Hello Surapon,
Since this thread hasn't picked up speed, I guess I will step up to explain a few things. And, I owe you that explanation, because you quoted me, and I didn't want you to run around with false information.
First, Canon DSLRs does do 23.98 FPS, 25 FPS., 29.97 FPS, 59.94 FPS... possibly 50 FPS and 120FPS (I think I'm rounding up with that last number; I'm just going to round up all the numbers from now on), and it depends on the cameras. I believe the Canon 80D, 7D mark 2, and the 1DC are the only cameras in the EOS line up right now that can do 1080p at up to 60 FPS; and only the 1DX mark 2 can do DCI 4K at 60p and can go up to 1080p at 120 FPS. Lets avoid talk about the other cinema cameras....
Now lets organize the different frame rates in terms of encoding systems. So all of North America, the top part of South America, and a few other countries use NTSC. Most European countries and Asian coutries use PAL.
NTSC frame rates are 24, 30, 60 & 120.
Whereas PAL uses 25, 50 & 100.
Its gets more deeper than that, but for general purposes, if you record in NTSC and then go overseas and its not working on their DVD/Blu-Ray players... well thats why... cause they are using PAL... if you really want to read more on PAL/NTSC/SECAM:
https://en.wikipedia.org/wiki/PAL
With that said, I know I said 24fps = cinematic, whereas 30fps = documentary/home video.
Its all personal preference too.
I guess I'm programmed to think 24FPS is cinematic.
Do this as an exercise. I know you probably have a camcorder, go record your family having fun in the park. Or watch an old event video, preferrably an old birthday party or wedding video. Put that aside.
Then go grab 3 to 5 of your favorite movies, and watch them straight, when you have time. No interruptions, just watch them on your computer, tell your wife its research for work or whatever. Preferrably blu-ray, but DVD is fine.
Then go grab your DSLR, record something in 24p, then record something else in 30p. Lastly compare what you have on your DSLR to that camcorder or event video, and then compare them to the movies you watched. What do you prefer??? What do you think is cinematic?
When you are shooting video, always remember double the shutter speed. So when you are recording 24p, set your shutter to 48 (50 if 48 is not available); and when you are recording 30p, set your shutter speed to 60.
Another example, when you are shooting at 100fps or 120fps, you set the shutter speed to be 200 or 240 (250 if 240 is not available).
I think you should watch this video to fully understand why you need to double the shutter speed:
https://www.youtube.com/watch?v=1ufPJk0MxJ4
Now for slow motion, the best way to understand it is.... lets say you shoot at 120fps.
How many frames more is it compared to 24fps? Its 5 frames more per second, thus 24X5 = 120fps.
What does that mean?
Imagine you are taking pictures, when you use your 5D SR, it can take 5 pictures per second (more or less). Technically speaking a frame is basically a picture.
And 24 pictures per second is the lowest frame rate needed for the eyes and brain to think its video.
So if you film at 120 pictures per second, you can think of it in 2 different perspectives... It takes 5 times longer to do a movement when slowed down, or you are crunching 5 frames into each frame of 24 FPS.
Its the same theory behind 60FPS, only its 2 times faster than 30FPS, and 2.5 times faster than 24FPS
Lastly, a few words about Twixtor and Timewarp... these are computer programs, effects modules in non-linear editors (NLE). What these programs do is.... it fakes slow motion by multiplying the frames. Remember, each frame is a picture. So for example, what Twixtor and Timewarp does is... take your existing footage, lets say it was all recorded in 24FPS, and you say... "crap... I want slow motion, but can't do it cause it was all recorded in 24FPS." Say you want want 120FPS, what Twixtor does is it takes each picture of the 24 picture per second video and copies each picture 5 times. So 5 of the same pictures over and over again...
The problem is this is not the same as recording video at 120fps, because there is a lot of micro-movements between each frame. And, it will become very evident when you slow the 24fps footage down with Twixtor/Timewarp, for example, you will definitely see a lot of warping.
Here is an example of warping:
https://www.youtube.com/watch?v=CCnYszQgieE
The other thing is... Twixtor/Timewarp is not usually used for small slowmotion tweaks. Nobody wants just 60FPS or 120FPS, in fact... if you only want small tweaks like that from your 24FPS footage... you dont' even need Twixtor/Timewarp... your regular NLE has a way to slow it down.... I never go below 75% of the regular speed, it gets really weird below 70% of the regular speed (if slowed down from your 24FPS footage).
What everyone really wants is 1000FPS and 2000FPS... and Twixtor/Timewarp can deliver that... and it works best with video that was captured in high speed. So, remember my first post in this thread, I put up 2 videos, the first video was done on the original 7D - 720p at 60 FPS. That guy used twixtor to slow it down to 2000FPS.
I'm sure the original creator of that video ran into warping too....
If he can do that with 60 FPS, imagine what he can do with 120 FPS.
If you have any more questions, feel free to ask.
I'd rather not. Going for 1dx2 for still-reasons, would give me the video dpaf "for free" in a sense.
