I try to reconstruct a camera of a video sequence via match moving techniques. After the reconstruction process all seemed to work as expected, but then I've realized my camera is moving forward instead of zooming into the 3d-scene like this:
Every dot of the path represents the position of the camera in 3d space (Frame 1 to 40)
I know that (initial situation):
- focal length is 35mm at frame 1
- focal length is 85mm at frame 40
- the distance to the object is 0.8m
When I try to animate this values by hand (see the image below) it is unfortunately not accurate enough, because of the camera man's delay in turning the lens.
Desired effect (Frame 1 to 40)
Is it mathematically possible to convert the camera motion into a zoom to get the correct focal length for every single frame?
A point to start with or any suggestions would be appreciated.