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?

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.

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.

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.

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.

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

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

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.

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).

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.

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.

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.

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.

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.

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.

I'm in agreement with Bill on this. Green screen for interviews is, for me, a technique of last resort. It just moves the problem down the road and introduces a whole new set of problems. I believe that it is absolutely needed in some circumstances, but I want to make sure that folks understand that it doesn't really make your life easier in an overall sense.

You could always try it but in you really don't like what it looks like, you can put him in a little box on the side.

Adding to this question, can anyone tell me a bit about shooting bluescreen with and XL2. Keying in FCP. Pros, Cons??? Thanks.

So far...
 

Hi guys:

So far, out of couple of hundred interviews with the ChromaFlex system, no major issues with composites. The system works better overall than traditional green screens, at least for me. I still occasionally shoot regular green screens when I have to use a prompter and it's such a pain in comparison, I usually need at least 2,000 extra watts of lights to do traditional green screen, plus a huge space. The beauty of the Chroma Flex system is that I can be crammed into a tiny office and still pull a great green screen key easily with no spill.

For all of you guys quaking in your boots about green screen, I can't see why. I am no great AE or compositing guy and with my green screens from the Chroma Flex, it's usually a one shot deal in post, just invoke the chroma key and tweak to taste on the edges. Y'all are living in the past when green screen was hard to do well.


Best,

Dan

Dan;
I agree with you that for an on-location interview, chromaflex is hard to argue against. My problem with it is the cost (~$3k for the mobile setup). An added problem for me is that I'll be shooting with HDV, which I'm becoming convinced is probably impossible to use without seeing edge effects.
Greg

Cromaflex and set lighting
 

Hi:

I noticed your posts vis-a-vis green screening and the Chromaflex system and wonder how you go about lighting your sets?

The Chromaflex web site describes the use of a single 650W Arri Key and a possible hair light in conjunction with the ChromaF. system but that limited array might not be appropriate for the desired effect, therefore, how much lighting can one safely employ without negating the efficiency of the LED Ringlight system?

Thank you in advance,
Ron

Well, Dan...
 

SNIP

For all of you guys quaking in your boots about green screen, I can't see why. I am no great AE or compositing guy and with my green screens from the Chroma Flex, it's usually a one shot deal in post, just invoke the chroma key and tweak to taste on the edges. Y'all are living in the past when green screen was hard to do well.


Best,

Dan[/QUOTE]


Dan, (first and foremost, hi!)

Secondly, I don't think we're particularly "quaking" - just relfecting the fact that if you use ANY kind of key behind an interview, you MUST figure out what to fill that key with in post - unless you're willing to run the interview over the ugly keygreen background.

The point is, that unless there's a specific purpose in pulling a key - setting up ANY kind of a keyable background is just acknowledging that you're purposly doing an "unfinished" shot that needs more work later.

I think that's something to avoid.

Also, personally, I almost always want any talking head scene I shoot to be as SHORT as possible. I'd rather have my audience listening to the VO over b-roll than have a floating "yapper" keyed shot.

Yeah, there are exceptions and I break my own rules a lot in this - but one of the smartest things I ever saw was an old unattributed internet sig that went...

"When the tool you have is a hammer - every problem starts to look like a nail."

I bet if someone ever did a study they'd find that shelling out $3k for the chromaflex system by itself makes guys WANT to shoot keyed interviews as a STARTING POINT - rather than deciding WHY the interview should be keyed in the first place.

Probably not a huge problem, but I bet if you linked THAT to an analysis of how many hours folks spent filling those "nice but unnecessary keys" with graphics or b-roll, you'd be surprised at how much "uncompensated" time it's eating up. (And I mean "uncompensated" in the sense that the client will pay you X bucks to shoot the scene traditionally - and exactly the same X bucks to shoot the scene as greenscreen - even tho it requires more time and work to fill the key in post)

For what it's worth.



Hey, any chance I'll see you at NAB this year? I know you don't typically go, but I'd love the chance to buy you a beer for old times sake!

Take care.