My first post so cheers to everyone out here :)
My question: What techniques do You use if You add an object (or image, whatever) to a clip and You want to make it look like it belongs there ? I mean - if I put for example image of a car to different shot it totally looks that it's added. I want to make it look like it is from this shot.
Example (that's what I do NOT want) - http://www.doblu.com/wp-content/uploads/2010/10/bttf2203.jpg
I used color correction, feathering edges, saturation, blur, but it's still not that.
Oh, and I'm talking about After effects definitely :)
The most important thing to make your composite shot look real is to match the lighting in the composited shot to the lighting in the back plate. Think about what's wrong with the bad example shot you posted: you've got two rows of white hot flame, and absolutely nothing is showing that on the two characters. It looks as if they were lit with standard three point lighting from soft boxes. They should have blown out highlights up to their waists, and then hard shadows bottom lit from the waist up. You can see the shadow on the guy on the left's face, and it's as wrong as it could possibly be. So...think out your background shot, then match to that lighting as closely as you can. Then all you'll have to do in post is a few tweaks.