Picture Quality in Detail

The ultimate deciding factor for a flat-panel TV is, of course, the picture quality. In this chapter, we'll describe in detail how well the Sony KDL-40 EX1 really performs in terms of contrast, black level, sharpness, and signal processing. We'll also back up our results with measurements from our test laboratory.

Contrast and Black Representation:
Whereas LCD devices of earlier generations display pale, washed-out blacks, the Sony delivers typical outer-space sequences, such as those in "Space Cowboys", with impressive depth and three-dimensionality. The TV manages to display white spots 2,700-times brighter than the black background. The contrast only sinks in the corners of the screen, where it measures around 1,900:1.

ANSI Contrast:

We determine the so-called ANSI contrast using this checker-board test pattern. This value is a measure of how strongly white areas of a picture brighten up nearby black areas. The higher the checker-board contrast, the more intense black and white areas of a picture will look. In comparison with the black areas, the white areas shine around 430-times brighter, giving an ANSI contrast of 430:1 - a truly excellent value.

Black Level Test:

This black test pattern shows how strongly a TV continues to shine when supposedly displaying pure black - experts refer to this as the black level. Theoretically, a black image should appear perfectly black whether viewed in a light or dark environment, but almost all TVs allow some light to leak through from the backlight.

Several factors affect how strongly the viewer perceives this residual illumination: For example, how strongly external light brightens up the screen (not much with LCDs, but quite strongly with plasmas), how high the TV's contrast ratio is, and how strongly the intensity of the residual illumination depends on the picture's contents. The Sony's black level, at 0.11 candelas per square meter (cd/m2), is excellent for an LCD TV.

In terms of LCD TVs, only a few TVs with "Local Dimming" can beat the Sony's contrast values. These TVs can vary the strength of their backlight for different areas of the picture. When compared with those of plasma trailblazers like the Pioneer KRP-500, the contrast values are clearly inferior. The Pioneer, for example, displays genuinely black letterbox bars, whereas the Sony shows a slight, bluish, residual glow.

But this isn't the whole truth - blacks remain black on the Sony even when viewed in bright conditions, unlike with plasma devices. Additionally, the adjustable backlight means you can set the brightness of the screen to suit the ambient illumination.

If you turn the backlight up to full, the Sony's picture is clearly visible even in bright environments, producing a maximum luminance of 270 cd/m2. In the dark environment of a movie evening, for example, you can turn the backlight down and enjoy a dazzle-free image with deep blacks.

Viewing Angle Dependence:
If you view the Sony from one side, outer-space scenes look patchy, and glow with bluish and yellowish tints. At an angle of 60 degrees, the contrast sinks to just 28% of that in the center. Without a swivel pedestal, you cannot solve this problem - and certainly not if you wall-mount the Sony. You should therefore always sit directly in front of the screen.

Video Processing of Standard Signals:

Resolution test pictures tell us about a TV's sharpness and fine-detail reproduction. The test picture above judges sharpness and fine-detail in the horizontal direction. Other test pictures - not shown here - help us evaluate sharpness in the vertical direction, and show how finely the TV processes colored details.

The Sony uses sophisticated signal processing. Tricky camera pans across the beach in "Six Days Seven Nights" (chapter 5) and even across the fine picket fence in "Space Cowboys" (chapter 8) aren't enough to trip up the Sony's de-interlacer.

Without exception, the analog video inputs show decent sharpness. The Scart-RGB input is especially important in Europe, where it's needed for older devices - DVD players, satellite receivers - that lack an HDMI output. Though respectable, the fine-detail reproduction won't be setting any records.

The Sony fritters away some quality on standard inputs thanks to significant picture cropping (overscan). On all sides, it cuts off around five percent of the picture, meaning the image is magnified to fill the screen - this then makes artifacts and blurring effects more obvious than they need be.

Video Processing of HDTV Signals:

Here, the weaknesses of wireless transmission start to appear. Particularly when colored details appear in an HDTV picture, the fine-detail reproduction isn't entirely impressive. Our reference movie "Casino Royale" is a good example - the fine details of the animated opening sequence challenge a TV's video processing enormously.

