red accessory idea

[kraemer]

Hey Jim, I had an idea for a Red "add on"...
I was watching "return of the jedi" and got to thinking how I would do the forest speederbike scene with a red. One of the toughest problems would be matching the shadows when compositing the rendered objects (bikes, etc) into the scene. Then I thought, hey why don't they have some kind of light reading device that maps light readings to camera movements in 3 dimensional space?

You could have a "half pipe" 180 degree cluster of light meters mounted over the camera and a GPS/dead reckoning (gyro) sensor package that records all this data as the camera moves through the scene and lays the data down into one of the audio (or data) channels. The only caveat would be the camera has to "pass through" the path of the space its shooting and not skirt around it. Once the light is "mapped" then effects artists can place models into accurately lighted 3d space taken from the actual filmed scene.

[Noah Kadner]

It's pretty easy to figure out lighting using reflective mirror balls and witness cameras which is how it's done now. Not to mention many shots do not involve the camera passing through the entire lighting setup.

-Noah

[Emery Wells]

There are other ways to achieve this in post.

HDRI and good compositing will get you most of the way there.

[Jonathan Payne]

I'm not expert on this but here goes: This is what light probes are for: http://www.debevec.org/Probes/ (granted they represent light sampled from one area in space, not several). A proper light probe image would not only provide high dynamic range (HDR) grade lighting references but also the direction and color of light to a good degree of precision. The only advantage (and it is a big one) that your proposed device would have over a light probe based method is the concept of continual light readings from multiple places in space. The thing is most scenes aren't switching from light to dark and then taking light probe images would basically cover everything else you would be trying to accomplish more elegantly.

ILM (and several other leading effects houses) use this approach quite often to realistically integrate CG characters or elements into a scene. This is why you see those pictures of John Knoll walking around the Star Wars sets holding that chrome ball on a stick.

[Jonathan Payne]

...And the best part is that your RED camera would be a sufficiently high quality camera to take the bracketed images....that would be so easy just flip the iris ring on the lens once a second and you're done.....so basically we just need a chrome ball

[kraemer]

Yes, but those chrome balls still don't drastically reduce the thousands of man-hours billed to hand tweak lighting in the "money shot"... :)