Using green screen for interview background? at DVinfo.net

Greg Quinn · February 24th, 2007, 12:43 AM

I have a number of interviews approaching for a documentary project that need to be made on location, and I'm considering using a green screen instead of a regular background, with the idea that this will give me greater options in post.

Has anyone attempted this on a project?

Paul Steinberg · February 24th, 2007, 05:40 AM

Sure, I'm working on a small doc for broadcast now and shooting the interviews over green. We've shot our background plates, marked the focal lengths for wide, medium and close-ups and will be shooting the interviews next week.

Vincent Rozenberg · February 24th, 2007, 06:39 AM

If you're in a hurry on interview sets, you have to do a couple a day for exemaple, on different locations, then try out the Reflecmedia Chromaflex solutions: http://www.reflecmedia.com/content.a...chromaflex.htm . I used it to do some quick chroma key shots on location with some kids with the down syndrome, when they where standing somewhere I quickly put the chromaflex behind the subject, but to lights only on the kid, pointed the camera and started shooting.

Greg Quinn · February 24th, 2007, 10:11 AM

Paul, Vincent, thanks for the feedback. Out of curiosity, which chromakey software are you combining with this? I'm toying with using Ultra, but I've yet to hear of anyone using this professionally.

Johnson McKnight · February 24th, 2007, 10:52 AM

I have been given a green light from my company to invest in a light kit, camera, tripod, mics...etc. The works. I have to shoot an industrial video for an Offshore Technology Conference in houston in the last week in April (many other videos will follow). I really wanted to key our head of operations into the video so that he would have less explaining to do at the conference and give people a better idea of what they are looking at.

I am going with a cannon but didn't know if I could accomplish this with the A1 or if I needed to get an H1 or G1 because of the uncompressed video.

I am also curious about the software.

Vincent Rozenberg · February 24th, 2007, 04:17 PM

Recently I used the build in key plugins from Apple's Motion. Works like a charm!

Dan Brockett · February 24th, 2007, 07:02 PM

I have been using the Chromaflex system for the better part of a year. It works very well. I shoot mostly with the HVX-200 although I have used the Varicam and F900 as well.

The only large drawback of the system is using it with people with glasses. The green LED ringlight will show up in the reflections from their glasses. You will have to key in a white/gray gradient behind the talent's head so that the green ring light reflections turn into mere lights reflecting. It requires an extra layer in the composite and more time.

And as far as teleprompter, forget it, we still have to do greenscreen the traditional way, the ChromaFlex will not work through a prompter.

Other than these two issues, the ChromaFlex works like dream. Highly advised. I would estimate I have now shot close to 100 interviews for various docs using greenscreen, it is a pain as far as post but it does let you selectively control your BGs more.

Best,

Dan

Bill Davis · February 24th, 2007, 07:46 PM

I think the last line in Dan's post about sums it up for me.

I do it occasionally, in fact, my studio is set up to do green screen interviews as I write this - but every time I set it up, I cringe - knowing that for every hour I spend shooting, I'll probably spend three-four times that much time shooting or finding background footage to run in the key, editing it, tweeking the matte, fixing stuff with garbage matts, etc, etc.

It think of greenscreen work as a "productivity killer" and a last resort unless the nature of the shoot REALLY requires it.

I do it on some of my own projects when I have time to futz around, but hardly EVER suggest it on a client's shoot unless the content compels is and they have a budget that supports all the extra work.

FWIW.

Greg Quinn · February 24th, 2007, 10:10 PM

Dan;
The Chromaflex system looks like a great idea, obviating the need for any extra background lighting, but running at more than $2K for the lowest price bundles, it's unfortunately out of my current budget.

Bill, thanks for the advice, and with my limited experience in using green screen keying, I think you're correct, but the ability to modify the background in post would be very helpful for my project(s).

Richard Andrewski · February 25th, 2007, 02:46 AM

Ultra 2 is quite easy to use and gives good results even sometimes on unevenly or wrinkled backgrounds. I've been using it for almost 2 years.

