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Old April 16th, 2007, 01:40 PM   #1
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Ultra Cheap Bullet Time Effect

I am trying to come up with a way to do a bullet time effect as cheap as possible. Here is what I'm thinking so far:

Using disposable cameras, set in locations that are carefully measured and pre planned to ensure they are the right distance apart and the right height, then alligned by approximating through the viewfinder.

Rigging up some sort of electronic controlled shutter release on the cameras, so when I press a button all the cameras fire simultaneously.

Painstakingly scanning each individual image by manually and assigning each one a number, so they can be imported into the NLE as a JPEG sequence.

Now I know this will give me a series of frames, each one will be slightly out of allignment and with slightly different exposure. I am hoping that a newer version of photoshop or some other software will be able to batch color correct all the images so they match and that Borris Red's camera shake utility will be able to fix the alignment problems so the resulting footage doesn't appear shakey.

If anyone has any thoughts on this process, or has experience doing this kind of thing, or has any software to suggest to perform the color correction/correct allignment please let me know.
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Old April 16th, 2007, 04:13 PM   #2
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I wouldn't trust software to de-shake the final image. I watched the DVD bonus footage and the raw "bullet time" effects were done differently. The cameras weren't lined up perfectly, so they cropped off the edges and repositioned the frames manually to get the smoothest motion. The rough cut looks funny because the edges of the frames are all out of line, but the subject's motion looks fluid, because that's what has been centered. This will be cheaper than buying Boris Red at least. The Matrix bullet time was also done with a movie camera at either end of the camera line, and the still camera's shutters were delayed a fraction of a second so the resulting video was still moving somewhat, although a lot slower than real time.
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Old April 16th, 2007, 05:17 PM   #3
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they used a single camera for some "bullet timey" kinds of effects in "A glitch in the matrix" over at http://www.sequentialpictures.com/ They detail how they made it in the behind the scenes things...and I think they have some BTS vids too.
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Old April 17th, 2007, 11:31 PM   #4
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and the individual frames are morphed between to get them to animate smoothly.
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Old April 18th, 2007, 04:33 PM   #5
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Disposable cameras seems a pretty hopeless idea IMO. What disposable cameras come with an electronically controlled shutter? Are there even any that can be mounted on a tripod? How are you going to make sure the framing and exposure are consistent? How will you make sure that the shutter triggers at the exact right instant?


Shooting it:

Better way would be with a couple of DV cameras (preferably identical models) each up them up at the start & end point. Shoot the action so you get the right framing (multiple takes because you can't reframe if the actor is off his marks). Also shoot empty frames of just the background. Use a clap-board to mark a sync point for both cameras. The two angles can't be too radically different (maybe at maximum 30% difference in angle) and really should be at very if not identical focal lengths (generally the wider the better - also makes framing the action easier). The backgrounds need to generally much the same features and the active person should be centred in the frame.

Post Prod:

Find the frames you want to bullet time (BT) by scanning through your two angles and looking for suitable frames. Use the clap mark so you can get exactly the same point in time on both clips (e.g. 1 minute 12 seconds 18 frames after the clap)

Export the frames as images suitable for photoshop or whatever Graphics programme you prefer. De interlace the shots (Very important!)and then cut out all of the background till you just have the actor.

Import these frames into morphing software (there are freeware versions out there for Windows and Mac. Do that morphin' thang.

Find empty background shots, do the same (de-interlacing shouldn't be necessary) make sure there are no inconsistencies with the original footage (people in the background, moving clouds etc.) that will suddenly pop up in the background when it's cut into your sequence (this may not be important, see below).

Morph between the two background plates as best you can for the same number of frames as you did for the .

Composite the morph of your foreground actor onto the morph of the background.

et viola - using this technique it you can have live action run ups and out of the bullet time moment, though this is where continuity between the background plates and the foreground action plates is important, though if you have the time you can do some masking there too to hide any inconsistencies.

You can even have Matrix style slow movement BT (which is actually what BT really is as opposed to simply freezing the action. Simply choose an end of BT image a few frames later than your start of BT.

Now it won't look as good as pro BT, but this is cheapish. It avoids needing some horrendously complex electronic triggering mechanism, the cameras are much easier to frame focus and expose for consistency. It's easy to capture a simultaneous frame (within 60th of a second anyway). The weak point is the morphin to create the movement. Sometimes features in the frame won't move naturally but with blend and blur. Some images morph better than others. A way around this is to get more cameras to fill in the spaces. For a 90 degree turn, about 4 cameras would be good (actually more than that and your cams will end up in each others shots) but that of course means getting more identical model cameras and more time morphing between shots.

