What Resolution Do I Need?

There are two letters you can’t sell a TV without these days: H and D. High Definition is the new buzzword, and everyone wants to lay claim to being High Def. HD can be confusing, though, because it can refer a variety of things.

Resolution refers to the number of dots of light on a screen, and says nothing about the size of the screen. Imagine you were bringing a tray of cupcakes to a party. If the only tray you had was a one foot by one foot tray, and you wanted to bring enough cupcakes for 30 people, you’d need to make very small cupcakes to pack them all in. But, if you only had a three foot by two foot tray, and you only wanted to bring 6 cupcakes, the tray would look very sparse. Matching the appropriate size of tray to the number of cupcakes makes for a good presentation. In the same way, you want enough dots of light, or pixels, to be well-spaced on the screen. The larger the screen, the more pixels you need for them to be well spaced. If you pack too many pixels onto too small a screen, the pixels would be too small to be seen from any distance.

Standard Definition

SD, or Standard Definition, is the old type of television, and it has 480 lines of resolution (TV resolution is measured by the number of vertical lines). If we were to measure TV resolution in Megapixels, like we do for digital cameras, standard definition would be 0.3 MP (640×480=307,200 total pixels).  Two new formats have emerged, both of which are considered High Definition, because they are greater than the old Standard Definition. 720 is the equivalent of 0.9 MP and 1080 is the equivalent of 2 MP. High Definition is not a single level of resolution, but simply means anything more than the old standard. That’s why some manufacturers have taken to calling 1080 ‘Full HD’ to try to differentiate it from 720. Of course, they’re going to regret calling it ‘Full HD’ when they decide to make something with higher resolution.

Digital televisions start at 720 lines of resolution, they don’t make them in the old Standard Definition format (at least, not that I’ve ever seen). 1080 screens start at around 40” in size. Why don’t they offer them in smaller sizes? The answer is distance from the screen. TVs are designed to be watched while sitting on a couch 10 feet away.

Getting in Close

When you want to see the detail on a painting in an art gallery, what do you do? You go closer. The closer you are, the better able you are to see the fine detail. From further away, the detail all blends together. You are magnifying the image by getting closer. The same thing happens with TV. The closer you are, the more detail you can see. A 30” television that offered 1080 resolution would be indistinguishable from a 720 television of the same screen size from a distance of ten feet. The dots would have to be so small to be packed into such a small space that you wouldn’t be able to see the fine detail of that image unless you were very close to the screen. You aren’t likely to be watching from that close, so it would be a waste of money to pay for the extra resolution.

The larger a screen is, the easier the detail is to see from further away. The easier it is to see from further away, the better able you are to pick up the fine details on the screen. On a 50” television, 1080 resolution makes a big difference. The screen size is big enough that the pixels are stretched over a large enough area that having the extra resolution really improves the image quality in a noticeable way. Manufacturers still offer 50” screens in 720, and they look OK, but they aren’t ideal and they’re becoming more rare.

Between 40” and 50” its a judgement call whether you want to move to the highest resolution available. 1080 resolution starts at about 40” in screen size and you don’t pay much of a premium for the highest level of resolution at that screen size. The difference at the time of this writing is as little as $100 more for the higher resolution at a 40″ screen size.

Finding the Right Content

To further confuse matters, very little content is available at 1080 resolution. Almost no one broadcasts television at the highest level of resolution. Virtually all cable and satellite television at the time of this writing is 720. So, if you buy a 1080 television, you are essentially future-proofing, getting ready for the day when having the best resolution available will actually matter for main-stream content. Unless you make your own content or you have a Blu-ray or HD-DVD player (more on what that is in a future posting) it doesn’t matter yet what level of HD resolution you have because the companies that deliver content to you have had such a hard time agreeing on how they’re going to deliver high definition video to you.

What’s the Bottom Line?

The bottom line is that if you have a TV below 40” in size, 1080 isn’t really available. For that size 720 is your only option and all you really need. For screens above 40” in size, 1080 will make a difference if you have a video source capable of delivering 1080 resolution to the screen. If your screen is 50” or higher, a 1080 screen is definitely worth spending a little more on.