Greg Quinn · February 25th, 2007, 12:00 PM

In respect to the Chromaflex system, what would be the difference between using that or a Digi-Slave light ring,
http://www.bhphotovideo.com/bnh/cont...ist&sku=469329
with a green/blue gel attached (which has the advantage that you can swap keying colors) and some cheap reflective fabric (probably sourced from China)? That whole setup would probably be way less than $1000

Richard Andrewski · February 25th, 2007, 06:30 PM

Quote:

Originally Posted by Greg Quinn

In respect to the Chromaflex system, what would be the difference between using that or a Digi-Slave light ring,
http://www.bhphotovideo.com/bnh/cont...ist&sku=469329
with a green/blue gel attached (which has the advantage that you can swap keying colors) and some cheap reflective fabric (probably sourced from China)? That whole setup would probably be way less than $1000

A lot of difference. The other system all works together to make a background that will key out but keep the person (or whatever) in the foreground from keying out with it. What would keep the person from having green/blue light from spilling on them with the light ring you mentioned? Its a totally different idea and wouldn't work at all. Good try though. That's the reason those systems are more expensive because they have a particular fabric and a particular wavelength of light that work together to make a key without spilling strange colored light on the foreground.

I've seen these systems work and I don't think they are 100% perfect though as many would portray them.

Greg Quinn · February 25th, 2007, 10:00 PM

Quote:

Originally Posted by Richard Andrewski

A lot of difference. The other system all works together to make a background that will key out but keep the person (or whatever) in the foreground from keying out with it. What would keep the person from having green/blue light from spilling on them with the light ring you mentioned?

Richard, I'm sure that you've probably forgotten more about lighting than I'll ever know (and I don't mean that sarcastically), but in this case I believe that I'm on the right track; the Chromatte system's elegance is in its simplicity. In theory, you do get some spill on the subject, since the light is pointing right at them. The assumption is that this is "drowned out" by regular subject lighting, and that pretty much all of the reflected light from the special reflective material is directed back at the light source (i.e. the lens area), so the LED light source doesn't need to be that bright. I've used Scotchlite extensively in a professional context for many years, and it really works very well.

Quote:

Originally Posted by Richard Andrewski

That's the reason those systems are more expensive because they have a particular fabric and a particular wavelength of light that work together to make a key without spilling strange colored light on the foreground.

I can believe that their system is more expensive because they're using colored diodes in a ring, which is probably a custom build, but I'm not convinced that the material and lights are wavelength-matched.

Quote:

Originally Posted by Richard Andrewski

I've seen these systems work and I don't think they are 100% perfect though as many would portray them.

My suspicious nature also tells me it's not a foolproof system - hopefully I'll win the lottery this weekend and be able to get a system to play around with.

Richard Andrewski · February 26th, 2007, 06:55 AM

Well, why not try it and report back then. Just make a fluorescent ring light and gel it and give it a go if you've got some scotchlite or something similar. Maybe you'll come up with an interesting DIY version of that system.

Greg Quinn · February 26th, 2007, 10:10 AM

Quote:

Originally Posted by Richard Andrewski

Well, why not try it and report back then. Just make a fluorescent ring light and gel it and give it a go if you've got some scotchlite or something similar. Maybe you'll come up with an interesting DIY version of that system.

Richard, will do.

February 24th, 2007, 12:43 AM	#1
Greg Quinn Major Player Join Date: Oct 2006 Location: San Diego, California Posts: 505	Using green screen for interview background? I have a number of interviews approaching for a documentary project that need to be made on location, and I'm considering using a green screen instead of a regular background, with the idea that this will give me greater options in post. Has anyone attempted this on a project?

February 24th, 2007, 10:52 AM	#5
Johnson McKnight New Boot Join Date: Feb 2007 Location: Lafayette, LA Posts: 10	What camera are you guys shooting on? I have been given a green light from my company to invest in a light kit, camera, tripod, mics...etc. The works. I have to shoot an industrial video for an Offshore Technology Conference in houston in the last week in April (many other videos will follow). I really wanted to key our head of operations into the video so that he would have less explaining to do at the conference and give people a better idea of what they are looking at. I am going with a cannon but didn't know if I could accomplish this with the A1 or if I needed to get an H1 or G1 because of the uncompressed video. I am also curious about the software.

