should I be using a Nanoflash or Ki Pro Mini with my AF100 for green screen shooting?

N

Nicholas Natteau

Veteran
For my green screen shooting I'm using a Panasonic AF100 and Reflecmedia Litering and Chromaflex.

Despite ensuring that my scenes are well lit, I'm getting terrible noise in my composites after applying AE's Keylight 2.0

Could it be that the AF100's 24 Mpbs bitrate may not be good enough to handle green screen work?

If so, would shooting to Apple Pro Res at a much higher bit rate (say 50 Mpbs or more) on Nanoflash or Ki Pro mini be the solution for achieving a much cleaner key?

Thanks in advance for your help/advice.
 
I used the onboard codec, recording to cards and keyed fine with keylight for FCP. I would say it has more to do with your scene file than anything. I'm sure it would be a plus to use an external recorder, but I hardly think it's necessary.
 
I'll chime in only to echo the previous statements. We have had clean keys for footage shot for broadcast spots with the on board codec. I was overly worried before we did our first greenscreen shoot with the AF100...did a test first and worked fantastic. No need for external recorder in my opinion.
 
swanny said:
I used the onboard codec, recording to cards and keyed fine with keylight for FCP. I would say it has more to do with your scene file than anything. I'm sure it would be a plus to use an external recorder, but I hardly think it's necessary.
Click to expand...
It depend on the project and the final output. for a web-commercial or fast product presentation with final output in SD it work well , But for music vidéo, or fast action footage over green screen, i'll say you have to go on 4:2:2 color sampling.And if you want the best quality for broadcast or you want achieve complex effect like shooting a real scene with some green part of the frame for compositingn or detailled moving object ( like water, fire... ), you have to look at a 10 bit codec, it will be more "safe".bye.
 
Hello everyone,

Thanks very much for all your suggestions. So it must be something I'm doing wrong. If any of you have a minute, here is a sample clip I shot of myself showing the source, alpha channel, and keyed footage. You need to download the full 1920x1080 size to see the problem around the edge: noise

http://www.vimeo.com/29286886


I originally had my footage on Cine-D and I read somewhere that's it's a bad setting for green screen. But I didn't get better results with the HD Normal setting. Thanks again for everyone's help.
 
You've totally overlit the greenscreen, which is not helping with your edges.
50-60 IRE should be max - you're clipping things there, and so your edges will react accordingly.

Try some lightwrap from the background in the comp to help things a bit.
 
Nicholas,

I down loaded you shot and played with it a little. The AF100 is capable of great Green Screens.
A few Green Screen pointers:
  1. Your reflective screen has a lot of mottling texture which is the same as uneven lighting.
  2. Because your chromaflex is not a point source it is causing a shadow all around your subject. Again uneven screen. The best part of the screen is out side the shadow.
  3. Uneven lighting means you have to turn up the screen gain to get a solid matte which means noise increase in the matte edges. The mottling texture will also show up as edge noise as he moves his head around
  4. A cloth or painted screen will give you much better results. Chromaflex is a quick and dirty way of doing Green Screens and the results are quick and Dirty.
  5. This shot can be improved by setting Screen pre-blur somewhere around 1.0 or less, and adding the Simple Chocker Effect and choking the matte about +1.0 to reduce the halo around his head .

    There a whole bag of tricks for using the AE plug-in Effects for fixing bad Screens and making good one even better . Find some books or online tutorials on screen lighting and Keylight techniques. There is a lot of stuff out there.


    Barry
 
Thanks again everyone, and thanks Barry for all those tips. Will try some more tests with a traditional green screen as well. I happen to have a 5x7 muslin screen. I was attracted to the idea of not having to light the background with a chromaflex and Litering. But I'll do more tests with the Litering as well and post another clip with it. Thanks again.
 
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