Group test: 1080-line TVs

A month or so ago we ran a feature entitled Full HD or Not Full HD, in which we covered the arguments in favour of step-up TVs with 1080 native lines of pixels, rather than the 768 or 720 lines found on most 'normal' HD tellies. So it seemed only sensible that we follow that feature up by actually getting our reviewing hands on four of the TVs currently claiming to offer native 1080 resolutions.

Read on to find out which of them turns out the best - and to discover if any or all of them really do make a convincing case for the '1080 advantage'…

Overview Price comparison: Hitachi 42PD9700 More info: Hitachi Size (inc stand): 1135(w) x 728(h) x 350(d)mm Weight: 45kg Native aspect ratio: 16:9 Resolution: 1024x1080i (ALIS) Claimed max contrast ratio: 3000:1 Claimed max brightness: 1400cd/m2 Connections: Twin HDMI input; Three Scarts (2 RGB); Component video input; Composite video input; S-Video input; stereo audio inputs; RF input; PC D-Sub input; CI slot; Composite video output; SD card slot; Subwoofer line out

Hitachi 42PD9700

We've always felt that the best policy with technology is to get the confusing stuff out of the way first, while your brains are still fresh. Which is why we're kicking off this group test with Hitachi's 42PD9700: a 42in plasma TV which claims to have 1080 lines of pixels, but actually doesn't. Even though it sort of does. To explain…

The key to what we're babbling on about is a Hitachi/Fujitsu technology called Alternate Lighting of Surfaces - or ALIS, for short. On a standard plasma, all pixels are permanently illuminated. But with ALIS, the phosphor surface areas of the plasma display are expanded, electrodes are altered to drive two pixel lines rather than a single line, and the even and odd lines of pixels are lit alternately every 1/60th of a second, allowing the screen to effectively double its perceived vertical resolution.

Since half the lines in the 42PD9700's claimed 1080i resolution are thus 'created' rather than comprising actual hard pixels, you end up with a bizarre native pixel count for the 42PD9700 of 1024x1080. But don't worry; this does not mean the screen's nearly square; it's very much still a widescreen TV.

If you're not entirely convinced by all this ALIS jiggery pokery, the 42PD9700 does a great job of backing up its 1080-line claims with its picture quality. A few native 1080i feeds from an attached Sky HD receiver and Xbox 360 really impress in their sharpness and freedom from video noise - exactly the traits we'd hope to see in a native 1080 screen.

Other more general benefits include vibrant but mostly natural colours, decent (though not world-beating) black levels, and plenty of subtle shadow detailing.

The only time the 42PD9700 loses the plot is with poor-quality digital sources, which look softer and murkier than we'd expect.

Overview Price comparison: Philips 42PF9631D More info: Philips Size (inc stand): 856(h) x 1138(w) x 290(d)mm Weight: 44kg Native aspect ratio: 16:9 Resolution: 1024x1080i (ALIS) Claimed max contrast ratio: 3000:1 Claimed max brightness: 1400cd/m2 Connections: USB, CAM slot, RF jack, Two HDMIs, Two Scarts (both RGB), Stereo audio input, Digital audio input, Digital audio output, Composite video input, Component video input, Stereo audio output, S-Video input

Philips 42PF9631D

This is the second 42in plasma we've featured in this group test, and like the Hitachi it also uses ALIS technology to deliver its 1080 'thrills'. So again it arguably more 'creates' its 1080 lines rather than providing 1080 lines of real pixels. But this didn't seem to harm the Hitachi too severely, so hopefully the Philips will fare as well.

Its 1080-line claims are far from the 42PF9631D's only intriguing feature. It also sports Philips' Ambilight 2 technology, whereby fluorescent tubes on the TV's rear can output light sympathetic to the content of the picture. Gimmicky though this sounds, it really does make extended viewing more relaxing.

There's also a built in digital tuner, a digital audio throughput system to reduce lip-synch audio delay issues, MPEG noise reduction, and even a USB port for playing JPEGs, MP3s, and streaming video. Unfortunately, the 42PF9631D's pictures are marginally the weakest in this group, thanks to three problems. First, black levels aren't quite as deep as we'd like. Second, some greens and reds can look slightly unnatural during dark scenes. And third, colour blends sometimes appear as stripes rather than smooth transitions.

There's plenty of good news too, though, including the sort of sharpness and freedom from noise that seems characteristic of all the 1080 screens we've seen. Bright colours are strikingly vibrant too, and Pixel Plus 2 HD does its thing with hardly any unwanted side effects.

