Every year it seems there's a new catchy spec in the HDTV realm everybody likes to talk about. A few years back it was 1080p resolution. Then we heard about 120Hz, which is supposed to reduce motion blur in fast-moving images on LCD TVs. Well, this year, the latest and greatest spec is 240Hz, which is supposed to do what 120Hz does, but better.
Not too long ago, our video guru David Katzmaier gave his initial impressions on 240Hz in a post titled "Is 240Hz worth waiting for?" When he wrote that piece, he'd just seen his first 240Hz TV in action and wasn't sold on the new technology. Now that he's reviewed four 240Hz HDTVs and has a fifth review (the LG 47LH55) in the works, he's still not sold, but he admits the verdict isn't totally clear-cut.
Part of the problem is that there's a difference between what your eye sees in everyday material you watch and objective testing done with test patterns. As Katzmaier notes in his post, "Standard LCD and plasma TVs refresh the screen 60 times per second, or 60Hz, which is plenty fast enough to eliminate flicker and create the illusion of motion from a series of still images. In fact, most sources sent to your display arrive at the nominal rate of 30 frames per second, and each frame is repeated once by the television to achieve 60 total fps."
For most people, including me and Mr. Katzmaier, it's very difficult to see the impact that "faster" LCD sets have on picture quality. We spent some time in our AV lab watching various source material from 120Hz TVs and 240Hz models and it's really hard to detect any difference (it's hard to detect any difference between 120Hz and 60Hz models, too). To be clear, I'm referring here to motion-blur reduction because of faster refresh rates, not to dejudder processing, which smooths out motion and makes film-based material shot at 24fps look more video-like. When dejudder is engaged, you can easily spot its impact on the picture. (It's also worth mentioning that the dejudder processing on the 240Hz TVs we tested so far wasn't any better--or worse--than than the dejudder on 120Hz TVs). … Read more