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View Full Version : Lighting subject in Green screen for sunny video background



brian2day
08-26-2010, 09:50 AM
Anyone have experience with this? I'm curious as to how difficult it is to get a realistic final result.

crashnburn
08-26-2010, 06:20 PM
What format are you shooting with. It can be very difficult to key off DV footage. Also depends on how you are shooting your subject, i.e. close up shot etc. More info about what you are doing will help people help you.

Welcome to the forum.

BigHache
08-26-2010, 08:15 PM
Additionally, you'll need to make sure you match the lighting of the footage you are to composite with. You may even want to do some testing before your actual shoot and make notes. The lighting will be key, not only on your subject but also on the screen itself.

What are you compositing with, out of curiosity?

ericsmith
08-26-2010, 10:49 PM
What you really need to be thinking about here is duplicating the same lighting scenario as the "sunny background".

The sun is just a big light, very far away. So to simulate that with artificial lighting means matching the relative size of your key light with it's distance from the subject. Let's pretent that the sun is 100 miles away, and it's 1000 feet across (of course that's no where near reality, but it's just to explain the math). So if you had a light that was 10 feet across, you'd need to place it 1 mile away to similate the same relative size. If it was 1 foot across, you'd need to place it 1/10 of a mile away.

You can cheat to a certain extent and get away with it, but the farther off you are with the math, the less realistic your lighting will be. You also need to consider the extensive fill that happens outdoors, and reproduce that. The sky is one giant diffuse light, and the ground and surroundings all bounce light. Your key light will do similar, but not nearly as much as a source as bright as the sun. So you'll need to design your fills very carefully.

On the other hand, you could just set up your greenscreen outside and shoot at roughly the same time of day and same angle as your background material. That would be the easy way.

Eric

biliousfrog
08-27-2010, 01:25 AM
If you can get away with blue screen you could even shoot against a clear blue sky, on a rooftop for example

Sarford
08-27-2010, 06:24 AM
A good advice is to buy this webinar. It will explain everything you'll need to know. And Steve Wright is a guy who knows what he is talking about.
Trust me, it is REALY worth the money. Little errors during the shoot can result in a LOT of extra work during compositing.

webinar-make-your-green-screen-shots-look-great-on-the-web-mobile-devices-and-tv/ (http://www.newmediawebinars.com/on-demand/webinar-make-your-green-screen-shots-look-great-on-the-web-mobile-devices-and-tv/)

CC Rider
08-30-2010, 01:57 PM
Is shooting outside an option? Let mother nature be your gaffer and you can't make a mistake. (Keep the greenscreen in shadow if possible though)