February 24th, 2007, 07:02 PM	#7
Dan Brockett Inner Circle Join Date: Feb 2006 Location: Los Angeles, California Posts: 2,109	Reply I have been using the Chromaflex system for the better part of a year. It works very well. I shoot mostly with the HVX-200 although I have used the Varicam and F900 as well. The only large drawback of the system is using it with people with glasses. The green LED ringlight will show up in the reflections from their glasses. You will have to key in a white/gray gradient behind the talent's head so that the green ring light reflections turn into mere lights reflecting. It requires an extra layer in the composite and more time. And as far as teleprompter, forget it, we still have to do greenscreen the traditional way, the ChromaFlex will not work through a prompter. Other than these two issues, the ChromaFlex works like dream. Highly advised. I would estimate I have now shot close to 100 interviews for various docs using greenscreen, it is a pain as far as post but it does let you selectively control your BGs more. Best, Dan

February 25th, 2007, 02:46 AM	#10
Richard Andrewski Major Player Join Date: Jun 2006 Location: Shenzhen, China Posts: 781	Ultra 2 is quite easy to use and gives good results even sometimes on unevenly or wrinkled backgrounds. I've been using it for almost 2 years. __________________ Richard Andrewski - Cool Lights USA - RED #114 http://www.coollights.biz

February 26th, 2007, 06:55 AM	#14
Richard Andrewski Major Player Join Date: Jun 2006 Location: Shenzhen, China Posts: 781	Well, why not try it and report back then. Just make a fluorescent ring light and gel it and give it a go if you've got some scotchlite or something similar. Maybe you'll come up with an interesting DIY version of that system. __________________ Richard Andrewski - Cool Lights USA - RED #114 http://www.coollights.biz

February 24th, 2007, 05:40 AM	#2
Paul Steinberg Regular Crew Join Date: Feb 2007 Location: Toronto Posts: 50	Sure, I'm working on a small doc for broadcast now and shooting the interviews over green. We've shot our background plates, marked the focal lengths for wide, medium and close-ups and will be shooting the interviews next week.

February 24th, 2007, 06:39 AM	#3
Vincent Rozenberg Major Player Join Date: Jan 2006 Location: Rotterdam, The Netherlands Posts: 475	If you're in a hurry on interview sets, you have to do a couple a day for exemaple, on different locations, then try out the Reflecmedia Chromaflex solutions: http://www.reflecmedia.com/content.a...chromaflex.htm . I used it to do some quick chroma key shots on location with some kids with the down syndrome, when they where standing somewhere I quickly put the chromaflex behind the subject, but to lights only on the kid, pointed the camera and started shooting.

February 24th, 2007, 10:11 AM	#4
Greg Quinn Major Player Join Date: Oct 2006 Location: San Diego, California Posts: 505	Paul, Vincent, thanks for the feedback. Out of curiosity, which chromakey software are you combining with this? I'm toying with using Ultra, but I've yet to hear of anyone using this professionally.

February 24th, 2007, 04:17 PM	#6
Vincent Rozenberg Major Player Join Date: Jan 2006 Location: Rotterdam, The Netherlands Posts: 475	Recently I used the build in key plugins from Apple's Motion. Works like a charm!

February 24th, 2007, 07:46 PM	#8
Bill Davis Trustee Join Date: Jan 2004 Location: Scottsdale, AZ 85260 Posts: 1,538	I think the last line in Dan's post about sums it up for me. I do it occasionally, in fact, my studio is set up to do green screen interviews as I write this - but every time I set it up, I cringe - knowing that for every hour I spend shooting, I'll probably spend three-four times that much time shooting or finding background footage to run in the key, editing it, tweeking the matte, fixing stuff with garbage matts, etc, etc. It think of greenscreen work as a "productivity killer" and a last resort unless the nature of the shoot REALLY requires it. I do it on some of my own projects when I have time to futz around, but hardly EVER suggest it on a client's shoot unless the content compels is and they have a budget that supports all the extra work. FWIW.

February 24th, 2007, 10:10 PM	#9
Greg Quinn Major Player Join Date: Oct 2006 Location: San Diego, California Posts: 505	Dan; The Chromaflex system looks like a great idea, obviating the need for any extra background lighting, but running at more than $2K for the lowest price bundles, it's unfortunately out of my current budget. Bill, thanks for the advice, and with my limited experience in using green screen keying, I think you're correct, but the ability to modify the background in post would be very helpful for my project(s).

February 25th, 2007, 12:00 PM	#11
Greg Quinn Major Player Join Date: Oct 2006 Location: San Diego, California Posts: 505	In respect to the Chromaflex system, what would be the difference between using that or a Digi-Slave light ring, http://www.bhphotovideo.com/bnh/cont...ist&sku=469329 with a green/blue gel attached (which has the advantage that you can swap keying colors) and some cheap reflective fabric (probably sourced from China)? That whole setup would probably be way less than $1000