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Sony Bravia KDL-40ZX1 40in LCD TV - Sony Bravia KDL-40ZX1
Watching a 1080p/24 Blu-ray - Iron Man - reveals pictures on the TV that seem to lose not one pixel of image data, and which seem to suffer with no extra noise caused by the HD broadcasting process. Walking between the screen and the media box doesn't cause the signal to break up either, and it's worth noting too that there doesn't appear to be any significant delay between the media receiver obtaining a source and it being wirelessly transmitted the screen. This latter point will be a relief to console gamers.
The only problem revealed at this stage is the fact that the picture you're watching isn't actually 1080p/24. This is because the wireless system apparently handles 1080i - though curiously when the receiver shook hands with my Blu-ray player, it chose an output from the player of 1080p/60. If you want the screen to receive 1080p/24, you'll have to use the monitor HDMI input built into the screen itself.
Turning to the issue of whether the TV's slimness affects its performance is less straightforward. And I guess the simple answer is that actually, yes it does.
The key to why this is so lies in the LED lighting the TV employs. For unlike standard LED TV we've recently tested, the 40ZX1's LED backlight array doesn't lie directly behind the screen, but rather lies around its edges - a development that's responsible for the TV's ground-breaking slimness.
These edge-mounted LEDs throw light across the screen using reflective sheets, with angled sections within these sheets steering the light forward and out of the screen. Unfortunately, though, this approach - for now, at any rate - stops the 40ZX1 from being able to employ that key LED trick of local dimming, whereby the multiple LED arrays that make up an LED TV screen can be controlled individually.
The lack of local dimming inevitably damages the 40ZX1's contrast versus the terrific black level efforts of Sony's X4500 and Philips' 42PFL9803H LED models, since it can't deliver such extremes of bright and dark within the same single frame.
As a result, really dark scenes in Iron Man, such as those in the desert cave where Tony Stark is held hostage, definitely suffer with more greyness than you get with the X4500 ‘true' LED models.
That said, the 40ZX1's black levels still look deeper than those witnessed on all but the very best standard LCD TVs, and even give one or two of the world's weaker plasmas a run for their money. They're stable, too, and don't suffer with the slight ‘blooming' issue witnessed on some LED sets, most notably Samsung's 956 series.
The 40ZX1's colours aren't quite as intense as those of the X4500 range, presumably on account of the set not having RGB LED dimming. But again that's not to say that colours aren't still very likeable, with solid saturation levels, good blend subtlety from the Full HD resolution of the screen, and mostly impressively natural tones. Only a tiny undercurrent of green during some very dark sequences causes any concern - provided, at least, that you don't leave the TV on the truly dismal Vivid image preset, and opt for Cinema or a carefully calibrated concoction of your own instead.