I tried this a few years ago in Turkey (actually not that long after The Matrix came out) with three VX1000s and a freeware morphing programme I found on the 'net. I wish I still had the footage but really it was just a test, messing around. The results were OK to my eyes by obviously a fudge, but still good enough to make most lay person go "how the hell..." (In Turkish though)
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Old April 19th, 2007, 01:57 AM   #6
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Quote:
Originally Posted by Dylan Pank View Post
Disposable cameras seems a pretty hopeless idea IMO. What disposable cameras come with an electronically controlled shutter? Are there even any that can be mounted on a tripod? How are you going to make sure the framing and exposure are consistent? How will you make sure that the shutter triggers at the exact right instant?
First of all, thank you Dylan for your very in depth response.

Disposable cameras I know do not have an electronic shutter, I was intending to mount selenoids to each one to push the shutter button and wire all the selenoids up to single trigger. I also was aware that the framing and exposure wouldn't be consistant.... hopefully using photoshop to batch process and correct exposure and color differences as well as using Borris red to correct for the framing issues.

However, I have backed awayfrom this idea of using disposable cameras. At first I was intending to photograph every single individual frame of the animation, requiring hundreds of cameras. After doing more research though I think I could probably get away with 30-40 cameras and using morphing software to morph between the shots. Also, only having to use 30-40 cameras I could perhaps consider inexpensive, 1megapixel digital cameras, so there are no film developing costs. Also digital cameras by there very nature have an electornic shutter control... the shutter button is just an electronic switch.

The reason I can not fake the effect by using a single camera and moving it while the actor holds his position is that a human is not my subject, rather I need to capture a complex park scene including water droplets from a fountain as they are suspended in mid air.
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Old April 19th, 2007, 05:19 AM   #7
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Adam,

I think digital cameras might be the way to go, but even then, you've got to be sure that the cameras will open and close the shutters in sync. Cheap digital cameras tend to have a delay between pressing the button and capturing the image (usually around 1/2 a second) and I've no idea if it's always consistent between even in the same model of camera. I know even with the film SLRs they used for the Matrix BT effects they had problems as the electronic shutters would only poll the button once every 20th of a second, so they had to jury rig some system that perfectly synchronised the cameras (IIRC, I'm remembering an article I read a LONG time ago) and those were pro SLR neg cameras.

I do think it's an improvement on your solenoid idea as thumping something into the top of the cam risks shaking the image which disposable cams are prone to anyway.

Good luck with it - will you post the results?
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Old April 19th, 2007, 04:18 PM   #8
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Hi guys,
I was a grip on a shoot for a Discover Card commercial that employed the bullet time cameras, you can watch the behind the scenes video I made for Martin Agency at my website in my signature. I talked extensively with the Big Freeze experts who were there to set them up (one guy, Steve, was the man who designed and created the PocketWizard, known to all in pro photography--a little odd, but he knows his stuff), and they made it very clear that this is *not* a simple "hit the button at the same time" situation. The cameras must be synced down to microsecond precision and even with the entire day's worth of setup time that was employed, the results were still less than perfect.

I urge you to reconsider before you waste your money, or at least redesign your idea to incorporate more accuracy.
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Old April 19th, 2007, 05:12 PM   #9
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if you go for a digital solution, there could be an easy solution.
you build a cheap delay circuit (a simple 555 circuit and a transistor and potentiometer that shouls cost few dollars).
you mount this circuit on every digital camera, then you calibrate each camera to be in sync with the other (taking picture of something moving for example a water drop falling along a metered scale).
when all circuit are properly adjusted, one pulse should be able to give you a picture properly timed for each camera.
http://home.cogeco.ca/~rpaisley4/LM555.html
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Old April 19th, 2007, 08:25 PM   #10
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Could you provide a sketch of the environment and proposed camera path you intend to shoot. We can all make more informed decisions at that point. I would say no fewer than 500 cameras and no more than 5 cameras depending on the scope of the move. ;) Just a 90-180 degree around a person, you could get away with 5-7 cameras. A large complicated path through a park, you would want to get a map and plot the overlap of the frames to figure out what the minimum you can get away with is. Cheapish DV cams will allow more control over the shutter :) Then you can pick precisely the set of frames you'd like to morph between...maybe some sanyo xactis or something cheapish, but with decent resolution.
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