Lies, Damn Lies, and HDTV Spec Numbers

If you are considering the purchase of an LCD HDTV any time soon, it’s a good idea to be armed with some information before stepping foot into the store.  Of course that’s always true, but it’s especially true when buying LCD TVs, because for some reason manufacturers, web sites, retailers, and sales people try to get you to focus on the wrong numbers when trying to figure out what TV to buy.

Screen resolution is important (720p? 1080p?), but it isn’t the most important number when buying an LCD TV if you’re looking for a good picture.  The real numbers that give you a guideline on how accurate a model’s colors and brightness are much more important, but your salesperson isn’t going to know them.  The single most important number in assessing the quality of an LCD TV is the static contrast ratio, but you’re probably going to have a hard time finding it.

Last week a friend of mine texted me from the local electronics store asking me for advice on what to get.  I told her to ask the salesman what the static contrast ratio was.  Not only did he not know, he got defensive and told her that that number is meaningless and that the dynamic contrast ratio was much more meaningful.  He couldn’t have been any more wrong.

Allow me to define a few things.

Contrast ratio is a number which represents the disparity in brightness between the brightest white and darkest black that a TV can display.  If a measurement of the brightest white on a TV is 10,000 (units don’t matter) and it’s measurement of darkest black is 100, that TV has a 100:1 contrast ratio.

Dynamic contrast ratio is the ratio between the brightest white that a particular model can display and the darkest black it can display.

Static contrast ratio is the brightest / darkest ratio at a given time.

The exact method used by different TV manufacturers to determine dynamic contrast ratio is all over the map.  But basically they might turn up the brightness on the TV all of the way, take a measurement of the white level, turn the brightness down all of the way, then take a measurement of the blackest black.  Or worse yet, the TV will artificially turn up or down the brightness of the backlight behind the screen while taking the measurements. 

Static measurements are taken with both black and white are on screen at the same time.

The problem with the dynamic measurement is that when we watch TV, we don’t watch test patterns.  When was the last time you watched a show that was just a black or white picture?  There is some full brightness white and full darkness black on the screen nearly all of the time with real video (some part of the image will be white, and some other part will be black), so the static contrast ratio is much more meaningful.  It much better represents how a TV’s picture is going to look with real video, not test patterns.  The dynamic number is a cheat.

The manufacturers’ marketing departments want the dynamic contrast ratio number to be as high as possible, and the people taking measurements to create the specification numbers on the box will use whatever methods they want to come up with whatever numbers they want.  If you see a number like 10,000:1, that number is really bogus and meaningless.  No real image you could display on your TV would ever be able to achieve that number.  It’s a little like putting 500 MPH rated tires on a car with a speed governor of 30 MPH.  That 500 MPH just isn’t ever going to happen. 

Why does it matter? 

Well, for one, when blacks aren’t really black, the TV is effectively adding a little bit of white or gray to everything on screen.  Colors become much more muted.  The picture details in the darker parts of the image become difficult, if not impossible, to discern.  It just looks… blech.  

Televisions that have great static contrast ratios have color that pops yet looks realistic.  You can see details in the shadows of the picture.  Blacks actually look black instead of gray. 

You’ll have to dig through the web sites of various TV manufacturers to find static contrast ratios.  A television with a 2000:1 static contrast ratio is EXCELLENT, with numbers around 1000:1 being much more typical.  If you’re seeing numbers over 5000, they’re giving you the dynamic ratio, not the static.  Keep looking.  If the manufacturer lists two contrast ratios, the static number is always going to be the lower of the two.  Many web sites mix these numbers up frequently.

When going into a store to buy a TV, the first question you should ask the salesperson is, “what is the static contrast ratio on this TV?”  If they give you a blank stare or tell you it isn’t important, thank them for their time and walk away.  They aren’t going to be even a bit helpful in helping you make your buying decision.

A few other helpful tips:

• 720p vs. 1080p : If the distance between your couch and the TV is more than 3 times the width of the TV you’ll never see the distance between 720p and 1080p.  The closer you sit, or the larger the TV, the more of a difference the higher resolution of 1080p makes.
  
