Scott Fritzshall

Oops, sorry Adrian, I was addressing Fred, not you. I was asking those things because from the way it's described, it sounds like it could easily be a compositing error.

So that I'm understanding you properly: Are you saying that the subject exposure stays the same, and the background plate exposure stays the same, and the only only difference is the exposure of the blue screen? Does the background plate actually change brightness depending on the foreground plate you're using?

Regarding camera tracking, you won't really be able to use your actors for tracking points since they will be moving. The math for solving camera movements depends on the assumption that all of the points you give it are totally static. Most of the time, you can track off of objects and features in the scene, but sometimes you may need to place your own tracking markers at key points. You want distinct features or points of contrast at multiple planes of depth, so that you get some parallax. You won't really be able to key the markers out, you'll need to paint them out or track or project patches over them. When you shoot your defocused clean plate, you should probably move the camera back or use a wider lens, so that you get enough of the scene to cover the full range of camera movement. Depending on how the camera moves, you may possibly need multiple clean plates that you stitch together. The other option is to actually paint the performer out in each shot, which would give you an image that already moves properly and matches, that you could then defocus yourself. As for the suits, you can certainly try to find a suit that exposes better, but rotoscoping is pretty much inevitable. You're never going to get a perfect key off of something that has contours and uneven lighting and moves around a lot. Even if you can get a pretty good key, you're going to have to clean it up with roto.

Well, what exactly is going on in these shots? What will you be replacing the suited actor with?

You generally don't end up actually keying people in suits like this; you generally end up using them to delineate the areas that you'll be removing by other methods. If the problem is that they're reflecting too much green light onto the rest of the scene, maybe you can replace it with a black suit.

NPR program The Business just aired an interview with Edwards yesterday that's probably worth listening to for anyone interested. Particularly of note is that the figure they're now quoting for his budget is actually $250k, which is considerably more believable. I'm wondering if that figure includes Edwards' pay, or if his fee is accounted for separately. You can download the interview here: http://www.kcrw.com/etc/programs/tb/tb101025true_blood_music_sup (fyi his interview is in the second half of the program)

The best way to light a subject in front of a greenscreen is to replicate as closely as possible the lighting that they would be in if they were actually in the environment you're comping them into. If you're putting them on a spaceship or a beach or a skyscraper, would there be magenta light on them? If not, don't use it. Even with a perfect key, your composite will suffer terribly from being improperly lit.

Actually, that's not half bad for a blue screen shot. You should be able to get good results from that. It looks like that camera is XDCam, is that correct? First of all, make sure that you're capturing it properly, and that you're working with uncompressed images when you do your keying. The camera is already applying all sorts of compression and screwing with the image in various ways, and this may be part of what is tripping you up. Make certain that you don't have the sharpening turned on in the camera settings (sometimes called "detail"), because this can give you edge artifacts that can be almost impossible to get rid of. I'm guessing, though, that most of your problem is probably just in how you're doing the keying, if you don't have experienced people doing it. Don't try to key the entire image at once. You may get settings that work for the hair that don't work for the rest of the body, for instance. Pull multiple keys and draw rotoscope shapes to use to combine them. You can add the results of keys on top of each other as well. A common technique is to get a key that just works for the edges, but may have holes on the inside, and then get another key that is really solid inside but doesn't extend out to the edges, and add them on top of each other. I don't think that you need to change the lighting or add a backlight to your subject. Your lighting should match the conditions that would be present in the background you're using. Just try to keep your subject's lights off of the screen. If you can post a single uncompressed frame, I can take a crack at keying it and see if there are any other problems.

Ehhhhhhhhh this is going to be one of those movies that gives everyone really unrealistic expectations. He made the movie for $15k because no one got paid, including himself. He's also a very experienced visual effects artist with a really really good eye, and he made his film on the fly in ways that made the effects easy for him to do. He says a lot of stuff in that interview that's really misleading as well, and implies that all you need is a computer and a camera and you can make professional quality movies. The thing about Edwards is that he's one of those one-in-a-million people who can do everything the wrong way and end up with something that looks right, and while there are definitely clever techniques at play in his work that are picking up on, you really have to take him with a grain of salt or else you'll risk inadvertently picking up some really bad ideas. With those caveats in mind, if you want to see a really thorough breakdown of how he works, www.fxphd.com had a course with him where he went through a whole bunch of shots from his previous film Attila and showed how he did them. It doesn't look like they're offering that class now, but they might have it again in the future.

Oh, damn, I didn't even know that capability existed. Further evidence that I need to get on set more often...

I don't know offhand whether that kind of equation exists, although I wouldn't be surprised if it did. Try pre-vising this out in a 3d program- set up a scene with correct proportions and a camera with the correct film back and lens settings, and play with moving the camera and zooming in. The way you'd automate these things if you were shooting is with a motion control rig.

As Brian said, unless you can get really clever with your photography, you're going to need to do it in post. How complicated this will be will depend on a number of factors- does the camera move? What, if anything, crosses in front of the sky?

I've actually been needing to ask this same exact question, except I need to sync like 5 or 6 of them to each other. Is it even possible?

Keep in mind that you don't actually need greenscreen unless something is crossing in front of your piece of paper, and even if something does, it may be easier to just roto it. From what you're describing, here's what I would do. Print a black square- just an outline- on the paper, to define where you want the video to go. Maybe put some small red dots just inside each corner. Film your shot, then track each corner. You may need to track it by hand at some points. Then corner-pin your video to the tracking points. That will make it follow the motion of the paper. If the paper bends or twists into anything other than a completely flat plane, you'll probably need to do some warping of the video to get it to match, but since you have that black square on the paper for reference, you can use that as a guide to where the video should be and how it should be bending. You'll then want to rotoscope anything that crosses in front of it, and color-correct the video to match the rest of the shot.

Really you only need greenscreen over the areas of the screen that your subjects are crossing. It might be more necessary to have green over the area where they'll be falling. The big problem with shooting in a stairwell, other than the logistics of actually framing and staging it, is that it's going to be nearly impossible to light it to get it to look like outside.