slow motion?

[PhilPowers]

Hi guys - I have been asked to shot a sequence where a scientist will break a wine glass with powerful sound waves. I have seen this done before and can remeber it fracturing very fast. My director has asked if this action can be slowed in any way. Can you advise me? It will be shot on digi beta and we will be able to do the demo a number of times. I also have a PD150 "ehh!" at my disposal. There has been mention of some split screen stuff.

 

How can I make this look good using video??

 

Any sugestions would be gratfully accepted..

 

All the best - Positive Phil. B)

[David Mullen ASC]

There are specialized video equipment for shooting high frame rates, and of course, there are film cameras as well. And the Panasonic Varicam can do 60 fps but that's probably not fast enough.

 

But if you're stuck with a regular video camera, you'd probably be slowing it down in post so at least use a short exposure time to reduce blur. Also a regular 60i video camera is capturing motion sixty times a second as fields, so compared to the Varicam at 60P, you aren't actually getting any more motion samples, just better vertical resolution by using 60P instead of 60i.

[Phil Rhodes]

Hi,

 

As I understand it, cracks travel through breaking glass at an extremely high speed. You probably won't see cracks zigzagging across the surface - I'd get a nice high speed shot of the glass exploding and expect to do the cracks in post.

 

Phil

[Mitch Gross]

To capture what you're talking about would require framerates in the hundreds if not thousands of frames per second. There are specialty scientific imaging systems in both film and video that can do this, but it isn't an inexpenive operation.

[Alvin Pingol]

Hi Phil, I posted a reply in your other topic of the same name. It explains techniques you can use with 60i video.

 

http://www.cinematography.com/forum2004/in...findpost&p=8303

[DanStewart]

Consider getting a clean background plate - you may get better results doing a cg glass. I'm assuming it's geometrically simple, and any of the usual packages (max, maya or lightwave) can do a fracture animation very easily. You'll need someone who knows what they're doing with the renderer, but this will probably still end up being cheaper than a massively high speed shoot.

[Kei Sugimoto]

I was on a production where we shot a shower head at 120fps, expecting to see the water droplets slowly coming out. After seeing the footage we found out that 120 fps was no where near what we needed to get ultra slow motion. If you've got an exploding glass, I definitely think creating the glass in post is the only way to go.

[phillipjantzen]

Phil,

Your best bet is to do this in high speed. Cracking glass happens quite fast, and it will neer look right writh a standard camera. Most shots like this are taken around 2500fps. if you were to take it at around 5000fps you should be able to see the sound waves actually hitting, distorting, and passing through the other side of the object, which makes quite an effect. And it doesn seem like this can be done in post....just an idea

phil

[David Cox]

Hello,

 

We've posted a few jobs shot with the Phantom camera, hired from green door films. link to camera. It can run at up to 1000FPS at near HD quality, and up to 144,000FPS as you reduce resolution. The neat trick is that it continually records a "window" of frames, so in your case you can have the camera begin to record, keep breaking glasses 'till you think you've got the right shot, then look at the last few thousand frames in the cameras memory to see if it is good. The results we have had have been very good, although sometimes you get a low frequency luminance pulse as the frame rate clashes with the lights. Nothing we couldn't fix though.

 

I gather the hire rate is £1000 per day (which is several million dollars at todays exchange rate :P). There is also a slightly cheaper one that has a lower resolution / frame rate.

 

happy glass breaking...

[phillipjantzen]

David,

Do you have any work that i can see? I'm always curious to see what everybody is doing with the phantom.

[phillipjantzen]

Oh, btw if you set the frame rate to a muliple of 60 (most likely 50 in europe) the flickering of the lights lines up with the frame rate. what kind of lights were you using?

[David Cox]

Oh, btw if you set the frame rate to a muliple of 60 (most likely 50 in europe) the flickering of the lights lines up with the frame rate. what kind of lights were you using?

<{POST_SNAPBACK}>

I think when you get to some thousands of frames per second, you start to show how far off exactly 50 or 60 Hz the lights are, as this shows itself as a brightness cycle that lasts a number of seconds. As I mentioned though, nothing that a little dynamic grading didn't fix.

 

phillipjantzen: I'll try and remember to quicktime some examples to you on monday. :-)

[Guest Jon Armstrong]

When the freeze frame circular tracks were done for the Matrix, 24 Canon D60 still cameras were used. These were fired simultaneously. The effect is a sudden freeze.

 

I have currently been playing with other still sequences in various forms.

 

Glue the glass down onto a surface and use a hit to break the glass. Set up 24 digital still cameras (the resolution need be no more than 2K) tightly around the glass.

 

run a release from each camera with one wire running to a pin (negative) the other wire to a bus bar hinged at one end and able to swing down onto all of the pins (like a Gilotine). When action is called, slam the bar down, this will almost instantly close all the circuits. You have now shot one second in a nano second.

