The camera tracker is meant to follow the movement of the camera, not the movement of an object. It sounds more like you should be using Mocha or AE's point tracker to do motion tracking rather than camera tracking. Read more about motion tracking here.
you are right Szalam: this test was for tracking the hand movement. The tarjet is to put an AE or C4D generated object in the hand. Like a ball or even a hole.
I made some tests with Mocha, the AE included versión is for 2D tracking only. This is why I tried AE camera tracking.
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AE does not come with a 3D motion tracker. The camera tracker tracks fixed geometry in a scene and figures out how the camera is moving. You can fake this kind of thing with Mocha or, if the shot is done correctly, you can Motion stabilize the shot, crop to only the hand portion of the shot, then camera track and get a camera move for the hand, then do a bunch of calculations to try and figure out whats is going on and make it work.
A better, and much less expensive way to do this kind of thing with footage that was shot with 3D tracking in mind would be to download Blender and learn how to use the motion tracker in Blender. It works quite well. Blender is open source (free) 3D software that is amazingly capable but a bit difficult to use.
I have used the isolate an object and camera track that technique many times. The trick is on setting up the shot properly. Notice in Andrew's example footage his brother didn't change his facial expression and all. There was a bunch of fixed geometry in the face for AE's camera tracker to capture. The tracking markers were probably not necessary to make the shot work.
Your original question was about 3d tracking a hand. As long as the fingers don't move and the hand remains in approximately the same shape and position in the frame and you can mask out or crop out the background you should be able to get a successful camera track. If the shape of the hand is changing because let's say the fingers are moving, then AE's Camera Tracker is not the right tool for the job. If there is some slight movement in the fingers you may still be able to get a decent track by eliminating the tracking points that attach themselves to the fingers but generally you must carefully plan and shoot the shot with camera tracking in mind.
Let me say one thing about tracking marks. In about 90% of the cases I have seen in the last 3 or 4 years they are not necessary and just add additional work to the project. The only time you must add tracking markers is when there is no detail in the surface you are tracking that can be used to extract data.
I hope this helps a lot. There are a few step by step tutorials out there that show how to effectively track a moving head. Andrew's live demo was not very helpful as a tutorial.
If you could post the footage we may be able to give you some better pointers. Let us know how we can help.