In depth buying guide - Know before you buy! My advice before buying your Plasma or LCD TV would be:
Read through this site first and understand what you need to be looking out for.
From all the information you get from this site hopefully you should be able to choose a tv for the price you like.
Go to you local store and ask to see the model you like and ask to see HD and SD content on the tv to make sure you are happy with the picture. Then compare their price with the prices we have listed on our product reviews. In most cases you will find the prices we have listed to be cheaper as we have partnerships with tv stores and dealers where they can save you a lot of money by cutting out the middle man and the expensive store to run.
It is important to make sure you are confident that the store is showing both HD and SD content. I always have a look at the back of the tv to check that the HDMI port on the tv is connected to an HD source such as a Blu-ray player or Sky HD box. DO NOT MAKE ANY DECISIONS ON A TV SHOWING IMAGES FROM A NORMAL AERIAL! (I have seen some stores do this - it amazes me how they think you can make any decisions on picture quality this way).
So what should I be looking out for on a tv?
Size of screen
If you want a big screen (i.e. 42'' or more preferably) then I would go for Plasmas. Bear in mind though you also need a big room to appreciate that size. Anything less than 42'' then something called bleeding can occur in Plasmas. That is when the image colours start to mix in with adjacent colours. Oh yes, and if you want to enjoy HD don't get a TV less than 32 inches as you are not really enjoying the benefit of HD. With the extra lines of resolution you can afford to go for a bigger picture now. After all there only a few formats that look good at the cinema - film and HD. Therefore HD on a 42" screen will look fantastic.
Contrast Ratio
Plasmas in general are better for contrast ratios (5,000:1 is a good ratio). This is often thought as being the crucial aspect in picture quality. One of the main reasons why Plasmas produce deeper blacks is due to LCD TVs having to polarize it's continuously on backlight to block the light where the picture should be black. This will more often than not lead to some light leakage causing the pixel to be grey. Also cheaper LCDs can have light leakage around the edge of the screen again causing the picture to look more grey (see our techonology section to explain how LCDs and Plasmas work). Admittedly LCDs are beginning to improve their contrast ratios but they still have a way to come to compete with top end Plasmas. However, there is another aspect that is of importance.....pixel resolution.
Pixel Resolution
Basically the higher the number of pixels the better picture you get. However, you may be paying unnecessary amounts of money for bigger resolutions when the picture being broadcast is smaller. In other words, if Eastenders is being broadcast at 720 x 576 pixels (as it is on Freeview, Analogue, Standard Sky or Cable), the picture is not better on a 1920 x 1080 pixel television. In fact the picture could look a lot worse than your old tv, especially if you buy a cheap flat screen tv as the technology in the tv to "uprez" the picture can be very poor quality. The reason being that pixels have to be duplicated to make up the remaining pixels. Out of interest I believe at present Sky and Virgin broadcast HD at 1440 x 1080 (this is to save on bandwidth). Therefore the only way to see full HD at 1920 x 1080 is via a Blu-ray or HD-DVD player or PS3. These can all output at 1920 x 1080 progressively (see below for further info.)
Refresh Rate
This is more important if you like watching fast moving images on your television, like Formula 1 etc. If you do, then get a 100Hz TV. Otherwise if you are trying to limit the money you spend and you don't watch many fast moving images then personally don't worry too much about spending another £100 for this feature.
Basically this describes how a picture is filmed and displayed on your television. Normal home video cameras (i.e. DV cameras etc.) shoot interlace. Old TVs (when we say old, we mean the bog standard CRTs or Cathode Ray Tubes) display the image interlaced.
EXPLANATION:
CRTs have 720 lines of vertical pixels and 576 lines of horizontal pixels. In the UK (i.e. Pal) it takes 1/25th of a second to display all 576 lines. It does this by displaying 288 alternate lines in the first 1/50th of a second and the other 288 lines in the second 1/50th of a second, therefore taking 1/25th to display all the lines. Picture it like this:
xxxxxxxxxxxxxxxxxxxxxxxxxxx The x lines are displayed first from top left to bottom right in that order, the TV then displays
yyyyyyyyyyyyyyyyyyyyyyyyyyy the y lines again from top left to bottom right. This all occurs in 1/25th of a second.
xxxxxxxxxxxxxxxxxxxxxxxxxxx
yyyyyyyyyyyyyyyyyyyyyyyyyyy
xxxxxxxxxxxxxxx etc.
LCDs, Plasmas and film are inherently progressive. This means that the image is captured and displayed in one pass. It does not do the X's first then the Y's, instead each line is displayed at the same time. Most people (including the sales advisors in the shops) are unaware that LCDs and Plasmas DO NOT DISPLAY INTERLACED IMAGES. If something is shot interlaced and is shown on an LCD TV or Plasma TV,the TV will De-Interlace it and display all the lines in one pass (1/25th of a second).
What does this mean in terms of picture quality?
Progressive normally means better picture as it will give you a better spatial resolution. 1080i means at any one moment in time only half these lines are being shown (i.e. 540), 1080p means that any one time all 1080 lines are being shown. More lines = better image resolution. However, interlace's advantage is with fast moving images, you capture the next 1/50th second of movement, whereas on progressive the image is still the same.
The best way to picture it is like this. Film is progressive, therefore how does a projector work when it shows film? It shines the light through the negative, which displays the whole image in one go. Interlace will theoretically show half the alternate lines of an image first then the second half of alternate lines next.
THEREFORE, PROGRESSIVE THEORETICALLY DOES MEAN BETTER PICTURE QUALITY, but to a certain extent is still comes down to a subjective opinion and what type of programme you are watching. Rule of thumb is whatever way it was filmed is the ideal way to watch it on your tv. Therefore films (normally filmed on film) are progressive therefore watching it in progressive will be the best way to watch it, and anything filmed interlaced will look better viewed on an interlaced tv. Sports on the other hand is an interesting one as there are lots of variables. Theoretically, sports should look better interlaced because you will capture an extra 1/50th sec. of information from one frame to the next. This is also why refresh rates are important when watching sports. However, often sports are filmed 720p at 60 frames per second. Therefore you are getting that extra 1/50th sec. of information that interlaces give you temporally.
At present all broadcasts are interlaced (partly to save on bandwidth and the history of television) therefore the only 'definite way' to benefit from an HD progressive TV is by watching a Blu-ray or HD-DVD disc. Now, we say 'definite way' as it is possible to watch progressive (1080p) broadcasts - if the programme was filmed progressively then you can still watch it progressively as all plasma and LCD tvs are inherently progressive. Eventhough the image is interlaced when transmitted, in good quality tvs that have good de-interlacers inside, this interlaced image is then put back together. Thereby reproducing an image in the same progressive format as it was captured. Unfortunately, most people won't know how good the de-interlacer is in their tv and normally how a programme was filmed (sometimes it can be a mixture), therefore the only 'definite way' to watch progressive HD is via Blu-ray or HD-DVD.
Summary
1. Get a plasma for large screens (42'' or more) with a good contrast ratio.
2. If you don't have Sky HD, Virginmedia HD or a Blu-ray/HD DVD player then there is little point spending extra money on a television that has full 1920 x 1080 resolution when you will not see the benefits. Of course when it comes to picture quality it has a lot to do with the amount of data being sent per second Mb/sec (and there is little you can do to effect this).
3. Don't worry too much about refresh rate if you are not watching many fast moving pictures (i.e. if you mainly watch Eastenders and Coronation street and you don't want to spend lots of money, then I wouldn't spend an extra £100 for a higher refresh rate).