View Full Version : Slow motion tests


Paul Joy
July 27th, 2007, 01:22 PM
I was messing around with some slow motion stuff today, I shot some footage using 50i with a high shutter speed (1/3200) and then messed around with it in FCP. The clip below shows each clip as captured, then with the interlace lines split into frames to produce 25fps footage at half speed, and finally that half speed footage at 50% speed with frame blending.

http://www.olikai.com/archery/xh-slowmo.html

I was quite pleased with the results, although I don't like the flashing line at the top of the frame - I've seen that mentioned before. It also does a great job of highlighting my incredibly bad archery form, although I think that's mainly due to concentrating on the camera more then what I was doing... that's my excuse and I'm sticking to it!

Paul.

Luke Ross
July 27th, 2007, 01:32 PM
I am not seeing video but can hear the audio. Is it just me? Windows, with Quicktime Pro 7.16. Tryed downloading the mov file as well and playing in stand-alone player and still didnt see video.

Paul Joy
July 27th, 2007, 01:35 PM
Hmm, hard to say as I'm on a mac. I'm using quicktime 7.2, although I'm not sure if that makes any difference.

The clip is encoded as H264 video and Apple AAC audio.

Paul.

James Klatt
July 27th, 2007, 01:41 PM
I'm on a mac too. It's just white. I also tried downloading as well.Neither works.

Paul Joy
July 27th, 2007, 01:44 PM
Weird - works fine for me. I'll look into it and upload another file.

Thanks

Paul.

Paul Joy
July 27th, 2007, 01:54 PM
I've just re-encoded and uploaded a new file, I cut back a little on the complexity of the compression settings - that's the only thing I can think that I've changed recently.

Let me know if it makes any difference.

Paul.

Luke Ross
July 27th, 2007, 02:12 PM
There we go.. Now it's working and it looks good. :)

Was that a bee or something flying by after the first shot?

Paul Joy
July 27th, 2007, 02:33 PM
Yes it's a bee, not even 1/3200 will freeze that flying past though :)

I'd be interested to try the experiment again but with a less drastic shutter speed that's aimed at smooth motion. This time round I really just wanted to see if I could capture an arrow leaving the bow so went as fast as I could whilst trying to maintain a correct exposure.

Henrik Reach
July 27th, 2007, 11:16 PM
Out of curiosity, at what speed are you playing the slowdowns?

Paul Joy
July 28th, 2007, 02:44 AM
The timeline is 50i and footage is being deinterlaced when encoded.

Each shot is shown three times as follows:

Part 1: 50i footage (25fps // 100%)
Part 2: 50i footage is separated (fields to frames) so it's still 25fps but running at 50% of the original speed.
Part 3: The same clip as created for part 2 but with the NLE running a slowdown of 50% and generating frame blends for the additional frames, so the final part of each shot is 25% of the original speed but only having to blend every other frame.

Paul.

Evan Donn
July 28th, 2007, 11:06 AM
Are you doing everything in FCP? I've experimented with this in the past and found that After Effects tends to produce less of the flickering line effect - you have to use the 'preserve edges' option in the interpret footage dialogue. I haven't tried it yet with the A1 but if I get some time in the next week I'll try to post a sample.

Kyle Prohaska
July 29th, 2007, 07:56 AM
People miss the idea of shooting interlaced footage for slowmo. The trick is to deinterlace to 60p (or in your case 50p) so you can have double the frames to play with. After Effects for instance will allow you to do that.

- Kyle

Paul Joy
July 29th, 2007, 12:35 PM
That's exactly what I did here, although I did it the time consuming way! I don't have after effects, if anyone knows of a plugin for FCP or motion that will do the same job I'd be interested in hearing about it.

Thanks

Paul.

Evan Donn
August 6th, 2007, 12:16 AM
Nattress has smart-deinterlacing in his film effects package:

http://www.nattress.com/Products/filmeffects/filmeffects.htm

It may help with the flickering lines, I believe you can download a demo to give it a try.

Shiv Kumar
August 7th, 2007, 04:18 AM
Paul,

This is one of the sharpest videos I've seen! I just love the clarity. I don't get this kind of clarity with my camera :(.

Care to share the light conditions, expsure etc.?