24p slow mo

xjerx wrote on 6/23/2005, 10:58 AM
Is it generally agreed that 24p stretched for slow motion is not as good as 29.97 stretched for slow motion?

Thats including footage shot with native 24p and also footage shot with 29.97 and then converted to 24p in post; if there is any difference.

I've done slow motion with both and find 24p to be a little jerky in slow motion...and 29.97 to be much smoother.

I'm wondering because I'm looking at a camera that only shoots 24p...but if it doesn't offer smooth slow mo..then its no good for me.

thanks...I hope that makes sense
Jeremiah

Comments

Chienworks wrote on 6/23/2005, 11:53 AM
Video is not a continuous medium. You have a group of distinct still images each second. To create slow motion from an existing clip the frames' duration must be extended, which means fewer frames per second, which means jerkier motion. If you slow a clip down to 50% then 29.97fps clips end up as if they are playing at about 15fps while 24fps end up playing as if they were 12fps. Obviously 15fps will show smoother motion than 12fps, though the difference shouldn't be very big.

Ideally you should be looking for a camera that shoots 60p or higher when you want to produce slow motion. They do exist, but they're quite expensive.
Coursedesign wrote on 6/23/2005, 11:55 AM
You need software that creates intermediate frames, for example Twixtor.

If you shot the footage already, you may need ReelSmart Motion Blur also to remove some of the motion blur if you shot at standard shutter speeds.

Both of these are plugins that run in After Effects, Combustion, etc.
farss wrote on 6/23/2005, 1:43 PM
If you're looking at 24p then you're thinking 'film like', and what do the film guys do, they overcrank the camera, pretty simple really, you just make the motor go faster, better still, you can ramp the speed. Many TV productions have been shot on film rather than video simply because thats the only way to do it really well.
As not many of us have that kind of budget then the trick is to shoot at the highest possible frame rate and with fast shutter speeds. The Z1 might be the way to go, shooting HDV at 60i and then convert fields to frames to give 60p and that'll slo mo pretty well. Obviously converting fields to frames will halve your vertical res but if the delivery is SD you can afford the loss.
Beyond that, I've had a serious look at high speed video cameras and they cost, big time.
Bob.
David Jimerson wrote on 7/1/2005, 2:47 PM
It's not a perfect solution, but you will get glass-smooth slomo on a 24p timeline if you shoot in 60i.

What you do is drop the clip onto a 24p timeline and slow it to 40%. This will give you one field per frame, and the motion will be smooth.

You will, however, lose up to half your vertical resolution, so it's imperfect. But given the choice between it and the choppiness of 24p slowed down, it's often the better way to go.

You'll also get some cover for your resolution loss becuase someone watching already knows it doesn't look the same as the 24p footage -- it's slower. Most will concentrate more on that than they will on the resolution.

Certainly, a 60p solution would be superior. But there are no prosumer cams yet on the market which will give you both 24p and 60p.

Which camera are you looking at that shoots *only* 24p? I'm not aware of one.