Slow down/speed up effect?

A client is asking for some of these slow down / speed up effects.
As at about 0:55 in this video:


Anyone have some good tips on how to achieve those in FCPX? Is there a name for them? Any tutorials anywhere?

And, I assume they work best when footage was shot in slow motion to begin with? Anyone had any success doing it with footage not shot in slowmo? Footage actually doesn't look very good when slowed down 50% but client is persisting so though I'd explore it a bit...

thanks

Variable speed Retiming:
www.geniusdv.com/news_and_tutorials/2011..._final_cut_pro_x.php

And to get a better slowmo, you can try:
- select your clip and choose in the Retiming menu: video quality -> optical flow
- or alternatively you can try the plugin Twixtor

User manual.
help.apple.com/finalcutpro/mac/10.2/#/ver15f86b6a

Yes, true slow motion is almost always better if you need to slow down to that point. That said, in the video you linked, it doesn't look like there was any true slow motion and it still looked OK when they slowed it down. Keep in mind that if you shoot slow-motion, you will likely not get the same kind of motion blur as normal speed, depending on the framerate.

Btw, the geniusdv link is for sure outdated. The help file above is up to date. One of the key differences is that you control how smooth the speed-up or slow-down is. Also, I think they added blade speed (shift- at some point, so you don't have to select a range. You can simply blade-speed where you want the ramp, and then adjust the speed of each side accordingly.

Motion blur is an artifact of bad slo-mo.

They shot at faster frame rate (60), dropped it into a timeline of slower frame rate (24).

Yes, there is slo mo there, all in camera, very simple & easy. All in the user manual.

I think what haysoos means is the lack of classic motion blur when shooting at higher frame rates. Traditionelly shooting 24p at 180 degrees shutter results in 1/48 shutter speed. This leads to a certain amount of motion blur when moving the cam or the subject at enough speed. When shooting at higher frame rates you have to reduce the shutter speed accordingly to be physically able to shoot, say, 120fps. This results in a crisper picture with less motion blur (think of "Crank") so the slomo might in fact look different.

Thanks all. Will try and see if I get it

One thing: I cannot select "Optical Flow" all the options in Video Quality are greyed out (with "normal" selected). ANy idea why this is?

Ripple Training has a great video about the Blade Speed thingie:


Now it's starting to clear up