Post by jeffolie on Jan 8, 2011 10:59:53 GMT -6
Buying a TV
When we shopped for a big new TV years ago, I took Olie and kids to look at them.
They could not tell the difference between most and a few brands did get eliminated.
The critical result was that each of us had different vision issues resulting in the supposedly most advanced or expensive TVs not looking any better through our eyes.
So, ignore the hype and specifications when TV shopping and use your family's eyes to determine viewing quality.
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Don't fall for the HDTV marketing myths
Buying a new HDTV? You'll be bombarded with a bunch of technical lingo that may not make much sense, and you'll probably make your buying decision based on specifications presented by the manufacturers.
Well, here's what the manufacturers don't want you to know: These specifications may mean little to the quality of the set, and the numbers may be inaccurate at best.
Contrast ratio
Contrast ratio is the difference between a display's blackest black and brightest white. The higher the ratio, the clearer and crisper the picture. That's in theory, anyway.
In truth, contrast ratio only matters in certain situations. If there is little or no ambient light, contrast ratio is important, but many people watch television in situations with lots of ambient light. The reflections on the screen will overpower the display's blacks. Also, contrast ratio only matters when significant portions of the picture are dark.
To top it off, manufacturers use tricks to boost contrast ratio specs. For example, some manufacturers may claim 1,000,000:1 or infinite contrast ratios. When you see numbers like these, you can bet they're citing the dynamic contrast ratio.
TECH TIPS: Ask Kim
With dynamic contrast ratio, the black value is measured when the display is in standby. This reduces the display's light output, making blacks appear darker. Contrast ratio should be measured when lights and blacks are displayed at the same time.
The best LCDs have a contrast ratio between 1,500:1 and 2,000:1.
Response time
Response time is the time it takes for a pixel to change color. If the response time is too slow, you'll see motion blur. This is a particular problem with fast-moving images. For example, you may notice it when watching sports.
The problem with response time lies in the way it is measured. The industry standard is to measure rise and fall. This is the time it takes a pixel to change from black to white to black.
But most transitions are more subtle. A pixel is more likely to change from gray to a different shade of gray. Surprisingly, this takes the display longer. And, gray-to-gray transitions are more important to preventing motion blur.
Manufacturers don't usually specify how they measure response time. But, most manufacturers will stick with the industry standard rise and fall. They can list a faster response time — and sell more sets.
Color gamut
Color gamut is the range of colors that a display can produce. So, when it comes to color gamut, bigger numbers are always better, right? Think again. Be wary of manufacturers promising more than 100% of a particular color standard.
You want the display to use the same color gamut that was used to create the content. For HDTVs, that color gamut is ITU-R BT.709, or Rec.709. The color gamut will specify how colors are produced on screen. The display can't show colors that aren't in the original content. A larger gamut simply makes content appear more saturated.
Now, the Rec.709 color gamut doesn't cover the full range perceived by the human eye. But, colors that fall outside the range aren't common in nature. It is unlikely that you'll ever need them.
Premium cables
You'll encounter another myth when shopping for an HDTV. This one isn't perpetrated by the television manufacturers. Rather, sales clerks and accessories companies are behind it. They'll tell you to buy expensive cables to get the best picture.
HDMI cables start around $1 on Amazon.com. Premium ones sell for $200 or more. The truth is, expensive cables aren't worth the premium. You'll get an excellent picture from moderately priced cables. Budget $20 to $30 for a quality HDMI or component cable. Save the extra money for your cable or satellite bill.
www.usatoday.com/tech/columnist/kimkomando/2011-01-08-hdtv-myths_N.htm
When we shopped for a big new TV years ago, I took Olie and kids to look at them.
They could not tell the difference between most and a few brands did get eliminated.
The critical result was that each of us had different vision issues resulting in the supposedly most advanced or expensive TVs not looking any better through our eyes.
So, ignore the hype and specifications when TV shopping and use your family's eyes to determine viewing quality.
==========================================================================================
Don't fall for the HDTV marketing myths
Buying a new HDTV? You'll be bombarded with a bunch of technical lingo that may not make much sense, and you'll probably make your buying decision based on specifications presented by the manufacturers.
Well, here's what the manufacturers don't want you to know: These specifications may mean little to the quality of the set, and the numbers may be inaccurate at best.
Contrast ratio
Contrast ratio is the difference between a display's blackest black and brightest white. The higher the ratio, the clearer and crisper the picture. That's in theory, anyway.
In truth, contrast ratio only matters in certain situations. If there is little or no ambient light, contrast ratio is important, but many people watch television in situations with lots of ambient light. The reflections on the screen will overpower the display's blacks. Also, contrast ratio only matters when significant portions of the picture are dark.
To top it off, manufacturers use tricks to boost contrast ratio specs. For example, some manufacturers may claim 1,000,000:1 or infinite contrast ratios. When you see numbers like these, you can bet they're citing the dynamic contrast ratio.
TECH TIPS: Ask Kim
With dynamic contrast ratio, the black value is measured when the display is in standby. This reduces the display's light output, making blacks appear darker. Contrast ratio should be measured when lights and blacks are displayed at the same time.
The best LCDs have a contrast ratio between 1,500:1 and 2,000:1.
Response time
Response time is the time it takes for a pixel to change color. If the response time is too slow, you'll see motion blur. This is a particular problem with fast-moving images. For example, you may notice it when watching sports.
The problem with response time lies in the way it is measured. The industry standard is to measure rise and fall. This is the time it takes a pixel to change from black to white to black.
But most transitions are more subtle. A pixel is more likely to change from gray to a different shade of gray. Surprisingly, this takes the display longer. And, gray-to-gray transitions are more important to preventing motion blur.
Manufacturers don't usually specify how they measure response time. But, most manufacturers will stick with the industry standard rise and fall. They can list a faster response time — and sell more sets.
Color gamut
Color gamut is the range of colors that a display can produce. So, when it comes to color gamut, bigger numbers are always better, right? Think again. Be wary of manufacturers promising more than 100% of a particular color standard.
You want the display to use the same color gamut that was used to create the content. For HDTVs, that color gamut is ITU-R BT.709, or Rec.709. The color gamut will specify how colors are produced on screen. The display can't show colors that aren't in the original content. A larger gamut simply makes content appear more saturated.
Now, the Rec.709 color gamut doesn't cover the full range perceived by the human eye. But, colors that fall outside the range aren't common in nature. It is unlikely that you'll ever need them.
Premium cables
You'll encounter another myth when shopping for an HDTV. This one isn't perpetrated by the television manufacturers. Rather, sales clerks and accessories companies are behind it. They'll tell you to buy expensive cables to get the best picture.
HDMI cables start around $1 on Amazon.com. Premium ones sell for $200 or more. The truth is, expensive cables aren't worth the premium. You'll get an excellent picture from moderately priced cables. Budget $20 to $30 for a quality HDMI or component cable. Save the extra money for your cable or satellite bill.
www.usatoday.com/tech/columnist/kimkomando/2011-01-08-hdtv-myths_N.htm