slow to normal to fast motion

J

JitCam

Well-known member
If anybody can help..i got a question regarding a technique which involves using slow motion which goes to regular motion within the same scene. In other words I want to shoot an action scene which will involve slow motion at points which will then go to faster motion or regular motion, from what i know this has to be done in post right? would i shoot the whole scene in slow motion then speed it up at the point i want?


thanx!
 
yep, shoot all at 50fps. You can then play with animation curves.

Your cheapest route would be getting shake and using adaptive retiming.
If you already have FCP studio, then use motion.
 
so this shouldn't be done in FCP by just ramping the speed? how would you do it in motion? i haven't messed around with that a lot.
 
how about for pc? i use vegas and after effects, im sure this is possible in after effects.. anybody have any experience with this?
 
It is possible in After Effects, if you have version 7 or greater. Look for time remapping when you right click on a clip that has been inserted in the compilation. For further information, a good reference tutorial is found amongst the many at Video Copilot
 
FilmBoy77, there are the standard editing package retimes that are basically either frame duplications or frame averages. Good for blocking out retime pacing etc, used all over the place, but questionable and jerky/mixy results.

Then there's optical flow, or adaptive retiming. Shake has it, so does Motion and other packages. This is where the motion in the shot is analysed by the software, and 'inbetween frames' are then created by the software, giving much smoother/better results. This comes from military research into motion estimation, used for satellite image analysis etc. About a decade old in all.

At the top you have specialist software/plugings such as Twixtor (which I use), Cyborg, Retimer etc. This is cutting edge optical flow software, same type of technology as Shake, Motion etc, but developed further, and costs accordingly.
Shakes adaptive retiming is equivalent in quality to Cineon's Cinespeed (the software was dropped by Kodak about 7 years ago). The current Twixtor is much more refined than this (7 years more developement really)
Twixtor for example allows you to define layers in a scene to help with object 'occlusion', and use trackers and rotoscoping to guide the flow, and refine the quality of the retime.

I use Twixtor in Shake, but you can also get it for FCP, After Effects, Fusion etc.

JitCam, check out the sample movie on their webpage:

http://www.revisionfx.com/products/twixtor/
 
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After Effects in version CS3 has adaptave retiming capabilities. Previously it merely blended the frames on each side, but there's an extra setting in the CS3 release that will interpolate new frames for you. I don't know how well it does that in comparison to the plugins etc., but its there if you have CS3.
 
Motion 3 does a very credible job in achieving this effect. It incorporates Shake's functionality

I would shoot in a p mode however.
 
JitCam, check out the sample movie on their webpage:
Click to expand...

yeah ive heard of twixtor, i used it a couple of times with my old minidv cam.. but im sure it will be much better with my hvx. I will definately give it a try. another thing... does using plugins like twixtor or speeding up the footage in afterfx or another NLE create any quality loss? lets say you shoot at 50fps for slomo, and you want to speed up the film at a point... this is done naturally i presume in the editor? Or is there recalculations involved which cut back on the quality? Im looking for a way to do this with no quality loss or motion artifacts, just pure fast and slow motion effects.

btw sorry about all the questions.. i will be getting a p2 card in about a week or so, so i havent got the chance to actually test this stuff on my own yet!
 
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