How can I over/under crank to slo mo or fast look in XL2?

[Zia Basith]

Hi guys,

I'll be shooting a music video soon and I'm trying to achieve the slow motion look and be able to lip sync audio with that slo motion.
Is there a way to get slow motion look by over cranking or fast motion by under cranking in XL2? Is it something to do with Shutter Speed?
Is there any other way to achieve slow motion?
Any help or tip would be greatly appreciated,
Thanks in advance,

Zia

[Jay Gladwell]

The XL2 does not have the capability to do under or over crank.

[Steve Phillipps]

The only thing you can do is shoot in interlaced (50i or 60i) and then de-interlace it in the edit (this splits the two fields and two frames) this will give you 50 or 60 fps.
Steve

[Zia Basith]

Hey thanks Steve,
Does the audio need to be playing at a faster rate during the shoot to match the video in post?
I guess my ? is,
Should the audio be played at 200% during the shoot with XL2 at 60i?
What shutter speed should I use?
What percentage do I change the video speed in FCP to sync with audio playing at normal speed?
Thanks once again,

Zia

[Josh Bass]

Perhaps I'm wrong, but that doesn't sound right. I don't think shooting interlaced and then deinterlacing in post adds extra frames or changes the framerate. You still have 30 (for NTSC) discreet images per second, they're just handled differently. When they're interlaced, you're seeing two images at once, in a sense, on any given frame, when they're deinterlaced, there's only one image. They software will interpolate based on your settings on how they missing field is created. But it's still 30 images (in NTSC) per second. You might try playing with higher shutter speeds (1/250, or 1/500 or something). This is technically not giving you more frames per second, but it can give the appearance of that, since you see motion much more clearly (motion blur will be eliminated, giving all your movement a very clean look). This might aid in better results if you slow it down in post. As for how fast to play the sound, etc., just experiment. Find a video setting in the camera that gets you the best results (maybe I'm wrong and Zia is correct), and then try different things with the playback to see what fits best.

[David Odell]

This is a good guide: RAREVISION - New Media & Broadcast

The solution there is to shoot 50i (Pal) with a shutter speed of at least 1/120 and deinterlace it to 25p and make it 200% faster (read 50p). It will give you nice slowmotion but not as great as native.

[Josh Bass]

My bad. But you have to have after effects or another plugin to do this, right? Not just simply converting your interlaced footage to progressive in FCP or Vegas and then adding slo-mo would accomplish the same thing, would it?

[Josh Bass]

It looks like the key to the method is the "interpret footage" function in AE, that tells the program to create whole frames from the fields and therefore extra frames instead of just deinterlacing the footage and keeping the framerate the same.

[Krystian Dobak]

Originally Posted by Josh Bass

It looks like the key to the method is the "interpret footage" function in AE, that tells the program to create whole frames from the fields and therefore extra frames instead of just deinterlacing the footage and keeping the framerate the same.

And do not forget that using this method you decrease vertical resolution to half of the original as you use odd field to make first frame and even to make second one and so on.
You will finish with 720x288 resolution footage. Sometimes using Twixtor or even After Effect's frame blend you will get better results. SOMETIMES is very important word here :)

[Josh Bass]

I thought the program could fill in the missing field, and maintain resolution?

[Matt Newcomb]

How would it get this extra resolution that was not recorded?

[Josh Bass]

I thought it was possible the software could see what two given lines in a field looked like, and guess what the missing line between them would look like, and fill it in.

[Richard Hunter]

Originally Posted by Josh Bass

I thought it was possible the software could see what two given lines in a field looked like, and guess what the missing line between them would look like, and fill it in.

Hi Josh. Well it can upscale the 288 lines back to 576 but there is no new information added so the image will definitely be softer compared with having 576 lines to start with.

There are other ways of deinterlacing that don't just separate the fields, but in general they also have drawbacks such as smearing of moving objects because the data from different fields is blended.

Richard

[Steve Phillipps]

But Josh is basically correct, in that you don't end up with anything like a hlaf resolution image, the missing lines are interpolated, this is why some programmes are better at it than others, they "guess" the missing lines better. No editor myself but I have heard people saying good thing about the likes of Twixtor.
Even without the resolution issue though, there does always seem to be something odd with the look of de-interlaced material, there always seems to be some sort of jitteryness. Same is true of progressive 25P footage slowed in Smoke.
Steve

[David Odell]

Here is a few films that’s overcranked:

Tyv
Ingerstrand
Bullets

All these where shot with a SGpro.

In theory this could be done with any 50i PAL or NTSC camera.