Difference between 60hz and 120hz?

[SvennoJ]

Hynad said:

slowmo said:

Hynad said:

slowmo said:
I think the difference of a 120Hz TV to the 60Hz TV's is more to do with the beefed up scaler they use in the TV's rather than any actual big wow factor from the frequency as most sources will never exceed 60Hz except for 3D content and PC's.

The main benefit I see with 120Hz sets is that unlike 60Hz sets, 120 is a multiple of 24. 

So the standard of 24 images per seconds from the movie industry fits confortably in there. Meaning that the TV doesn't need to do the 3:2 pull down to compensate. Which introduces judders especially noticeable during camera pans. 24 FPS actually fits 5 times in 120. So the TV plays each frames 5 times, making for a smoother experience than on 60Hz sets.

That's only Bluray sources really though, every other source would usually be 60hz.  I just don't see the point of creating extra virtual frames personally.  My projector supports 24-120 hz but that was bought for 3D mainly rather than any perception of smoother performance.

The tv creates virtual frames only when the interpolation option is on. Otherwise, the TV [wont' create frames, but] will play 5 times the same frames if it's a 120Hz set, or 10 times if it's 240Hz. Otherwise, it will use 3:2 pulldown and judder will be introduced. In fact, for as long as we've been using 60Hz TVs (since before anyone here was born, really), we've been used to the imperfect motion of 24 fps for movies. That's why when you watch a movie like The Hobbit at 48Hz, it looks quite weird.

That doesn't make any sense for LCD/LED tv's. They don't paint an image over and over like CRT or DLP. The back light is always on. Playing the same frames 5 times is identical to only changing the LCD state 1 time. 60hz tvs are perfectly capable of timing the LCD state updates every 1/24th of a second. 3:2 pulldown has not been a problem for a while.
3:2 pulldown doesn't introduce judder, judder is there because 24fps is pretty low for pans. It is more noticeable in bright environments then in a dark cinema. The darker it is, the lower the frame rate you need to perceive smooth motion. If you want to lessen the impact of judder without affecting picture quality, turn off the lights and turn down the brightness.

3:2 pulldown is a messy way that uses interlaced frames to convert from 24fps to 30fps, it doesn't even convert to 60hz

Glad to be rid of that mess :)

Fine motion creates new frames, for 24 fps movies instead of A-B-C you get A A2 A3 A4 A5 B B2 B3 B4 B5 C. Just as we finally got the movies as they were made, we're going to even more radically change the source material.

For 30fps games you get A B C -> A A2 A3 A4 B B2 B3 B4 C. Obviously this can only be done after the next frame has been received, adding a full 33ms before any signal processing can start, actually some sets have been reported to add over 200ms of lag with enchanced fine motion turned on.

Here is an interesting article on why The Hobbot at 48fps looks fake:
http://movieline.com/2012/12/14/hobbit-high-frame-rate-science-48-frames-per-second/

But scientists and researchers in the field of consciousness perception say that the human brain perceives reality at a rate somewhere between 24 fps and 48 fps — 40 conscious moments per second, to be more exact — and exceeding the limit of the brain’s speed of cognition beyond the sweet spot that connotes realism is where Jackson & Co. get into trouble.

They’re not taking into account what’s called The Uncanny Valley in psychology. The Uncanny Valley says that, statistically, if you map out a consumer’s reaction to something they’re seeing, if they’re seeing something artificial and it starts to approach something looking real, they begin to inherently psychologically reject it.

120hz enhanced fine motion will solve the judder problem, at the cost that everything looks soap opera fake.