Slow-Motion problem & a few related questions

[Asker]

Hello everyone

I'm making my first music video, where I've shot a few clips that were meant to be in slow-motion using "Twixtor", but to my dissapointment they're full of warping.

I was wondering which settings you're meant to shoot in? I know that the highest possible fps is recommended, which is why I shot my "slow-mo" clips at 50 fps on my Canon 550D/T2i (highest fps is 50). I've also shot them with 1/100 shutterspeed, however they seem to be warping when using Twixtor even at 50 % speed. I've noticed that it's impossible to use slow-motion and Twixtor with a moving background, but I even have some clips of a "Graffiti-bottle" spinning around with full depth of field, and still I notice it is warping.

I'm using Sony Vegas, Twixtor Pro plugin and my project is 24 fps.

I've read on some sites that you should try to reach a 1/1000 shutter speed, BUT let's say I went with that, how the heck is it going to be bright? I know for a fact that 1/1000 shutter speed takes a lot of light, and no one wants to use 6400 ISO and get a completely grainy clip.


So, is it possible for me to use my current clips with 50 fps and 1/100 shutter speed and get a proper slow-motion? Is it Sony Vegas that is the problem? Or is 1/100 shutter speed not enough? And how do I use 1/1000 speed with enough brightness?

Thanks in advance!

 

[Asker]

Maybe I should have a mod move this to the "Newbie" section.

 

[ItDonnedOnMe]

And how do I use 1/1000 speed with enough brightness?

Add light.

Programs like twixtor can't work magic - they're basically mapping the trajectory of every single pixel in the shot, and then guessing at the in between positions in order to create the new frames. It's very difficult to do this accurately, especially when pixels get occluded - moving behind foreground elements - or are indistinct.

Generally you'll get the best results when the background is relatively smooth and featureless - think someone jumping a bike against a blue sky. Backgrounds like that hide any distortion.

Complex backgrounds are always going to be a challenge. The suggestion to use a higher shutter speed is intended to remove shutter blur; blurred elements are more difficult to track from frame to frame than ones with clear, sharp details. This means you're also going to have problems with backgrounds that are blurred due to shallow depth of field - so you'll probably need to run at a higher aperture (5.6-8) and stick to wider lenses so that the whole shot can be in focus. The required combination of high aperture and high shutter speed means you only have one option to improve your results...

Add light.

 

[WalterB]

A bit too late for you, but for anybody else it may be in time:

if you want to try something completely new: do a little test before shooting for real...

About lights:
kino flos or (some?) LED show no or hardly noticable flicker up to 400 fps.
But you'll need a lot of LEDs.
HMI and tungsten usually do at some point, depending on the lights and the ballast.

About warping:
software can't really tell forground from background, it only sees different pixels. (Hence the reason for high shutterspeeds) And that can cause huge problems indeed.
The software also just understands 'lineair' movements. Vortex like or other 'organic movements' like waing curly hair easely causes distortion as well...

 

[Asker]

I'm sorry I didn't get to reply to this thread a little earlier, but your questions kind of answered what I was looking for! I'm guessing it was the background that was the problem.