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Keyed model dancing to camera flashes
Hi there bovine chums,
Firstly, what a horrible subject header i know. Sorry.
Im working on a job where we have a model dancing in front of a greenscreen.
That’s all keyed fine and looking good.
We’ve got a stock movie of some paparazzi stlye camera flashes which is to be composited with said model.
Also fine. done.
I’ve got some VC Optical flares for added sparkle, etc so all is going good.What i’d like to do is get the model’s luma values to change when the flashes go off.
It doesn’t necessarily need to be exactly in time, coz it gets pretty fast, but i wondered if an expression might do the trick? or pickwhip some max RGB value to a slider to something…Anyway, I’ll not waffle on for too long.
Can anyone point me in the right direction?
Many thanks, fellow grass munchers.
Andrew.
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9 Replies
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Hi Dave,
Im sure im using one of your old Keylight tips on this job too btw! 😉
I don’t need shadows because its only been shot from the knee up and there’s no reflective surfaces.
I really was looking for an expression to overexpose the shot when the flashes go off – that’s a better way to explain what i meant.
should I shift this to the AE expressions forum?
Cheers,
Andrew. -
For clarity, are the flashes coming from footage or an effect in AE?
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Hi george,
They are a stock video file from istock.
The piece is only about 10s long, so i could probably keyframe what i wanted, but wondered if there was any super-pro tips out there!
Ta,
Andrew.
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Can you create a high contrast version of the layer with the flashes in? Crush out all of the blacks until all you can see are the flashes. Then you can take this layer, blur it, grade it, scale it, whatever, and add/max/screen it on top of your model. Then you have flashes whenever there are flashes.
You could even pull a key of your shadows, and use another copy of this layer set to max, to fill them in and keep Dave happy.
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Well if you use the layer with the flashes in, there will be light patches from different parts of the screen, so that will add a bit of directional light.
It’s never going to be perfect Dave. I know it’s good to strive for perfect, but as long as you sell the effect it’s good enough. Flashing the whole layer should be enough to get the message across. Especially if you can lift the existing shadows, and it’s quick.
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Knowing what you need to do to make something correct is an important skill as a VFX artist. Knowing what you can get away with is equally important.
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Hi guys!
What an awesome topic this turned into!
Conrad, your high contrast suggestion sounds like a perfect solution for what I was after! Cheers!
Dave, you make some good points. I didn’t even really think about the shadows on her face! D’oh!
the piece is only 10 seconds long and has about 15-20 cuts so its pretty quick.
we’re not going for the ultra-realistic thing, so i suppose as long as i can make it look good!And when I read your comment about DANCING! I laughed my ass off, it reminded me of the scene in Back to the Future: “1.21 Gigawatts!!! Great Scot!”
Anyway, thanks for all the suggestions guys!
Thank moo…
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I think what you need is an expression to link the flashes to the overexposure of your subject. The problem for me is that I wouldn’t know how to extract the data since your flashes are derived from footage rather than an effect. There is probably some way to get the luma value of the flash footage into keyframes much like how you keyframe audio, but I wouldn’t know how to do this.
If you can get that value though, you could write and expression that would tie the overexposure effect to the luma value of the flash footage.
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try this:
https://forums.creativecow.net/thread/227/20921
change the opacity value out for whatever effect you’re using to get the overexposed look of your dancer. It doesn’t help with the shadows, but hey, 1 problem down … or close to
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