7D - Green Screen, messing around

Rakesh Jacob

Rakesh Jacob

Veteran
Helped shoot a green screen commercial for a friend. I was just the cinematographer on it, so I have no idea what's acutally gonna be done with it or what thier process is gonna be.
I have never done green screen stuff before so I was just messing around with some of the bloopers.
I used the chroma keyer built into Vegas.
The green screen was a 5'x7' collapsible reversable felt blue/green screen. My friend had a 4 light lowell kit but only two lights had working lamps :( so the whole thing was only lit with a 500w Tota and a Rifa (not sure on the wattage)

So given the uneven lighting on the screen, my inexperience and I'm not sure how good the keyer in Vegas is or if I'm even using it right, I think some one who knows what they are doing can probably do decent keying work with the camera, especially if they expand the color space with ProRes or the like.

1080-24p, 1/50, Neutral pic setting, Canon 28-135 IS at around 30-35mm @ f4.0-4.5
Used a picture of some cool graffiti I found on flickr for the background with a slight gaussian blur and slow pan.
No additional color correction done.

http://vimeo.com/8304570
 
Very nice work. I've been thinking about picking up a 7D and green screen is a big part of
my work. This is very helpful in making my decision.

A few quick questions (if you don't mind)

1. How far away were you from the subject?
2. What were the dimensions of your green screen?
3. What was the size of file you uploaded to Vimeo?

I ask the 3rd question because I'm constantly challenged on what size of file
I should be uploading to get the best HD quality. Yours looks very good so
it would be nice to know the ratio of file size for 1:22 worth of video.

Thanks in advance. Again great stuff.

Peter
 
Thnx man

1) I think about 4-5 feet
2) The screen is 5'x7'
3) The file size is 83.48MB, I rendered @ 1080-24p WMV at 8Mbps,
I've gone as low as 6Mbps for 1080-24p WMV and it looks just as good.
 
Interesting. You export as a Windows Media File. That seems to go against the general advice
on this board (and Vimeo) which is to export using the H.264 codex.

However, I can't argue with the quality, which is terrific.

Do you find Vimeo uploads slow? 100 MB takes a minimum of 20 minutes or so for me.

Though I like Vimeo, I've been considering dropping them, as 1 GB file takes over an hour
and is impractical. I'm wondering if you experience the same, or have any suggestions.

Peter
 
Video editing tends to be mac-centric so anything with "windows" in the name like WMV is gonna be looked down upon regardless of reality. In my experience WMV creates the best looking final render for the least amount of space... but what do I know...
Also WMV will playback HD clips on PCs not fast enough for HD h.264 files, so that's a cool benefit and now that the PS3 plays back WMV, I love watching 1080p clips on my 47" 1080p LCD HDTV :)

I havnt had problems with Vimeo in a long time. I also havnt put up a really big file in a long time so for right now I'm happy with Vimeo.
 
Info P. You have an hmc as well right?

I can see a tiiiiny amount of green around her hair line but other than that it's a very good job keying. And like you said.. you don't have too much experience with keying so it's comforting to know that the 7d probably is perfect for it.

:bath:
 
If you keyed in a program better suited to visual work like After Effects and the like you could easily sort out the bleeding green edges with either a slight edge feather or a choker. Other than that small problem with post the shots were good and entertaining :P
 
Thnx guys for the tips. I was with the director/editor today helping him edit it in Final Cut, he hadn't done green screen before either LOL. But Final Cut's keyer is WAAAAY better and it was pretty easy to get really clean looking keying done. And that's still with no experience so I'd say the 7D is :thumbsup: for green screen work.

@Thomas, actually I have a HVX200a
 
Tip for future greenscreening: Acquire a larger screen, even for mediums, so that you can move the talent further way. The spill on the top of her head will take some adjusting, not impossible but definitely can be avoided.

As well, for the 7D (and 5D) keep your ISO at about 100 - 160 if you can. Use a Neutral profile with a bit of contrast and sharpness (I know) added. Just a little.

A doozy is choosing shutter speed: motion blur is difficult to key with the DSLRs (from experience), a 1/60th is a pretty safe place to be and you can add more blur back in post. But that's just a personal decision.

I'm not sure which background you guys are putting in, can't say much about lighting or composition, but if you're going to change the composition from a dead-center comp to something else... One other thing to remember, as well, although it may seem odd, is that if you can match composition in production even though there's nothing there, it'll look a lot more natural.

For instance, if your subject's supposed to be off to the right more-so, shoot with her off to the right of camera, even if that means you have to garbage matte out the parts of the frame the greenscreen doesn't cover. It helps to keep the perspective of live action material accurate.

Shoot 'em up~
 
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