How to decide what HDTV to buy?

 

Size Matters

Job one is to pick the right screen size for your needs. HD LCDs range from 19” to 65” and plasmas from 42” to 65”.  LCD screens 37” and smaller generally feature 720p resolution, though there are a few sets as small as 32” offering 1080p. There are 42” and 50” 720p plasma sets as well, with all plasma sizes available in 1080p.

Which size is right for you? Consider your budget, room size, seating positions and finally if it’s an issue for you, the size of the cabinet in which you’re placing the set. Our exclusive HD Guru viewing distance chart (link) tells you how close you need to sit to see full resolution with a given 720p or 1080p display. Sit further away and of course you will still get a great picture, but  human vision limitations will prevent you from seeing the set’s full resolution.

LCD or Plasma?

LCD is your only choice if size or budget constraints limit you to a below 42” size. While you have a choice of plasma or LCD at 42” and above, HD Guru and most other experts agree that plasma beats LCD (including those labeled “LED”) in overall picture quality.

Why? Plasma offers uniform picture quality as you move off-axis, meaning everyone in the room essentially sees the same picture. LCD does not. Off axis, all LCD displays exhibit changes in color, black level and brightness, though some that will be recommended in an upcoming article, offer better off-axis performance than others.

Plasma offers overall better black levels, with blacks always appearing deeper when viewed off-axis compared to LCDs, because plasma has the ability to shut light off at a pixel level. Because LCD is a backlit technology, the best it can do—and not all LCDs have it—is dim large blocks of pixels using a feature called “local dimming.” It’s not nearly as precise or effective as actually turning off individual pixels and adjacent high contrast images often produce a halo artifact.

CCFL Or LED Backlit LCD TV?

A relatively recent advance in LCD technology uses LEDs (light emitting diodes) to illuminate the picture in place of the more commonly used thin fluorescent tubes called CCFLs. Though some set manufacturers choose to call their LED backlit sets “LED TVs” they are still LCD TVs!  However, LED backlighting has a number of advantages, one of which is lower power consumption compared to both traditional backlit LCDs and plasma. For a given screen size, plasma and CCFL backlit LCDs have about the same energy efficiency.

Another LED advantage is the production of very bright images, which makes them preferable to both CCFL backlit LCDs and plasma if you day a lot of daytime viewing, especially in windowed rooms that lack shades or curtains.

Edge Versus Backlit LED

Manufacturers use LEDs to either edge light or back light their LCD sets. Edge lighting can produce thin profile sets that are just over an inch deep. Back lit sets are deeper but  offer the aforementioned advantage of local dimming, which can produce extremely dark black levels.

Edge lit LEDs have white and black uniformity issues at the picture perimeter while off-axis brightness of both LED formats tends to fall off somewhat more rapidly than does the same panel lit using traditional CCFLs. However, overall, LED backlit sets produce the best LCD pictures.

60Hz/120Hz/240Hz

Standard LCDs incorporate a 60 Hz refresh rate. This produces motion resolution of around 320 lines (per picture height) out of a possible1080 lines. 120 Hz refresh ups the motion resolution to around 600 lines, while 240 Hz kicks it up to 900 lines or higher.

Some sets incorporate circuits that produce even more frames per second in an attempt to further smooth motion, but the added smoothness comes at a price, which is an increase in picture artifacts (see related story here link).

For the best LCD picture, either traditional or LED backlit, choose one with either a 120Hz or 240Hz refresh rate. However, all 1080p plasma sets produce artifact free, full 1080 line motion resolution. Panasonic’s V and Z series plasmas offer a 96Hz refresh rate that produces images free of the judder found in all 60 Hz  panels (plasma and LCD) without the artifacts associated with 120/240Hz LED/LCDs.

Special Features

If you’re looking for the most accurate image reproduction, consider THX Certified designs that provide near ideal out of the box color temperature and color point accuracy when set to the THX picture option. User calibration controls included with many top of the line HDTVs allow (with proper test equipment and signals) near perfection image fine tuning.