Taken by itself, the 42PF9631D is a very solid, good value and feature-packed plasma TV. It's only in the context of its illustrious rivals in this group test that it comes up a little short.

Overview Price comparison: Pioneer PDP-5000EX More info: Pioneer Size (inc stand): 1282(w) x 750.5(h) x 98(d)mm Weight: 39.8kg Native aspect ratio: 16:9 Resolution: 1920x1080 Claimed max contrast ratio: 3000:1 Claimed max brightness: 1000cd/m2 Connections: Two HDMIs, one DVI, component video input (BNC type), one DVI PC input, one five BNC PC input, S-Video input, composite video input, speaker terminals

Pioneer PDP-5000EX

The 50in 5000EX's main claim to fame is simple but profound: it's the first 'affordable' plasma TV to deliver a 'real' pixel count of 1920x1080.

Making this possible has not been easy. Pioneer has had to shrink the traditional plasma cell (which makes up a single pixel) by almost 50 per cent, and develop a new T-shaped electrode driver system to stop the smaller cells misfiring.

Such innovation perhaps inevitably means that even though we said the 5000EX was affordable, we're still talking about an asking price of £6,000. Also, since Pioneer has made this cutting edge screen predominantly for the professional market, it doesn't feature a built-in tuner.

But the likely buyer of this screen will surely be far more interested in its HD potential than boring standard definition stuff - and in this regard the 5000EX is unusually well served by three digital video inputs (two HDMI, one DVI), all compatible with the hot new 1080p HD format.

Despite its 'professional' background, the 5000EX still employs all the new picture processing and screen construction developments that have made Pioneer's latest 'domestic' screens so successful. And actually, these developments together with the high-resolution panel deliver results that are simply sensational.

The aggressively rich but always natural colours, profoundly deep but subtly detailed black levels and almost complete suppression of traditional plasma noise problems that characterise all of Pioneer's latest screens are present and correct. But they're additionally joined during 1080i viewing by noticeably less colour noise than we've seen with Pioneer's non-1080 screens, as well as sharper edging, more texture and fine details, and crisper movement. ,p> In short, the PDP-5000EX is for our money the finest 50in high definition display we've seen - and as such, we'd argue that its £6K asking price isn't so OTT after all!

Overview Price comparison: Toshiba 42WLT66 More info: Toshiba Size (inc stand): 780(h) x 1050(w) x 360(d)mm Weight: 34kg Native aspect ratio: 16:9 Resolution: 1920x1080 Claimed max contrast ratio: 800:1 Claimed max brightness: 550cd/m2 Connections: Two HDMI inputs; Two Scarts (1 RGB); component video input; composite video input; S-Video input; D-Sub PC input; Stereo audio output; headphone jack; stereo audio inputs; CAM slot; RF input

Toshiba 42WLT66

For the last of our contenders, we turn to LCD - and a totally genuine 1920x1080 pixel count. LCD technology seems to be finding it generally easier to fit 1920x1080 pixels into its screens than plasma, presumably since plasma pixels are made up of individual gas chambers that are more difficult to miniaturise than LCD pixels.

That said, LCD TVs with 1920x1080 pixel counts remain rare. And even those that do exist tend to be expensive. Which is why we're so excited by Toshiba's 42in 42WLT66, which at just £1900 undercuts most 42in plasmas, and hardly seems to have attracted a premium at all for its unusually high resolution.

This is all the more noteworthy since the TV certainly isn't bereft of other features either, with highlights being a fully specified digital tuner and Toshiba's widely acclaimed Active Vision LCD image processing system.

In action with our bevy of 1080i HD sources - well, two, anyway! - the 42WLT66 does a sensational job of showing HD at its mind-blowing best. HD pictures look so sharp they should come in a protective cover, and they're blissfully free of the sort of shimmering, blocking or colour smudging that can be caused when 'normal' TVs scale 1080i down to their lower resolutions.

The Active Vision processing, meanwhile, helps the picture enjoy strikingly bright but generally natural colours, set against some likeably deep black levels that also contain plenty of the subtle shadow detail that gives dark scenes a sense of scale.

As with the Hitachi plasma, the 42WLT66's pictures struggle with weak standard definition sources slightly more than we'd like. But for the purposes of this group test it's the HD performance that really matters, and in that respect the 42WLT66 is an absolute peach.