Portable TVs: How to buy
Sales staff often use screen resolution and contrast ratio figures to impress customers. However, flat-panel TVs all use digital processing software to put a picture on the screen.
Fast moving action can reveal problems like smearing
Unless it’s spot-on, this process, known as ‘up-scaling’ and ‘de-interlacing’, can lead to unpleasant side effects.
Instead of being wowed by the ‘higher the better’ numbers orthodoxy, use your own DVDs, with some of the scenes suggested below and try these simple approaches to get a better idea of the real picture quality.
Picture quality
Check the source of the picture you are watching in the TV showroom – TVs in stores often screen HD pictures.
This will give you a good idea of how good HD can be but is certainly not representative of the picture quality you'll get via a standard broadcast signal or DVD.
Something plugged into the HDMI socket round the rear of the telly is a dead giveaway that you're being shown high-definition images.
Common problems to looks out for
Smearing
A ‘ghost-like’ effect, often visible on moving images. You’re unlikely to spot this on displays showing simple colourful images – cartoons, say – so watch a football match instead.
Picture judder
Like smearing, this is more easily spotted on real life fast-moving action and panning shots. Images fail to move smoothly across the screen, instead making slight stuttering and juddering movements.
Look for jagged edges on images of buildings or text
Edges
Watch out for over-enhanced edges on images, such as buildings or text. High resolution TVs sometimes over-sharpen pictures, leading to jagged lines.
Reflections
Keep an eye out for screen reflectivity. LCDs tend to reflect the least – plasmas are not quite as good. CRT screens are made of glass and tend to reflect more light than either
Washed out
LCD TV pictures often look a bit washed out. Check out a movie with very dark sequences, like the Matrix, and see how much detail you can pick out.
Colour-fade
The colour on some flat panel TVs starts to fade when not viewed head on. LCD and especially rear projection sets are particularly susceptible from acute angles.
Skin tones on a face may appear in bands rather than blending
Colour-banding
When watching a sunset, for example, instead of different shades of colour subtly blending into one another, colours appear in distinct bands.
Broken pixels
Some LCD TVs suffer from broken pixels. This is when one or more pixels are always on or off. A permanently lit pixel looks like a bright speck on the screen, while a defective pixel remains unlit and looks like a black speck.
Extras
Wall brackets usually have to be bought separately
Budget for the extras – most of the flat-panel TVs we tested can be wall-mounted but none come supplied with the necessary brackets.
Universal wall mounting kits cost extra but the smaller your TV the cheaper they usually are. However, your new TV's guarantee may only cover brackets bought directly from the TV manufacturer.
For more advice check out our full guide to buying TVs.