• Viewing angle: LCDs only have just one small “sweet spot” where the picture looks best, usually straight on horizontally and vertically.  The viewing angle numbers advertised for TVs are more or less totally bogus.  When in the store, take a step off to the side so you’re looking at the screen at a 45 degree angle.  The best TVs show little or no difference in brightness or color from an angle.  Look for areas of the picture where whites start to get darker, blacks start to get brighter, and where color intensity begins to fade or even shift toward another color altogether.  Walk back and forth between straight on and viewing at a 45 degree angle.  If you can see significant changes in the picture while moving back and forth, pick another model.  But even the best models have some color shift at just 15 degrees off of center.
  
• Best size: A good rule of thumb here is to get a TV at least as wide as one third your viewing distance.  If you will be sitting 12 feet away, a TV with a screen four feet wide is idea.  Keep in mind that TV sizes are given diagonally, so multiple by 0.87 to get the picture width.  You can always make a TV look bigger by rearranging your room so it’s closer to your sofa.
  
  Measure the distance from where you’ll be sitting to where you want to put the TV.  Multiply by 12 to get the distance in inches, divide that by three, then multiply by 1.15.  There’s your ideal minimum size TV.
  
• LCD vs. Plasma: Plasma TVs have the potential for a better picture than LCDs do, but it varies by manufacturer, model, TV settings, and elevation (yes, distance above sea level).  The higher your elevation the harder it is to make a plasma TV look good and keep it quiet.  But plasmas are becoming a better and better buy as the prices drop to compete with LCD.  Plus plasmas don’t have the viewing angle issue above, and have more control over contrast ratio.  Just watch for flashing and crawling dots on the screen.
  
• Projector vs. Television: I have people asking me why I don’t use my projector to watch TV all of the time.  Two primary reasons: (1) the bulb in the projector costs hundreds of dollars to replace and is only good for a couple thousand hours, and (2) projectors look terrible if you can turn off every light source in the room.  For a projector to look good during the day all windows in the room would have to be totally blacked out.  Any light in the room whatsoever will wash out the picture.  Ideally the side walls and ceiling would be painted with a dark color in non-reflective finish as well.  Projectors are great for watching movies when you have total control over the lighting in a room and a high quality screen to project on, but they are terrible any other time.
  
• The best TVs generally won’t do much on their own to make standard definition television look like high definition, but the more expensive models will definitely do a better job than the cheapest ones. 
  
• If you aren’t going to be sitting close enough to see the details in 1080p vs. 720p, Blu-ray isn’t going to help you either.  It’s hard to see the difference in picture between a good upscaling DVD player and Blu-ray on a 720p model.
  
• Invest in a good quality (more than $80) upscaling DVD player.  It makes all of the difference in the world when watching DVDs.  If your DVD player is more than 2 years old, or isn’t connected using an HDMI cable, retire that player to the bedroom and get a new one.  If you’re using your game console for DVDs (even the PS3 or Xbox 360), it’s time to give it up and get a real player.  You’ll thank me, I promise.
  
• My favorite television brands are the ones that start with S, T, and P:  Sony, Samsung, Sharp, Toshiba, Pioneer, and sometimes Panasonic.  They’ll give you a better picture and last much longer than TVs from other brands.  The L brand can be okay too. 
  
• A TV that lasts you 10 years (S, T, P) but costs 50% more than one that is going to last 2-3 is a much better buy, even if it means postponing your purchase to save up the difference.  Spend the extra initially and you’ll save in the long term and have a better experience the whole time.
  
• TVs look much bigger once you get them home than they do in the store.  Much bigger.
  
• Check reputable sites like www.cnet.com for unbiased reviews on different TV models before buying.  Take consumer reviews with a grain of salt; unhappy customers will always post their opinions, while happy customers rarely do.
  
• Televisions with 120 Hz or 240 Hz panels are nice, but if you get one turn the motion enhancement feature off.  Not only is it disconcerting, but it’s having to remove detail from your picture for the feature to work.  It’s a gimmick that actually hinders your viewing experience.
  
• Glossy screens may make blacks look blacker, but they also act like a big mirror and reflect any light in the room.  Skip the glossy screen and get something with a matte screen instead.
  
• Do NOT buy HDMI cables from your local electronics retailer unless you want to get ripped off.  Try www.bluejeanscable.com or www.monoprice.com.  Any HDMI cable that actually works is just as good as the most expensive one you can buy.  Spending more on one is foolish and a waste of money. 

Hope that helps.  Happy TV shopping!