Introduction
Selecting the right high def television (HDTV) can be a daunting prospect for sure. I will help to take some of the confusion out of it by showing you how to find the right match for an HDTV and you and your family.
As TV broadcasting technology imminently changes from analog to digital, the number of choices for you to make is increasing dramatically and rapidly. When you walk into your local T.V. sales store and see walls of TV’s staring at you, the task can seem monumental and even overwhelming to say the least. So, let me walk you through some of the basics and I hope this article will help to focus you on your decision.
Why Native Resolution is Important
The first important component we need to understand in selecting the right HDTV for you is screen resolution. A digital TV does not necessarily mean that it is a high definition digital TV. There are TV’s on the market that are digital, but do not have HiDef resolution. So, what is a high definition television, or HDTV? In order for a TV to be considered “HiDef”, it needs to have a screen resolution of at least 720p. A 720p TV has the capability to display 720 horizontal lines of pixels (or “color dots” that appear on the screen). The highest resolution [number of pixels or color dots] a television is capable of producing is called “Native resolution”. What this means is that a TV producing a native resolution of 1280×720, is capable of reproducing 1280 dots [pixels] in a horizontal line by 720 lines of dots [pixels] vertically. The highest resolution that is currently available is 1080p (1920 horizontal ×1080 vertical lines) and 1080i (1920 horizontal ×1080 vertical lines). The more lines of pixels, the higher resolution an HDTV is capable of producing.
Television screens are measured diagonally. For HDTV screens measuring less than 45 inches (remember, this is measured diagonally), you probably will not be able to tell the difference between a 720p and 1080p picture, because the lines are pushed closer together. When selecting a smaller HDTV, consider that it may not be worthwhile to pay a higher price for the higher resolution. With that in mind, I would not purchase a 1080 resolution HDTV for anything smaller than a 45 inch screen. You just simply will not see the difference.
The Difference Between Progressive Displays (720p, 1080p) and Interlaced Displays (720i, 1080i)
People are generally very confused when it comes to knowing the difference between progressive and interlaced scanning. I’m going to help sort it out for you. The ‘p’ (in 1080p for example) stands for a progressive scan, which means that each line is displayed on the screen in a progressive order (line 1, line 2, line 3, line 4, line 5, etc.) one line after the other. The ‘i’ (in 1080i for example) stands for an interlaced scan, which means that the odd lines are displayed in one pass and the even numbered lines in the next pass which lessens the resolution slightly and slows the rate that motion can be projected to the screen. A standard analog television uses interlacing technology. Progressive displays are not necessarily better, but they can be. Most people can not tell the difference between a 1080i picture and a 1080p picture because the resolutions are the same. But, a 1080p HDTV will stand out while viewing fast motion that happen in action movies, video games and sporting events. 1080p provides smoother resolution and less distortion in fast paced scenes. So if you are a fan of action movies, video games or sporting events and want a big screen HDTV, 1080p will definitely be your best choice.
Viewing Distance Should be Considered When Determining the Size of the Screen
It can be a big mistake to rush out and purchase the biggest HDTV you can find. Why? Because an HDTV is quite different than your trusty old standard definition television. A standard resolution television signal will almost always look slightly distorted on an HDTV if you are too close, but as you back away to a proper viewing distance, the images will become greatly improved. A very large screened HDTV in a small room will give you poor quality looking pictures if viewing a standard definition program. However; viewing a high resolution video game, Blu-ray movies or high definition cable or satellite signals will produce a much more pleasing viewing.
Viewing Distance: The Formulas
The basic rule for HDTV viewing is that you should not sit closer than 1.5 times the diagonal measurement of the screen. And also, for the best viewing quality, you should not be more than a maximum distance of about 3 times the diagonal measurement of the screen.
An example calculation is as follows:
For a 40 inch screen, the minimum viewing distance would be 60 inches (or, 40 x 1.5 = 60 inches – about five feet) and the maximum viewing distance should be 120 inches (40 x 3 = 120 inches -about ten feet). The optimal viewing distance for a 40 inch screen would be about 7 ½ feet away from the screen (which is the middle point between the minimum and the maximum viewing distance).
