Re: Bit of a Con Really - Follow-up ...

[Arfa Daily]

Well, I saw one of these LED backlit TV sets from Sammy in a store last night, and I have to say that I was not particularly impressed with the picture quality. Comparing to conventionally backlit (CCFL) Sony and Panasonic offerings in immediate proximity to the Sammy, it was my opinion that the rendition of skin tones, which we previously agreed was a good test of a colour display's performance, was actually nothing like as good. Both the Pan and the Sony had a near identical 'tone' to the skin of a newsreader's face. On the Sammy, that same face was rather pink and florid looking. I also did not think that the black level was any better than on the other two sets, which is a point that they are making a lot of, claiming that it substantially increases the contrast ratio.

I don't know what 'set-ups' this TV has, in terms of brightness, contrast, colour saturation, tint/hue, but in my experience, most LCD TVs - which is, after all, what this is - are set correctly 'out of the box', but I accept that this particular one that I saw might not be a good example of the technology.

I forgot to have a look round the back of it to see if there was a rating plate, but next time I'm in that store, I will try to remember.

In the set's favour, it is very pretty-looking. The slimness of the display is extremely impressive, and at this point in my evaluation, far outweighs any display-quality aspects being claimed for it ...

Arfa

> Based on the assumption that it is a PAL set probably brightness, > contrast, and maybe color saturation. Digital TV sets are not PAL per > se, but they still use the same luminance, color, sync, signals that are > used by PAL (and slightly differently by NTSC). > > They are also still 25 or 30 frames per second depending upon whether or > not thay are interlaced as in 1080i or not. An interlaced frame is still > 2 fields, at 50 or (almost 60Hz) combined. > > The main differences between a digital TV signal and an analog one are > that > since each frame is discrete, there really is no need for a syncronization > pulse to define the begining of each frame and more importantly, there is > no color subcarrier. > > If you were to look at a digital TV signal decoded as if it were a > stream of pixels, you would see something that looked a lot like an > analog TV signal. > > Computer displays, BTW are red-green-blue with seperate horizontal and > vertical > sync, which is very different. > > > Geoff. >

Yes Geoff, I'm aware of all that. I work with the technology all the time. Did you read the original thread from last week ? We were not discussing the differences between transport and encoding systems, rather the moral - if not technical - validity of Sammy advertising this new offering of theirs as a "LED TV", which it isn't. It's an LCD TV with an alternate form of backlighting (LEDs rather than CCFL).

One of the main selling points that they claim, is that because they can control the intensity of the backlighting in individual areas, they can deepen the blacks, effectively improving the contrast ratio. On the example that I saw last night, I observed no such improvement that was obvious, compared to the sets around it. The reason that I questioned what controls for picture setup are available on this particular set, was that given that the backlighting is formed by RGB LED arrays, not white LEDs, then the overall colour temperature would in theory be adjustable - sort of a grey scale adjustment for LCDs, if you like. If this was the case, it might be accessible to the customer via the standard controls menu, as something like "tint" or "hue", and the reason that this particular set (they only had the one on display) did not seem to produce good flesh tones compared to the sets around it, might be because some sales erk had been playing with the controls to see if he could 'improve' it ...

Someone - maybe William - commented last week in the original thread, that they had seen one in Fry's in the U.S., and that they weren't especially impressed, either.

Arfa

[meow2222]

surely the flesh tones are entirely down to the colour settings, ie background, drive, or hue, colour temp etc. Any 3 channel display except early LCDs can do a palette including all the usual skin tones.

NT

[The Natural Philosopher]

You would think so really, but going back to film photography, there are reasons why portraits were always shot on e.g. Konica, landscapes on Agfa or Fuji, , and no one used Kodak at all professionally - Except for Kodachrome..

[Archie]

The LCD only filters light from the backlight. If you don't have a full spectrum white in the first place the you can't expect decent colour. White LEDs aren't quite there yet are they?

Archie

[John]

P'raps it needs degausing - or the convergence tweaking!

Ahh - my old Dynatron with 27 pots on a hinged panel to play with.

[William Sommerwerck]

No one? Kodak sold -- and still sells -- professional color-negative film that's often used for wedding photography. In fact, GYF recently introduced an ultra-fine-grain professional color-negative film. If there weren't a market for it...

I should tell you that, when I use color-negative film, it's Fuji. Part of the reason is price, the other is that Costco uses Fuji paper. Fuji on Fuji produces better results than Kodak on Fuji. (The opposite is also true.)

[William Sommerwerck]

Not so. All you have to do is hit the defined points in CIE diagram. The Pioneer plasma sets hit them dead-on.

[meow2222]

Film is a whole nother business. You've got a lot less control over its 'colour settings' than you have with a display screen, and ditto re optical linearity. The issues with an LCD screen are quite different.

NT

[meow2222]

Indeed. None of the major display techologies deliver full spectrum, nor do they need to.

NT

[meow2222]

thats one thing I DON'T miss. I thanked god for inline guns.

NT

[The Natural Philosopher]

well in the sense that they all use combinations of RGB (or CYMK) to produce a 'full colour spectrum'and none succeed perfectly for all applications, they are considerably identical, actually.

[Schrodinger's cat]

No, they aren't.

Very basically, you have to understand that:

A printed image is sending reflected light to your eye. It can only reflect some portion of the spectrum of light it has absorbed.

A screen is is sending transmitted light to your eye, which has no reflective element to speak of.

Put even more simply, a printed image varies dramatically under different lighting conditions, unlike a screen.

They could hardly be less identical and the analogy with different brands of film is not applicable at all.

HTH

[John]

One day we will be like the aliens in the classic Cadburys Smash adverts - "So you fired electrons at phosphor dots and steered them with coils of copper wire!!!"

But at least I could understand how it worked (a bit)

[meow2222]

issues very different.

[The Natural Philosopher]

Color transparencies which are used in pro film applications say your are a liar.

[The Natural Philosopher]

Proof by assertion.

[Dave Plowman (News)]

The term printing was highjacked by photography and film - doesn't mean the same as the original use. Which was transferring dyes from an impression to paper, etc.

[meow2222]

I find it hard to believe that anyone could think the same controls were available to them with a paper/transparency process as with a computer monitor. I cant think of any possible motivation to prove whats quite obvious to anyone's that done photographic printing.

NT

[Arfa Daily]

Absolutely true, except that this particular TV doesn't use white LEDs in its 'revolutionary' backlighting scheme. It uses small RGB arrays, which is why I was questioning whether there was any control over the individual elements in each array, such that the colour temperature of the nominally white light that they produce, could be varied. Which would then, of course, have a corresponding effect on the displayed colour balance. It just seemed to me that given they have gone to the trouble of using RGB arrays, rather than white LEDs, the reason for that might have been to get a full(er) spectrum white.

Arfa

[Arfa Daily]

If they ever resolve the legal battles over SED technology, we'll be firing electrons at phosphors again (although not steering them with copper) and at last, we will be able to return to pictures as good as CRTs produced ... :-)

Arfa