R5 does amazing super slow motion equivalent to 240 fps

Markr041 wrote:

Rudy Pohl wrote:

Markr041 wrote:

Rudy Pohl wrote:

One thing I really like about the R5's video capabilities is that the image quality of its 4K120p ALL-I format, which outputs at a staggering 1880 Mbps, is so good that you can slow down the footage another 50% in post giving you effectively 240 frames per second—and it still looks good.

Have a look at the last clip in this little sequence and see what you think.

Rudy

By the way, this is the area where I grew up and still live today and it just happens to be the best Snowy Owl country in Eastern Ontario. How great is that?

I am confused by what you did and what you are claiming.

How slow the 120 fps footage is in the rendered video depends on the frame rate you choose for the timeline. If you choose 60 fps, then stretch, the slowdown is 2X. If you choose 24 fps, and stretch, the slowdown is 5X. So by changing the timeline fps I can more than double the slow down with no loss of resolution.

So, what do you mean you can slow down another 50% in post exactly? And why is that equivalent to 240 fps?

Just to show I shoot 120P 4K with the R5:

I think I used a 30p timeline, so the slowdown is 4X. But I could have increased the slowdown by 25% with a 24p timeline to 5X. Now if I wanted more, then I would have to interpolate frames. Is that what you did?

240p with with a 60 fps timeline is 4X, with a 30p timeline it is an 8X slowdown. Is that what you are showing from the 120 fps shot video? 8X?

Hi Mark,

Sorry for the confusion and that I wasn't clearer. Let me try that again.

- In the SHOOT1 menu I set the format to 4K-U 119.9P ALL-I.
- As you know, the R5 internally processes this footage and outputs it at 29.970fps.
- This output as I understand it is 120fps slowed down x4 or 1/4 normal speed.
- I place this 29.970fps output footage on a 29.970 timeline to maintain 120fps.
- I then reduce the Speed of the timeline by 50%, which halves the frame rate to 15.285fps (seen in DaVinci interface) which results in effect similar to 240 fps.

This footage was not originally sampled at 240fps, but at 120fps, so it should not be considered as true 240fps footage. I referred to it as "equivalent" to 240fps to make the distinction. However, the image quality of a true 240fps sample would be much higher than a 120fps sample so I probably should have referred to it as "somewhat similar to" 240fps instead of using the term equivalent.

Hope this clears things up a bit.
Rudy

Yes, thanks. Perfectly.

One suggestion, by doing what you did DaVinci Resolve has to make up the missing frames. If you use the option "optical flow" to do that, it will do an even better job on interpolation. It is slow but works very well.

Hi Mark,

Glad this helped, again sorry for not being clear.

Regarding Optical Flow... I always use this option when I do Davinci-based post-production stabilization except for the odd times when it produces wonky results. For example, I found that it's nearly impossible to get my panned clips to play back smoothly without using Optical Flow. I also find that the "Enhanced Better" option in the Motion Estimation in the Retime and Scaling section works well with Optical Flow.

By the way, nice to chat with a fellow Davinci user.

Cheers,
Rudy