slow motion help

diego1235467

diego1235467

Well-known member
I'm trying to get the smoothest slo mo possible, but I have a few questions.

First of all, the best way to get slo mo I've found is using Optical Flow in Motion. I recorded a clip using 60i on my 100a, captured it into FCP, and then sent it to Motion. Once in motion, I changed the timing to 40% and used Optical Flow. I then saved it and brought it back into FCP with fantastic results. On to my questions.

1. Would Optical Flow work just as well with 24p footage as opposed to 60i?

2. Once the footage was back in FCP, the length of the clip was the same as it was in the original speed. When the slo mo was done in FCP, the clip became much longer. Is it simply smaller because the slo mo was done in Motion? Is this normal?

3. When doing slo mo work in 60i, what seems to be the best shutterspeed to use? do we want motion blur, or no motion blur?

4. In your guys' opinion, what is in fact the best way to do slow motion?

All help is greatly appreciated.
 
There is a plugin for FCP called twixtor that does pretty good slowmo, inside FCP, so no need to go to Motion.

I found that the optical flow retiming thing worked well for some things and not others. I shot some fire at 200 frames per second and then slowed it down again by 50 percent using optical flow in post, and it looked very nice, however filming something like sport dosn't really slow down too well in post.

http://www.vimeo.com/5035917
 
So what would you say is the best way to create slow mo using 60i video? That 40% looks choppy unless taken through Motion.

(I'll look at that Twixtor plugin).
 
I cant remember what the reasoning behind this is, but someone told me once that slowing video by 33 percent or 66 percent gave the best results.

Try 33 percent instead of 40 and see if that looks better....
 
I may have to try this, though it seems pretty damn complicated. Motion works well, but it's slow as hell to render even the tiniest clip, and the more movement the camera has, the more distortions the image gets. I'll try that method and see if it works.

Anyone else have other ideas?
 
There's a great way to do slow motion by taking 30fps interlaced footage and splitting the fields to give you true 60 fps progressive and then conforming THAT to 24... better than 50% slow down. I do it in shake, but can be done in compressor too.

Here's an example of it -- slow motion starts right before 1min in.

http://web.mac.com/captmench/Site/Zachary_Movies/Entries/2009/8/9_Fountain.html

I have a tutorial for 60i to 24p in Shake... but not for compressor, though I've done it before. Maybe after SnowLeopard is released I'll do another with the compressor variation. Let me know if you like it first -- then I'll tell you how I did it.

Mike
 
diego1235467 said:
It looks pretty great!
You can't shoot 30i on a DVX though, can you?
Click to expand...

As CaptMench said, it's 29.97 interlaced (or, in the case of a DVX, Progressive "Off"). The confusion comes from the fact that some people call it 29.97, some call it 30i, some call it 60i. They're all talking about the same thing.
 
diego1235467 said:
It looks pretty great!
You can't shoot 30i on a DVX though, can you?
Click to expand...

Nope, that would be 15 fields (half frames) per second. You can shoot 60i on a DVX, and if you're going for slow motion the more FPS the better.

While not a solution for already shot footage, a bunch of Sony HDV cameras can shoot at 120fps bursts if you want something really smooth for slow mo @ a cheap price point.
 
I tried a software called JES Deinterlacer, and I've gotten pretty satisfying results. I'll post the video, but there are a few problems.

For some reason my videos aren't uploading right, and end up jumpy and overall ugly. If you guys can help me out on that issue, I put a post in the Cafe section.

Second, the shot doesn't show much motion except for the camera, so it doesn't show the slow mo very well, but hopefully you get the idea. I'll try to get a better test shot, and put it up once I know what I'm doing wrong in the upload process.

http://vimeo.com/6293852
 
zijital said:
Nope, that would be 15 fields (half frames) per second. You can shoot 60i on a DVX, and if you're going for slow motion the more FPS the better.
Click to expand...

30i is actually what the manual calls it. D'Oh. It is 29.97 interlaced. 60i is too confusing. Sounds like 60 frames interlaced a second.

CaptM
 
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