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Green Screen Filming

Trolley Ronnie's picture
Last seen: 2 weeks 5 days ago
Joined: 06/03/2013 - 5:12am
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Good Morning Gentlemen, I have not entered this forum before so I hope I am conducting this correctly. I am hoping for some guidance on what I suspect to many of you are well understood matters, but as a beginner I am finding it difficult to find what I need to know. I have a canon xm2 and have begun playing with Green Screen recording, with poor results, I have now become aware of the possible significance of colour ratios i.e. 4.1.1. 4.2.2. etc, but do not understand them. I have tried but failed to discover which of the "4.4.4." ranges my XM2 records in, so cannot say if my poor result is because the XM2 is limited, or if I am just doing it wrong. This has come to a head as I am looking at the canon XF100 which says 4.2.2 and claims to therefore be good for Green screen - why and how? Is it possible that someone could shed some (not to technical) light on this for me? I would be most appreciative of any guidance. Yours faithfully, Trolley Ronnie, Cambridge, England.


Woody Sanford's picture
Last seen: 2 months 1 week ago
Joined: 10/19/2010 - 7:33am
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Type "Green Screen" in the search bar in the upper right. You will find many good articles on how its done. Color space (ex: 4:2:0 or 4:2:2) is technically significant however, there was a time when many of us pulled our green screens with the GL2/XM2. You can pull great chroma keying with 8bit color and bad with 10bit just the same. There are other factors involved such as lighting and spill. The articles you will find on this site will walk you through setting up for it and set you up for success.


rs170a's picture
Last seen: 1 week 49 min ago
Joined: 03/07/2011 - 2:12pm

Woody is correct about keying with older gear. I used to do it a lot with miniDV footage and never had any problems. Very important things to consider are how the screen and talent are lit as this makes a LOT of difference in the keying process. The tool(s) used make a difference too as some are better than others. Telling us what editing software you're using will be of some help for us to help you.

 

Mike


Trolley Ronnie's picture
Last seen: 2 weeks 5 days ago
Joined: 06/03/2013 - 5:12am
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Good evening Gentlemen, thank you for taking the time to share your advice, which I appreciate. I will indeed access the information that Mr. Woody recommends, and in reply to Mr. Mike, I am using Sony Vegas 11 software. My environment in which I attempted the Green Screen filming was in my garage, with brightly lit Green Background and gently lit "Talent". My most noticable shortcoming was that my "Talent" had a shirt with high collar, and a "speckling" effect was shown in the small triangular region where the collar was folding down towards the shoulder, and some instances where his black hair also "sparkeld" somewhat - a most curious, but not unattractive effect- albeit not what was wanted!I am hoping to make another attempt this week-end when Garry who is my in front of camera "talent" will be coming to stay, and am hoping before then to be better guided as to which aspect I am mostly in need of improving.  Thank you again for your valuable help. Yours faithfully, Ron. Cambridge, England.


Laguna Hiker's picture
Last seen: 5 days 6 hours ago
Joined: 05/27/2013 - 12:33pm
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I'd second the comments about lighting. I do a lot of green screen work, and I put my talent about four feet in front of the green screen, with the green-screen lights between the talent and the screen. Soft, even lighting on the green screen is very important--most apps key much better as the lighting improves. I use 5500K fluorescents, one on each side, to light my screen.


Kevin Duffey's picture
Last seen: 8 months 1 week ago
Joined: 12/03/2012 - 10:02am

Hi, I suspect your stuck with your camera? I used an old handycam and did "ok" green screen. As others have said..lighting the green screen and ironing out any wrinkles is important. If you can keep it pretty smooth and tight so that a slight breeze doesn't move it, and light it evenly across the entire thing possilby with a top light behind the actors (if you have a big enough green screen area) or two side lights (out of frame) that evenly light it. 

 

Also make sure your talent has no green at all, not even light green, stripes, etc. Funny story..I just did some green screen with my daughter for a project and she had what looked like a beige outfit but it turned out to have some green in it.. it was too late to reshoot, and she basically looked like a ghost in the final product. I completely forgot to look at her outfit in different lighting so it didn't appear greenish at all.

 

Anyway, if a camera was in your budget.. I'd seriously consider the Black Magic pocket cinema camera for $1000. Given the dynamic range, recording to pro-res (and supposedly RAW eventually) and it's price.. at least for green screen work I'd consider it probably the best value out there..especially if it can shoot RAW eventually. The cards won't be cheap.. something like $150 for a 64GB card that will give like 20 minutes of RAW.. but if you're shooting clips and not a solid 1/2 hour or longer..that may be ok. Of course you'd have to counter the 3x zoom the smaller sensor size gives, probably have to buy (or if you have) a 14mm to 28mm wide angle to make use of it in a small area. I have a 85mm Rokinon cinema lens that is fantastic that also make a 24mm that is like $700 that I am looking to buy eventually, might be good for this sort of stuff as well.

 

One other thought.. at least with Adobe After Effects there is the ability to "pad" (or soften?) the edging of the green screen matte, so that you can effecitvely smooth out potentially jagged edges like where hair and clothes intersect with the background. Sometimes in bad green screen with no padding you'll see almost a small greensih glow around shoulders and heads, usually due to lighting reflecting off the green screen on to the back of your talent. The padding helps remove this by removing a couple pixels around the edges. I don't know if Vegas can do this or not but I'd imagine so.

 

 


Laguna Hiker's picture
Last seen: 5 days 6 hours ago
Joined: 05/27/2013 - 12:33pm
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Good advice. Most professional editing programs have a 'garbage matte' filter that you can use to isolate glitches like wrinkles in a muslin green screen--that helps with any imperfections. I generally use paper, to avoid those problems, but paper isn't always practical. Do some online research into which editors do the best green screen. I'm most familiar with Adobe Premiere, and both versions (Elements and Pro) have good keyers. Elements is a surprisingly good editor for its price, and I'd recommend it as being worth a look.


Michael Daly's picture
Last seen: 3 months 4 weeks ago
Joined: 07/31/2011 - 10:06pm
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Laguna Hiker is right on the ball here. The biggest assist I got was to put lighting between my subject and the screen so as to defeat shadowing. Also I use a pop up green screen which has a metal band all around. It minimises wrinkles.