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Hi,
As person who has necer done any green screen I have to shoot a clip where the protagonist has no head and is walking around in her room looking for it.
The actor will have a clothing with a [URL=”http://www.raresplendors.com/images/Custom%20Dress%20Shirt%20Collar%201.jpg”%5Dconcrete collar[/URL] and we would choose the camera angles carefull so we wouldnt have to do any postproduction 3d/cgi neck building. At least thats how I imagine it in my head :rolleyes:The first idea is was to put a kind of green screen bag around the actors head but then I thought it would wrinkle up, create shadows and thus mess up the keying.
I know it easier to mask out the backround with static shots but how should I approch the dynamic ones, ie character is walking near a wall and the camera is panning along with her movement? Plus would the lighting be an issue with the moving shots, meaning does the light exposure/amount has to be equal during the whole movement trajectory?As I saind I have no prior experience in green screen but I assume that the dynamic shots are no easy task so I’m not hoping for few quick replys that would resolve the issue.
I’ve bought a book called [URL=”http://greenscreenmadeeasy.com/%5DGreenscreen Made Easy[/URL] but I doubt it’ll be enough.
So all the indeas, tutorials, books that you guys can reccommend me, woud be really really appreciated.Thak you!
My advice is to talk with the person who will be doing the VFX compositing work for you.
It sounds like this may not necessarily be a green screen shoot. You are correct about the green hood/wrinkle/shadows thing. If you try a key on that hood, it is certain that you will need to do some garbage masking/tracking to complete the removal of the head. It may be easier to do the entire head removal with gmask/tracking in post. Obviously, if the actress has long hair tie it back to keep it off of clothing and to avoid shadows.
Remember, you don’t need a green hood to get rid of the head. What you need to do is replace the background behind the head. Get clean plates for that (most important) .
Foreground objects passing in front of the missing head would have to be roto’d so keep that in mind. The green hood could possibly help there but in my experience, you’ll end up having to roto anyway.
You are correct about the static shots being easy for masking out the background. If your camera is panning with the actor, all that is needed is to track the missing background back in. The more you move the camera around, the more complex the composite gets. Depending on what is available to you in post, you may be better off limiting your shots to static, and panning and tilting on sticks. Going hand-held and moving all around the room will increase the complexity of the composite.
Also, you described a concrete collar she will be wearing. If your camera angle is high, you will have to replace in post the part of the collar covered up by the actress’s neck. Keeping the camera angle low, all you will have to do is garbage mask along the collar’s front edge.
Too many variables to give specific advice. Talk to whomever is doing your post.
Best of luck!
Thank you for replying StevieB. Problem is we don’t have a specific post guy, we have I as the cinematographer and an editing girl whos done some minor green screen stuff before. So we have to figure it out ourselves..
Plan is to to shoot some tests and kinda go trial and error from there.When you are shooting your scene, it is essential to have a good idea of the post workflow. I suggest you either find someone experienced in VFX compositing, or a student with a Smoke on Mac who wants to get experience with this kind of work. If you yourself are a student, you can get a free 3-year Smoke on Mac student license to learn on.
Planning on doing a green screen hood as I mentioned earlier wont work (99 percent sure). I would suggest using static shots and then simple masking in post to remove the head, unless you have someone who knows how to match move and track and composite your final scene. Replacing the background on panning, tilting, zooming camera shots is easy for someone with the knowlege and tools to do it. Unless you know for certain that your editor/compositor can do it with the tools she has available to her, don’t attempt it.
Ideally your VFX person will be on set with you, placing tracking markers, giving you advice on camera angles, etc.
If this is just an experiment to see if it will work, go ahead and give it a try. Do some tests. Let me know how it comes out.
If you need more specific advice/info let me know.
Steve B.
I don’t see a need for a green bag. You can roto off the head no problem. Keying it would be overkill. All you need to do is garbage mask out the head and stick a clean plate behind it.
Getting a clean plate is easy to hard, depending on your camera move:
Lock-offs are easy. Shoot one right before or after you get the shot.
Pans are a bit more complicated, but not by much because there’s no parallax. Shoot a clean pan–the moves won’t match, but you can stabilize the two and can extract a patch to replace the head without much trouble.
Fully moving cameras is another matter entirely. I recommend avoiding them.
@ceptor 38105 wrote:
Thank you for replying StevieB. Problem is we don’t have a specific post guy, we have I as the cinematographer and an editing girl whos done some minor green screen stuff before. So we have to figure it out ourselves..
Plan is to to shoot some tests and kinda go trial and error from there.So, how did it turn out?
I think maybe a luminance mask inside a garbage matte would work if you wrapped the head in white. Convert the segment to B/W first. To increase the chance of success you can run the mask inverted on a second pass, or you can adjust the key every few frames as needed. Still better than manual roto.
If you know how to use a tracker, the tracker can do the garbage matte.
Thanks for the advice! I have been attempting to accomplish something like this but have been at a loss on how to go about it. I have a question about filming in green screen. It may be a rather novice question but I have to ask because I am curious. When filming in green screen, does it matter what type of lens you use? I’m just wondering because I am getting some weird results when I attempt it. The whole image seems to look a little blurry, as if I’m forgot to put my contact lenses in. I find myself squinting in attempt to clear the image, which really doesn’t do anything for the picture it’s self. I appreciate it if you guys can help me figure out where I’m going wrong here.
The same way you would go about it using PShop, but on a moving and changing target. Check out “color difference masking”.
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