How can I use an After Effects Camera for a nice background blur?
by Sean Harper
on
Jul 15, 2008 at 4:38:12 am
Is it possible to use a Camera in After effects to blur out the background behind the Actors or what I want in focus? Without having to do anything directly from the camera?
The reason I ask is my camera has poor focusing capabilities and I need to find a way to slightly blur the area behind my actors in a fight scene
If this is possible to do, please tell me exactly how. Myself being a noob requires a step-by step guide:)
For example- What mm camera should I use 35, 50, etc
Re: How can I use an After Effects Camera for a nice background blur? by Simon Bonner on Jul 15, 2008 at 10:45:06 am
You can enable depth of field in your camera, but this will only affect 3D objects that are different distances from your camera. Imagine 3 solids, 50x50 pixels, that are close, near to and far away from the camera. You could change the focus settings to make each of these solids come into focus in turn.
Your video is a 2D layer, though. AE can't just "work out" which areas should be in focus and which shouldn't. Instead forget about the camera completely and add an adjustment layer above the footage. Apply a fast blur to the layer and then draw a mask on this layer around the actors. Feather out the mask so that the blur edge isn't stark. Then you will have to keyframe the mask shape/path property if your actors are moving. It's a tricky thing to get right, so I would advise using it sparingly. If you use a tripod and your actors are relatively immobile though, it can look pretty decent.
Re: How can I use an After Effects Camera for a nice background blur? by Sean Harper on Jul 17, 2008 at 5:01:01 am
Thank you, and may I ask-
frischluft.com has a product called LensCare which I am eager to try out. Unfortunately it cost 100$ and I won't buy a product that expensive unless I am absolutely positve that it will work.
Re: How can I use an After Effects Camera for a nice background blur? by Kevin Dearing on Jul 15, 2008 at 5:54:20 pm
Hi Sean,
Like Simon mentioned, AE can't separate a 2D image without you telling it what to separate as foreground, subject and background.. And, in a fight scene I'm guessing that would be a fair bit of work to rotoscope....
I know you said that your camera has poor focus capability but if you can reshoot go get yourself a ND (Neutral Density) filter so that the camera's iris opens up to properly expose the subjects. This causes the camera's depth of field to be smaller.. Also, zoom in on the subject as much as possible without introducing bad camera shake (hopefully you have a tripod). The longer the lens the smaller the depth of field as well.
If you can't shoot again, well, it sounds like a lot of work doing it the way Simon mentioned - draw masks around your subject and animate them (ie, rotoscoping them)..
