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Chroma key/Green screen help
Hi guys,
From what ive heard, these are one in the same. Please correct me if im wrong. I’m really wanting to learn how to use this feature, and did a post search but was not able to find anything. I also looked through all of Ed’s newsletter articles and didnt see a tutorial on it, but i may have over looked it. Can anybody point me in the right direction? I’m using version 6.
Thanx, Carson
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7 Replies
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We do alot of blue screen work.
It takes alot of trial and error.
Lighting is crucial !!!!!!
Look up “chromakey” in the help file to understand the Vegas controls.You can test this easily with any solid back ground.
-film a colored ball against a white wall.track 1
-add a chroma blur effect to the event, set it to medium.
-then add the chromakey effect to the same event.
-use the eyedropper and make a small selection of the white wall.
-check, use the “mask” button to see how tight your mask is.
-solid white is not transparent and black will be transparent.
-place a different video event below. (track 2)-adjust the hi, low sliders to get a clean edge without over doing it.
-You will notice subtle “foaming” where the light isn’t an even background.
-experiment with the controls to get a clean edge.you should now see your ball sitting on top of your background video.
-dont forget to uncheck your “mask button.The blur slider softens the jagged edge. easy does it !
This is the basic fundamentals.
Green and blue are commonly used cuz their colors tend to be rare.
you can get very complex with other chromakeying sofware
Ultrakey is very popular.
but with good lighting, technique and practice Vegas does a pretty good jobZipedit
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Great info thanx a lot, this will be a big help!
Now you mentioned to film whatever it is i want to superimpose with a white background, which totaly makes sence, but i was entertaining the thought of a possible project of imposing footage of my little brother playing football, and then using some NFL footage as the background. So it would look as if he were playing with the big boys, so to speak. For example, using a bit of NFL footage showing a reception as the background, and then I would want to get rid of the NFL reciever (which I have no clue as of yet how to do) and then use footage of my brother receiving the ball.
1) So if i use footage with a lot of motion will i have to mask it by making several key frames to follow the movement through the whole duration of the clip, or will the mask stick to the object once i initially create it?
2) I figure that the lighting will be quite different as well. Are there any filters that i could mess with to try to adjust the lighting?
3) Has anybody tried this, and if so how did it work out?
If anybody has any advice, i would love to hear it!! Hope what i typed makes sence
Thanx,
Carson -
Once you move the camera (pan,dolly,zoom) in a green-screen shoot – you enter the realm of track motion – (matching the background motion with the camera motion.) It really starts to get tricky at that point. So try and pick static shots for your backgrounds and match the camera angle.
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superimposing your son without a controlled set
with proper lighting gets into a whole other realm.1) yes the mask will follow the edge of your video motion.
2) if he is running around you will need a large bluescreen set with alot of even lighting.
However…maybe experiment with some short tight shots.
Get a small Blue screen. maybe 8×8 feet.
you’ll have to match him and your angles ahead of time to the existing footage.
maybe film him down low at the snap,
then cut to the last step before the throw.
take out the running stuff cuz running in place doesnt look real.you’ll soon find matching angles, depth will be you enemy.
experiment small and fine tune.also see the links from the other responses.
zipedit
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The article in the previous message is very good. I would like to add one technique I have discovered to deal the issue of a background that is not lit evenly. In short if you have sections that are darker/lighter, duplicate your track once or more and use pan/crop to mask your image into sections that can be chromakeyed each a little differently.
Mary Waitrovich
UW-Madison
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