[shortround]

Ok, I think I understand the principle of slow motion from a film perspective. Let's say I was working in the 24fps format, and I wanted some of the footage to appear as if it was going in slow motion at half the speed of normal motion, but with the same 'fluidity' of motion. In this case, I would simply shoot the footage at 48fps, and then slow it down to 24fps in post production.

But what if I wanted to do the opposite? If I wanted a piece of footage to go at double the speed of normal motion, but with the same fluidity of motion, how exactly would I need to shoot the footage? Obviously, the final footage would still only be kicking out 24fps, as you can't have multiple frame rates within a finished product!

My first thought was that you simply shoot at normal frame rate (24), and then simply remove every other frame so that 48 frames (2 seconds of time) would be compressed into 24 (1 second of time). But when I thought about this, I realised that this would mean the amount of motion between each frame would be a lot greater, since the intermediate frames had been removed. Wouldn't this then mean that the motion itself wouldn't be as fluid as 24fps, and therefore look a bit jerky?

Is there some basic principle I'm missing here?

Any help is much appreciated!

[senu]

Normally one leaves this sort of thing to software , but the results are not always guaranteed to not be " jerky"
It ultimately depends on how good the software algorithms
What I think the software does is to cleverly create extra "frames" by duplicating " intermediate" frames to allow the motion to look sped up when played back
The footage would have been shot at normal speed

[shortround]

Thanks for the info. I kind of suspected that you would just shoot at the normal frame rate. I just couldn't think of any examples where this had actually been done in a feature film, so I couldn't check to see what it looks like.

Anyone happen to know of any good examples of this kind of thing?

[mmace]

after effects has a feature called frame blending, you literally tick one box for it to work, it's excellent for changing speeds and motion blur etc, it creates frames based on other frames or cuts them out (if speeding up) but does it in a way that keeps the motion smooth!
After Effects CS3

am sure other packages will have something similar

[senu]

Originally Posted by mmace

after effects has a feature called frame blending, you literally tick one box for it to work, it's excellent for changing speeds and motion blur etc, it creates frames based on other frames or cuts them out (if speeding up) but does it in a way that keeps the motion smooth!
After Effects CS3

am sure other packages will have something similar

They mostly all do.
Some better than others. After Effects may well be one of the much better titles but then it should be.. It isn't cheap..
I have done it with Avid Liquid 7 ( which Avid seem to be " abandoning") a few times with quite good results

[Mr Cheese]

Are you actually using film? Do you have an option of filming at 12 fps using a different shutter speed/shutter angle? What type of camera are you using? I have experimented with both film and video with varying results. With the video camera I was after an effect where I wanted the motion sped but up with motion blur. Although I could do this in post I was really interested in doing this 'in camera'. Maybe try some experimenting with various shutter speeds might be useful. Good luck!

[shortround]

I'm using a Canon HF100, potentially in conjuction with a Canon 1014xls super 8 camera. So yes, I can adjust shutter speed and exposure manually.

Are you saying that a lower shutter speed to increase motion blur would offset the 'jerkiness' caused by removing intermediate frames when doubling the speed? That certainly makes sense to me.

[Mr Cheese]

Man, I used to have the exact same camera as you, the Canon 1014!

All I'm saying is that its worth experimenting. I don't think you will totally eliminate the jerkiness. By its very nature, speeding footage up will introduce exaggerated movement. I was actually trying to introduce blur to produce an effect. Honestly I don't know the results would be using film - I used to try all sorts of things then, but I suspect Super 8 film was more readily available and cheaper in those days!!

I did some in camera slo-mo with my Canon super 8 camera in this film I made a few years ago. If you're interested!

Ceremony Promo

[J1mbo]

Fast motion on film if produced 'in-camera' (as opposed to a post effect) is achieved by 'undercranking' the camera - using a slower frame rate, for example 1 frame per second as opposed to 24. Experimentation will tell you how slow you need to go. It's quite possible to get this effect with a digital stills camera that has a timed continuous shutter as well, by running all the stills together.

More difficulty is introduced though if you want to move the camera during the fast footage.

If your video camera has no option for this, I would suggest using an edit effect such as any mentioned above or the velocity envelope in Vegas.

[senu]

Originally Posted by J1mbo

If your video camera has no option for this, I would suggest using an edit effect such as any mentioned above or the velocity envelope in Vegas.

Thank you,
Id forgotten all about Vegas velocity envelope which I've also used to good effect

[shortround]

Originally Posted by Mr Cheese

I did some in camera slo-mo with my Canon super 8 camera in this film I made a few years ago. If you're interested!

Awesome! Can't beat a good bit of super 8!

It seems you can now get super 8 telecined to HD too. I wonder how good it would look!? I might get a test reel done just to see how it turns out.

[glesgaguyav]

Originally Posted by shortround

Awesome! Can't beat a good bit of super 8!

It seems you can now get super 8 telecined to HD too. I wonder how good it would look!? I might get a test reel done just to see how it turns out.

So basiclly they'll be pointing an HD cam at your cinefilm, I've already done that

Sorry, off topic

[shortround]

Originally Posted by glesgaguyav

So basiclly they'll be pointing an HD cam at your cinefilm

No, you can get it properly scanned in HD.

16mm High Definition Film Transfer by Debenham Media Group

It's mainly about 16mm, but they do super 8 too.

[Mr Cheese]

Thats a great idea. Just looking at super 8 tends to get it scratched/dusty. Editing it with sticky tape on a super 8 editor tape really damages it even if you're careful. Telecineing it straight to video seems like a brilliant plan!