How to shoot on a projected background?

2 replies [Last post]
yankeet
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Joined: Feb 4 2008

Hi, I need to shoot some interviews, and instead of shooting against green screen and then having to replace it (hdv, render times your general list of issues there....) I'm wondering if there is a way to project a different background for each person (say, a livingroom picture) in slide or powerpoint etc. Has anyone had any experience with this, or knows where I can find some info on it?

Thanks

stuart621
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Joined: Oct 24 2001

I haven't done this but I would imagine that lighting it would not be easy and you also have to contend with the noise of the projector.

Rob James
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Joined: Jun 26 2001

The only way it will work in an even vaguely convincing way is to use a technique known as FAP or Front-Axial Projection. This uses a retro-reflective screen and is expensive , time-consuming and difficult to get right. Have a look here.
http://books.google.com/books?id=e16x9LJW6mwC&pg=PA65&lpg=PA65&dq=%22Front+Axial+Projection%22&source=web&ots=zngD-yq01p&sig=mG-WnpahCjFiHUO1z5Gd8q56w2U

or here:

http://books.google.com/books?id=DiN9EZLNepsC&pg=PA214&lpg=PA214&dq=%22front+axial+projection%22&source=web&ots=ts1S_ztNwe&sig=Me6X_hPg8SIjEFzUUiWNp1CRExM#PPA214,M1

The alternative, back projection is rarely convincing and still expensive.

This is why green screen has become so popular. (Can be done in real time with some relatively inexpesive hardware. E.g. Datavideo)

Rob The picture is only there to keep the sound in sync