In the following two photos, you first see the scene as the Sony displays it using the wireless connection. Below this you then see how the scene should look - the Sony can do this too, but only if you connect the Blu-ray player directly to the HDMI input on the TV itself.

Here, you can see that the red line looks rougher when using wireless transmission, and that it's surrounded by faint interferences. In the relevant jargon: The color resolution is reduced and the image shows compression artifacts.

With test patterns, we see that the finest details appear a little blurry, and that fine, horizontal lines flicker slightly - the picture does not, therefore, display the maximum possible sharpness.

Clearly, you won't notice these kinds of subtleties if you sit three meters away from the screen. Quality-fanatics, however, find it irritating if a TV degrades an otherwise perfect Blu-ray picture.

The media receiver only accepts 60-Hertz signals, so you'll have no luck feeding it 24p signals from a Blu-ray player. This results in poorer motion depiction, an effect that you can see clearly in the opening sequence of "Casino Royale": With accurate 24p playback, the animated playing cards fly across the screen with a slight but regular stutter - you can see this well on the red diamond at playing time 00:05:45. With 60-Hertz signals, on the other hand, you see an irregular, 3:2-pulldown judder.

Again, the Sony is actually capable of using the better technology - but only if you connect the Blu-ray player directly to the monitor's HDMI input. Then the signal processing is faultless, the picture shows the maximum possible detail of Blu-ray, and 24p signals appear correctly. The Sony is only unable to differentiate blacker-than-black areas. This isn't apparent in movies, but rather only on some test discs intended to aid perfect brightness adjustment.

Sony's developers have neglected to provide aspect-ratio switching for HDTV signals, as have many of their colleagues from other manufacturers. Nonetheless, this can be very irritating for the user - namely, if you've set your satellite receiver to output 1080i, and a broadcast comes along in 4:3 or letterbox format: The Sony then stretches the picture horizontally. You can only fix this if the satellite receiver allows you to set the correct picture format, which few devices will do.

Tuner Picture:
For digital cable reception (DVB-C), the TV tuner impresses with a sharp, accurate picture. The analog TV picture, on the other hand, is a little disappointing. Although it looks natural, the picture impression is rather too soft, even with the sharpness setting turned up. It's very important for analog reception that you turn off the noise filter in the picture menu. The filter provides a relatively noise-free picture when reception is poor, but the flip side quickly becomes apparent: Fine skin pores blur if the camera moves even slightly.

Picture Uniformity and Digital Picture Errors:

One common criticism of LCD screens is that they tend to blur when displaying fast motion - that is, they lack motion clarity. In this respect, the KDL-40 EX1 puts in an average performance. The picture blurs in fast camera pans, especially with the Motionflow setting deactivated.

With Motionflow activated, the motion clarity improves during slow or medium-speed motion. With very fast-moving objects, however, Motionflow has little effect - colored objects look blurry and washed out.

If you find the motion depiction in movies unnaturally smooth, you should switch off Motionflow, since this setting removes the natural stutter of film-based recordings by generating and inserting intermediate frames. The effect is that movies then look as smooth as TV material.

But, be careful: Sony now markets three different motion-enhancement technologies under nearly identical names. We like the 200 Hz Motionflow technology best, but only Z-series models have this version. The KDL-40 EX1, on the other hand, provides the older 100 Hz Motionflow technology.

Errors of wireless connection:

The wireless connection between the media receiver and the display can lead to certain special errors. In our laboratory, the connection worked at distances of almost ten meters, but beyond that the picture cut out suddenly. People walking past the media receiver cause brief noise in the picture. Interruptions in the signal manifest as drop-outs and in the form of a distorted, doubled image.

Here are some tips:

• With sporadic interruptions, it can help to switch the media receiver off and then on again.
• At shorter distances, the signal is less vulnerable to interference from other devices, such as 5-GHz WLAN or a microwave oven.
• With persistent interruptions, try changing the transmission frequency manually - there are four channels to choose from.
• If you see no Blu-ray picture, make sure that 24p output is disabled on your Blu-ray player if you're using wireless transmission.