I believe (and I could be wrong) the the 18-24 frames per second was the standard on old technology tv's.
Read up first on how the eye works vs frames per second and with motion here:
add a 'w' to the link below...this forum won't let me post URL's yet...
ww.100fps.com/how_many_frames_can_humans_see.htm
The USAF, in testing their pilots for visual response time, used a simple test to see if the pilots could distinguish small changes in light. In their experiment a picture of an aircraft was flashed on a screen in a dark room at 1/220th of a second. Pilots were consistently able to "see" the afterimage as well as identify the aircraft. This simple and specific situation not only proves the ability to percieve 1 image within 1/220 of a second, but the ability to interpret higher FPS.
With the higher resolutions we watch today, the high-action motion picture actually needs more frames per second so the picture doesn't get all sketchy looking. The reason for the higher HZ is to support the higher frame rates.
You can prove this for yourself by simply ripping a high-motion action movie DVD (martial arts movies work good for this test) movie to 24 frames per second and then trying to watch it. You will see areas where your eye can fully detect missing elements of the action because there aren't enough frames in the screen to catch all the movement. Now repeat the test at 29.9 frames per second, and you'll notice the difference. But even at 29.9 you'll see some artifacting during high motion scenes. Now pop the DVD into your dvdplayer and watch it in comparison to the two above. Notice how it's all nice and smooth? several factors are being utilized to get the images to this quality.
Most human's eyes can see these issues at 24 frames per second, but as we approach the eye's limits (30 frames per second) the issues start to dissapear.
Now the only reason they added 60 frames a second at first, was to do interlacing or progressive scanning. The second frames get scanned in between the first ones, therby making the motion smoother.
What the hell 120 frames per second is going to do for you, not sure. We simply can't see that fast. It must be for future compatibility for things like 3D, where they need that extra band width for the other eye.
I'm with you guys though, the current options are way too expensive.
But I'm glad I was born when this stuff is being invented. Over the next 5-10 years we're going to see some very amazing devices come to market.
Question is, will we be able to afford them without mortgaging our houses...
~~Startiger