Green screen Music Video

[Kevin Camp]

if your plan is to match a 3d comp camera to the greens, take a lot of notes on camera position and settings. things like distance to subject, disatnce to chroma wall, height of camera, the exact movement of the dolly (distance, and distance to/from subject or wall, you may actually want to plot each shot on a x,y grid), lens focal length, focal distance and i’m sure some others that i’m missing. that data will be important to get 3d layers, layered in space within ae to match movement and dof of your footage.

it should probably be a pa’s job just to measure and record these notes for every shot.

i think i would also try a test for creating the 3d scene and matching it to footage. it wouldn’t need to be greens, you could shoot on a brick wall, take notes, then try creating a scene and camera movement to match using a quicky garbage matte to mask the footage. it should be enough to test if your process will work, and/or what will need to change.

when you shoot, think about what you’re going to track for the point of interest for your 3d camera (unless you shoot following a tracking dot, or your subject is standing still, you may have problems).

Kevin Camp
Designer – KCPQ, KMYQ & KRCW

[Steve Roberts]

What app are you using for the 3D matchmoving?

[Herminiocordido]

I have been looking into Voodoo, but not there yet 🙁
H

[Brendan Coots]

My honest first recommendation would be to run out and buy Stu Maschwitz’ book The DV Rebel’s Guide. It is packed with useful info from the shoot to After Effects, specifically dealing with special effects, greenscreen etc. You will get a lot from that book, including all the needed camera measurements MoldyBoot mentioned.

My second suggestion would be to do a complete test run using a DV camera just so that you can test your workflow and weed out any issues before shooting expensive film. This is almost mandatory unless you just really like living on the edge. Tracking dots (or even gaffer’s tape Xs) are pretty important, I would use yellow so that they can be keyed/roto’d a little easier but different folks prefer other colors. You should also really, really try to nail down the environment you will composite into the background BEFORE you shoot so you have some idea what type of lighting, and from what direction etc. you will light the live shoot.

My third reco would be to consider very carefully your post process in terms of Codecs you will use, the pipeline, editing system etc. You will definitely want to stay in 10-bit to preserve the film’s latitude and retain high color sampling. Personally I would never do a project like this using AVI files, because it mostly limits you to Windows machines and certain codecs. There is no DVCPRO HD option, and the Video for Windows 10-bit implementation is sketchy (can truncate to 8-bit even though you THINK it’s a 10 bit file).

[Rene Aguilar]

1st check the quality of the dolly or steady or mechanich arm. I have a terrorific experience with one arm that don’t make smooth movements… first I stabylize the shoot and later make the changes.
2nd verify the size of your control marks (yellow spheres) this objects don’t gonna be tiny on the screen.
And finally check the illumination on the scene (specialy on the green screen area).
Have a good shot!

[Steve Roberts]

… and get the book on Matchmoving by Tim Dobbert.