Is a 100hz or 200hz Lcd or Plasma TV worth the premium?
An Introduction to 50hz tv pictures
A regular PAL television changes the picture at a frequency of 50 Frames Per Second (FPS) or 50Hz. The illusion of movement in the picture is produced by the successive frame changes of the picture 50 times per Second. A 50 FPS (50Hz) Cathode Ray Television (CRT) creates the picture with an electron scan and there is a visible flicker that is sensed by the human eye.
The Human eye is at occasionally sensitive to this frequency depending on the intensity of darkness, the speed of the image, and the degree of brightness thus you will occasionally notice the picture flicker on a 50Hz TV. The flicker becomes more apparent on larger screen.
How 100 hertz used to work
A 100 FPS (100Hz) television operates at twice the Frequency by creating a copy of each frame and putting it after the one before. As a result of doubling the scan frequency to 100Hz and inserting a duplicate frame this effect is eliminated, as far as the eye is concerned. The consequence of this is to drastically lower the flicker.
How does 100hz work on LCD and Plasma Tv ?
LCD and Plasma televisions dont produce flickering because they don’t produce the picture with an electron scan. However LCD TV’s still benefit from 100Hz because advanced digital circuitry creates an extra frame or middle image. This is done by the TV inventing an extra frame using complex interpolation and motion compensation calculations to work out what the extra fields and frames look like rather than inserting a replica frame. (e.g. the second frame is not the same as the first frame).
However even at 100 FPS the picture still does not deliver a entirely smooth picture particularly with fast motion images. Some television manufactures attempt to reduce this further by employing digital picture processing. Typically there is still a little blurring on quick moving images but the benefits are clearer and better-defined surfaces, sharper pictures, and smoother movement than is possible from 50 Frames Per Second Plasma and LCD televisions.
e.g. For a football that travels ten pixels from left to right between frames one, two and three, the 100 hertz TV will digitally create two further frames between one and two, and two and three, between which the ball will move five pixels. This will result in five frames where the football moves a total of ten pixels i.e. the original frames one, two and three plus the digitally created frames inserted between one and two, and in between two and three. The result of this is that the eye sees an image that moves smoother than before.
The benefits of 100 Hz
100Hz televisions have the clear benefit of eliminating a lot of the ghosting effects occasionally seen in LCD TVs. Ghosting effects caused by the next image being shown before the earlier one has faded away. Even on Plasma tv the creation of the middle frame results in a more fluid picture
Manufacturers such as JVC, Panasonic, Samsung, Toshiba, LG, Sony, Philips, Hitachi and Pioneer have got 100 hertz Plasma and LCD televisions.
Sony lead the way into 200Hz
Sony has just launched a 200Hz range which digitally inserts three additional frames between the original 50Hz frames. The effect of this is that fast moving sequences are delivered with a smoother, more fluid and sharper picture than 50Hz or even 100Hz TV’s.
Additional benefit for photosensitive epilepsy sufferers
Studies have shown that 100Hz televisions can help prevent seizures in patients with photosensitive epilepsies when viewing television or playing video games.