Minimum Viewing Distance Formula: Screen Size x 1.5 = inches away
Maximum Viewing Distance Formula: Screen Size x 3 = inches away
Optimal Viewing Distance Formula: Max distance + Min Distance /2 = Best Viewing Distance
Remember that when you are in a show room, the viewing resolution can be greatly misrepresented due to the size of the room. Be sure that you know what your viewing room distance will be. Use the calculations to determine what screen size your room is best suited for, BEFORE you go shopping.
What Type of HDTV Should You Choose: Rear Screen Projection, LCD or Plasma?
The next and perhaps most difficult decision you will need to make is what type of HDTV to purchase. I will try to help you sort this out.
Rear projection screens tend to have the cheapest out-the-door cost, but they are frequently the most expensive over the life of the television due to the cost of their projection bulbs. Projection bulbs are very expensive and can range from $300 to $500 or more, and they have to be replaced every 4 or 5 years or sooner depending on the TV’s usage. Another downfall to projection TV’s is that the viewing angle tends to be very limited. If you are not sitting directly in front of the screen, you will not be viewing the best picture.
Liquid crystal displays (LCD’s), are quickly becoming the most popular style of HDTV due [in part] to the fact that they are becoming very affordable. LCD screens were once limited in maximum screen size. But this is also becoming less of an issue as technology advances, LCD screens are growing ever larger. LCD’s are known for reduced power consumption and they also produce a better image quality in a well-lit or partially lit room.
Plasma TV’s have their positive and negative points as well. Plasma screens are becoming more and more affordable and they are known for their great color replication. One of the biggest downsides to a plasma screen is its power consumption. Most plasma TVs consume about tow times the energy as a like-sized LCD TV. Plasma screens have had trouble replicating deep, dark black, so they look best when they are viewed in a very dark room. Plasma screens have excellent viewing at almost any angle.
In summary, if you like watching television in a totally dark room most of the time, then a plasma screen will probably work best for you. If you tend to view TV in a partially lit environment, then an LCD screen might be your best choice. And, if you have a direct straight-on view of your TV, then a rear projection could work well for you.
Refresh Rate, Contrast Ratios and the Truth about Color Selection
What is refresh rate and is it important to me? Well, the short answer is, “yes” refresh rate is a very important factor and is very often the most overlooked technical spec when selecting a new HDTV. The refresh rate is the amount of times an entire frame or image is displayed on the screen for every second of viewing time. The refresh rate is usually identified as Hz. Hz (or Hertz) is how many times the screen is renewed per second. Most HDTV’s are 60 Hz, which means the screen is reformed 60 times in one second. The newer HDTV’s have a refresh rate of 120Hz and the very high-end HDTV’s are now pumping out at a blazing 240 Hz (that’s renewing the screen picture 240 every single second!). You may have heard of motion blur but do you know what it is? Well, in video games, it can be programmed into the game for dazzling effects, but on an HDTV, motion blur can ruin a fast paced action scene, a sporting event or video game that doesn’t need more than it already has. Motion blur is caused when the HDTV screen can’t process the information fast enough and it causes the picture to appear blurry. If you want the crispest picture, look for the highest refresh rate that you can afford. Refresh rate is one of the most important factors in selecting a new HDTV if you plan on clearly watching any fast paced programming.
Contrast ratios have become a sales and marketing point for manufacturers and sales people. But these sales pitches can be somewhat misleading. So, what is a contrast ratio? Well, it is simply the difference between the white and black color levels. What we are generally not told as consumers is that there is a multitude of ways for manufacturers to measure contrast ratios. Contrast ratios should be considered in your purchase, but you should not base your entire decision on this one technical item. In general though, a good contrast ratio will produce darker blacks, which can help colors stand out much brighter and more vibrant. As a rule of thumb, Plasma screens tend to have better contrast ratios than rear projection screens and LCD screens. While you are at your local HDTV retailer, notice the difference in the black levels of the different TV’s as you walk past them. Don’t ignore contrast ratios, they can help, but trust your eyes and remember that the blacker the black, the better the color resolution will be.
Refresh rate, contrast ratios and blackness have the most impact on your overall picture quality and color portrayal. But remember that when you are in a showroom, brightness and contrast factors can be misleading due to the brightness level of the showroom. What looks good in the showroom might look awful in your home.
I hope this quick guide has provided you with a good knowledge base for when you are ready to take that big step into your next TV purchase. It can be frightening, if you don’t know what you are looking for.
Authored by: Tina D