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Sharp LC42XD1E Picture Quality

by Vincent Teoh
17 February 2007

Out Of The Box

To remain competitive on the sales floor, most HDTV manufacturers like to maximise contrast to the point of clipping white, increase colour temperature to sky-high levels (blue) as it's brighter, and then introduce red push to counteract the bluish tinge so that skin tones look more realistic.

Sharp was no different in this regard – the LC42XD1E we received was shipped by default with the "Dynamic" mode preselected, producing a bright and attention-grabbing picture... and unrealistic colours that we couldn't really tolerate. We really wanted to dial out the infamous red push from the word go as it was hurting our eyes across all source material, but had to hold our urges to do some preliminary checks first.

We first checked for dead pixels... our set had none. The mid-grey screen that was put up however highlighted another problem - there were faint vertical "bands" at the centre of the screen probably due to uneven backlight. Fortunately this did not affect picture quality (pre- and post-calibration) at all even on vertical or horizontal pans.

banding

With that out of the way, it's time to get down to business.

Calibration

Brightness, Contrast & Sharpness

Adjusting these were pretty straightforward, although a potential hurdle surfaced in the form of below black clipping (i.e. the outermost black bar not seen on the DVE PLUGE pattern in Title 12, Chapter 2 despite cranking brightness to the max) when connected to a HTPC through DVI-HDMI. The solution? Change the "Dynamic Range" (Menu > Connection > HDMI Setup > Dynamic Range) to "Enhanced".

Greyscale

From our experience, calibrating an LCD TV to ISF standard is about as difficult as trying to hit the bullseye of a tiny dartboard. While most of the time it's reasonably easy to flatten the greyscale around D65 from 30% stimulus onwards, the fact that there's usually no way to modify the colour decoders means that more often than not the final picture (while more accurate) will look worse compared to the best default setting.

So it was with trepidation that we started experimenting with the preset colour temperature settings to see which one came closest to D65. As expected the default "Mid-High" was off the charts (>10,000 K), but imagine our delight when we discovered that the "Low" setting produced greyscale tracking that was within 500k of D65 from 40% stimulus onwards:

temp

And things were about to get better...

Colour Points

The Sharp LC42XD1E's RGB primary colour points were as close to accurate as we'd ever seen on any LCD TV: red and blue were virtually sitting on the vertices of the PAL/SECAM CIE triangle; green, just a shade off. With this and the greyscale in place, all we needed to do was to adjust the secondary colour points... thankfully Sharp were kind enough to enable tint control even for HDMI connections unlike most other LCD TV manufacturers, so this was achieved with ease.

cie

Gamma

The resultant gamma curve post-calibration was as smooth as we hoped it would be, and average gamma measured in at a very acceptable 2.32. Just make sure you turn "Black Expansion" off as this applies an S-shaped disruption to the curve (explained under Technology).

gamma

Real-Life Viewing

It's all very well that we managed to obtain near-D65 greyscale calibration complete with a smooth gamma curve and accurate colour points, but how do all these translate to in real life?

One word... awesome.

Gone was the overbright and artificial pre-calibration picture... in its place we feasted our eyes on some of the most natural-looking images we'd ever seen on LCD TVs. The sweeping North American plain dotted with bisons in Planet Earth (BBC HD) was so breathtakingly portrayed with faithful colours that – when married with the deep blacks (see next section) – it created a thumping 3-dimensional effect. Skin tones were for once healthy rather than cyanotic or erythematous. Yes, there remained a hint of red oversaturation, but the turnaround in overall colour balance was so enthralling that we chose to lose ourselves into the visual splendour rather than nitpick the push.

Black Level & Shadow Detail

As mentioned, the Sharp LC42XD1E produced fantastic blacks that surpassed that of the Philips flagship LCD 42PF9831D, and rivalled the reference level black found on the Panasonic TH42PH9 plasma. As a result, perceived contrast was enhanced and the video images came across as livelier and punchier.

This deep black is achieved, however, at the (very slight) expense of shadow details – the darkest scenes were not rendered as clearly as the plasma. As the camera panned upwards from the bottom of the cliff at night in King Kong HD DVD (1:03), the outline of each rock were a tad more visible on the plasma than the LC42XD1E.

When examined up close or from an angle, the blacks in the LC42XD1E also adopted a bluish tinge, as can be confirmed by the post-calibration correlated colour temperature (CCT) chart showing a rising colour temperature (i.e. more blue) as the percentage stimulus gets lower (i.e. darker). Accessing the service menu for further calibration might allow us to dial this out, but we refrained from doing so for fear of voiding the warranty – we were hard pressed to pick up the low-stimulus blue tinge from 8 feet away anyway.

Detail & Resolution

The Sharp LC42XD1E's ability to resolve and fit every pixel of an incoming 1080 signal onto its native 1920 x 1080 panel (1:1 mapping) grants it significant advantage over lesser competitors. Certainly during the Man U – Portsmorth FA Cup HD broadcast, the carpet of grass blades intertwined with chewed-up turf was noticeably sharper when compared to the Philips 42PF9831D (1366 x 768 resolution) and Panasonic TH42PH9 (1024 x 768)... even from 8 feet away.

On the other hand, maybe this dot-by-dot mapping was part of the reason why the LC42XD1E fared poorly in removing digital noise from its screen. While the 42PF9831D and TH42PH9 could depend on downscaling and blurring to stabilise their respective pictures, the Sharp exhibited a high level of graininess and pixel swarming. When inspected up close, this problem was most apparent in areas where there were slight gradient changes – it was as if the pixels couldn't muster enough colour bit depth to handle this gradation so low-level dithering was applied resulting in constant swirling/ shimmering. As expected, standard-definition DVDs with their accompanying MPEG compression artifacts worsened the symptom (larger blocks emerging... NOT macroblocking), whereas HD DVDs largely eliminated it.

Of course, high-resolution displays are generally unforgiving towards low bit-rate standard-definition content, a trait shared by the Sharp LC42XD1E. Watching Freeview using its internal DTV tuner from 8 feet away was a mixed bag depending on channel and source quality (best = E4 Ugly Betty; worst = Sky 3), but by and large it was tolerable... although if we really wanted to be critical we could pick out all the scaling and deinterlacing artifacts at will.

Here, the digital noise again reared its ugly head – in this respect Philips' Pixel Plus/ ClearLCD technology and Panasonic's internal scaler/ deinterlacer did better jobs than Sharp's own erratic TruD. As you will find out from the Technology section, you can try enabling TruD for video material to improve SD viewing... just don't expect it to perform miracles.

Viewing Angle

Do not be fooled by the viewing angle of 176° as quoted by Sharp in the manual – what they neglected to mention is the fact that the screen's contrast drops off severely once you go past 30° from the centre. In reality, the actual horizontal viewing angle was around 60°, beyond which the people on screen looked anaemic as their skins lost saturation. Notice in the following photos how the colour was drained from Leeloo's face in The Fifth Element when looked upon from 45° off-axis (the same exposure and white balance were used for each camera shot with no Photoshop post-processing):

on-axis
off-axis
On-axis
45°off-axis

Unfortunately the vertical viewing angle behaved similarly – this was particularly noticed especially while we were playing tennis on the Nintendo Wii, and had to look down at the screen.


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