With 240Hz LCD TVs on the market now, the question is whether it’s worth the extra money to make that one of your shopping criteria.

Sure the manufacturers are going to have demonstrations and the numbers to suggest the real-world difference in 120Hz and 240Hz is extremely great. Sure the test patterns specifically designed to highlight these differences suggest that 240Hz is a “must have”, but in regular viewing

it’s probably not noticeable.

The deciding factor in paying extra for the latest-and-greatest option, in this case 240Hz operation is, does it improve the television viewing. Unfortunately, 240Hz operation alone probably isn’t something to get overly excited about, and definitely not anything to pay a lot extra for. Sure a high refresh rate is desirable, but even 120hz should be sufficient to create a motion-blur free image.

With standard television refresh rates of 60Hz, or 60 times per second, that should theoretically be enough to produce a blur-free image, especially when you consider film is 24 frames per second, but LCD technology is just  different.

Motion blur like this isn’t an issue with plasma or other display types, whether 60Hz or otherwise, because they use different methods to create the illusion of motion.

When you add in dejudder processing in the LCD televisions, which smooths out motion and makes film-based material shot at 24fps look more video-like, you do see a very noticeable improvement in the 120Hz, and especially the 240Hz devices.

To reduce blurring, most 120Hz LCD displays use a system called MEMC (motion estimation and motion compensation) to slip in a new frame between each of the original frames. The end result is one extra frame for every true frame.

You’d think, then, that a 240Hz TV would just double up to achieve an even more blur-free picture. Alas, it’s a little more complicated than that. The problem is there are actually two different types of 240Hz, including one that doesn’t bill itself as true 240Hz but rather as a “240 effect.” Here’s a breakdown of the two versions and which companies employ them.

  • MEMC (motion estimation-motion compensation): Both Sony and Samsung 240Hz sets use MEMC to basically double the 120Hz process described above. However, instead of getting one extra frame for each “true” frame, you actually get three extra frames. (See reviews of the Sony KDL-52XBR7, the Sony KDL-XBR9 series and the Samsung LNB750 series).
  • Scanning backlight (240 effect): LG, Toshiba, and Vizio use what’s called “scanning backlight” technology. Such TVs use MEMC once to get to 120Hz, but instead of doubling the interpolation, a backlight flashes on and off very quickly to achieve what Toshiba calls a “240Hz effect.” LG, for its part, fails to make that distinction and uses the 240Hz term without qualification to describe its scanning-backlight models.

Although there might be a very small difference in the two versions of  MEMC, the bottom line is, the real-world difference in the 120Hz and 240Hz LCD TVs isn’t very noticeable, and most would be better off putting the extra money into their new Blu-Ray device.

Although motion-blur is something you want to avoid, the latest LED LCD TVs, and the LED DLP TVs are at a state that most people will be totally satisified with which ever slection they make. The extremely descriminating (picky) viewer will probably always be able to find a slight flaw in any television image.

Filed under: LED TV News