 

The first pin trigers the bullet hit and the first camera and then the others in sequence.

 

To get everything looking schmiko set the shutter speeds to 1/2000 th of a second

 

Contact me if you want more

 

regards Jon

[Phil Rhodes]

Hi,

 

I own the DVD of "The Matrix', and I can tell you there's a hell of a lot more than 24 cameras in that rig. 124 maybe.

 

Phil

[David Landelle]

shot a sequence where a scientist will break a wine glass with powerful sound waves.

 

Phantom cameras are a solution (I'm currently working on V7).

 

You may also consider Photron camera, which slowmotion output is direct video (slowmotion playback intregrated in camera).

 

Olympus also has a nice camera called i-SPEED which output is video.

 

You will need a very strong and stable light (sunlight, or halogen).

Also you will probably need color and gamma correction to match the rest of your shot :)

 

Olympus is used in medical, and camera price is around 25K$, it is probably the lowest priced camera (also for hire).

 

Sincerely.

[Guest Jon Armstrong]

Trust me, I was there when the work was done. The basic rig was 24 canon D60's. which allowed for a basic arrangement of 1 sec. The system was increased for slower tracks and a certain amount of Post was done. It was the only way of creating 4K files to print to film.

 

Jon

 

Hi,

 

I own the DVD of "The Matrix', and I can tell you there's a hell of a lot more than 24 cameras in that rig. 124 maybe.

 

Phil

<{POST_SNAPBACK}>

[Elhanan Matos]

I've been working with slow motion with the Cine Speedcam on features, music videos, and commercials for the past 8 months. The biggest problem I have come across has been light. You will need a lot of light to get your shot. Last Monday I was shooting tests with several DP's and Visual Effects guys, one of them, Greg McMurry, wanted to shoot a glass of wine being shot by an air rifle, we did tests at 1,000 fps at HD resolution, and then tests at 4,000 fps at SD resolution with a 360 degree shutter (1/4000 sec). The latter seemed to have worked the best.

 

Working with high speed cameras isn't cheap though, to get a proper exposure at 1/4000 of a sec you need a lot of light! We used two 4k HMI's on that shot, and that was for a close up shot of the glass with a backdrop behind it. If you are planning on lighting an entire laboratory for the shot you decribed you will probably need something like a 12k HMI or a 50k Softsun.

[Phil Rhodes]

Hi,

 

On which shots were only 24 cameras used?

 

Phil

[Guest Jon Armstrong]

Dont ask. Very often the visual effects technicians. Those that are asked to do this. Seldom see what has been done later. Matrix was an American film shot in Sydney Australia using Australian Effects personell.

 

The fffect that I am refering to is the freeze frame with a track around. Basically speaking, the cine camera becomes the first shot of the sequence. Real time action occurs and is recorded in super 35. At a selected moment, the still cameras are released simultaneously each one recording the moment from a different angle.

 

The images are then converted from RAW file to Targa and then either printed to film or sent digitally for additional work.

 

The 1 second clip can then be spliced in in a frame accurate form.

 

The draw back is that the sequence has to have some movement either a track or a track and crane cos you cant put all the cameras in the same spot.

 

regards Jon

[David Cox]

... also from my experience of putting together these "timeslice" shots, there is a lot of post work to stabilise the shot. The cameras and their lenses never quite line up, so theres a lot of repositioning work and regrading work to make the shots smooth and of constant exposure. In one case, I would suggest that less than half of the framed shot made it into the final sequence, because the camera to camera line up was so bad thats how much repositioning had to be done!

 

Anyway, that's timeslice and I think this original thread was about straight high speed stuff?

[Phil Rhodes]

Hi,

 

There's a shot in The Matrix showing Keanu Reeves as Neo leaning far over backwards to dodge bullets - it's the famous one that's in all the trailers. There's material showing the setup on the DVD, and there are most certainly more than 24 cameras.

 

Another shot includes what has to be at least a full 360-degree track around Hugo Weaving and Reeves again suspended in mid-air - that's got to be more than 24 source frames.

 

Phil

[David Landelle]

"The Matrix" is nice, but it is not about high speed imaging, it's about polyscopic vision (many POV at a unique timecode).

 

Here is a low res sample (5MB WM, 360x288) made with video cameras : Matrix Video (I made it with my MVR)

 

Photron and Phantom are quite expensive, that's true, but please check Olympus i-SPEED camera ;) . Even if it is far less sensitive, it's output is quite sharp at 800x600.

 

Off course you will need some light (sunlight is the best, because even high frequency gas lamps may produce artifacts). You may also use a TELE lens in WIDE position to get more light (i-SPEED uses CMOUNT lens).

 

Hope this helps !