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Motion Tracking in After Effects CS 3

With the stabilize motion tool in After Effects and an expression we can fix even the worst footage 99% of the time By David Basulto

Ok its that time of year. The holidays are upon us and we are all shooting video like crazy. But what happens when Uncle Bob smacks us in the back as we are filming? Are we to be stuck with shaky and wobbly footage? Not if Adobe After Effects CS 3 has anything to do with it.

With the stabilize motion tool in After Effects and an expression we can fix even the most terrible footage 99% of the time. Lets take a look.

Step 1
Open After Effects CS 3 and then double click in the project area on the left. This will open the import dialogue. Select your clip and import it.


Step 2
Drag your footage to the ?make new composition icon at the bottom of the Project area. This will create a new comp with all the properties of your footage in place.

Step 3
Control click (right click) and from the popup menu choose Stabilize Motion. This will open the Tracker Controls. Feel free to move the tracker panel any place you like. You can customize the After Effects layout at any time.

Step 4
In the Tracker Controls make sure you choose Position and Rotation. This will give you two trackers to use.

Step 5
Time to place the trackers. After Effects loves high contrast, well defined areas to track. Do not attach the trackers to areas that change a lot in the shot. Also make sure the points are co planer or equidistant from the camera.

Step 6
Ok now lets track. Click on the track forward control and let After Effects do its job. When its done click apply. A window will pop up asking if you want it in the x and y, click yes. If you wanted it only in the x or the y you would most likely want to use an expression.

Step 7
If you want to see how well the track is click on the confidence in the Track Points area and enable your graphs. For best results you really want the confidence to be anywhere from 80-100%. If youre happy lets move on. If not its time to re-track. Sometimes it may take quite a few tries with difficult footage.


Step 8
Ok the footage should look a lot better. But we arent done. In the timeline context click (right click) then choose New > Null Object. A new Null Object will appear above our footage. In the original footage go to Transform > then choose Anchor Point, Position, and Rotation. Copy and Paste the tracking info to the Null layer. Make sure you are at the beginning of the timeline or After Effects will place the information where you are.

Step 9
Now context click (right click) and choose New > Camera. In the Camera box choose 50mm from the drop down. This is a good lens, not too wide or too long.

Step 10
Enable 3D in both the Null layer and the Footage layer. This will let us view through the camera.

Step 11
Use the pick whip to ?parent the Camera to the Null.

Step 12
Now it is time to add an expression. If you want to learn about expressions in After Effects I highly recommend visiting Harry Franks website at http://www.graymachine.com and Dan Ebbets site at http://www.motionscript.com/ . Both are gurus in After Effects expressions.

We are going to choose the Anchor Point property in the Null Object transform area. Now Alt/Option click to create an expression. In the expression presets choose Property > Smooth. You will see smooth(width = .2, samples = 5, t= time). In expressions you have a command and one or more arguments. Our command is ?smooth. Our arguments are the width, samples, and time. Lets change the width to 2 instead of .2. For the samples you will need to try different numbers until you are satisfied. Possibly 1 per frame.

Step 13
Everything looks good now except the black edges that pop in and out. The good news is since we have a camera added we can use the camera zoom to remove them. Try scaling up 5% or so.

Step 14
Render out your completed footage. Well done.

I give all the credit to my friend and mentor Marc Christiansen whose book Adobe After Effects Studio Techniques has loaded me with the knowledge to do work like this. For those interested Mark teaches advanced After Effects at www.FXPHD.com .

 

 


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David Basulto is an independent filmmaker in Los Angeles. After 17 plus years, David is well versed in all aspects of filmmaking from development to distribution. He produces, directs, edits, and now is addicted to motion graphics and 3d. His last film, Death Clique is in Blockbusters nationwide. David is also the host of the www.filmmakingcentral.com. In his spare time David is an avid gamer and can be found slaying monsters in the world of Vanguard. For more info visit www.davidbasulto.com
Related Keywords:motion tracking, stabilize footage, motion graphics

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