There are many things to consider when selecting a high definition display. Plasma or LCD? How well will it handle motion? Has it got HDMI connectivity? Here’s some of the basic things to consider when HD TV shopping.
In the article High definition gear to get you started we alluded briefly to the number of lines displayed by a TV. If only choosing a HDTV were as simple as considering just that figure. In fact, there are many choices to be made to get the best picture for not just the 2008 Beijing Olympic Games, but also for your general HDTV, DVD and Blu-ray viewing.
And it isn’t all just raw ‘specifications’. Various new technologies have been introduced that actually make the picture even better in some circumstances than that originally captured!
Throughout the GadgetGuy site are articles to guide you through all these in more detail, helping you know what to look for and how to get the best performance out of your TV. But right here, let us introduce this range of considerations.
Resolution
From the picture side of things, HDTV is all about resolution: how many dots, or pixels, make up the picture. The more the better. With digital cameras we talk about megapixels, or how many millions of pixels altogether that constitute the picture. With TVs we talk about the horizontal and vertical resolution. Each of these is also measured in pixels. The picture of Australian DVDs has a resolution of 720 pixels across by 576 vertically, and is expressed as
720 x 576. The same for SDTV.
HDTV comes in three different varieties. As we write, SBS offers a pseudo HD format called 576p that offers no more detail than standard definition TV for the great majority of shows. ABC TV offers 1280 x 720 pixels for its HD broadcasts, while the commercial stations deliver either 1440 x 1080 or 1920 x 1080 pixels. Channel 7 and its regional affiliates will be giving us the 2008 Beijing Olympics in this full high definition picture, called 1080i (1920 x 1080).
Digital TV: Three quality levels
| 576p | ‘High Definition’ (according to law, but not in reality) digital TV, broadcast by SBS |
| Good: 720p | High Definition digital TV, broadcast by ABC TV |
| Better: 1080i | High Definition digital TV, broadcast by Channels Seven, Nine and Ten |
Motion
There are things that TVs can do, also, to improve the appearance of motion. One is simply by providing a highly responsive display. Older LCD TVs were not very good with this, but modern units have largely overcome the problem of ‘lag’. Some higher-end models offer 100 hertz processing by which they make the images move even more smoothly than when they were first captured on TV camera.
Contrast ratio
An important thing to consider is the ‘contrast ratio’ of the TV. This is the range of brightness that can be delivered by the TV. Modern panel TVs have no problems delivering plenty of brightness when the picture calls for it, but some have more trouble with darker scenes.
Size
And we cannot forget size. When we were limited to analog TV, the largest TVs tended to be around 66 cm in size, although towards the end widescreen 76 and 82 cm models stated appearing. For DVDs and, later, digital TV, good results could be achieved with screens up to 106 cm (42 inches) in size. Go much bigger than that and the picture quality becomes bit of a problem. Except, now that we have high definition TV, 106 cm becomes the starting point. Get ready for really large images.
Technology
You will also want to choose between the various ways of producing a picture: plasma, LCD or maybe even a front projector. Only the last – for the moment at least – will allow a massive 200 to 240cm image in your home.
Connections
To make all your gear work at its best, you will need to tie them all together with some form of signal cable. This used to be a complicated issue, but increasingly it can all be dealt with using four letters: HDMI. We shall explain further in a few pages.
Looks
Finally, there is styling. All this is fine, but a TV is a large piece of furniture and it really must look good in your home, even when it is not in use.
GadgetGuy tip
Specifications for TVs and other equipment are important because they can help us to understand the strengths and weaknesses of particular products. But don’t rely solely upon them. Take the time to stand in front of any TV you are considering purchasing and see if its performance is pleasing to your eye.
