Probably the most important decision you must make before buying a plasma TV, other than the budget, is to chose the size you wish your plasma TV to be. Most plasma TV models have sizes from 42" up to 65" and the bigger they are, the higher the price is. But the cost is not the only factor you should use when deciding what size your plasma TV should have. One very important thing you have to know, is how the plasma TV size, resolution and the viewing distance relate with the amount of picture detail you are capable of seeing. The goal is to match the plasma TV size and resolution with the distance between you and the plasma TV in such way that you will benefit from the best viewing experience. In simpler words, it means that knowing the distance between where you will be sitting and where your plasma TV will be installed, you have to figure out what size and resolution your plasma TV should have so that you see the highest level of detail possible. We can have this problem the other way around too. That is, having a plasma TV of a certain size and resolution to find out how far from it we should sit in order to have the best viewing experience.
The Old Formula
The problem of finding the best TV size for a given viewing distance is not new. Moreover, it is a problem that applies to all kind of displays – LCD, DLP, Projectors and CRT (the old tube TV). Since the CRT TVs are the oldest it’s only natural that the answer to our question has been given first for this type of display. But the important thing you must understand is that the formula used for a CRT TV doesn’t apply to the new high definition displays. The reason for that is the much higher resolution that high definition displays have and also the fact that HDTVs don’t all have the same resolution. Just in case you are curious, the rule of thumb for CRT TVs is that the viewing distance should be at least 2 times and at most 5 times the diagonal size of the display.
If you happen to find a guide that tells you what is the optimal viewing distance or range for each size of TV but does not also tell you the resolution considered, you should know that those figures are inaccurate when reported to HDTVs. That’s because one important variable (resolution) was not used in the calculation. Those numbers are correct only for old CRT TVs or HDTVs that display very low resolution content (480p). The same is true in the case of the numbers (or charts) that are referring to HDTVs but don’t specify the resolution because you don’t know if the number refers to 1080p displays or 720p displays. The latter is more accurate than the former though.
Viewing Distance and 1080p vs. 720p
One important note to make, is that, depending on the viewing distance, you may not see any difference between 720p and 1080p. To explain this better, imagine that you have in front of you two displays of the same size. One has 1080p resolution while the other has 720p. If you sit close enough to get the best detail from the 1080p display you will probably notice the pixels of the 720p display (which ca be very annoying). On the other hand, if you sit far enough to get the best detail from the 720p display, you will no longer see the full detail from the 1080p display (the image will look the same on both). Knowing this might just save you some money when shopping for a plasma TV. If for any reason (e.g. limited budget or space) you settle on a certain plasma TV size, and you realize that your viewing distance is optimal for 720p, then buying an 1080p display will give you no advantage in picture detail. Of course, that is true only if you don’t intend to move your armchair closer every time you watch a 1080p movie.
Size & Viewing Distance for High-Definition Displays
As I said above, in order to determine the correct size based on viewing distance we must also take into consideration the resolution of the display. Below is a table with the recommended viewing distance for each popular plasma TV size. There is of course, one recommended viewing distance for 1080p displays and another one for 720p displays. Since most of us know the viewing distance and need to deduct the best plasma TV size, we can use the recommended distance column and see what size of plasma TV suits us best. There’s a great chance you will not find your exact distance in the table, but that’s not a big deal. Just look for the closest match.
|Plasma TV Size
for 720p (inch)
for 1080p (inch)
Make sure you also read Plasma TV & HDTV Resolution because it is related to this guide.