dig around the menus to try and see if you can spot something like this...

Guillaume

Cheers friend, I did this and as a consequence pretty sure I have already disabled any 'enhancement' settings.

My first suspicion was the Eco mode, which alters overall power according to the ambient light, but that made no difference; theres also enhancement setting and noise settings which have been disabled in this case.
Al.

richms

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#545287 14-Nov-2011 17:45

Have seen this on many TV's. Stuff like that is really common to get higher dynamic contrast scores which the sheeple buying TVs lap up almost as well as PMPO power levels and stupid wattages on vacuum cleaners.

Let us know how they respond because I had the same problem on a TV I tried a while ago as a secondary monitor. As soon as the playback controls appears the pictures contrast changed drastically, and it didnt have to be very dark to get affected.

Richard rich.ms

ageorge

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#545292 14-Nov-2011 18:01

richms: Have seen this on many TV's. Stuff like that is really common to get higher dynamic contrast scores which the sheeple buying TVs lap up almost as well as PMPO power levels and stupid wattages on vacuum cleaners.

Let us know how they respond because I had the same problem on a TV I tried a while ago as a secondary monitor. As soon as the playback controls appears the pictures contrast changed drastically, and it didnt have to be very dark to get affected.

I'm sure Panasonic will do the best they can; their response so far has been good, now I just need to see some action.

What happened with the TV you brought? You dont have to accept sub-standard, consumer act is quite clear:
Acceptable qualityThis means goods:

Do what they are made to do.
Are acceptable in appearance and finish.
Are free from minor defects.
Are safe and durable.

Its unfortunate that so many folks will put up with a sub-standard because they cant be bothered. Its only by feedback from clients, that companies can improve their product. I am a manufacturer, and we have had to go into damage control mode before, but at the end of the day, its to the customers benefit and in the long term, the manufacturer too - nothing worse than getting bad feedback.

richms

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#545313 14-Nov-2011 19:04

I was borrowing it while a friends house was being renovated for a few months. It was a 768px high panel so nothing looked good on it anyway. Never bothered to look into it furthur.

It amazes me that TV's have such a hard time doing what monitors have done forever, which is just display what they are given without butchering it.

Richard rich.ms

ageorge

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#560873 23-Dec-2011 08:42

I have taken the Panasonic TH-L42E3Z back as its luminance problem was repeatable and consistent throughout all this model. Running more tests I also found that its chroma was not consistent as well. Full marks to Panasonic for providing a refund.

I consider these faults to be minor defects, as the model is perceived to be a higher quality LED TV. However, they have known the faults exist for over a month, and continues to be sold as is.
There is a picture setting which overcomes the majority of the luma problem, but still leaves poor chroma eg inaccurate skin tones and green and red enhanced colours.
They assure me that their higher end sets do not display these faults.
Regards,
Alistair.