Shooting for Twixtor

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dvx_yaaaaaay

Active member
Hey guys.

I'm doing a shoot next week where a chair will be thrown across the frame, and I would like to slow it down v e r y s l o w. I have Twixtor 4.0, but have never had the opportunity to use it thus far. I have been told it would work well for this effect. My question is, how would I go about shooting for the best Twixtor slow motion? I'm assuming 60i, but should i use a faster shutter speed? Help is very much appreciated.
 
For film, the faster the shutter speed, the slower and smooth the movie is. The slower the shutter speed, the faster and ultimately more choppy the movie is. You want to film at as many FPS as your camera can handle, because speeding up frames isn't a problem - your computer can delete some or blend them together - making fast framerates slower presents a problem, because the computer cannot create new frames, it usually just doubles each frame, which makes it even choppier than before.

So, you want to shoot at the highest shutter speed possible. The only problem is the sound will not sync. You should use a separate microphone and slow it down, or just add sound effects later. Twixtor does work for this effect, but a basic NLE can suffice.

z
 
i'm sorry but shutter speed really has nothing to do with slow motion. in film, film cameras use an adjustable frame rate to acheive slow motion. so you shoot at 96fps and then playback at 24fps to achieve slow motion. adjusting the shutter speed affects the amount of light going into the camera. a slower shutter speed lets in more light; a higher shutter speed lets in less light. zach you did mention "FPS" and that's right, but shutter speed and frames per second are two different things.

as for twixtor i wouldn't shoot 60i because even though you're thinking more frames will give you a better slow motion look. you need 60 full frames not 60 interlaced frames. your video will get deinterlaced and you lose a field of resolution. best bet since you have a DVX shoot either 30fps or 24p and get full resolution to work with and your video will look that much better.

just in case you missed it...

http://www.dvxuser.com/V6/showthread.php?t=49917
 
Twixtor Quirks....

Twixtor Quirks....

dvx_yaaaaaay said:
Hey guys.

I'm doing a shoot next week where a chair will be thrown across the frame, and I would like to slow it down v e r y s l o w. I have Twixtor 4.0, but have never had the opportunity to use it thus far. I have been told it would work well for this effect. My question is, how would I go about shooting for the best Twixtor slow motion? I'm assuming 60i, but should i use a faster shutter speed? Help is very much appreciated.
Click to expand...

I use Twixtor a great deal, because I rotoscope footage (turn video in animations) at 12P or even 8P, which I then bring back into FCP and use Twixtor to generate the "tween" frames, back up to 24P which is what it was shot at in the first place. It creates a more fluid motion than just doubling or tripling the frames, or using straight up frame blending. The thing about Twixtor is it is EXTREMELY texture dependent, meaning, it needs to be able to see the detail of your footage well otherwise the guess it makes will result in a "splatter" frame. This does not mean just turn it over to thin setting, as that may be the exact opposite of what it needs to do it's job right. My suggestion, shoot the footage numerous times. Look at how the lines of motion of the shot line up - is everything clearly defined? Is something distracting behind the chair from the chair's motion?

As far as shooting 60i goes, my personal notion would be for Twixtor, shoot 30P or 24P instead, as it doesn't seem to react as well to deinterlaced footage versus true progressive in my experience, and if you shoot 60i, you'll need to deinterlace it in post. Make sure things are well lit, well defined with lighting, shadows aren't distracting, and perhaps fall out of the frame, otherwise Twixtor might mistake a shadow for a moving object, or make it part of the object. Also taking your footage and using a texture skeleton as an Alternate Motion Source when processing helps a great deal with high motion footage. Here's yet another suggestion. If possible, make this a static camera shot, and only have the chair moving itself, not the camera. It will help Twixtor a great deal. Good Luck!!!
 
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novelt said:
i'm sorry but shutter speed really has nothing to do with slow motion. [/url]
Click to expand...

I knew what I meant, and I know what you mean. Haha, I really did type shutter speed. I meant to say frame rate, but yeah, I see how that's confusing. Shutter speed doesn't have anything to do with frame rate, but I think one mistake per forum is okay.

Haha, thanks for catching me on that one.

Z
 
but zach you may be on to something...adjusting the shutter speed does make the image less blurry and more crisp. doing so would help create better images with detail for twixtor to work with. as duct tape noted you could end up with a "splatter"...i have MotionPerfect and have made some great looking slo-mo videos with it, but when people are running do to the blur you could get a 3-legged person. ah but if you can reduce the blur by adjusting the shutter speed...see where i'm going. so your mistake zach was a great find...just like all great inventions :thumbsup:
 
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