new tv - picture slightly dark at the corners

JohnB47

I've just bought a Panasonic Viera TX-32AS600 tv. I'm pretty happy with it but I've noticed that the corners are slightly darker than on the rest of the screen. Its called vignetting, I believe. The sort of thing you see on old photographs taken using early cameras with poor optics.

This is my first experience with led tv's - I've been using a crt one for many years now.

So, for those of you who have an led tv, is this normal and just something I need to accept, or is it maybe a fault?

wongataa

A LED TV is a TV with a LCD panel and a LED backlight instead of the CCFL backlights in older LCD sets.

The corners can often be darker than the middle as the light from the backlight is not always properly spread evenly across the whole screen. Some sets are worse than others and you can't really be sure how good an individual set is until you use it.

You could try and exchange it but you would not be guaranteed that the replacement is any better I'm afraid.

Syman

I have not noticed this on my LED tv. (LG 575LN i think?)

JohnB47

Thanks guys.

Hmmm. So, I've just spent £400 on a new telly and its touch and go if the corners are slightly dark. Yes, I've bought from a good retailer and returning it will be relatively simple but I can't be cycling through their whole stock to find one that doesn't have this effect.

The store does employ manufacturer experts on the sales floor, so perhaps I'll speak to one of them about this. It's certainly not something I expected, that's for sure.

InsideInsurance

Unfortunately no technology is perfect otherwise there would be only one technology.

LED can suffer from dark corners and clouding - look at a solid coloured screen and you will see that its not 100% perfect image and indeed would look like there are clouds/ areas of slightly lighter and darker areas. In normal TV/Film viewing this doesnt make much impact as rarely is the whole screen a uniform colour.

LCD, its predecessor, is basically the same screen but had a different lighting arrangement which consumed more power, was more bulky and often meant the edges were lighter/ brighter than the centre of the screen.

Plasma, is basically a dead technology so no point discussing its issues anymore

OLED is pegged as the future, doesnt suffer the lighting issues as each cell self illuminates and so is closer to Plasma in that sense. Down side? Very expensive at the moment as its the bleeding edge of technology.

RumRat

InsideInsurance wrote: »

Unfortunately no technology is perfect otherwise there would be only one technology.

LED can suffer from dark corners and clouding - look at a solid coloured screen and you will see that its not 100% perfect image and indeed would look like there are clouds/ areas of slightly lighter and darker areas. In normal TV/Film viewing this doesnt make much impact as rarely is the whole screen a uniform colour.

LCD, its predecessor, is basically the same screen but had a different lighting arrangement which consumed more power, was more bulky and often meant the edges were lighter/ brighter than the centre of the screen.

Plasma, is basically a dead technology so no point discussing its issues anymore

OLED is pegged as the future, doesnt suffer the lighting issues as each cell self illuminates and so is closer to Plasma in that sense. Down side? Very expensive at the moment as its the bleeding edge of technology.

Just for clarification LCD is not the predecessor of LED. They are both LCD screens..(As per post #2).
The LED just refers to the method of back lighting the screen. This also breaks down into back and edge lit screens.
OP:- Re the dark corners - Go back to the store and look at the demo model and see if there is much difference in yours.
Unfortunately it's a flaw of LCD technology and can be there to a greater or lesser degree in any set. If it's driving you to distraction and the demo set is better, get an exchange. (If they have nothing to compare it with then change it anyway).
Better that than sitting for weeks wondering..;)

thescouselander

I had an old Panny that did the same thing. You could try adjusting the contrast and brightness and backlight level (if adjustable) to make the effect less noticeable but I don't think you'll get rid of it completely. unfortunately this sort of thing is just a limitation of the technology in that sort of TV.

InsideInsurance

RumRat wrote: »

Just for clarification LCD is not the predecessor of LED. They are both LCD screens..(As per post #2).
The LED just refers to the method of back lighting the screen. This also breaks down into back and edge lit screens.

It is a predecessor in that it came out first. As per my own post, which you quoted, its the same screen with different lighting

RumRat

InsideInsurance wrote: »

It is a predecessor in that it came out first. As per my own post, which you quoted, its the same screen with different lighting

Not really CCFL preceded LED. LCD hasn't been superseded, yet. Anyway I don't think it matters much as CCFL lit LCD's are getting rarer.
As you say OLED is the way forward, once they crack the manufacturing costs.

thescouselander

Just happened to be in John lewis earlier and had a look at some display tv's - quite a large proportion had the problem the op describes. My plasma TV might be obsolete but I think I'll be sticking with it for a while.

JohnB47

Thanks for all the info folks. Perhaps i just need to get used to it. Let's see over the next few days.

I tried changing the backlight level but it didn't make any difference. In fact moving from level 70 to 100 didn't change much, I thought.

Technology eh? Too steps forward and three backward.

Now to figure out how to access the 40D and ITV stuff that's supposed to be available on this set, to let you watch catch up programmes. All I can see is BBC iPlayer.

Anyone else got one of these Panasonics, that are supposed to give you acces to previously broadcast programs on all of the main channels?