By Philip Wong, CNET Asia
09/12/2009
URL: http://asia.cnet.com/reviews/home_av/tvs/0,39037594,62055663,00.htm

There're recurring instances where we've received identical queries from our readers regarding HDTVs and which to purchase. So we thought it might be a good idea to list out the most-asked ones in topic form, to share with the rest of you. Feel free to submit more queries via Ask CNET Asia if you have further question. You may also like to recount your experiences and feedback with fellow A/V buffs here by contributing in the Talkback section below.

1. Which type of HDTV is better: Plasma or LCD or LED-lit?

As long as LCD panels employ some kind of backlighting, their plasma counterparts will always have an edge over them in terms of black level and native contrast. This is because plasmas can moderate screen brightness at the pixel level, though LED-backlit LCDs enhanced by local dimming functions have closed the gap noticeably in recent years.

Another point to note is that for 42-inch and smaller HDTVs, LCDs offer higher resolution up to 1,366 x 768 pixels compared with plasmas' usual 1,024 x 768 pixels.

2. Which HDTV do you recommend as the best?

"Best" is quite subjective and mostly depends on the individual's requirements such as good picture quality, aesthetics and value for money. For consumers where budget is not an issue, the mid- to-higher-end models featuring enhanced A/V processing and functions should be a good start. As for bargain hunters, the entry-level sets are hardly shabby, considering their price and performance ratio, though you should lower your expectations on design and appearance.

3. Which is the screen size to get for my room?

The screen size should be determined by the viewing distance between the TV and your seating position a.k.a. sweet point, not the room size. As a rough guide, this should be one to two times the screen length. You can also watch programs closer to the TV without the potential image pixelation found on higher-resolution full-HD models. However, having to tilt your head to follow the onscreen action close-up could result in some neck strain.

Refer to our HDTV Buying Guide for more information regarding TV and room sizes.

4. Why are there two contrast ratio ratings?

There're two contrast measurements commonly used by HDTV manufacturers: Native (ANSI) and dynamic (full on/full off). The former is a more accurate yardstick of a display's performance for real-world content, calculated via a black-and-white checkered test pattern. The latter usually provides an inflated rating by measuring the peak level in ideal conditions such as a fully darkened test room.

It's worth noting that there's no industry standard for determining dynamic contrast ratio, so you should use the figure strictly for general reference. Having said that, many vendors have stopped providing native contrast ratios in their product literature.

5. What are the differences between full-HD and HD-ready panels?

Full-HD refers to a resolution of 1,920 x 1,080 pixels, while HD-ready is anything between 1,280 x 720 and the former. Some benefits of a higher pixel density include better image details and less jaggies, though other factors such as playback materials and screen sizes will also determine the overall picture quality. Generally, full-HD displays should deliver the best bang-for-your-buck in rendering Blu-ray movies (especially for animation) and HD games, as well as providing sharper visuals on the 46-inch and larger models due to their finer dot pitch.

6. Does the HDMI version in an HDTV matter?

Actually, there should not be too much concern over the HDMI version on your HDTV since both versions 1.2 and 1.3 can adequately support 1080p input signals. The only tangible advantages for HDMI 1.3 here are Lip Sync to automatically synchronize audio and video playback, and Deep Color for supporting higher color depth. That said, compatible content for Deep Color is currently limited to homemade videos recorded on the latest HD camcorders.

7. What is plasma burn-in and how can one avoid it?

This very much depends on individual plasma TVs, though most brands implement some form of anti burn-in feature such as pixel orbiter to minimize the risk and white wash to correct accidentally "burned" images. Anyway, it's recommended to avoid static graphics such as station logos, game scores and news tickers for a prolonged duration, say, around an hour or longer. This is particularly crucial for the first 100 to 200 hours of run-in time after initial installation. Another recommendation is to tune down the screen brightness level to reduce potential burn-in.

8. Are 200Hz LCD TVs twice as good as 100Hz models?

In certain panning scenes, we do encounter slight differences in motion fluidity between 100Hz and 200Hz HDTVs. Most of the time, however, there's negligible improvement between the two. There's also the question of personal tolerance to motion blur and judder. Some consumers are pretty particular when it comes to these artifacts. On the flip side, there're also videophiles who associate judder with film-like movie reproduction. For users on a budget, a 100Hz model which is increasingly common and affordable should suffice for now.

9. Is it advisable to purchase an HDTV from overseas?

There're a few considerations to note when importing an HDTV. These include additional shipping cost, international warranty and local aftersales service. Most importantly, you'll have to ensure that the model is compatible with your local power grid and broadcasting system. A US-centric panel, for example, runs on 110V AC and with ATSC digital tuners. It's unlikely to operate properly in UK-oriented Asian countries on 220/240V AC and the analog PAL broadcast standard.

Having said that, a quick workaround for the power supply issue is a step-up/down transformer to adapt foreign electronics for local usage, as well as a universal adapter to accommodate different power plugs.

10. How do I calibrate my HDTV?

You could explore inexpensive DVD calibration discs to tune those basic video parameters such as colors and brightness. The discs will cost around S$50 on average and can be imported from the US through Amazon.com. For more accurate adjustments, there are specialized calibration tools such as DataColor SpyderTV which minimizes error using an optical probe and computer software. Alternatively, just toggle to your TV "Standard" or "Movie" picture modes for starters and fiddle with the settings for best results.