Blackmagic Forum

Hello all good people.

I have shot a few clips in a green screen room and changed the green screen background with a static image in fusion. I have tracked the main subject (a lady dancing and I moved the camera in front of her in parallax). I applied the tracking to the background. Both (background and foreground ) are now moving accordingly but the background which is a far away mountain is moving « too much » as if it was just a few meters behind the subject. I wanted to know if there was a way to decrease the strength of the tracking to the background in order to adjust the perspective movement. Just to explain my idea, if I film someone and do a parallax move in front if the subject and there is a mountain far away, the movement of the background will be much less than if there is a very close background like a house or a tree for instance. I want to be able to replicate the low parallax with the far away background image. Hope it’s clear.

Thank you in advance.

I was just stumbled across a way to scale tracking data (apart from a way Bryan Ray showed me a load of months ago). The size control in the tracker node track modifiers, appears to scale the tracking data as far as I can see from a simple test. You will have to suss it out for yourself or maybe someone more knowledgable will explain. As I say I just realised what it was doing yesterday, so I haven't had a chance to try it on more than a single track or ask a semi sensible question about it.

Search for a thread headed 'Scale Tracker movement' for the solution Bryan posted.

Another method I had been using was simply to use a transform node to scale the image appropriately, track the rescaled image and then apply that tracking data to the original sized image.